Brined Cheeses

Edited by

Dr Adnan Tamime Dairy Science and Technology Consultant Ayr, UK

1405124601_1-3 (prelims).indd iii 06/04/2006 18:56:38 Brined Cheeses

Edited by

Dr Adnan Tamime Dairy Science and Technology Consultant Ayr, UK

11405124601_1-3405124601_1-3 ((prelims).inddprelims).indd iiiiii 006/04/20066/04/2006 118:56:388:56:38 Brined Cheeses

Editorial Ofﬁ ces: Blackwell Publishing Ltd, 9600 Garsington Road, Oxford OX4 2DQ, UK Tel: +44 (0)1865 776868 Blackwell Publishing Professional, 2121 State Avenue, Ames, Iowa 50014-8300, USA Tel: +1 515 292 0140 Blackwell Publishing Asia Pty Ltd, 550 Swanston Street, Carlton, Victoria 3053, Australia Tel: +61 (0)3 8359 1011

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First published 2006 by Blackwell Publishing Ltd

ISBN-10: 1-4051-2460-1 ISBN-13: 978-1-4051-2460-7

Library of Congress Cataloging-in-Publication Data Brined cheeses / edited by Adnan Tamime. p. cm. Includes bibliographical references and index. ISBN-13: 978-1-4051-2460-7 (alk. paper) ISBN-10: 1-4051-2460-1 (alk. paper) 1. Brined cheeses. I. Tamime, A. Y. SF272.B76B75 2006 637’.35--dc22 2005030970

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Preface to Technical Series xiii Preface xv Contributors xvii

1 Constituents and Properties of Milk from Different Species 1 T. HUPPERTZ, V.K. UPADHYAY, A.L. KELLY & A.Y. TAMIME 1.1 Introduction 1 1.2 Chemical composition of milk 3 1.3 Constituents of milk 4 1.3.1 Lactose 5 Introduction 5 Biosynthesis of lactose 5 Physical properties of lactose 6 Reactions of lactose 7 Signiﬁ cance of lactose in dairy products 8 1.3.2 The milk salts 8 Introduction 8 Partitioning of milk salts between the colloidal and soluble phases of milk 9 Factors affecting the salt balance in milk 9 1.3.3 Lipids 10 Introduction 10 Composition and fatty acid proﬁ le 11 Milk fat globules 11 Stability of the milk fat emulsion 12 1.3.4 Proteins 15 Introduction 15 Whey proteins 15 Caseins 17 Casein micelles 19 1.3.5 Indigenous milk enzymes 24 Plasmin 24 Lipoprotein lipase 26 Alkaline phosphatase 26 Lactoperoxidase 27 Other indigenous milk enzymes 27 1.4 Rennet-induced coagulation of milk 29

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1.4.1 Introduction 29 1.4.2 Primary stage of rennet-induced coagulation of milk 29 1.4.3 Secondary stage of rennet-induced coagulation of milk 30 1.4.4 Factors that inﬂ uence rennet-induced coagulation of milk 31 Milk pH 31 Calcium concentration 31 Ultraﬁ ltration (UF) 32 Cold storage 32 Heat treatment of milk 33 High-pressure treatment of milk 33 1.5 Conclusions 33 References 34

2 Feta and Other Balkan Cheeses 43 E.M. ANIFANTAKIS AND G. MOATSOU 2.1 Background 43 2.2 Feta cheese 43 2.2.1 Introduction 43 2.2.2 Production methods 44 2.2.3 Manufacturing stages 45 Milk for cheese production 45 Treatment of the cheese milk 47 Renneting 48 Cutting and moulding 49 Salting 50 Packaging and maturation of the cheese 51 2.2.4 New trends in Feta cheese manufacture 53 2.2.5 Properties of Feta cheese 53 2.2.6 Defects of Feta cheese 60 2.2.7 Feta cheese whey 60 2.3 Miscellaneous brined Greek cheeses 61 2.3.1 Sfela cheese 61 2.3.2 Batzos cheese 62 2.3.3 Kalathaki Limnou cheese 63 2.4 Telemes (Telemea cheese) 63 2.4.1 Manufacturing stages 63 2.4.2 Characteristics of Telemes cheese 67 2.5 Some examples of Balkan brined cheeses 68 2.5.1 Bjalo Salamureno Sirene (white brined cheese) 68 2.5.2 Belir Sir U Kriškama (white cheese in pieces) 69 2.6 Turkish brined cheeses 69 Acknowledgement 71 References 71

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3 Industrial Manufacture of Feta-Type Cheeses 77 A.Y. TAMIME, R.K. ROBINSON AND G. KIERS 3.1 Background 77 3.2 The cheesemaking process 79 3.2.1 Composition and hygiene quality of raw milk 81 3.2.2 Milk reception and storage 82 3.2.3 Optional preliminary treatments 83 Bactofugation 84 Microfi ltration (MF) 85 3.2.4 Standardisation of the casein-to-fat ratio 86 3.2.5 Tetra Tebel process 87 Pretreatment 87 Module 1 88 Module 2 88 Module 3 89 Packaging 92 3.2.6 Tetra Tebel Casofi ll® glucono-δ-lactone (GDL) 92 3.2.7 Tetra Tebel Casofi ll® cast Feta-type 94 3.3 Miscellaneous additives and treatments related to Feta-type cheeses 95 3.3.1 Starter cultures 95 3.3.2 Calcium chloride 95 3.3.3 Decolorising agents 97 3.3.4 Lipase 98 3.3.5 Preservatives 99 3.4 Recombined Feta-type cheeses 99 3.4.1 Introduction 99 3.4.2 Recombination of powders 100 3.4.3 Mimic the traditional method of production 101 3.4.4 Ultrafi ltration of recombined powders 102 3.4.5 Miscellaneous recombination methods 102 3.5 Plant specifi cation 103 3.6 Implementation of a hazard appraisal (analysis) critical control points (HACCP) system 103 3.7 Conclusion and future development(s) 107 References 109

4 Halloumi Cheese 117 P. PAPADEMAS 4.1 Historical background 117 4.2 The importance of Halloumi cheese to the Cypriot economy 117 4.3 Forecasts on the future of Halloumi cheese 118 4.4 Raw materials used for the production of Halloumi cheese 118 4.4.1 Milk 118

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4.4.2 Salt 121 4.4.3 Mint 121 4.4.4 Coagulant 122 4.4.5 Starter cultures 122 4.5 Manufacturing methods 122 4.5.1 Outline of the traditional process 122 4.5.2 Outline of the industrial process and comparison with the traditional method 123 4.5.3 Experimental production of Halloumi-type cheese using ultrafi ltration (UF) technology 126 4.6 Types of Halloumi cheeses 127 4.6.1 Fresh Halloumi cheese 127 4.6.2 Mature Halloumi cheese 128 4.6.3 Low-fat Halloumi cheese 128 4.7 Chemical composition and microbiological quality of the cheese 129 4.7.1 Chemical composition 129 4.7.2 Microbiological quality 130 4.8 Sensory profi ling and rheological properties of the cheese 132 4.8.1 Flavour and taste 132 4.8.2 Texture 133 4.8.3 Sensory profi ling 134 4.9 Quality and safety of dairy products 134 4.10 Nutritional value of Halloumi cheese 135 4.11 Conclusion 135 Acknowledgement 136 References 136

5 North African Brined Cheeses 139 M. ABD-EL SALAM AND N. BENKERROUM 5.1 Background 139 5.2 Production and consumption of dairy products in North African countries 141 5.3 Egyptian pickled cheeses 142 5.3.1 Domiati cheese 142 Technological aspects 142 Coagulants 143 Starter cultures 144 Cheese yield 144 Compositional changes during the storage period of the cheese in brine 145 Texture and microstructure of the cheese 147 Microbiological quality 148 5.3.2 UF Domiati cheese 149 Introduction 149 Technical aspects 150 Compositional quality and yield of the cheese 150 Texture and microstructure of the cheese 151

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Packaging of the cheese 151 5.3.3 Tallaga cheese 151 5.3.4 Mish cheese 152 Technical aspects 152 Compositional quality and general characteristics of the cheese 153 Microbiological quality 154 5.4 North African brined cheeses 154 5.4.1 Traditional technology and properties of the cheeses 154 Milk preparation 156 Milk coagulation 156 Draining and moulding of the curd 159 Salting and preservation of the cheese 160 Maturation of the cheese 162 Quality appraisal of the cheeses 162 5.4.2 Some examples of North and East African brined cheeses 166 Soft-type brined cheeses 166 Semihard brined cheese 171 Camel’s milk brined cheeses 172 5.5 Conclusion 175 Acknowledgement 180 References 180

6 Brined Cheeses from the Middle East and Turkey 188 I. TOUFEILI AND B. ÖZER 6.1 Introduction 188 6.2 Middle Eastern cheeses 188 6.2.1 Cheese speciﬁ cations, standards and chemical composition 188 6.2.2 Technology of manufacture 188 General aspects 188 Mujaddal or Braided cheese 189 Nabulsi cheese 190 Comparative compositional quality of brined cheeses 194 6.3 Traditional Turkish cheeses 194 6.3.1 Technology of cheesemaking 195 6.3.2 Microbiological quality 200 Starter cultures (lactic acid bacteria, LAB, and non-starter lactic acid bacteria, NSLAB) 200 Microbial contaminants 204 6.3.3 Development of texture and microstructure of White cheese 204 6.4 Concluding remarks 205 References 207

7 Brined Cheeses and Analogues of Latin American Origin 211 M.N. OLIVEIRA AND C. BRITO 7.1 Background 211 7.2 Main brined cheeses produced in Brazil 212

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7.2.1 Introduction 212 7.2.2 Minas cheese (fresh and matured) 215 Minas Frescal 216 Minas Padrão 221 Meia Cura 223 7.2.3 Prato cheese 223 Traditional process 223 Ultraﬁ ltration (UF) process 227 7.2.4 Rennet cheese 227 7.3 Chilean dairy industry with particular emphasis on cheese production 229 7.3.1 Introduction 229 7.3.2 Cheese varieties produced in Chile 236 7.3.3 Main brined cheeses produced in Chile 237 Chanco 237 Gauda 241 Other cheese varieties 242 7.4 Conclusions 244 Acknowledgement 244 References 245

8 Indigenous Brined Cheese of the Philippines 249 V.L. BARRAQUIO 8.1 Introduction 249 8.2 Physicochemical and microbiological quality of the milks used for cheesemaking 250 8.3 Manufacturing methods 253 8.4 Modiﬁ cations to the manufacturing methods 255 8.5 Yield, composition and microbiological quality of the cheese 258 8.6 Conclusion 261 References 261

9 Quality of the Brine 264 T. BINTSIS 9.1 Introduction 264 9.2 Role of brining 265 9.2.1 Methods of salting/brining 266 9.2.2 Mechanism of brining 268 9.2.3 Factors affecting the rate and quantity of salt absorbed 269 Brine concentration and duration of salting 269 Composition of the curd and the brine 270 Temperature of the brine 270 Size and shape of the cheese block 271 Brine volume/cheese weight 271 9.3 Chemical composition of brines 271 9.4 Low-sodium cheeses 272 9.5 Microbiology of brines 274

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9.5.1 Effect of salt on microbes 274 9.5.2 The microfl ora of the brines 276 9.5.3 Defects caused by spoilage microorganisms 277 9.5.4 Use of preservatives 279 9.5.5 Survival of pathogens in brines 280 Listeria monocytogenes 280 Staphylococcus aureus 282 Enterohaemorrhagic Escherichia coli 282 Yersinia enterocolitica 283 Salmonella species 283 9.5.6 Stressed cells 284 9.6 Control measures 285 9.7 Quality control of brines 286 9.7.1 Physical and chemical control 286 9.7.2 Microbiological control 289 9.8 Purifi cation methods for cheese brines 290 9.8.1 Chemical treatment 290 9.8.2 Heat treatment 291 9.8.3 Treatment with UVC light 291 9.8.4 Treatment with UVA light plus furocoumarins 292 9.8.5 Kieselguhr fi ltration 292 9.8.6 Microfi ltration 293 9.9 Conclusion 294 References 294

10 Utilisation of Brined Cheeses in Other Food Preparations 302 A.Y. TAMIME AND R.K. ROBINSON 10.1 Background 302 10.2 Salad dishes 303 10.3 Snacks and savoury dishes 303 10.3.1 Cheese snacks 303 Halloumi recipes 303 Akkawi recipes 305 Creamy Chanco (Gauda) recipes 306 Rennet cheese 306 10.3.2 Savoury dishes 307 Lebanese cuisine 307 Moroccan cuisine 308 Miscellaneous Greek dishes made with Feta cheese 309 Turkish cuisine 309 Brazilian cuisine 310 Philippine cuisine 310 10.4 Desserts 310 10.4.1 Knafeh, Kunafeh or K’nefe bi-jibn (pastry with cheese) 310 10.4.2 ‘Sweet’ cheese 312 10.4.3 Hosmerim 313

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10.4.4 Brazilian sweet cheese dishes 314 10.5 Conclusion 315 Acknowledgement 315 References 315

Index 317

11405124601_1-3405124601_1-3 (prelims).indd(prelims).indd xiixii 006/04/20066/04/2006 18:56:4018:56:40 Preface to Technical Series

For more than 60 years, the Society of Dairy Technology (SDT) has sought to provide education and training in the dairy fi eld, disseminating knowledge and fostering personal development through symposia, conferences, residential courses, publications, and its journal, the International Journal of Dairy Technology (previously known as Journal of the Society of Dairy Technology). In recent years, there have been signifi cant advances in our understanding of milk systems, probably the most complex natural food available to humanity. Improvements in process technology have been accompanied by massive changes in the scale of many milk/dairy processing operations, and the manufacture of a wide range of dairy and other related products. The Society has now embarked on a project with Blackwell Publishing to produce a Technical Series of dairy-related books to provide an invaluable source of information for practising dairy scientists and technologists, covering the range from traditional to modern large-scale operations. This, the third volume in the series, on Brined Cheeses, under the editorship of Dr Adnan Tamime, complements the fi rst volume's on Fermented Milks in taking the use of microorganisms into the production of longer-life dairy products. Brined cheeses form a group of early cheese types originating from the Eastern Mediterranean and Middle East, which are resistant to high ambient temperatures and do not require refrigeration in their traditional forms. Some of these cheeses, particularly feta, have become accepted worldwide and add further variety to the dairy products on offer to the consumer.

Andrew Wilbey President, SDT March 2005

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This is the third book within the Technical Series promoted by the Society of Dairy Technology (SDT). The range of brined cheese varieties covered includes Feta, Bulgarian white, Akkawi, Halloumi and Hispanic-type. The increasing economic value of these products in the Middle East, Balkans, South America and the rest of the world is a refl ection of consumer acceptability and increased basic research into starter cultures, manufacturing methods and mechanisation over the past couple of decades. Furthermore, these products are highly profi table and very important within the dairy industry worldwide and particularly in Europe where some of these cheese varieties are produced for export. Equally important is the fact that the technological developments, and the metabolic activities of the starter cultures, including the different blends available for production purposes, have provided consumers in different markets with a wide range of brined cheese varieties. Consequently, these products have become popular, as refl ected by the increased world production and exports. As mentioned elsewhere, recent scientifi c input to these cheese varieties by many researchers in different parts of the world has been extensive, and the primary aims of this multi-author publication are to detail the manufacturing methods in different parts of the world (Middle East, North Africa, South America, Europe and the Far East), and to provide an overview of the properties of these white brined cheeses. It is of interest to note that the review on how these cheese varieties are utilised in different countries may provide scientists and marketing personnel with further incentives to develop or modify some of the characteristics of these products to suit the demands of consumers in different markets. The authors, who are all specialists in these products, have been chosen from around the world. There is no doubt that the book will be an important component of the Technical Series, and it is anticipated that it will be useful to dairy scientists, students, researchers and dairy operatives involved with these cheese varieties. A.Y. Tamime March 2005

11405124601_1-3405124601_1-3 (prelims).indd(prelims).indd xvxv 006/04/20066/04/2006 18:56:4018:56:40 Contributors

Dr A.Y. Tamime Prof. E.M. Anifantakis Dairy Science & Technology Consultant Agricultural University of Athens 24 Queens Terrace Department of Food Science and Ayr KA7 1DX Technology United Kingdom Laboratory of Dairy Technology Tel. +44 (0)1292 265498 Iera Odos 75 Fax +44 (0)1292 265498 118 55 Athens Mobile +44 (0)7980 278950 Greece E-mail: [email protected] Tel. +30 210 5294653 Fax +30 210 5294616 Dr Thom Huppertz E-mail: [email protected] University College Cork Department of Food and Nutritional Dr Golfo Moatsou Sciences Agricultural University of Athens Cork Department of Food Science and Ireland Technology Tel. +353 21 4901412 Laboratory of Dairy Technology E-mail: [email protected] Iera Odos 75 118 55 Athens Dr Vivek K. Upadhyay Greece University College Cork Tel. +30 210 5294630 Department of Food and Nutritional Fax +30 210 5294672 Sciences E-mail: [email protected] Cork Ireland Dr R.K. Robinson Tel. +353 21 4902453 University of Reading E-mail: [email protected] School of Biosciences P.O. Box 226 Dr A. Kelly Reading RG6 6AP University College Cork United Kingdom Department of Food and Nutritional E-mail: [email protected] Sciences Cork Ireland Tel. +353 21 4903405 Fax +353 21 4270213 E-mail: [email protected]

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Mr G. L. J. Kiers Dr Imad Toufeili Tetra Pak Tebel B.V. Department of Nutrition and Food Science P.O. Box 370 Faculty of Agricultural and Food Sciences 8901 BD Leeuwarden American University of Beirut The Netherlands Riad El-Solh 1107 2020 Tel. +31 58 23 32 960 Beirut Fax +31 58 23 32 999 Lebanon Mobile +31 6 5148 8275 Tel. + 961 (0)1 343002 ext. 4551 E-mail: [email protected] Fax 961 (0)1 744460 E-mail: [email protected] Dr P. Papademas Kyklos Scientiﬁ c Services Ltd Dr B. Ozer P.O. Box 14055 Harran University CY-2153 Nicosia Faculty of Agriculture Cyprus Department of Food Engineering Tel. +357 (0)22 877 220, +357 (0)99 63040 Sanliurfa 559159 Turkey Fax +357 (0)22 877 221 Tel. +90 414–247 41 95 E-mail: [email protected] Fax +90 414–247 44 80 E-mail: [email protected] Prof. M. Abd El-Salam National Research Centre Prof. M. Nogueira de Oliveira Dairy Department Universidade de São Paulo Tahrir Street Departamento de Tecnologia Bioquimico- Dokki Farmacêutica Cairo 12622 Avenue Prof. Lineu Prestes 580, Bloco 16 Egypt Sao Paulo 05508–900 Tel. +202 5685026 Brazil Fax +202 5685026 Tel. +55 (0)11 3091 3690 Mobile +20 12 3502030 E-mail: [email protected] E-mail: [email protected] Prof. C. Brito Prof. N. Benkerroum Universidad Austral de chile Institut Agronomique et Vétérinaire Instittuto de Ciencia y Technologia de los Hassan II Alimentos Department Sciences Alimentaires et P.O. Box 47 Nutritionnelles Valdivia P.O. Box 6202 Chile 10101-Rabat Tel. + 56 63 221250 or 221302 Morocco Fax + 56 63 221353 Tel. +212 37 77 58/59 E-mail: [email protected] Fax +212 37 58 38 E-mail: [email protected]

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Dr V.L. Barraquio Dr T. Bintsis University of the Philippines at Los Banos 25 Kappadokias Street College of Agriculture 55134 Thessaloniki 4031 College Greece Laguna Tel. +30 6942632757 Philippines E-mail: [email protected] Tel. & Fax + 63 49 536 2205 E-mail: [email protected]

11405124601_1-3405124601_1-3 (prelims).indd(prelims).indd xixxix 006/04/20066/04/2006 18:56:4118:56:41 Brined Cheeses Edited by Dr Adnan Tamime Copyright © 2006 by Blackwell Publishing Ltd 1 Constituents and Properties of Milk from Different Species

T. Huppertz, V.K. Upadhyay, A.L. Kelly & A.Y. Tamime

1.1 Introduction

It has long been recognised that milk is perhaps nature’s ultimate food, containing all the nutrients required by the neonate; in addition, milk is also a rich source of protective agents (e.g. immunoglobulins), enzymes and growth factors. It meets the requirements of neonates and is of nutritional signifi cance to consumers of any age. As a result, for millennia, humans have domesticated mammals for the purpose of milk supply. The fi rst animals domesticated for this purpose were probably sheep and goats, approximately 8000–10 000 years ago, followed by cattle, which are now the dominant species for dairying (Fox, 2003a). Annual total world milk production has since then risen to ~600 million tonnes (IDF, 2003). A signifi cant proportion of total milk produced worldwide is converted to cheese. Cheesemaking is one of the oldest methods known to mankind for preservation of milk, and it consists of: (a) fermentation/acidifi cation; (b) concentration of the milk solids; and (c) salting and/or brining. Modern cheesemaking may have evolved from the concentration of fermented milk for the production of labneh (~26 g 100 g–1 total solids) using cloth bags for separation of the whey. Furthermore, labneh is concentrated further for the production of yoghurt cheese (>35 g 100 g–1 total solids); hence, the method of processing such products is similar to that for the fresh/soft cheese varieties that are preserved in brine. World cheese production has today risen to ~16.5 million tonnes (FAO, 2002), more than 60% of which comprises the hard and semihard varieties (e.g. Cheddar, Swiss-types, Gouda and Edam) (Tamime, 1993). Brine-salted cheeses are one of the oldest varieties of cheese, originating from the Middle East and the Mediterranean around 8000 years ago. Today, they are still traditionally produced in these regions, often on a small scale; brine-salted cheeses account for ~5% of world cheese production. Of the brine-salted cheese, Feta and Feta-type, which is produced in a number of European countries, is probably the best-known variety and also has the largest production volume. While Feta cheese is traditionally made from ovine milk or a mixture of ovine and caprine milk, varieties are now produced in Denmark and Germany are now produced from bovine milk. Modern developments in production methods have included the use of ultrafi ltration (UF) to concentrate milk before production (see Section 1.4.4). In the mid-1980s, exports of brined cheeses, mainly Feta-type from the European Union (EU) to Iran, reached a high volume of 91 000 tonnes, but this level dropped to 1000 tonnes in 1999 as a result of major economic and social upheavals (Griffi n,

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1997; IDF, 2001). Currently, few published data are available on the production fi gures for brined cheeses in many countries in the Middle East, including Iran; however, the trend of most governments in this region since the 1990s has been to reduce the dependency on imports and enhance the self-suffi ciency in milk production and the manufacture of dairy products; hence, a wide range of brined cheeses is locally made in large and centralised factories, often using the latest developments in technology, including automation. A characteristic feature of brine-salted cheeses is that they are matured in brine, in many cases without refrigeration, in sealed or semipermeable containers; the high osmotic pressure (due to the high salt content) provides good microbiological stability, even in warm climates. As a result, brine-salted cheeses have biochemical, microbiological and structural characteristics that are, in many cases, unique. Brine-salted cheeses are rindless and vary in moisture content and texture from soft to semihard. The cheeses made from ovine, caprine or buffalo milk are generally white in colour; if bovine milk is used, it may be decolorised prior to cheesemaking. Brine-salted cheeses generally taste clean, acidic and salty when fresh, and develop a piquant fl avour on ripening. An overview of the varieties of brine-salted cheeses is given in Table 1.1. Many of the typical characteristics of brine-salted cheeses are determined by the type of milk used. In this chapter, the principal constituents of milk will be discussed in turn, exploring the differences in each case between the principal milk-producing species, that is, bovine, ovine, caprine or buffalo. Furthermore, the principles of

Table 1.1 Some examples of brined/pickled cheese varieties

Country/region Name of cheese Type of milk used Former Yugoslavia Beli Sir U Kriŝkama, Bijeni Sir, Tucani Sir Ovine, bovine or mixture Middle East (Arab countries)a, Akawi (Akavi, Akkawi), Stambuli (Istambuli), Bovine, caprine or ovine Iran and North Africa, Israel, Jibneh Baida, Oriental, Lightvan (Lighvan or Russia, Czech Republic, Iranian white), Brinza (Bryndzâ), Jerevansky Armenia Syr Turkey, Armenia, Bulgaria, Beynaz-Peynir, Bgug-panir, Bjalo, Bulgarian Ovine Caucasus, Czech Republic, White, Eriwani (Elisavetpolen, Karab, Kasach, Hungary, Crimea, Romania, Kurini or Tali), Liptauer (Atsohl, Bryndza, Poland, Greece, Cyprus, Landoch, Klencz, Neusohl, Siebenburger or Lebanon Zips), Maile, Monostorer, Ser Solankowy, Sirene, Touloumisio, Halloumi Armenia, Caucasus Sulguni, Cecîl Ovine or bovine Greece and many other Feta (Fetta) and Feta-type Ovine, caprine, bovine or countries mixture Egypt Domiati, Kareish (Kariesch) Bovine or buffalo Caucasus, Greece, Syria Ossetin (Tuschinsk or Kasach), Kefalotyri Caprine or ovine Turkey, Greece, Bulgaria, Teleme (Telemea or Brandza de Baila) Caprine, ovine, bovine, Romania buffalo or mixture a Akawi is currently made in the Czech Republic for export to the Arab countries. The reader is referred to the FAO website regarding the technical information of some of these cheeses (http://www. fao.org/docrep/003/t0251e/T0251E00.htm#TOC). Data compiled from Tamime et al. (1991), Kafedjiev and Mihailova (1998), Kafedjiev et al. (1998a, 1998b) and Al-Jedah & Robinson (2001).

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rennet-induced coagulation of milk, factors affecting it, and differences in rennet coagulation properties of milk from the aforementioned species are also covered.

1.2 Chemical composition of milk

Milk can be regarded as a colloidal suspension, containing emulsifi ed globules of fat, a heterogeneous family of major and minor proteins, the carbohydrate lactose, minerals, vitamins and enzymes. While milk of all species has similar overall characteristics and classes of constituents, these differ in specifi c terms both quali- tatively (i.e. the exact nature of constituents) and quantitatively (i.e. the amount of each constituent per litre). The utilisation of milk from different species is determined largely by geographical conditions. The cow has long been the principal dairying species in many regions of the world, while buffaloes contribute signifi cantly to milk production in the Indian subcontinent and Egypt. Sheep and goats are primarily of importance in the Mediterranean regions, parts of the Middle East and some regions of Africa. The camel is an important source of milk in arid or semiarid areas, such as desert regions of North and East Africa, and the Middle East. Other dairying species that have been domesticated in different regions of the world include: yaks in Nepal, Bhutan, Mongolia and Tibet; reindeer in Lapland; and mares in Central Asia. The composition of milk from milk-producing species varies greatly (Table 1.2), also depending on the geographical location and requirement for the neonate(s). In 2003, the world production fi gure of bovine milk was ~505 million tonnes, compared with 73, 8 or 12 million tonnes of buffalo, ovine or caprine milk, respectively (see Tables 1.3 and 1.4).

Table 1.2 Chemical composition (g 100 g–1) of milk from different species

Species Fat Protein Lactose Minerals Total solids Antelope 1.3 6.9 4.0 1.3 25.2 Bison 1.7 4.8 5.7 0.96 13.2 Buffalo 10.4 5.9 4.3 0.8 21.5 Camel 4.9 3.7 5.1 0.7 14.4 Cow (Holstein) 3.5 3.1 4.9 0.7 12.2 Cow (Guernsey) 5.0 3.8 4.9 0.7 14.4 Cow (Jersey) 5.5 3.9 4.9 0.7 15.0 Dolphin 14.1 10.4 4.9 – 30.4 Goat 3.5 3.1 4.6 0.79 12.0 Donkey 1.2 1.7 6.9 0.45 10.2 Horse 1.6 2.7 6.1 0.51 11.0 Human 4.5 1.1 6.8 0.2 12.6 Pig 8.2 5.8 4.8 0.63 19.9 Reindeer 22.5 10.3 2.5 1.4 36.7 Seal 53.2 11.2 2.6 0.7 67.7 Sheep 5.3 5.5 4.6 0.9 16.3 Whale 34.8 13.6 1.8 1.6 51.2 Data compiled from http://classes.aces.uiuc.edu/AnSci308/milkcomp.html

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Table 1.3 World production (in million tonnes) of bovine, ovine, caprine and buffalo milk

Type of milk 1993 1995 1997 1999 2001 2003 Bovine milk 460.1 465.2 472.1 483.0 492.0 505.3 Buffalo milk 50.0 54.5 59.7 64.9 68.9 72.7 Caprine milk 9.9 11.8 12.1 12.1 12.5 12.4 Ovine milk 7.8 8.0 8.2 8.0 8.2 7.8 Other 1.2 1.3 1.3 1.3 1.3 1.3 Total 529.0 540.8 553.4 569.4 582.9 599.6 Data from IDF (2003)

Table 1.4 World production ﬁ gures by continent/country (in million tonnes) for bovine, buffalo, ovine and caprine milk Type of milk/continent/country 1993 1995 1997 1999 2001 2003a Bovine Africab 4.8 5.3 5.4 5.3 4.8 4.7 North Americac 83.5 86.0 87.0 91.2 93.2 96.0 South Americad 27.4 31.6 34.3 36.7 36.8 37.0 Asiae 57.9 58.0 59.8 63.7 66.0 72.0 Europe 226.7 222.9 214.0 212.5 210.6 213.9 Oceania 17.4 18.5 20.2 22.4 24.6 25.0 World 460.1 465.2 472.1 483.0 492.0 505.3 Buffalo Indiaf 29.3 35.7 38.4 41.9 43.6 47.1 Pakistan 12.8 14.0 15.6 16.9 17.5 – Egypt 1.4 1.4 1.9 2.0 2.1 – Italy 0.1 0.1 0.1 0.2 0.2 – World 50.0 54.5 59.7 64.9 68.0 72.7 Caprine and ovine Africa 3.3 4.1 4.1 4.3 4.4 – Asia 8.7 10.2 10.5 10.3 10.3 – Europe 4.5 5.1 5.4 5.2 5.2 – World 17.7 19.8 20.3 20.1 20.3 20.3 a Estimated. b South Africa, Kenya and Zimbabwe. c USA, Canada and Mexico. d Argentina, Brazil, Chile, Uruguay and Venezuela. e China, Japan, India and Asian CIS. f Dairying year ending in March of the following year. Data compiled from IDF (2003).

1.3 Constituents of milk

In general, the main constituents of milk are water, lactose, protein, fat, and salts or ash; also milk contains minor constituents, such as vitamins and enzymes, which will be brieﬂ y reviewed.

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1.3.1 Lactose Introduction

Lactose (4-O-β-D-galactopyranosyl-D-glucopyranose) is present in milk from most mammals, but in the milk of some mammals, such as sea lions, some seals and opossums, lactose is absent, or only present in very low concentrations (Jenness & Holt, 1987). In milk from most mammals, lactose is the major carbohydrate, but small amounts of other carbohydrates also occur; bovine milk contains ~10 mg L–1 monosaccharides (glucose and galactose) and ~100 mg L–1 oligosaccharides (Renner, 1983). Bovine, ovine and buffalo milk contain ~4.8 g lactose 100 g–1, whereas caprine milk generally contains a lower level of lactose (i.e. ~4.1 g 100 g–1; Harper, 1992). Lactose is responsible for ~50% of the osmotic pressure of milk, which is equal to that of blood. In bovine milk, the concentration of lactose decreases progressively and signiﬁ cantly with lactation stage, and with increasing somatic cell count of the milk (Walstra & Jenness, 1984) – in both cases due to the inﬂ ux of NaCl from the blood and the resultant need to maintain the osmotic equilibrium (Fox, 2003b).

Biosynthesis of lactose

Lactose is a disaccharide composed of D-glucose and D-galactose; the aldehyde group of galactose is linked to glucose, through a β1,4-glycosylic linkage (see Fig. 1.1). As depicted in Fig. 1.2, lactose is synthesised in the Golgi apparatus of the mammary secretory cells (Larsen, 1985) from glucose, which is absorbed from the blood. The presumed signifi cance of α-lactalbumin (a protein, further described in Section 1.3.4) in the synthesis of lactose is that, in its presence, the nonspecifi c galactosyltransferase becomes highly specifi c for glucose. Thus, α-lactalbumin is an enzyme modifi er, which terminates the synthesis of lactose if necessary, for example, to regulate and control osmotic pressure.

Fig. 1.1 Chemical structure of α-lactose.

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hexokinase (1) Glucose hexokinase Glucose-6-phosphate

ATP ADP

Phosphoglucomutase (2) Glucose-6-phosphate Glucose-1-phosphate

(3) Glucose-1-phosphateUDP-glucose-pyrophosphorylase UDP-glucose + P-P hhl + UTP

(4) UDP-glucose UDP-4-epimerase UDP-galactose

Galactosyltransferase (5) UDP-galactose Lactose + Glucose -lactalbumin

Fig. 1.2 Pathway for synthesis of lactose.

Physical properties of lactose Mutarotation Through the open-chain aldehyde form, the C1 atom of glucose can easily change from the α- to the β-form and vice versa (mutarotation; see Fig. 1.3). α-Lactose and β-lactose differ in their speciﬁ c rotation to polarised light, that is, +89.4° or +35.0°, respectively, in water at 20°C; a solution of lactose at equilibrium under these conditions has an optical rotation of +55.7° (i.e. 37.3% α-lactose, 62.7% β-lactose).

Solubility Compared with other sugars, the solubility of lactose is relatively low, although considerable supersaturation can occur before crystallisation commences. The solubility characteristics of the α- and β-isomers of lactose differ considerably; the initial solubility of β-lactose in water is considerably higher than that of α-lactose. The solubility of both forms increases with temperature, that of α-lactose in an exponential manner, whereas the solubility of β-lactose increases in a near linear manner (Jenness & Patton, 1959).

Crystallisation The common crystalline form of lactose obtained from supersaturated aqueous solution or cheese whey at a temperature below 93.5°C is α-lactose monohydrate. These crystals are very hard, slightly hygroscopic, dissolve only slowly, and are

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α-lactose β-lactose

H OH H OH HO HO H O HO O 4 6 H 6 O HO 4 5 O 5 2 HO OH 2 1 HO 2 1 H 3 H H OH H H 1 H 3 H OH H H H H OH HO Galactose Glucose

Fig. 1.3 Mutarotation of lactose.

often relatively large; the most common crystal shape for α-lactose monohydrate is the so-called tomahawk form (Van Kreveld & Michaels, 1965). Other crystalline forms of lactose are anhydrous α-lactose, prepared by dehydration of α-lactose monohydrate in vacuum at 65–93.5°C, and β-lactose anhydrous, prepared from aqueous solutions at a temperature above 93.5°C.

Reactions of lactose Changes in lactose on heating Lactose is a reducing sugar that can react with amino groups in the Maillard reaction, leading to nonenzymatic browning. The Maillard reaction involves interaction between a carbonyl (e.g. lactose) and an amino group (in milk particularly lysine residues) to form a glycosamine, that is, lactosamine. Lactosamine may undergo an Amodori rearrangement to form a 1-amino-2-keto sugar (Amodori compound), which can be degraded further, leading to the formation of a range of active alcohol, carbonyl and dicarbonyl compounds, and ultimately brown-coloured polymers called melanoidins (O’Brien, 1996, 1997; Van Boekel, 1998). Isomerisation of lactose may also occur on heating; the isomer lactulose can be formed, in which the glucose moiety of lactose is isomerised to fructose. Lactulose is not present in raw milk or high-temperature short-time (HTST) pasteurised milk, but is produced on heating milk to sterilisation conditions. Trace amounts of the isomer epi-lactose (disaccharide of galactose and mannose) are formed on heat treatment (Berg & Van Boekel, 1994; O’Brien, 1996, 1997).

Enzymatic hydrolysis and fermentation of lactose Lactose can be enzymatically hydrolysed to its constituent monosaccharides (glucose and galactose) by some β-galactosidases (EC 3.2.1.23); β-galactosidases that hydrolyse lactose are commonly referred to as lactases (Mahoney, 1997). Lactose is readily fermented by lactic acid bacteria, particularly Lactococcus spp. and Lactobacillus spp. Enzymatic hydrolysis of lactose is the ﬁ rst step in lactose

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fermentation, followed by degradation of the monosaccharides. Homofermentative bacteria produce lactic acid only, through the following reaction:

Glucose + 2 ADP + 2 H3PO4 → 2 lactic acid + 2 ATP + 2 H2O Heterofermentative bacteria can use a number of pathways to produce lactic acid, as

well as a range of other products, such as acetic acid, ethanol and CO2. Pathways for microbial fermentation of lactose are further described by Cogan and Hill (1993), Cocaign-Bousquet et al. (1996) and Tamime (2006).

Significance of lactose in dairy products Fermentation of lactose forms the basis of the characteristics of a wide variety of dairy products; for instance, it gives the desired acidic taste to products like sour milk or buttermilk, as well as kefi r, langfi l or viili (IDF, 1988; Tamime, 2005). The most popular fermented milk product is yoghurt, which may be described as an acid-coagulated fermented milk product; lactose fermentation leads to a reduction in milk pH, until coagulation of casein micelles occurs (Tamime, 2006; Tamime & Robinson, 1999). In the manufacture of cheese, up to 98% of the lactose from the milk is removed in the whey; the fi nal concentration of lactose in the curd depends on its concentration in the milk and the moisture content of the curd. The breakdown of the degradation of lactose in the curd has a major effect on the quality of the ripened cheese; for example, excessive lactic acid in cheese curd leads to a low pH, strong, acidic, harsh taste, and a brittle structure (Fox et al., 1990). In some varieties, for example Dutch cheeses, the curds are washed to reduce their lactose content, and thus regulate the pH of the cheese. Lactose is the most abundant constituent in most dried dairy-based powders (e.g. ~37 g 100 g–1 in whole milk powder, ~50 g 100 g–1 in skimmed milk powder or ~70 g 100 g–1 in whey powder). Some of the lactose in milk or whey powders is in the amorphous form, which is very hygroscopic and readily absorbs moisture from the air; this leads to the formation of a crystal lattice, which results in clumping or caking of the powder particles. In the case of drying whey products, modifi cations to the drying process are often a necessity to prevent caking or clumping (Holsinger, 1997).

1.3.2 The milk salts Introduction The salts in milk are mainly phosphates, citrates, chlorides, sulphates, carbonates and bicarbonates of sodium, potassium, calcium and magnesium. The average content of the major mineral constituents in bovine, ovine, caprine and buffalo milk is given in Table 1.5, and the most signiﬁ cant difference between the species is that the concentration of calcium and phosphorus is considerably higher in ovine or buffalo milk than in bovine or caprine milk.

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Table 1.5 Average concentration (mg L–1 milk) of mineral constituents in bovine, ovine, caprine and buffalo milk Minerals Bovinea Ovinea Caprinea Buffalob Sodium (Na) 550 440 420 450 Potassium (K) 1400 1200 1700 1000 Calcium (Ca) 1150 1700 1000 1850 Magnesium (Mg) 110 180 130 190 Phosphorus (P) 920 1500 900 1500 Chloride (Cl) 1000 820 1500 640 a After Tamime et al. (1991). b After Sahai (1996)

Milk contains organic and inorganic salts; thus, the level of salts is not equivalent to the level of mineral substances, and the level of salts is by no means equivalent to the ash content, because ashing causes the loss of organic acids (citrate and acetate), and the transfer of organic phosphorus and sulphur to inorganic salts. The composition of milk salts is inﬂ uenced by a number of factors, including species, stage of lactation and feed. Salt composition is also inﬂ uenced by the breed of species; for example, milk from Jersey cows usually contains more calcium and phosphorus, but less sodium and chloride than milk from other bovine species. A mastitic infection leads to increased levels of sodium and chloride in milk.

Partitioning of milk salts between the colloidal and soluble phases of milk Certain salts in milk (e.g. chlorides and the salts of sodium and potassium) are sufﬁ ciently soluble to be present almost entirely in the milk serum. However, the concentration of several other salts, particularly calcium phosphate, is considerably higher than can be maintained in solution at the normal pH of milk; thus, these salts exist partially in soluble form and partially in a colloidal form, that is, associated with the casein micelles (for reviews, see Holt, 1985, 1997). The colloidal salts are commonly referred to as colloidal calcium phosphate (CCP) and, while calcium and phosphate predominate, some magnesium and citrate are also present. CCP plays an important role in the structure and stability of the casein micelle, as discussed in more detail below in Section 1.3.4. The distribution of calcium and phosphorus between the colloidal and soluble phases of milk differs considerably with species, as indicated in Table 1.6. In general, milk that contains a high level of calcium or phosphorus (e.g. ovine or buffalo milk – see Table 1.5), also contains a high level of these minerals in the colloidal phase (Table 1.6).

Factors affecting the salt balance in milk The salt balance in milk is inﬂ uenced by various treatments, as reviewed by Holt (1985) and De la Fuente (1998). For example, acidiﬁ cation of milk is accompanied by a progressive solubilisation of CCP, and is complete at a pH <4.9. Alkalinisation has the opposite effect and at a pH >11.0, almost all soluble calcium phosphate

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Table 1.6 Distribution of calcium and phosphorus (%) between the soluble and colloidal phases in different milks Calcium Phosphorus Mammalian milk Soluble Colloidal Soluble Colloidal Bovinea 32 68 53 47 Caprineb 34 66 41 59 Ovineb 20 80 39 61 Buffaloc 22 78 32 68 a Data compiled from Walstra et al. (1999). b Data compiled from De la Fuente et al. (1997). c Data compiled from Sahai (1996).

occurs in the colloidal phase. The solubility of calcium phosphate is also markedly temperature-dependent. Unlike most other compounds, the solubility of calcium phosphate decreases with increasing temperature; thus, heating causes precipitation of calcium phosphate, whereas cooling has the opposite effect and leads to solubilisation of CCP, that is, increasing the levels of soluble calcium and phosphate. Storage at 4°C for up to 48 h increased the level of soluble calcium by 10% or 7% in bovine or caprine milk, respectively, whereas the level of soluble calcium in ovine milk was unaffected by cold storage (Raynal & Remeuf, 2000). Shifts in the mineral balance of milk induced by low temperatures are completely reversible, but changes induced by heating at high temperature are only partially reversible. Dilution of milk causes solubilisation of CCP, whereas concentration has the opposite effect (Holt, 1985; De la Fuente, 1998). Furthermore, treatment of milk at high hydrostatic pressures also causes solubilisation of CCP, as Lopez-Fandino et al. (1998) observed for bovine, ovine or caprine milk, and Huppertz et al. (2005) observed for buffalo milk. A physicochemical property of milk closely related to the salt balance of milk is its pH. Changes in the salt balance of milk that result in solubilisation of CCP (i.e. cooling, dilution or high-pressure treatment) result in an increase in pH, whereas those that result in precipitation of calcium phosphate (i.e. heat treatment or concentration) result in a reduction in pH. Increases in milk pH as a result of solubilisation of CCP are probably the result of an increase in the level of phosphate ions in the soluble phase of milk, as these can bind to hydrogen ions and thereby increase pH.

1.3.3 Lipids Introduction Lipids are deﬁ ned as esters of fatty acids and related components that are soluble in apolar solvents (e.g. ethyl/petroleum ether or chloroform/methanol). The milk from all mammals contains lipids, but the concentration varies widely between species. Fat content ranges of bovine, ovine or caprine milk are 33–47, 40–99 and 41–45 g L–1, respectively (Christie, 1995); whereas buffalo milk contains ~70 g fat L–1 (Sahai, 1996). The milk from marine mammals in particular contains very high levels of fat, for example, milk from the harp seal contains >50 g fat 100 g–1. The

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Table 1.7 Principal fatty acids (g 100 g–1 fat) in triacylglycerols in different mammalian milks

Fatty acids Bovine Ovine Caprine Buffalo

C4:0 3.1 4.0 2.6 3.6

C6:0 1.6 2.8 2.9 1.6

C8:0 1.3 2.7 2.7 1.1

C10:0 3.0 9.0 8.4 1.9

C12:0 3.1 5.4 3.3 2.0

C14:0 9.5 11.8 10.3 8.7

C16:0 26.3 25.4 24.6 30.4

C16:1 2.3 3.4 2.2 3.4

C18:0 14.6 9.0 12.5 10.1

C18:1 29.8 20.0 28.5 27.7

C18:2 2.4 2.1 2.2 2.5

C18:3 0.8 1.4 – 2.5

C20–C22 Trace – – Trace Data compiled from Christie (1995).

concentration of lipids for any species varies with breed, individual animal, stage of lactation, mastitic infection and plane of nutrition.

Composition and fatty acid profile The lipid fraction of milk comprises 98 g 100 g–1 triglycerides and ~1 g 100 g–1 phospholipids, plus small amounts of diglycerides, monoglycerides, cholesterol, cholesteryl esters and traces of fat-soluble vitamins and other lipids. Ruminant milk contains an extremely wide range of fatty acids; in bovine milk fat, over 400 different fatty acids have been detected (Christie, 1995), but most of these only occur in trace amounts. The concentrations of the principal fatty acids in milk fats from bovine, ovine, caprine or buffalo milk are shown in Table 1.7. The most notable difference

is that ovine and caprine milks contain more C4:0–C14:0 acids than bovine or buffalo milks and that ovine milk contains less C18 acids than bovine, caprine or buffalo milk. The fatty acid composition markedly infl uences the crystallisation properties and the melting point of the fat (i.e. the melting temperature increases with fatty acid chain length and with the level of saturation) and, thus, is important for products such as butter or spreads. Fatty acid profi le is infl uenced signifi cantly by lactation stage, and so in countries where milk production is seasonal (e.g. New Zealand or Ireland), large seasonal variations in the hardness of butter can be observed.

Milk fat globules In 1674, Van Leeuwenhoek ﬁ rst reported the presence of fat globules in milk; since then, it has been established that almost all the lipids in milk are found in the milk fat globules. Thus, milk can be considered as an oil-in-water emulsion, the physicochemical aspects of which are essential when considering changes that occur on storage or processing of milk. Fat in milk is present predominantly in spherical droplets ranging in diameter from <0.2 to >15 μm; bovine milk typically contains >1010 globules mL–1.

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Since lipids are incompatible with aqueous systems, an emulsiﬁ er is required to reduce interfacial tension and thus prevent phase separation. In milk, this emulsiﬁ er is a surface layer that surrounds the milk fat globules called the milk fat globule membrane (MFGM), which comprises ~2–6% of the globule mass. The composition of the MFGM differs considerably from either milk fat or milk plasma and is, in fact, much closer to that of the cell membrane, from which it is largely derived. The MFGM consists primarily of protein (~75 g 100 g–1; including enzymes such as alkaline phosphatase and xanthine oxidase), phospholipids (~20 g 100 g–1), cer- ebrosides (~3 g 100 g–1) and cholesterol (~2 g 100 g–1), whereas other substances (neutral glycerides, water, carotenoids, vitamin A, iron and copper) are also present at lower levels (Walstra et al., 1999). The MFGM consists of an innermost layer, which existed on the surface prior to secretion, plus a bilayer membrane that has a dense proteinaceous coat (10–50 nm thick) oriented on the inner membrane face (Keenan & Mather, 2003). Compared with bovine milk, average milk fat globule size is lower in caprine (Attaie & Richter, 2000; Fahmi et al., 1956; Mehaia, 1995) and ovine milk (Fahmi et al., 1956; Mehaia, 1995), but is higher in buffalo milk (Fahmi et al., 1956; Mehaia, 1995).

Stability of the milk fat emulsion The stability of the milk fat emulsion is signiﬁ cant with respect to a range of physical and chemical characteristics of milk, which in brief are as follows.

Creaming Milk fat globules have a lower density than the milk plasma; hence, they rise under the inﬂ uence of gravity. The rate of rise, v, for individual globules can be described by Stokes’ law: × × 2 v = (ρp – ρf) g r /18η

where ρp and ρf are the densities of the milk plasma and milk fat globules, respectively, g the acceleration due to gravity, r the radius of the fat globule and η the viscosity of the milk plasma. The rate of rise of bovine milk fat globules, particularly at refrigeration temperature, is considerably faster than predicted by Stokes’ equation. This is due to the fact that fat globules in bovine milk form approximately spherical clusters, of up to 1 mm in size. Cluster formation occurs at a temperature below 37°C and is more extensive at lower temperatures, and is hence referred to as cold agglutination (Huppertz & Kelly, 2006; Walstra, 1995). Cold agglutination of milk fat globules involves the formation of large aggregates out of three components (Euber & Brunner, 1984): • the milk fat globules; • immunoglobulin M (IgM); and • the so-called skim milk membrane (SMM), consisting of lipoprotein particles present in the milk plasma.

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Immunoglobulin M can interact with both milk fat globules and SMM, but interactions between SMM and milk fat globules do not appear to occur. Cold agglutination can be impaired through several treatments; IgM is heat-labile and whereas SMM is homogenisation-labile (Euber & Brunner, 1984), Honkanen-Buzalski and Sandholm (1981) showed that fat globules could also be agglutinated by addition of anti-bovine IgA. Cold agglutination does not occur in ovine, caprine and buffalo milk and hence these milks cream a lot more slowly than bovine milk (Fahmi et al., 1956).

Homogenisation The formation of a cream layer as a result of the creaming process is generally regarded as negative; to prevent this, milk is often homogenised. During homogenisation, prewarmed (~40°C) milk (in which the fat is in a liquid state; homogenisation is less effective when the fat is partially solid) is passed through a small oriﬁ ce at a pressure of 10–20 MPa. Shearing, impact and distortion effects combine to stress the fat globules to such an extent that they split into a greater number of smaller globules (usually <2 µm diameter; Walstra, 1975, 1995). In recent years, high-pressure homogenisers have been deployed, which can reduce milk fat globule size even further (Hayes & Kelly, 2003; Thiebaud et al., 2003). The effect of conventional and high-pressure homogenisation on the size distribution of milk fat globules in bovine milk is shown in Fig. 1.4. Due to the reduction in fat globule

Unhomogenised Conventional homogenisation: 18/3 MPa High pressure homogenisation: 100/5 MPa Volume frequency

0.1 1 10

Globule diameter (µm)

Fig. 1.4 Volume frequency distribution of milk fat globules in unhomogenised bovine milk. The milk was conventionally homogenised at a primary homogenisation pressure of 18 MPa and a secondary homogenisation pressure of 3 MPa or high-pressure homogenised at a primary homogenisation pressure of 100 MPa and secondary homogenisation pressure of 5 MPa. Reproduced by permission from T. Huppertz.

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size by homogenisation, the surface area of the fat globules is increased signifi - cantly (up to tenfold). The material of the original MFGM is insuffi cient to cover the newly formed membrane and, thus, the proteins of the milk plasma, primarily caseins, absorb onto the membrane. Fat globules in homogenised milk, due to their small size and the presence of a high level of casein on their surface, can, in effect, behave like casein micelles, which has signifi cant implications for the heat-, acid- or rennet-coagulation properties of milk and hence for the properties of resulting products. These effects can be positive in the case of acidifi ed milk products, such as yoghurt, but they are generally undesirable in the case of cheese.

Lipid oxidation The chemical oxidation of lipids is a free radical autocatalytic process involving the methylene group between a pair of double bonds in fatty acids. Lipid oxidation is a chain reaction involving initiation, propagation and termination stages, as depicted in Fig. 1.5. The removal of a hydrogen atom from the methylene group adjacent to a double bond, which generates a fatty acid radical (alkyl radical, R•), forms the initiation step. In milk, this reaction is initiated by polyvalent metals, especially copper and iron, UV light or ionising radiation. The extremely reactive alkyl radical can combine with oxygen to form a peroxy radical (ROO•), which can combine with another unsaturated fatty acid molecule to form the corresponding hydroperoxide (ROOH) and a new alkyl radical. Hydroperoxides are unstable and degrade to yield

Initiation

RH → R• + H•

Propogation

• • R + O2 → ROO ROO• + RH → ROOH + R• ROOH → RO• + •OH RO• + RH → ROH + R• • • OH + RH → H2O + R RO• + ROOH → ROH + ROO• ROOH → nonradical end products

Termination

R• + R• → RR RO• + RO• → ROOR RO• + R• → ROR ROO• + R• → ROOR

Fig. 1.5 Reaction pathways for lipid oxidation.

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volatile, nonradical end products, many of which result in off-ﬂ avours. Alternatively, the hydroperoxides can degrade to produce an alkoxy (RO•) or hydroxyl (•OH) radical, both of which can propagate the chain reaction with further RH molecules. The

reactions terminate when the supply of RH molecules is exhausted, if O2 becomes limiting, if radicals react with each other or if radicals react with antioxidants, that is, vitamin E in milk (O’Brien & O’Connor, 2003). The rate and extent of lipid oxidation in milk is inﬂ uenced by a range of param-

eters, for example the concentration of O2, which may be reduced by replacement with an inert gas such as nitrogen, and the presence of metals, principally copper and iron. Furthermore, exposure to light is a very effective promoter of lipid oxidation, to an extent depending on the wavelength of the light and the intensity and duration of exposure (O’Brien & O’Connor, 2003).

1.3.4 Proteins Introduction Technologically, the milk proteins are probably the most important constituents of milk, due to their unique properties, which allow for rather easy conversion of milk into a wide range of products, such as cheese or yoghurt. Research on milk proteins dates back to the start of the 19th century, and milk proteins are now probably the best characterised of all food proteins. Milk proteins can be divided into two classes, that is, those soluble and those insoluble at pH 4.6. The pH 4.6-insoluble proteins are called the caseins, whereas the pH 4.6-soluble proteins are referred to as serum proteins or whey proteins (Fox, 2003c; Ng-Kwai-Hang, 2003). Indigenous milk enzymes, which are often also classiﬁ ed as milk proteins, are described in Section 1.3.5.

Whey proteins The whey, or serum, proteins represent ~20% of total milk protein in bovine (Walstra et al., 1999), buffalo (Sahai, 1996), caprine (Juarez & Ramos, 1986) or ovine (Anifantakis, 1986) milk. Whey proteins in their native form are soluble at pH 4.6 or in saturated NaCl, remain soluble after rennet-induced coagulation of casein micelles, and cannot be sedimented by ultracentrifugation. The class of whey proteins consists of a number of proteins, primarily β-lactoglobulin, α-lactalbumin, blood serum albumin, immunoglobulins and proteose peptones. These whey proteins occur in milk from most species, although large interspecies differences in their relative proportions exist, as shown in Table 1.8. In milk from all species, β-lactoglobulin is the most abundant individual whey protein. One marked difference between the milks is that, compared with bovine, ovine or caprine milk, buffalo milk contains a very high level of proteose peptones, but only very little immunoglobulin.

β-Lactoglobulin (β-lg) This is the major whey protein in bovine, ovine, caprine and buffalo milk (Table 1.8); β-lg is synthesised in the epithelial cells of the mammary gland and consists

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Table 1.8 Relative proportions of the whey proteins (g 100 g-1 total whey protein) in different mammalian milks Whey proteins Bovinea Ovineb Caprineb Buffaloc β-Lactoglobulin 50 51 39 45 Albuminsd 25 25 40 19 Proteose peptone 13 6 9 35 Immunoglobulins 12 18 12 1 a Data compiled from Walstra et al. (1999). b Data compiled from Kalantzopoulos (1993). c Data compiled from Sahai (1996). d Consisting of α-lactalbumin and serum albumin.

of 162 residues per monomer, with a molecular mass of 18.3 kDa and an isoelectric point at pH 5.1. Some slight interspecies differences in amino acid sequence occur, as outlined by Sawyer (2003). In bovine milk, β-lg is generally present in the A or B genetic variants, although the C and D variants have also been identifi ed. Genetic polymorphism of β-lg has also been identifi ed in caprine (Jenness, 1980) or ovine (Sawyer, 2003) milk, but buffalo β-lg does not exhibit genetic polymorphism (Sahai, 1996). In bovine, ovine, caprine or buffalo milk, at its natural pH, β-lg is present in the form of dimers, formed through hydrophobic interaction (Sawyer, 2003). Native β-lg is a globular protein with a well-defi ned three-dimensional structure, consisting of an α-helix along one side of a β-barrel (Creamer & Sawyer, 2003). β-Lg contains two intramolecular disulphide bridges plus one free sulphydryl group, which, in its native state, is unavailable for interaction. However, at a high temperature, high pressure or in the presence of 6 mol L–1 urea, the β-lg molecule can unfold, thereby exposing the free sulphydryl group and making it available for interaction, for example through sulphydryl–disulphide interchange reactions, with α other proteins, such as -lactalbumin (α-la), β-lg, κ-casein and possibly αs2-casein (Creamer & Sawyer, 2003; Sawyer, 2003).

α-Lactalbumin (α-la) This is the second most abundant whey protein in bovine, ovine, caprine or buffalo milk. The polypeptide chain of bovine, ovine, caprine or buffalo α-la consists of 123 amino acid residues and has a molecular mass of 14.2 kDa and an isoelectric point at pH 4.80, 4.92, 4.92 or 4.70, respectively (Brew, 2003; Zhang & Brew, 2003). α-la is synthesised in the rough endoplasmic reticulum; from there it is transported to the Golgi apparatus, where it has an important function in the synthesis of lactose (see Fig. 1.2). α-la contains eight cysteine residues, which form four intramolecular disulphide bonds, and all known α-lactalbumins contain a tightly bound calcium

ion. The three-dimensional structure of α-la consists of three α-helices and a 310 helix (Brew, 2003).

Serum albumin (SA) Serum albumin is the most abundant protein in the circulatory system of the mammal, consisting of ~50 g 100 g–1 of the protein in bovine blood serum, but is present in

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only small quantities in milk. Bovine SA has a molecular weight of ~66 000 Da and consists of 582 amino acids; it contains 17 disulphide bonds and one free sulphydryl group (Fox, 2003c). In bovine milk, SA is present at concentrations of 0.1–0.4 g L–1 (Fox, 2003b), whereas in caprine milk, the level of SA may be as high as 1.0 g L–1 (Juarez & Ramos, 1986). Ovine milk also contains a higher level of SA than bovine milk (Anifantakis, 1986). Owing to its low concentration, particularly in bovine milk, SA probably has little inﬂ uence on the properties of milk.

Immunoglobulins (Ig) These proteins are present in the colostrum and milk of all lactating species, with the biological function of providing immunological protection to the offspring against microbial pathogens and toxins. Levels of immunoglobulins are very high in colostrum, but decline rapidly with advancing stage of lactation. The Ig classes of bovine (Butler, 1999; Marnila & Korhonen, 2003), buffalo (Sahai, 1996), ovine (Butler, 1999) and caprine (Jenness, 1980) milk are IgG, IgM and IgA. IgG occurs

predominantly in two subclasses, IgG1 and IgG2, and has a molecular mass of ~146 kDa. IgA and IgM have molecular masses of ~160 and ~970 kDa, respectively (Marnila & Korhonen, 2003). IgM plays an important role in the creaming of bovine milk (see Section 1.3.3). Pahud and Mach (1970) reported that levels of IgA and IgM are comparable in bovine, caprine or ovine milk, whereas the level of IgG in bovine milk is slightly higher than that in ovine or caprine milk. Few data are available on the contents of immunoglobulins in buffalo milk, particularly for direct comparison with data from other species.

Proteose peptones (PP) The proteose peptones are often described as the pH 4.6-soluble proteins that are not denatured by heat treatment but are insoluble in 12 g 100 g–1 trichloroacetic acid (TCA). The proteose peptone fraction of milk appears to consist of two groups of proteins/peptides, that is, those that are indigenous to milk (e.g. osteopontin, proteose peptone 3 – PP3), and those that are derived from the action of proteolytic enzymes, primarily plasmin, or caseins (Fox, 2003c). Hydrolysis of caseins by plasmin is further discussed in Section 1.3.5. The electrophoretic pattern of proteose peptones in buffalo milk is similar to that in bovine milk (Majumder et al., 1972). PP3 in ovine or caprine milk is almost identical to that in bovine milk (Mati et al., 1991; Sørensen et al., 1997)

Caseins The caseins represent ~75–80% of total protein in bovine, ovine, caprine or buffalo milk and are thus the most abundant class of milk proteins. The caseins are a class of phosphoproteins, whose properties differ considerably from most other proteins; they are hydrophobic, have a relatively high charge and contain many proline and only few cysteine residues. Caseins have little tertiary structure, with only small α-

helical regions present. Most milks contain four types of casein, denoted αs1-, αs2-, β- and κ-casein. These caseins occur at different ratios in milks from different species,

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Table 1.9 Relative proportions of casein fractions (g 100 g-1 total casein) in different mammalian milks

Caseins Bovinea Ovineb Caprinec Buffalod α -casein 38 16 5 42 s1 α -casein 10 15 25 7 s2 β-casein 39 47 50 38 κ-casien 13 7 20 13 a Data compiled from Walstra et al. (1999). b Data compiled from Kalantzopoulos (1993). c Data compiled from Juarez and Ramos (1986). d Data compiled from Sahai (1996).

as indicated in Table 1.9. Perhaps the most notable difference is the extremely low

αs1-casein content of caprine milk, compared with bovine, ovine or buffalo milk.

αs1-Casein

Of the caseins, αs1-casein has the highest charge and the highest phosphate content. Bovine, ovine, caprine or buffalo αs1-caseins each consist of 199 amino acids, have a molecular mass of ~23.6 kDa, and contain 8, 10, 11 or 8 phosphoserine residues per

molecule, respectively (Martin et al., 2003). αs1-Casein exhibits progressive consecu- tive self-association to dimers, tetramers and hexamers; the degree of association

is strongly dependent on pH and ionic strength. αs1-Casein is easily precipitated by addition of calcium (Swaisgood, 2003).

αs2-Casein This casein fraction is the least abundant of the caseins in bovine, ovine or buffalo milk, and is the least hydrophobic and most highly and variably phosphorylated of

the caseins (Creamer, 2003). Bovine or buffalo αs2-caseins consist of 207 amino acid residues, whereas the ovine or caprine variants consist of 208 amino acid

residues (Martin et al., 2003), resulting in a molecular mass of ~25.2 kDa for αs2- casein from the aforementioned species (Ng-Kwai-Hang, 2003). The structure of

αs2-casein is characterised by distinct domains of high charge (Swaisgood, 2003). Association studies have shown that αs2-casein behaves very similarly to αs1-casein (Creamer, 2003).

β-Casein This is the most hydrophobic of the caseins, and contains a large number of proline residues. β-Casein has a hydrophilic C-terminus and a very hydrophobic N-terminus (Creamer, 2003). Bovine or buffalo β-caseins consist of 209 amino acid residues, whereas ovine or caprine β-caseins contain 207 (Martin et al., 2003), all having a molecular mass of ~24.0 kDa (Creamer, 2003); however, bovine β-casein contains ﬁ ve phosphoseryl groups. β-Casein is readily cleaved by the indigenous milk proteinase, plasmin, leading to the formation of γ-caseins and proteose peptones (see Section 1.3.5). β-Casein is precipitated in the presence of calcium, and at temperatures >5°C, β-casein molecules undergo self-association, leading to the formation of micelles.

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κ-Casein This casein fraction differs greatly from the other caseins, primarily because it is the only one of the caseins that is glycosylated. In bovine milk, approximately two thirds of κ-casein molecules are glycosylated; carbohydrate groups include galac- tosamine, galactose and N-acetylneuraminic acid residues. κ-Casein is amphipathic, with a very hydrophobic N-terminus and a rather hydrophilic C-terminal end, which plays an important role in stabilising the casein micelles (see below). Furthermore, enzymatic hydrolysis of κ-casein by chymosin, or other milk-clotting enzymes, is the crucial primary step in rennet-induced coagulation of milk (see Section 1.4). Bovine or buffalo κ-caseins consist of 169 amino acid residues, whereas κ-caseins from ovine or caprine milk consist of 171 amino acids (Martin et al., 2003); κ-casein has a molecular weight of ~19.0 kDa (Creamer, 2003). Unlike the other caseins, κ-casein is not sensitive to calcium, but it does, like β-casein, tend to form micelles in solution (Swaisgood, 2003).

Casein micelles The vast majority of caseins in milk from most mammalian species exist not in solution, but in the form of casein micelles. These micelles are highly hydrated –1 (2–3 g H2O g protein), and also contain inorganic mineral constituents (primarily calcium and phosphate, but also some magnesium and citrate and, collectively, are referred to as colloidal calcium phosphate – CCP). The calcium-sensitive caseins,

αs1-, αs2- and β-casein, are aggregated with the CPP in the micelles; however, κ- casein is soluble in high concentrations of calcium and reacts with, and stabilises, the Ca-sensitive caseins in the micelles. Casein micelles have an average molecular weight of ~108 Da, with a diameter ranging from 50 to 600 nm. Compared with their counterparts in bovine milk, casein micelles in buffalo milk are larger, contain more CCP, and are less hydrated (Ganguli, 1973; Sood et al., 1976). In ovine milk, average casein micelle size is lower (Buchheim et al., 1989; Richardson et al., 1974), micellar hydration is lower (Sood et al., 1979), and the micellar CCP content is higher (O’Connor & Fox, 1977) than in bovine milk. In caprine milk, average casein micelle size is higher than in bovine milk (Buchheim et al., 1989), micellar hydration is slightly lower (Sood et al., 1979), and the micellar CCP content is higher (O’Connor & Fox, 1977).

The microstructure of casein micelles The microstructure of casein micelles has been subject to considerable research and discussion over the last ﬁ ve decades, but there is still a lack of general consen- sus about this topic. Numerous models have been proposed for the bovine casein micelle. Perhaps the initially most widely supported model is the submicelle model, several variations of which have been published, as reviewed by Rollema (1992). These submicelle models assume that the casein micelle consists of submicelles with a molecular weight of ~106–107 Da. The κ-casein is located on the micellar surface and its hydrophilic C-terminus protrudes from the micelles, creating a hairy layer around the micelle, and providing electrostatic and steric stabilisation.

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Fig. 1.6 Cross-section of a casein micelle according to the submicelle model. Reproduced from Walstra et al. (1999) by permission of Marcel Dekker Inc.

Some variations of this model claim the existence of two types of submicelles; those largely devoid of κ-casein, which are located in the core of the micelle, and those containing a relatively high level of κ-casein, which can be found primarily in the outside of the micelles. Differences between the various submicelle models arise mainly from the manner in which the submicelles are bound in the micelle, that is, through interactions between the calcium-sensitive caseins or through CCP (Rollema, 1992). In a recent submicelle model (Fig. 1.6) presented by Walstra et al. (1999), it is proposed that the CCP is present in clusters inside the submicelle, rather than between the submicelles. In the last decade or so, several authors have expressed reservations about the submicelle model and have proposed alternative models. Holt (1992) proposed a model of the casein micelle in which no subunits are present. In this model, the calcium-sensitive caseins are linked by nanoclusters (microcrystals) of calcium phosphate, leading to a depiction of the micelle as a tangled web of casein polypeptide chains cross-linked by calcium phosphate interactions. Although the presence of calcium phosphate nanoclusters is now widely accepted, some reservations exist regarding the accuracy of this model proposed by Holt

(1992). This model cannot explain the limited growth of the casein micelles (αs1- and αs2-caseins have more than one phosphoserine cluster so cross-linking options should be unlimited). Furthermore, the model proposed by Holt (1992) does not have a role for κ-casein because it does not have a phosphate cluster to bind with the calcium phosphate nanoclusters (Horne, 2003a). In the calcium phosphate nanocluster model described by De Kruif and Holt (2003), some of these reservations have been overcome (see Fig. 1.7). This model proposes a more or less homogeneous distribution of protein, with the periphery partially drained by solvent. It is assumed that no calcium phosphate is present in this drained layer, but that calcium phosphate nanoclusters are otherwise randomly distributed throughout the micelle. Casein micelles grow to colloidal dimensions because of a balance between cross-linking of casein, and the

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Fig. 1.7 Model of the structure of the casein micelle showing relatively homogeneous protein matrix containing calcium phosphate nanoclusters (•). Reproduced from De Kruif and Holt (2003) by permission of Kluwer Academic/Plenum Publishers, New York.

formation of loops in the protein chains. Growth terminates because the formation of nanoclusters terminates or because the weak attractive interactions between the calcium-sensitive caseins are prevented from propagating by a competitive equilibrium interaction with κ-casein (De Kruif & Holt, 2003). An alternative view of the microstructure of the casein micelle is presented in the dual-binding model proposed by Horne (1998, 2003a), which assumes that micellar assembly and growth take place through a polymerisation process involving two distinct forms of bonding: (a) cross-linking through hydrophobic bonding or (b) bridging across calcium phosphate nanoclusters, as depicted in Fig. 1.8. Micellar integrity is maintained through localised excess of hydrophobic interaction over

electrostatic repulsion. In this model, αs1-, αs2- and β-casein can interact through both hydrophobic bonding and cross-linking between a negatively charged phosphoserine cluster and a positively charged calcium phosphate nanocluster. κ-Casein can only link through hydrophobic bonding at its N-terminus; thus chain and network growth are terminated at this point, leaving the casein micelle network with a surface layer of primarily κ-casein molecules (Horne, 1998, 2003a). Recently, Dalgleish et al. (2004) suggested, based on ﬁ eld-emission scanning electron microscopy, that the caseins within the micelles are organised in tubular structures of ~20 nm in diameter and that the surface of the casein micelle may be considerably more complex than previously thought. To date, however, there has been no conclusive evidence presented for the complete accuracy of any one of the models for the microstructure of the casein micelles, and this topic will undoubtedly remain an active and interesting issue of considerable research, discussion and debate in the future.

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Fig. 1.8 Schematic representation of the binding of caseins and calcium phosphate nanoclusters according to the dual-binding model. Hydrophobic regions (B) are represented by bar structures, phosphoserine clusters by P and the hydrophilic casein macropeptide of κ-casein by C. Reproduced from Horne (2003a) by permission of Elsevier, Amsterdam.

Stability of casein micelles The stability, or instability, of casein micelles against various treatments has also been the topic of considerable research interest. The various methods through which the stability of the casein micelles can be affected can be divided into two categories, namely those that cause dissociation of the casein micelles, and those that cause aggregation of the casein micelles. The dissociation of the casein micelles can be achieved through various means. • Addition of urea to skim milk at a concentration of >6 mol L–1 causes a marked decrease in the turbidity of the milk, due to the fact that urea disrupts hydrophobic and hydrogen bonds (McGann & Fox, 1974). However, micelles extensively cross-linked by strong linkages to calcium phosphate are not disrupted by urea (Holt, 1998). • Removal of CCP, e.g. through dialysis, causes dissociation of the casein micelles, demonstrating the importance of CCP in maintaining micellar integrity. Removal of CCP can also be achieved by addition of a calcium-chelating agent, such as trisodium citrate at a level of >50 mmol L–1 (Walstra, 1990). Casein micelles in buffalo milk are more stable to removal of CCP by addition of trisodium citrate than those in bovine milk (Huppertz et al., 2005). • Treatment of milk under high hydrostatic pressure results in a considerable increase in the light transmittance of milk under high pressure (Kromkamp et

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al., 1996). Recent studies by Huppertz et al. (unpublished) indicated that the extent of disruption of casein micelles at 400 MPa is similar to that achieved by addition of >6 mol L–1 urea or >50 mol L–1 trisodium citrate. Some re-formation of casein particles occurs when pressure is released (Kromkamp et al., 1996), but average casein micelle size is considerably lower in bovine milk treated at 300–800 mpa than in untreated milk (Huppertz et al., 2004). • Addition of sodium dodecyl sulphate (SDS), a widely used protein-dissociat- ing agent, also results in disruption of casein micelles, probably through rup- ture of hydrophobic bonds. Partial dissociation of casein micelles occurs at 0.8 g 100 mL–1 SDS, whereas dissociation is complete at 2.0 g 100 mL–1 SDS (Fox & Kelly, 2004). • Heating a 1:1 mixture of skimmed milk and 70 mL 100 mL–1 ethanol to a temperature >70°C causes a considerable increase in the light transmittance of milk, suggesting dissociation of casein micelles under such conditions due to increased solubility of casein, as a consequence of reduced phosphoseryl- mediated cross-linking and increased protein hydrophobicity (O’Connell et al., 2001a, 2001b). • Cooling of milk results in dissociation of individual caseins from the micelle, particularly β-casein (Ali et al., 1980; Creamer et al., 1977; O’Connor & Fox, 1973). This is probably the result of the weakening of hydrophobic bonds (Walstra, 1990). Cold-induced dissociation of micellar β-casein occurs in bovine, ovine and caprine milk, the extent of dissociability being in the order bovine > caprine > ovine (O’Connor & Fox, 1973).

Aggregation of casein micelles can be achieved in the following ways: • Rennet-induced coagulation of casein micelles forms the ﬁ rst step of the cheesemaking process. This process involves the enzymatic hydrolysis of κ-

casein at the Phe105-Met106 bond by chymosin or another milk-clotting enzyme, leading to the release of the hydrophilic C-terminal casein-macropeptide (CMP; residues 106–169). The resulting para-casein micelles can aggregate to form a coagulum (Hyslop, 2003). Rennet-induced coagulation of milk is discussed in more detail in Section 1.4. • Acid-induced coagulation of casein micelles forms the basis of the manufacture of a variety of dairy products, most notably yoghurt. Acidiﬁ cation of milk results in solubilisation of caseins and CCP, an increase in the level of soluble calcium and a reduction in the net-negative charge on the micelles. Acid coagulation of caseins occurs at the isoelectric point (pH 4.6). Acid coagulation of casein micelles is described extensively by Lucey and Singh (2003) (see also Tamime, 2005). • Addition of calcium to milk causes precipitation of the casein micelles. An excess of calcium ions enhances the possibility of calcium bridge formation; furthermore, addition of calcium decreases the charge on the micelles and results in deposition of CCP, which lead to reduced steric repulsion (Mellema et al., 1999; Walstra et al., 1999).

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• Heat-induced coagulation of casein micelles occurs only at very high temperatures (i.e. >130°C for bovine milk). The heat stability of milk is inﬂ uenced markedly by pH; heat-induced changes in milk, which contribute greatly to the stability or instability of milk, are dissociation of κ-casein from the micelles, association of heat-denatured whey proteins with the casein micelles, and heat- induced precipitation of calcium phosphate. The heat stability of milk is discussed in detail by O’Connell & Fox (2003). Buffalo (Sahai, 1996) or caprine (Fox & Hoynes, 1976) milk is less stable to heat-induced coagulation than bovine milk, whereas the heat stability of ovine milk is, at natural milk pH, comparable with that of bovine milk (Fox & Hoynes, 1976). • Addition of ethanol can result in destabilisation of casein micelles, leading to aggregation. Plotting the ethanol stability of milk against milk pH results in a sigmoidal curve with the stability increasing with pH. Ethanol-induced aggregation of casein micelles may be due to two effects: the collapse of the hairy layer responsible for steric repulsion and precipitation of calcium phosphate (Horne, 2003b). Caprine milk has a considerably lower ethanol stability than bovine milk (Horne & Parker, 1982), whereas the ethanol stability of buffalo milk is comparable with that of bovine milk (Huppertz, unpublished data).

1.3.5 Indigenous milk enzymes In bovine milk, the presence of ~60 enzymes has been reported, of which ~20 have been characterised. The remaining 40 enzymes, which are, at present, of little or no signiﬁ cant interest, have only been demonstrated via their activity. Indigenous milk enzymes may originate from various sources (e.g. blood, somatic cells, the milk fat globule membrane or the cell cytoplasm) and are found in or associated with various fractions of the milk (e.g. casein micelles, milk fat globule membrane, milk serum or somatic cells). Although present at only low levels, indigenous milk enzymes can be of considerable importance; for example, they can be used as indices of animal health or thermal history of the milk; they can result in quality deterioration or induce desirable changes in milk and dairy products, but they may also offer protective effects (Fox, 2003d). In this section, the principal technologically important indigenous milk enzymes, that is, plasmin, lipoprotein lipase, alkaline phosphatase and lactoperoxidase, will be described.

Plasmin Plasmin (EC 3.4.21.7) is the predominant indigenous proteinase in milk. It is part of a complex protease system in milk, consisting of its inactive precursor, plasminogen, plasminogen activators, which catalyse the conversion of plasminogen to plasmin, plus inhibitors of plasmin and plasminogen activators (see Fig. 1.9). The origin of plasmin and plasminogen in milk is the mammal’s blood. Plasmin is a trypsin-like serine protease, which is optimally active at a pH of ~7.5 and a temperature of ~37°C. In milk, plasmin and plasminogen are predominantly associated with the casein micelles (Bastian & Brown, 1996; Kelly & McSweeney, 2003; Nielsen, 2003).

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Plasminogen Plasmin Proteolysis

Plasminogen activator inhibitor Plasmin inhibitors

Plasminogen activator

Fig. 1.9 Schematic representation of the plasmin system in bovine milk.

Plasmin, which is highly speciﬁ c for peptide bonds to which lysine or, to a lesser extent, arginine contributes the carboxyl group, is active on all caseins, but par-

ticularly β-casein and αs2-casein. In bovine β-casein, the primary cleavage sites for plasmin are Lys28-Lys29, Lys105-His106 and Lys107-Glu108; this leads to the formation of γ-caseins and proteose peptones, as described in Table 1.10. Plasmin cleaves

αs2-casein at eight sites (Lys21-Gln22, Lys24-Asn25, Arg114-Asn115, Lys149-Lys150, Lys150- Thr151, Lys181-Thr182, Lys188-Ala189 and Lys197-Thr198) (Bastian & Brown, 1996; Fox, 1992; Kelly & McSweeney, 2003). The other caseins (i.e. α - and κ-casein) are α s1 hydrolysed at a considerably lower rate than β- and s2-casein, whereas the whey proteins α-la and β-lg are not hydrolysed by plasmin. Few data regarding plasmin activity in milk from species other than bovine are currently available. Plasmin is of signiﬁ cant interest for several dairy products. The cheese-making properties of milk deteriorate as a result of plasmin activity (e.g. increased rennet coagulation time and curd moisture content), whereas in the cheese itself, plasmin contributes to primary proteolysis, i.e. the conversion of caseins into polypeptides. Furthermore, the role of plasmin and plasminogen in the physical instability or age gelation of UHT milk has also received considerable attention, although the exact mechanism remains to be elucidated (Bastian & Brown, 1996; Fox, 1992; Kelly & McSweeney, 2003; Nielsen, 2003).

Table 1.10 Hydrolysis products of bovine β-casein by the activity of bovine plasmin

β-Casein (CN) fragment Name β-CN f1–28 Proteose peptone 8 fast (PP8f) β-CN f29–105 Proteose peptone 8 slow (PP8s) β-CN f29–107 Proteose peptone 8 slow (PP8s) β-CN f29–113 Proteose peptone T (PP-T) β-CN f1–105 Proteose peptone 5 β-CN f1–107 Proteose peptone 5 β-CN f29–209 γ1-casein β-CN f106–209 γ2-casein β-CN f108–209 γ3-casein β-CN f114–209 γ4-casein β-CN f184–209 γ5-casein Data compiled from Kelly & McSweeney (2003).

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Lipoprotein lipase Lipases hydrolyse ester bonds in emulsiﬁ ed esters at the oil–water interface. Milk lipase is a lipoprotein lipase (LPL; EC 3.1.1.34), which is synthesised in the mammary gland secretory cells and then transferred to the milk in the mammary gland. LPL is a glycoprotein (containing 8.3 g 100 g–1 carbohydrate), which consists of 450 amino

acid residues (Mw 100 kDa); it is optimally active at a pH of 9.2 and a temperature of 37°C (Olivecrona et al., 2003; Shakeel-Ur-Rehman & Farkye, 2003a). LPL liberates fatty acids from the 1 and 3 positions in tri-, di- and monoglycerides in two steps. First, the enzyme is absorbed at the lipid–water interface, and then the enzyme aligns its active site against the target site of the substrate and hydrolyses it. Lipolysis leads to the release of free fatty acids (FFA), which can result in the development of hydrolytic rancidity in milk. The activity of LPL is inhibited by its products, for instance, long-chain FFA; ionic calcium and serum albumin are capable of binding FFA and thus preventing inhibition of LPL activity (Deeth, 2003). In bovine milk, most LPL is associated with the casein micelles, some is in the serum phase and only a very small amount is associated with the MFGM. Buffalo milk contains an LPL similar to that of bovine milk and in comparable quantities, of which ~23 g 100 g–1 is found in the cream phase and the rest attached to the casein micelles (Balasubramanya et al., 1988). In caprine milk, two distinct forms of LPL, with a molecular weight in the range 55–60 kDa, have been identiﬁ ed, which differ considerably from LPL in bovine milk (De Feo et al., 1982). LPL activity in caprine milk is considerably lower than in bovine milk, and LPL is equally distributed between the cream and serum phase, with a small amount (~10%) attached to the casein micelles (Chilliard et al., 1984). LPL activity in ovine milk is lower than in bovine milk (Chandan et al., 1968); information about the distribution of LPL between the cream and serum phase in ovine milk is currently not available.

Alkaline phosphatase Alkaline phosphatase (ALP; EC. 3.1.3.1) indigenous to milk originates from the mammary gland; ALP is a phosphomonoesterase with an optimum activity in the pH range 9.0–10.5 and at a temperature of 37°C. ALP is a dimer of two identical subunits of 85 kDa each, and contains four zinc atoms per molecule, which are required for activity. In milk, ALP is predominantly found in the MFGM, where it is associated closely with phospholipid particles, known as microsomes (Andrews, 1992; Shakeel-Ur-Rehman & Farkye, 2003b; Shakeel-Ur-Rehman et al., 2003). Like many other phosphomonoesterases, ALP is active against a wide range of substrates and hydrolyses most phosphate ester bonds. ALP can dephosphorylate caseins under suitable conditions, but the technological signifi cance of this process is unknown. The technological signifi cance of ALP for most milk products, however, is not related to dephosphorylation reactions, but to its inactivation on thermal treatment, and the relative ease of assessment of this process. Liquid milk products with an ALP activity below a legally specifi ed limit are considered to be

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adequately pasteurised for safe consumption (Shakeel-Ur-Rehman & Farkye, 2003b; Shakeel-Ur-Rehman et al., 2003). ALP activity in buffalo milk (Sahai, 1996; Sharma & Ganguli, 1971) or caprine milk (Coburn et al., 1992) is considerably lower than in bovine milk, whereas ALP activity in ovine milk is considerably higher than in bovine milk (Anifantakis & Rosakis, 1983; Belton & Lyster, 1991).

Lactoperoxidase Lactoperoxidase (LPO; EC. 1.11.1.7) is a peroxidase that catalyses the oxidation of a donor compound according to: → Donor + H2O2 oxidised donor + H2O LPO is synthesised in the mammary gland and is a glycoprotein (~10.0 g 100 g–1 carbohydrate) with a molecular weight of ~78 kDa and contains one haem group. In milk, LPO exists primarily in soluble form at a concentration of 30 mg L–1 in bovine milk. LPO has a pH optimum of ~8.0 (Bjorck, 1992; Pruitt, 2003; Shakeel- Ur-Rehman & Farkye, 2003c).

In milk, LPO has antibacterial activity in the presence of H2O2 and thiocyanate (SCN–), through the catalysis of the oxidation of thiocyanate to hypothiocyanite (OSCN–):

Donor + H2O2 → oxidised donor + H2O Oxidised donor + SCN– → donor + OSCN– Hypothiocyanite and its conjugate acid (HOSCN), with which it is at equilibrium, are responsible for the antibacterial activity of this system (Pruitt, 2003). LPO activity in buffalo milk is slightly higher than in bovine milk (Sahai, 1996), whereas in caprine milk, it is considerably lower (Fonteh et al., 2002). In ovine milk, LPO activity is considerably higher than in bovine milk (Morin et al., 1995).

Other indigenous milk enzymes Trace amounts of several other enzymes have been found in milk, some of which have an established function in milk or are essential for the development of the newborn. Furthermore, other enzymes may reﬂ ect the physiological changes and pathological state of the mammary gland during lactation, whereas some enzymes are of importance in the processing of dairy products. Below is a brief overview of such enzymes, which are discussed in more detail by Farkye (1992, 2003a, 2003b).

L-Lactate-dehydrogenase L-Lactate-dehydrogenase (LDH; EC. 1.1.1.27) is a tetramer with a molecular mass of 140 kDa that catalyses the reversible oxidation of L-lactate to pyruvate:

L-Lactate + NAD+ ↔ pyruvate + NADH + H+

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LDH activity in milk has been suggested as a useful indicator of mastitis and, in dairy processing, it is conceivable that LDH plays a role in dairy fermentations. LDH activity in caprine milk is comparable with that in bovine milk (Jenness, 1980; Kjellberg & Karlsson, 1967).

Catalase Catalase (EC. 1.11.1.6) is a haem protein with a molecular mass of 225 kDa that catalyses the decomposition of hydrogen peroxide as follows:

2 H2O2 → 2 H2O + O2 It has been suggested that catalase may play a role in lipid oxidation, but this has thus far not been proved. Catalase activity in buffalo milk is lower than that in bovine milk (Sharma & Ganguli, 1971).

Xanthine oxidase Xanthine oxidase (XO; EC. 1.1.3.22) is a nonspeciﬁ c oxidoreductase with a molecular mass of ~300 kDa, that catalyses the oxidation of xanthine to uric acid as follows:

– Xanthine + H2O + O2→ uric acid + O2 XO is a major component of the MFGM, comprising ~20 g 100 g–1 of globule-associated protein in milk. It has been suggested that XO has a role in the development of spontaneous oxidised ﬂ avour in milk, but this remains unclear. XO activity in buffalo milk (Sahai, 1996; Sharma & Ganguli, 1971) or caprine milk (Hart et al., 1967; Juarez & Ramos, 1986) is lower than in bovine milk, whereas XO activity in ovine milk is higher than in bovine milk (Kehagias & Dalles, 1986)

Superoxide dismutase Superoxide dismutase (SOD; EC. 1.15.1.1) catalyses the dismutation of the superoxide anion as follows:

– + – 2 O2 + 2 H → H2O2 + O2 The type of SOD present in milk (CuZn-SOD) is an enzyme with a molecular weight of ~31–33 kDa, and is found in the milk serum. SOD may be important in maintaining the oxidative stability of milk, through scavenging the superoxide ion produced by xanthine oxidase.

γ-Glutamyl transferase γ-Glutamyl transferase (GGT; EC. 2.3.2.2) is a glycoprotein with a molecular mass of 80 kDa, that catalyses the transfer of a γ-glutamyl residue from a γ-glutamyl- containing peptide to an acceptor L-amino acid (except proline) or peptides: γ-glutamyl-peptide + amino acid → peptide + γ-glutamyl-amino acid

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In milk, GGT is found in the milk serum and bound to the fat globules and has an optimum pH of 8.0–9.0. GGT activity in ovine and caprine milk is ~50% and ~14% respectively of that in bovine milk (Siambela & Wilbey, 1996).

1.4 Rennet-induced coagulation of milk 1.4.1 Introduction Coagulation of milk with rennet is the ﬁ rst step in the production of any rennet- coagulated cheese variety. Traditionally, for the production of rennet-coagulated cheeses, calf rennet, obtained from the fourth stomach of young calves, has been used. Such rennets contained two primary proteolytic enzymes, namely chymosin (~80%) and pepsin (~20%). Increased cheese production and demand for beef worldwide during the 20th century resulted in a shortage of calf rennet; hence, substitutes for calf rennet were sought. Such alternatives include: recombinant chymosin, produced by organisms such as Escherichia coli, Aspergillus niger and Kluyveromyces lactis; adult bovine rennet, which contains less chymosin and more pepsin; or microbial coagulants from organisms such as Rhizomucor miehei or Cryphonectria parasitica. In addition to these enzyme preparations, milk-clotting enzymes from abomasums of lambs and kids, rennet paste (which also contains lipase and pregastric esterase) or extracts from the ﬂ owers of thistles from the genus Cynara (mainly Cynara cadunculus) are used to coagulate milk. General and molecular aspects of milk-clotting enzymes were reviewed by Harboe and Budtz (1999), Andrén (2003) and Crabbe (2004). Rennet coagulation of milk is a two-stage process, where the primary stage involves enzymatic hydrolysis of the micelle-stabilising κ-casein (for reviews, see Dalgleish, 1992, 1993; Fox et al., 1996; Fox & McSweeney, 1997), and the secondary stage involves the aggregation of micelles, in the presence of calcium ions, at a temperature >20°C (see Dalgleish, 1992, 1993; Horne & Banks, 2004; Hyslop, 2003; Lucey, 2003). There is an overlap between primary and secondary phases of rennet coagulation, the extent of which depends on temperature, pH and protein content.

1.4.2 Primary stage of rennet-induced coagulation of milk The primary stage of rennet coagulation involves the enzymatic hydrolysis of the

Phe105-Met106 bond in κ-casein, yielding the N-terminal fragment para-κ-casein (f1–105 – referred to as para-κ-casein), and the C-terminal fragment κ-casein (f106–169 – referred to as the caseino-macropeptide – CMP); CMP from glycosylated κ-casein is often referred to as glycol-macropeptide (GMP). Para-κ-casein remains attached to the casein micelles, whereas CMP is lost in whey. Most of the

principal milk-clotting enzymes hydrolyse the Phe105-Met106 bond of κ-casein, except the coagulant from Cryphonectria parasitica, which hydrolyses the Ser104-Phe105 bond. The Phe and Met residues in the 105–106 bond of κ-casein are not essential per se for enzymatic hydrolysis but the amino acid sequence around the Phe-Met

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bond, particularly the region His98–Lys112, makes the Phe105-Met106 bond a very spe- ciﬁ c substrate for the action of the milk-clotting enzymes. The rate of hydrolysis by chymosin of this bond is ~1000 times faster than that of any other bond in the

caseins (Waugh, 1958). The strongly hydrophobic region of κ-casein, Leu103–Ile108, probably associates with the hydrophobic region of chymosin within the cleft where the active site is located; additionally, negatively charged residues in chymosin may

interact with positively charged residues in the κ-casein sequences His98–His102 and Ile108–Lys112 (Plowman & Creamer, 1995). Enzymatic hydrolysis of κ-casein appears to follow ﬁ rst-order reaction kinetics and can be described by Michaelis–Menten kinetics (Hyslop, 2003):

–d[S]/dt = Vmax [S]/(Km + [S])

where [S] is the substrate concentration, Vmax is the maximum rate of hydrolysis at inﬁ nite substrate concentration, and Km is the dissociation rate constant for the enzyme–substrate complex. The temperature coefﬁ cient (Q10) for the primary phase is ~2°C, and this reaction occurs even at 0°C.

1.4.3 Secondary stage of rennet-induced coagulation of milk When ~85% of κ-casein is hydrolysed, the secondary stage of rennet-induced coagulation of milk commences. The enzymatic hydrolysis of κ-casein during the primary stage of rennet coagulation results in considerable alterations in the properties of the casein micelle. Perhaps the most signiﬁ cant in terms of rennet-induced coagulation is the reduction in the net negative charge on the casein micelles, by ~50% (Dalgleish, 1984), leading to reduced intermicellar electrostatic repulsion. Furthermore, the removal of the layer of κ-casein on the micellar surface reduces the hydrodynamic diameter of the micelle by ~5 nm, and reduces steric repulsion. Because of the reduced electrostatic and steric repulsive forces between the para- casein micelles, they can aggregate on collision, which can occur due to Brownian motion. The attractive forces responsible for aggregation of para-casein micelles may include van der Waals forces, hydrophobic interactions and calcium bridges (Lucey, 2003). Prolonged aggregation will eventually lead to the formation of a rennet-induced milk coagulum.

The value for Q10 for the secondary phase is ~11–16°C, and this reaction takes place only very slowly or not at all at a temperature <15°C (Lucey, 2003). This may be due to the fact that, at low temperatures, hydrophobic interactions are weak and/or to the fact that the micellar surface is not exclusively covered by κ-casein, and the presence of some β-casein on the surface of the casein micelle may be sufﬁ cient to stabilise the micelles. Cold-induced dissociation of β-casein may further enhance the stability of casein micelles against rennet-induced coagulation in the cold (see Section 1.3.4). The temperature dependence of the primary and secondary stages of rennet-induced coagulation of milk has been exploited to develop methods for continuous manufacture of cheese or rennet casein.

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1.4.4 Factors that influence rennet-induced coagulation of milk Rennet-induced coagulation of milk is infl uenced by a number of factors, such as pH, calcium concentration, protein content, enzyme concentration and processing treatments (e.g. cold storage, heat treatment, high-pressure treatment, ultrafi ltration) (Daviau et al., 2000; Gunasekaran & Ay, 1996). Due to the differences in the compositions and constituents of milk from different species, as discussed in Section 1.3, rennet-induced coagulation properties of these milks vary; furthermore, caution should be exercised because of the large variation in composition and properties of milk between breeds of any particular species, and confl icting results reported in the literature. Comparative studies of rennet coagulation properties of milks of different breeds within species were reported by Storry et al. (1983) and Bencini (2002).

Milk pH The pH of the milk strongly infl uences the rennet-induced coagulation of milk. A reduction in milk pH to a value in the range 6.6–6.0 results in a reduction in the rennet coagulation time (RCT) of bovine (Shalabi & Fox, 1982), ovine (Balcones et al., 1996; Delacroix-Buchet et al., 1994; Duranti & Casoli, 1991; Manfredini et al., 1992; Pellegrini et al., 1997), caprine (Castillo et al., 2000), and buffalo milk (Fakhr El-Dien, 1994). Furthermore, a reduction in milk pH also reduces the degree of κ-casein hydrolysis required for the onset of gelation. The rate of increase in the fi rmness of the coagulum of bovine milk is also enhanced by reducing the pH (Daviau et al., 2000), probably due to solubilisation of CCP (Dalgleish & Law, 1989), a reduction in electrostatic repulsion, dissociation of casein from micelles (Dalgleish & Law, 1988; Gastaldi et al., 1996; Van Hooijdonk et al., 1986a, 1986b), and increased rennet activity. At a pH <6.0, the strength of the coagulum is reduced, probably due to excessive solubilisation of CCP, which is essential in maintaining micellar integrity. Milk pH has little infl uence on the rate of development of coagulum fi rmness for ovine milk (Bencini, 2002).

Calcium concentration

The concentration of calcium (i.e. in the form of CaCl2) also has a signifi cant effect on RCT (Balcones et al., 1996; Lucey & Fox, 1993; Montilla et al., 1995). Calcium plays an indirect role in primary hydrolysis of κ-casein by reducing pH, which can enhance the activity of the enzyme. Furthermore, addition of calcium can reduce the degree of κ-casein hydrolysis required for the onset of coagulation and increase the rate of development of fi rmness of the coagulum through neutralisation of the net negative change and the formation of calcium bridges; however, the rate of gel fi rming is reduced when excessive concentrations of calcium (≥0.3 M) is used

(McMahon et al., 1984). The addition of CaCl2 also decreases pH of milk, resulting in increased protein aggregation (Gastaldi et al., 1994). Removal of >30% of CCP disrupts the structure of the casein micelle, thereby preventing coagulation of milk; however, if the concentration of ionic calcium is increased, the adverse effects can

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be reversed. Addition of CaCl2 reduces the RCT of bovine milk (Balcones et al., 1996; Montilla et al., 1995), but has little effect on the RCT of ovine milk (Bencini, 2002; Montilla et al., 1995) or caprine milk (Montilla et al., 1995). Furthermore, the rate of development of ﬁ rmness of the coagulum from ovine milk was not affected by the addition of up to 2 mmol L–1 calcium (Bencini, 2002).

Ultrafiltration (UF) Casein content of milk is negatively correlated with the RCT. The rate of aggregation increases and coagulation occurs at a lower percentage of hydrolysed κ-casein (Lucey, 2003). One process used for increasing the casein content of milk is membrane separation (e.g. ultraﬁ ltration). Ultraﬁ ltration (UF) is a process that selectively separates macromolecules from solvent and dissolved solutes; UF of milk produces a permeate containing water, lactose, soluble minerals, nonprotein nitrogen and water-soluble vitamins, and a retentate in which the proteins, fat and colloidal salts are concentrated to an extent in proportion to the amount of permeate removed (Mistry & Maubois, 2004). If the same amount of rennet is added per volume of bovine milk of UF retentate, the RCT is not affected by the higher protein content in the UF retentate, but the rate of coagulum formation is higher in the UF retentate (Garnot, 1988; Garnot et al., 1982; Lucisano et al., 1985). The required percentage of κ-casein hydrolysed for the second stage of rennet coagulation to commence is considerably lower in UF retentate than for unconcentrated milk (Dalgleish, 1980). The RCT of buffalo milk is reduced by ~40% as a result of an approximately four- fold concentration by UF (Patel & Mistry, 1997), whereas the RCT of ovine and caprine milk is actually increased by ~30% as a result of an approximately twofold concentration by UF (Espinoza & Calvo, 1998).

Cold storage Cold storage of milk on farms is a common practice to reduce the collection costs. However, such storage results in dissociation of caseins, in particular β-casein, from the micelle (see Section 1.3.4) and solubilisation of CCP (see Section 1.3.2), which can affect rennet-induced coagulation of milk. Storage of bovine milk at a low temperature increases RCT and reduces the rate of development of coagulum ﬁ rmness (Ali et al., 1980; Raynal & Remeuf, 2000; Walstra & Van Vliet, 1986;). Conﬂ icting results have been reported on the effect of cold storage on rennet coagulation properties of ovine and caprine milk; Raynal and Remeuf (2000) reported that such storage has little effect on rennet coagulation properties of caprine or ovine milk, whereas De la Fuente et al. (1997) observed increases in the RCT of caprine or ovine milk on cold storage. Less pronounced cold-induced solubilisation of calcium and caseins (see Sections 1.3.2 and 1.3.4, respectively) in ovine or caprine milk upon cold storage may explain the smaller effect of cold storage on renneting properties of such milks compared to bovine milk.

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Heat treatment of milk Heat treatment of bovine milk at a temperature >70°C increases its RCT, compared with unheated milk, with both the primary and secondary phase being hindered (Dalgleish, 1990; Vasbinder et al., 2003). Heat-induced impairment of rennet coagulation of bovine milk is probably due to the association of denatured β-lg with the casein micelle; both the primary and secondary stages of rennet coagulation are affected, although it is thought that the effect on the secondary stage is far larger than that on the primary stage (Van Hooijdonk et al., 1987; Vasbinder et al., 2003). The negative effects of heat treatment on RCT can be reversed, if the heat treatment is not too severe, either by the addition of calcium or by reducing pH. In contrast to bovine milk, heat treatment of caprine milk at up to 90°C has little effect on its RCT (Calvo, 2002; Montilla et al., 1995; Raynal & Remeuf, 1998), whereas in milk of certain goat breeds, heat treatment may even lead to reduction in RCT (Alloggio et al., 2000). Some authors have reported little effect of heat treatment on the RCT of ovine milk (Balcones et al., 1996) whereas others reported increases in RCT after heating under certain conditions (Raynal & Remeuf, 1998), although considerably smaller than those in bovine milk. The effects of heat treatment on the primary phase of rennet coagulation also differ signiﬁ cantly between species; heat treatment reduced the rate of CMP release in bovine milk, but had no effect on the rate of CMP release in caprine or ovine milk (Calvo & Leaver, 2000).

High-pressure treatment of milk High-pressure treatment also has considerable effects on the rennet coagulation properties of milk. Treatment at 100–300 MPa reduces the RCT of bovine milk, whereas treatment at a pressure ≥400 MPa increases RCT (Lopez-Fandino et al., 1996; Needs et al., 2000; Zobrist et al., 2005). Treatment of ovine milk at 100 or 400 MPa has little effect on RCT, whereas treatment at 200 or 300 MPa increases it signiﬁ cantly; in contrast, the RCT of caprine milk was not affected by treatment at 100 or 200 MPa, but was increased signiﬁ cantly after treatment at 300 or 400 MPa (Lopez-Fandino & Olano, 1998). The RCT of buffalo milk increased with increasing pressure (100–800 MPa; Huppertz et al., 2005).

1.5 Conclusions

As shown throughout this chapter, there are considerable differences in composition and properties of milk from the four main milk-producing species, that is, bovine, ovine, caprine or buffalo milk. Many of the speciﬁ c characteristic properties of the various milks are responsible for the uniqueness of some of their derived products, such as brine-salted cheese, which will be discussed further throughout this book. However, considerable differences exist in the level of detail of characterisation of these milks. Whereas the constituents and properties of bovine milk are very well characterised at this stage, considerably less knowledge is currently available on

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caprine, and particularly ovine or buffalo milk. Further characterisation of these milks may be of potential beneﬁ t for optimal use of these milks for further processing.

References

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Ng-Kwai-Hang, K.F. (2003) Milk proteins: heterogeneity, fractionation and isolation. In: Encyclopedia of Dairy Sciences (eds H. Roginski, J.W. Fuquay & P.F. Fox), pp. 1881–1894. Academic Press, Amsterdam. Nielsen, S.S. (2003) Plasmin system in milk. In: Encyclopedia of Dairy Sciences (eds H. Roginski, J.W. Fuquay & P.F. Fox), pp. 929–934. Academic Press, Amsterdam. O’Brien, J. (1996) Heat-induced changes in lactose: isomerization, degradation, Maillard browning. In: Heat-induced Changes in Milk (ed. P.F. Fox), Special Issue 9602, pp. 134–170. International Dairy Federation, Brussels. O’Brien, J. (1997) Reaction chemistry of lactose: non enzymatic degradation pathways and their signifi cance in dairy products. In: Advanced Dairy Chemistry: Lactose, Water, Salts and Vitamins, 2nd edn (ed. P.F. Fox), vol. 3, pp. 155–231. Chapman & Hall, London. O’Brien, N.M. & O’Connor, T.P. (2003) Lipid oxidation. In: Encyclopedia of Dairy Sciences (eds H. Roginski, J.W. Fuquay & P.F. Fox), pp. 1600–1604. Academic Press, Amsterdam. O’Connell, J.E. & Fox, P.F. (2003) Heat-induced coagulation of milk. In: Advanced Dairy Chemistry: Proteins, 3rd edn (eds P.F. Fox & P.L.H. McSweeney), vol. 1, pp. 879–945. Kluwer Academic/Plenum Publishers, New York. O’Connell, J.E., Kelly, A.L., Auty, M.A.E., Fox, P.F., & De Kruif, K.G. (2001a) Ethanol-dependent heat-induced dissociation of casein micelles. Journal of Agricultural and Food Chemistry, 49, 4420–4423. O’Connell, J.E., Kelly, A.L., Fox, P.F., & De Kruif, K.G. (2001b) Mechanism for ethanol-dependent heat-induced dissociation of casein micelles. Journal of Agricultural and Food Chemistry, 49, 4424–4428. O’Connor, P. & Fox, P.F. (1973) Temperature-induced dissociation of casein micelles from the milk of various species. Netherlands Milk and Dairy Journal, 27, 199–217. O’Connor, P. & Fox, P.F. (1977) The proteins and salts of some non-bovine milk. Journal of Dairy Research, 44, 607–609. Olivecrona, T., Vilaro, S. & Olivecrona, G. (2003) Lipases in milk. In: Advanced Dairy Chemistry: Proteins, 3rd edn (eds P.F. Fox & P.L.H. McSweeney), vol. 1, pp. 473–494. Kluwer Academic/ Plenum Publishers, New York. Pahud, J.J. & Mach, J.P. (1970) Identifi cation of secretory IgA, free secretory piece and serum IgA in the ovine and caprine species. Immunochemistry, 7, 679–686. Patel, R.S. & Mistry, V.V. (1997) Physicochemical and structural properties of ultrafi ltered buffalo milk and milk powder. Journal of Dairy Science, 80, 812–817. Pellegrini, O., Remeuf, F., Rivemale, M. & Barillet, F. (1997) Renneting properties of milk from individual ewes: infl uence of genetic and non-genetic variables, and relationship with physicochemical characteristics. Journal of Dairy Research, 64, 355–366. Plowman, J.E. & Creamer, L.K. (1995) Restrained molecular dynamics study of the interaction between bovine κ-casein peptide 98–111 and bovine chymosin and porcine pepsin. Journal of Dairy, 62, 451–467. Pruitt, K. (2003) Lactoperoxidase. In: Advanced Dairy Chemistry: Proteins, 3rd edn (eds P.F. Fox & P.L.H. McSweeney), vol. 1, pp. 563–570. Kluwer Academic/Plenum Publishers, New York. Raynal, K. & Remeuf, F. (1998) The effect of heating on physicochemical and renneting properties of milk: a comparison between caprine, ovine and bovine milk. International Dairy Journal, 8, 695–706. Raynal, K. & Remeuf, F. (2000) Effect of storage at 4 °C on the physicochemical and renneting properties of milk: a comparison between caprine, ovine and bovine milks. Journal of Dairy Research, 67, 199–207. Renner, E. (1983) Milk and Dairy Products in Human Nutrition, Volkswirtschaftlicher Verlag, Munich. Richardson, B.C., Creamer, L.K., Pearce, K.N. & Munford, R.E. (1974) Comparative micelle structure. II. Structure and composition of casein micelles in ovine and caprine milk as compared to those in bovine milk. Journal of Dairy Research, 41, 239–247.

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Rollema, H.S. (1992) Casein association and micelle formation. In: Advanced Dairy Chemistry: Proteins, 2nd edn (ed. P.F. Fox), vol. 1, pp. 111–140. Elsevier Applied Sciences, London. Sahai, D. (1996) Buffalo Milk, Chemistry and Processing Technology. SI Publications, Karnal. Sawyer, L. (2003) β-Lactoglobulin. In: Advanced Dairy Chemistry: Proteins, 3rd edn (eds P.F. Fox & P.L.H. McSweeney), vol. 1, pp. 319–386. Kluwer Academic/Plenum Publishers, New York. Shakeel-ur-Rehman & Farkye, N.C. (2003a) Lipases and esterases. In: Encyclopedia of Dairy Sciences (eds H. Roginski, J.W. Fuquay & P.F. Fox), pp. 926–929. Academic Press, Amsterdam. Shakeel-ur-Rehman & Farkye, N.Y. (2003b) Phosphatases. In: Encyclopedia of Dairy Sciences (eds H. Roginski, J.W. Fuquay & P.F. Fox), pp. 934–938. Academic Press, Amsterdam. Shakeel-ur-Rehman & Farkye, N.Y. (2003c) Lactoperoxidase. In: Encyclopedia of Dairy Sciences (eds H. Roginski, J.W. Fuquay & P.F. Fox), pp. 938–941. Academic Press, Amsterdam. Shakeel-Ur-Rehman, Flemming, C.M., Farkye, N.Y. & Fox, P.F. (2003) Indigenous phosphatases in milk. In: Advanced Dairy Chemistry: Proteins, 3rd edn (eds P.F. Fox & P.L.H. McSweeney), vol. 1, pp. 523–543. Kluwer Academic/Plenum Publishers, New York. Shalabi, S.I. & Fox, P.F. (1982) Inﬂ uence of pH on rennet coagulation of milk. Journal of Dairy Research, 49, 153–157. Sharma, R.S. & Ganguli, N.C. (1971) Distribution pattern of certain enzymes in buffalo milk. Enzymologia, 40, 337–344. Siambela, A.C. & Wilbey, R.A. (1996) Evaluation of γ-glutamyltranspeptidase activity in ovine and caprine milk. In: Production and Utilization of Ewe and Goat milk, Special Issue 9603, p. 267. International Dairy Federation, Brussels. Sood, S.M., Sidhu, K.S. & Dewan, R.K. (1976) Voluminosity of different-sized casein micelles from the buffalo and the cow. New Zealand Journal of Dairy Science and Technology, 11, 79–82. Sood, S.M, Sidhu, K.S. & Dewan, R.K. (1979) Heat stability and the voluminosity and hydration of casein micelles from milks of different species. New Zealand Journal of Dairy Science and Technology, 14, 217–225. Sørensen, E.S., Rasmussen, L.K., Møller, L. & Petersen, T.E. (1997) The localization and multimeric nature of component PP3 in bovine milk: puriﬁ cation and characterization of PP3 from caprine and ovine milk. Journal of Dairy Science, 80, 3176–3181. Storry, J.E., Grandison, A.S., Millard, D., Owen, J.A. & Ford, G.D. (1983) Chemical composition and coagulating properties of renneted milks from different breeds and species of ruminants. Journal of Dairy Research, 50, 215–229. Swaisgood, H.E. (2003) Chemistry of caseins. In: Advanced Dairy Chemistry: Proteins, 3rd edn (eds P.F. Fox & P.L.H. McSweeney), vol. 1, pp. 139–202. Kluwer Academic/Plenum Publishers, New York. Tamime, A.Y. (1993) Modern cheesemaking – hard cheeses. In: Modern Dairy Technology, 2nd edn (ed. R.K. Robinson), vol. 2, pp. 49–220. Elsevier Science Publishers, London. Tamime, A.Y. (ed.) (2006) Fermented Milks. Blackwell Publishing, Oxford. Tamime, A.Y. & Robinson, R.K. (1999) Yoghurt: Science and Technology. Woodhead Publishing, Cambridge. Tamime, A.Y., Dalgleish, D.G. & Banks, W. (1991) Introduction. In: Feta and Related Cheeses (eds R.K. Robinson & A.Y. Tamime), pp. 11–48. Ellis Horwood Limited, Chichester. Thiebaud, M., Dumay, E., Picart, L., Guiraud, J.P. & Cheftel, J.C. (2003) High-pressure homogenization of raw bovine milk. Effects on fat globule size distribution and microbial inactivation. International Dairy Journal, 13, 427–439. Van Boekel, M.A.J.S. (1998) Effect of heating on Maillard reactions in milk. Food Chemistry, 62, 403–414. Van Hooijdonk, A.C.M., Boertiger, I.J. and Hagedoorn, A.G. (1986a) pH-induced physico-chemical changes of casein micelles in milk and their effect on renneting. 2. Effect of pH on renneting of milk. Netherlands Milk Dairy Journal, 40, 297–313.

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Van Hooijdonk, A.C.M., Hagedoorn, A.G. and Boertiger, I.J. (1986b) pH-induced physico-chemical changes of casein micelles in milk and their effect on renneting. 1. Effect of acidiﬁ cation on physicochemical properties. Netherlands Milk Dairy Journal, 40, 281–296. Van Hooijkdonk, A.C.M., De Koster, P.G. & Boertiger, I.J. (1987) The renneting properties of heated milk. Netherlands Milk and Dairy Journal, 41, 3–18. Van Kreveld, A. & Michaels, A.S. (1965) Measurement of crystal growth of α-lactose. Journal of Dairy Science, 48, 259–268. Vasbinder, A.J., Rollema, H.S. & De Kruif, C.G. (2003) Impaired rennetability of heated milk; study of enzymatic hydrolysis and gelation kinetics. Journal of Dairy Science, 86, 1548–1555. Walstra, P. (1975) Effect of homogenization on the fat globule size distribution in milk. Netherlands Milk and Dairy Journal, 29, 297–294. Walstra, P. (1990) On the stability of casein micelles. Journal of Dairy Science, 73, 1965–1979. Walstra, P. (1995) Physical chemistry of milk fat globules, In: Advanced Dairy Chemistry: Lipids, 2nd edn (ed. P.F. Fox), vol. 2, pp. 131–178. Chapman & Hall, London. Walstra, P. & Jenness, R. (1984) Dairy Chemistry and Physics. John Wiley and Son, New York. Walstra, P. & Van Vliet, T. (1986) The physical chemistry of curd making. Netherlands Milk and Dairy Journal, 40, 241–259. Walstra, P., Geurts, T.J., Noomen, A., Jellema, A. & Van Boekel, M.A.J.S. (1999) Dairy Technology: Principles of Milk Properties and Processes. Marcel Dekker, New York.

Waugh, D.F. (1958) The interactions of αs-, β and κ-caseins in micelle formation. Discussions of the Faraday Society, 25, 186–196. Zhang, Y. & Brew, K. (2003) Alpha-lactalbumin. In: Encyclopedia of Dairy Sciences (eds H. Roginski, J.W. Fuquay & P.F. Fox), pp. 1924–1932. Academic Press, Amsterdam. Zobrist M.R., Huppertz T., Uniacke T., Fox P.F. & Kelly A.L. (2005) High pressure-induced changes in rennet coagulation properties of bovine milk. International Dairy Journal, 15, 655–662.

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E.M. Anifantakis and G. Moatsou

2.1 Background

Brined cheeses are traditionally produced under different names in the Balkan countries, and it is likely that they have a common origin. The differences in their technology are related to local climatic conditions and the dietary habits of each region. These types of cheeses include the rindless varieties with slightly acid and salty taste, which are matured and kept in brine at low temperatures for a considerable time. Their characteristics result from an intense lactic acid fermentation that takes place during the ﬁ rst days after the manufacture and, in addition, these distinctive characteristics have been established during centuries of production by household practices or in small artisan-type factories. Traditionally, brined cheeses are manufactured from whole sheep’s milk but, at present, some cheeses are produced from goat’s or cow’s milk or from mixtures with sheep’s milk. Among the brined cheeses, Feta is the predominant variety in terms of production, qualities, worldwide acceptance and, therefore, of economic signiﬁ cance. This chapter reviews the developments in the traditional method(s) for the manufacture of Feta and other brined cheeses.

2.2 Feta cheese 2.2.1 Introduction Feta is a white cheese of high quality, manufactured from sheep’s milk or from a mixture of sheep’s and goat’s milk according to a specifi c technology, which is matured and stored in brine. It has a salty, slightly acid taste, and pleasant sensory properties that nowadays have a worldwide acceptance. The word ‘feta’ has a special meaning in the Greek language, and it is synonymous with the word ‘slice’ in English, ‘tranche’ in French, ‘pezza’ in Italian, and ‘schnitt’ in German. It has been a signifi cant dairy product in the diet of the Greeks since the time of Homer. The cheese that was made by the Cyclops Polyphemus was undoubtedly the ancestor of modern Feta, and there are many references proving the Greek origin of this cheese (Anifantakis, 1990, 1998; Anonymous, 1953; Courtine, 1972; Eekhof-Stork, 1976). It is estimated that the average annual Feta cheese consumption per capita in Greece is the highest in the world, standing currently at more than 12 kg; the annual production fi gure for Feta cheese is 140 000 tonnes (Department of Agricultural Statistics, personal communication).

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For many centuries, Feta cheese was known only in the Balkan region. However, during the 20th century, large Greek communities were established in various countries, mainly in Australia, USA, Canada and Germany, due to mass migration of Greeks, who retained their dietary habits. Moreover, during the last 30 years, new markets for Feta have evolved in the Middle East. Since the available quantities of traditional Feta cheese were not suffi cient to meet the demand in different parts of the world, attempts have been made to substitute sheep’s milk with cow’s milk for the manufacture of Feta-type cheese. In order to ‘mimic’ the sensory properties of traditional Feta cheese, chlorophyll, as well as lipase, were added to the cow’s milk before renneting, and the manufacturing procedure was modifi ed. However, despite their good quality, cow’s milk brined cheeses never acquired the qualities of traditional Feta. Some European countries have exported to Middle East markets large quantities of brined cheeses made with the addition of milk powder, caseinates, caseins, whey proteins, or made from ultrafi ltrated (UF) cow’s milk under the name Feta. Greece, in order to protect consumers and the quality of its traditional cheeses, has published individual standards of identity for many of them including Feta cheese (Anonymous, 2003), and the name Feta is registered as a Product of Designation of Origin (PDO) by the European Commission Regulation (EU, 2002); the standards are as follows: • Feta cheese is a soft cheese without rind with a pure white colour and slightly acid taste. It can be cut into slices and the characteristic of its texture is the presence of a few mechanical openings. • It is made of sheep’s milk or from its mixtures with goat’s milk, of which the latter must not exceed 30% of the total cheese milk. • The cheese milk must be produced exclusively in the geographic areas of Macedonia, Thraki, Ipiros, Thessalia, Sterea Ellada, Peloponnissos and Lesvos island. • The use of condensed milk and the addition of milk powder, milk proteins concentrate or caseinates in the cheese milk as well as the use of colourings and preservatives is forbidden. • The maximum moisture must be 56 g 100 g–1 and the minimum fat-in-dry matter (FDM) 43 g 100 g–1. • The maturation period must be at least 60 days.

2.2.2 Production methods Traditionally, Feta cheese was manufactured by the shepherds themselves in primitive installations using very basic equipment. Nowadays, most Feta cheese is manufactured in well-organised and equipped dairy plants. However, sheep’s and goat’s milk production is seasonal, and the lactation period of the animals lasts only 4–6 months. Most of the milk is produced from December to June because births take place mainly in the autumn (Fig. 2.1) and, consequently, most of the dairy companies in Greece manufacture cheese seasonally.

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10 Production 5

as expressed of the total (%) 0

l y t r r r r y ry ch ri ly s Ma Ju gu be uar rua Ap June mbe mbe Mar Au te cto embe Jan O v Feb Sep No Dece Month

Fig. 2.1 Monthly distribution of annual sheep’s (grey bars) and goat’s (black bars) milk production in Greece (percentage of total milk production).

In most cases, Feta is produced following the main principles of the traditional recipe, that is, draining by gravity, surface dry salting, temporary packaging and pre-maturing at 14–18°C or until pH drops to 4.4–4.6, and moisture is lower than 56 g 100 g–1; ﬁ nally, the cheese is transferred to refrigerated stores and matured for at least 60 days (Fig. 2.2). The pre-maturing period is an essential step for the formation of the ﬁ nal physicochemical and sensory properties of the cheese. In Greece, there are four types of Feta cheese production depending mainly on the size of the enterprise: • household production; • cheese plants with low production and basic equipment that are, for the most part, family businesses; • cheese plants with medium to high production and up-to-date equipment; and • cheese plants with very high production, where almost all the stages of cheesemaking are carried out mechanically.

2.2.3 Manufacturing stages Milk for cheese production Feta cheese is made from sheep’s milk alone or from its mixtures with goat’s milk, in which the proportion of the latter is not higher than 30%. About 6.8 million sheep and 3.7 million goats are milked, and the annual production of all types of cheeses in Greece is 700 000 and 458 000 tonnes, respectively, for the two types of milk (Department of Agricultural Statistics, personal communication). About 80% of the sheep’s milk and ~60% of the goat’s milk is used for cheesemaking, mainly for Feta cheese production. The breeding of sheep and goats is an ancient practice in Greece. Both species have been very important for the economy of the country, contributing substantially to its livestock revenues, and providing good means of

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Filtration and standardisation Pasteurisation at 65°C for 30 min Cooling to of the cheese milk or thermisation 63-66°C for 3-20 34-36°C

Renneting at 34-36°C in cheese vats Rest for Addition of CaCl2 and (300-500 L capacity) 15-30 min yoghurt as a starter

Cut into cubes Rest Gradual transfer of 2 cm for 10 min into the moulds

The following morning, remove the Draining at 16-18°C cheese from the moulds and cut into portions for 20 h

Dry salting Next morning, temporary packaging in barrels or plastic containers, and add dry salt between the layers of cheese

WashWash the the cheese cheese portion portion and and repackage in barrels Rest at 16-18°C repackage in barrels for 1-2 d oror plastic plastic containers containers

Rest at 16-18°C Transfer to cold stores for 2 weeks Final and mature for at least packaging until pH ~4.6 60 d post-manufacture

Fig. 2.2 Flow chart for the production of Feta cheese using simple equipment in cheesemaking plants.

exploiting the mountainous and semimountainous pastures that cover the greater part of the country. Sheep’s and goat’s milk in Greece are mainly produced from indigenous breeds consisting of animals that are small in size, well adapted to the different land and climatic conditions of the country, and fed mainly on pasture. From this point of view, the sheep’s and goat’s milk in Greece meets the major prerequisites of biological agriculture. Supplementary feed is given to the animals only during the last part of pregnancy or late lactation period, as well as during suckling. The average

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Table 2.1 Mean chemical composition (mL 100 mL–1) of milk of sheep and goat breeds in Greece

Breeds Fat Protein Casein Lactose Ash Dry matter Sheep Vlahiko 9.05 6.52 4.98 4.69 0.94 20.61 Karagouniko 8.70 6.60 5.02 4.58 0.93 20.31 Chiou 7.85 5.47 4.41 4.80 0.92 19.08 Attica 7.59 5.94 4.63 5.04 0.89 18.98 Boutsiko 7.86 6.04 4.59 4.80 0.93 19.30 Goats Indigenous (Attika area) 5.63 3.77 3.06 4.76 0.80 14.79 Indigenous (Southern Greece) 5.21 3.76 2.93 3.73 0.72 13.80 Ipiros (Metsovo) 5.18 3.56 2.80 4.74 0.76 14.12 After Anifantakis and Kandarakis (1980), Anifantakis et al. (1980), Baltadjeva et al. (1982), Morgan et al. (2003), Simos et al. (1991), and Voutsinas et al. (1988).

annual milk production per animal is very low; about 95 kg for sheep and 125 kg for goats, but their milk is very rich in protein and fat (Table 2.1). It is well known that sheep’s and goat’s milk differ from cow’s milk in both quantitative and qualitative aspects (Alichanidis & Polychroniadou, 1996). They have higher protein, fat and dry matter contents, which affect the yield and properties of the cheese. Both sheep’s and goat’s milk lack carotenes and, therefore, the cheese made is naturally white. Milk fat is a source of components that contribute a lot to the ﬂ avour and aroma of mature cheese. Sheep’s milk and, in particular

goat’s milk, have signiﬁ cant amounts of caproic (C6:0), caprylic (C8:0) and capric acids (C10:0) (Kondyli & Katsiari, 2000a; 2000b), resulting in the typical piquant, peppery ﬂ avour of Feta.

Treatment of the cheese milk Sheep’s milk for Feta cheese manufacture is delivered to the dairies once a day in the winter and early spring, and twice a day thereafter until the end of the lactating season. For the production of good-quality Feta cheese, the acidity of the milk has to be lower than 0.23 g 100 mL–1 lactic acid and the pH greater than 6.5. The fat content of the milk usually varies from 6.5 to 8 g 100 g–1 depending on the season; during the winter it is higher than in the spring. It is recommended that the fat content of cheese milk be adjusted to about 6.0 g 100 g–1 (Anonymous, 2003). The most suitable casein-to-fat ratio is 0.72 (Pappas et al., 1994). The quantity of added goat’s milk can infl uence the yield of cheese; for example, the yield of Feta made from sheep’s milk alone or from a mixture of 75% sheep’s milk and 25% goat’s milk is 25.6% and 22.6%, respectively (Mallatou et al., 1994). At present, the use of raw milk for Feta cheese production is very rare indeed. This practice is sometimes carried out during the household production of Feta, and the product is considered to have a strong fl avour and matures very quickly. First, the milk is fi ltered and standardised, followed by pasteurisation in plate heat-exchangers (PHE) at 72°C for 15 s or in an open vat (i.e. batch pasteurisation at 63–65°C for 30 min). Alternatively, the milk may be heated in an open vat

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at 63–65°C for 3–20 min, and this heating process is known as thermisation. The latter method of heating the cheese milk is more commonly practised in small and medium-sized enterprises. Afterwards, the milk is cooled to 32–36°C, fortifi ed with calcium chloride (up to 0.2 g kg–1 of milk) before the addition of rennet in order to ensure a better coagulation and quality of the curd, and is inoculated with lactic acid bacteria (i.e. starter culture). At present, the majority of Feta cheese plants use various combinations of lactic starter cultures, which are added to the cheese milk 15–30 min before renneting. For example, small cheese plants usually use a yoghurt starter culture (Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus, ratio of 1:1, and at a rate of ~0.3 mL 100 mL–1) because it is easier to prepare and preserve. However, in large industrial Feta plants, a blend of mesophilic starter cultures (e.g. Lactococcus lactis subsp. lactis and Lactococcus lactis subsp. cremoris) or a mixture of mesophilic and thermophilic starter cultures (Lac. lactis subsp. lactis and Lb. delbrueckii subsp. bulgaricus) is widely used at a rate of 0.5 mL 100 mL–1. The blend of starter organisms along with the amount added, the time of addition before renneting, and the temperature of cheese milk will affect the acidifi cation rate in the curd. In fact, mesophilic lactic acid bacteria (LAB) or a mixture of mesophilic and thermophilic strains are more suitable than using only thermophilic LAB or yoghurt culture for the high acidifi cation rate that is essential for the production of high-quality Feta (Kandarakis et al., 2001; Litopoulou-Tzanetaki et al., 1993; Pappa & Anifantakis, 2001a, 2001b; Pappas et al.,1996a). For the successful manufacture of Feta cheese, the pH value has to be <5.4 8 hours after renneting and <5.0 after 20 hours (Pappas & Zerfi ridis, 1989).

Renneting Under normal Feta cheesemaking practice, the rennet is added 15–30 min after inoculating the milk with the starter cultures. The amount of rennet added should be suffi cient to clot the milk and provide good curd fi rmness ready for cutting after 50 min. If cheese milk has high acidity or the weather is too hot, coagulation takes place at lower temperature, for example 32°C. Traditionally, the coagulation of the milk was achieved using liquid rennet preparations produced by cheesemakers themselves from the abomasa of lambs and kids slaughtered before weaning (Anifantakis, 1991; Anifantakis & Green, 1980; Moschopoulou, 2003). This is a very convenient practice for the small family enterprises, scattered in inaccessible mountainous or semimountainous areas. The most common practice for the production of this traditional artisanal rennet is to use whole abomasa, that is, including both animal tissues and clotted milk taken from animals fed exclusively with milk. After drying the raw abomasa are cut into small pieces, put into brine (10 g 100 g–1) in a ratio of 1:7 (abomasa/brine), kept at room temperature for about 24–36 h, and periodically stirred. The extract, which remains after the removal of the abomasa, is centrifuged or fi ltered through a cloth with small pores. The liquid obtained is the traditional rennet preparation.

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Fig. 2.3 Filling of moulds with Feta curd.

The development of the very pleasant aroma and peppery taste of traditional Feta made with artisanal rennet can be attributed to the lipase activity and/or the presence of pregastric esterases (PGEs) (Collins et al., 2003; Georgala et al., 2005). In large cheesemaking plants, the traditional artisanal rennet has been partially or fully substituted by commercial calf rennet. A mixture of the two types of coagulants in a ratio 1:3 (traditional/commercial) is used in many cases.

Cutting and moulding Around 50 min after the addition of the rennet, the curd is cut into cubes (2–3 cm), and left for about 10 min in order to expel part of its whey; thus, it obtains greater cohesion and resistance to damage. The curd is then carefully transferred into rectangular moulds (Fig. 2.3). The moulds should not be ﬁ lled all at once, because draining of the whey will be delayed, and the cheese retains more whey and has a tendency to blow. Gradual transfer of the curd into the moulds results in the formation of small, almond-shaped open structures in the cheese mass that is a characteristic feature of Feta cheese. The moulds used are of stainless steel or plastic, open at the upper side and with narrow oblong holes (0.2 × 2 cm) or small round holes (0.2 cm diameter) on the bottom and top. The size and the shape of the holes permit the fast draining of the whey without losses of curd ‘ﬁ nes’. In the bottom of the moulds, there are three small projections to form a void space between the bottom of the mould and the cheese table to facilitate easy drainage of the whey. For traditional Feta cheese ripened in

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Fig. 2.4 Traditional method of draining the Feta curd intended to mature in wooden barrels.

wooden barrels the moulds are circular, 20–30 cm high, and with a diameter that varies according to the size of the barrel used (Fig. 2.4). The moulds are ﬁ lled with curd, placed on an inclined table, and are turned over from time to time to facilitate whey drainage. After 2–3 h of handling, the moulds are turned upside-down with the aid of their lids and left at a temperature of 14–18°C for 2–3 h to complete the whey draining period. The temperature of draining at this stage is of great importance for both effective draining and pH development depending, of course, on the type of starter cultures used (Kandarakis et al., 2001). When the weather is cold and the cheesemaking room temperature is not controlled, the whey drainage time is delayed.

Salting When the cheese curd is cohesive enough, the moulds are removed. The curd blocks are cut into retail portions ~12 × 10 × 10 cm, which are carefully placed side by side on a cheese table and dry salted. Coarse, granular salt about the size of a rice grain is normally used, which will dissolve slowly. Fine grains of salt dissolve very fast and, as a consequence, the surface of the cheese becomes hard and oversalted, and draining of the whey is delayed. The following morning, the cheese portions are turned over and salted. This process is repeated every 12 h and, in total, the process is repeated four times so that every surface of the cheese portion is salted twice. The ﬁ nal concentration of salt in the cheese mass should be ~3 g 100 g–1. If there is a high risk of cheese blowing when using unpasteurised milk with high acidity or during hot weather, salting is

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carried out during transportation of the curd to the moulds or at the ﬁ rst stages of draining the whey. After salting, the cheese portions are left on the cheese table, and they are turned over every 24 h until a slimy layer appears on the surface; this is due to the growth of bacteria and yeasts. These microorganisms are considered to contribute substantially to the maturation of the cheese and, hence, to the development of the special sensory properties of the product. Currently, the capacity of most cheesemaking plants is high, and large numbers of cheese tables and rooms are required; therefore, the cheese portions are temporarily placed and salted in open wooden barrels or plastic containers (Fig. 2.5). Afterwards, they are transferred every two days from one barrel to another to facilitate the draining of the whey and salting the cheese portions, and on every occasion the position of the cheese portions in the barrel is changed.

Packaging and maturation of the cheese After 4–5 days handling the cheese portions on the draining tables or in the barrels and, providing that pH is ≤4.6 and moisture ≤56 g 100 g–1, each cheese portion is cleaned carefully using water or brine and a soft brush. Then, they are carefully placed and packed tightly in layers in wooden barrels of about 50 kg capacity so that no empty spaces are left between them. Parchment paper is usually placed between the layers of the cheese. After packing each wooden barrel there should remain an empty space of only about 2 cm in height, which will allow for the cheese volume to increase during the maturation period. Brine (7 g NaCl 100 mL–1) is added thereafter, the barrels are closed (ﬁ nal packaging), and transferred to rooms of high relative

Fig. 2.5 Temporary packaging of Feta cheese.

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humidity to complete the maturation at 16–18°C. The wooden lid of each barrel has a hole, which is closed tightly with a cork; from time to time during the maturation period, the hole is opened very quickly to allow the escape of the gases evolved due to microbial activity. It is closed immediately thereafter to prevent the entry of air, which can stimulate fungal growth on any cheese surface that is not covered with brine. Once a week, the barrels are rolled on the ﬂ oor and, from time to time, they are topped-up with brine. Then, the wooden barrels are transferred to the cold store at 3–4°C for at least two months from the date of manufacture (Anonymous, 2003). If the pH is lower than 4.4–4.6, the cheese acquires an acidic taste, loses moisture, and crumbles upon cutting, whilst at higher pH values, the shelf-life of the cheese will be short. Traditionally, Feta cheese was matured and kept in wooden barrels until it was delivered to the consumer (Fig. 2.6). As the cost of the barrels is rather high and their handling is very difﬁ cult, they have, to a large extent, been substituted by tins of smaller capacity. In such cases, the technology of the cheese remains the same, but rectangular moulds are used as described above.

Fig. 2.6 Wooden barrels for packaging and maturation of Feta cheese.

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2.2.4 New trends in Feta cheese manufacture As mentioned elsewhere, the technology for the manufacture of Feta cheese is based on the traditional method of production, and is practised in all small cheese factories around Greece. However, in big cheesemaking plants, automated equipment is used to reduce the production costs and to improve the quality of the product. The preparation of the milk, as well as the clotting and cutting of the curd, are carried out as described above. The curd is transferred to the moulds by gravity through a special outlet in the cheese vat. Pumps are not used to transfer the curd/ whey mixture for de-wheying and mould fi lling in order to avoid damaging the curd and minimise losses of curd ‘fi nes’ in the whey. The cheese moulds are placed on a conveyor belt, which moves automatically and delivers them to the curd fi lling station (Fig. 2.7). After 2 h of draining, the moulds are automatically turned upside down (Fig. 2.8) and, after completing the drainage, the curd is cut into portions and dry salted. The following morning, the salted curd blocks are placed in containers. Granular salt is added to the bottom of each container, and between the layers of the cheese portions to complete the salting (i.e. temporary packaging). Final packaging of the cheese in brine (7 g NaCl 100 mL–1) is carried out after 2–3 days.

2.2.5 Properties of Feta cheese The characteristics of Feta cheese are formed during the maturation period, which is divided in two distinct phases:

Fig. 2.7 Mechanised ﬁ lling line of Feta cheese moulds.

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Fig. 2.8 Mechanised system for turning the Feta cheese moulds during the draining of the curd.

1 the pre-maturing period, which corresponds to a duration of 2 weeks at 16–18°C, and 2 the maturation period, which is initiated from the time the cheese is transferred to the cold store.

It is evident that a great part of the maturation changes of the cheese occurs during the short pre-maturing period. Feta can be kept at 4°C for at least 240 days without any signiﬁ cant change in its quality and/or characteristics (Pappas et al., 1996a, 1996b). The mean gross chemical composition (g 100 g–1) of Feta cheese samples obtained from different market outlets in Greece was found to contain moisture 52.90, fat- in-dry matter 55.56, protein 16.71, salt-in-moisture (SM) 5.27, and lactose 0.17 (Anifantakis, 1998). The mean gross compositional quality and pH values of mature Feta cheeses that have been reported by various researchers are shown in Table 2.2. The calcium content of 60-day-old Feta cheese has been reported as 519 mg 100 g–1 (Katsiari et al., 1997) or 620 mg 100 g–1 (Anifantakis, 1998). Rheological measurements of matured Feta cheese (i.e. 60 days old) can be summarised as follows: (a) hardness (kg) (i.e. the maximum force necessary to cause a certain deformation) varied from 1.4 to 12.8, and (b) fracturability (kg) (i.e. the force needed to fracture the cheese sample) ranged between 0.5 and 5.5, and the compression at fracturability point (%) ranged between 12.9 and 22.5 (Kehagias et al., 1995; Kandarakis et al., 2001; Katsiari & Voutsinas, 1994; Katsiari et al., 1997, 2002; Mallatou et al., 1994; Moatsou et al., 2004; Pappas et al., 1994, 1996a,

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Table 2.2 Mean gross composition (g 100 g–1) and pH values of laboratory-made mature traditional Feta cheeses reported by many researchers

Feta (60–75 days old) Feta (120 days old) Composition Range Mean ± SD Range Mean ± SD Moisture 51.27–57.45 (n = 16) 55.07 ± 1.81 51.60–58.10 (n = 15) 54.99 ± 2.03 Fat-in-dry matter 44.07–55.35 (n = 12) 50.71 ± 3.00 49.38–58.05 (n = 11) 51.32 ± 3.31 (FDM) Protein 16.18–18.48 (n = 9) 17.10 ± 0.71 15.56–18.22 (n = 7) 16.35 ± 0.91 Salt-in-moisture (SM) 3.10–6.50 (n = 14) 5.19 ± 0.82 3.26–6.32 (n = 13) 5.15 ± 0.78 pH 4.36–4.90 (n = 15) 4.51±0.14 4.31–4.90 (n = 14) 4.53 ± 0.20 After Alichanidis et al. (1984), Anifantakis (1991), Anifantakis and Kandarakis (1983), Georgala et al. (2005). Katsiari & Voutsinas. (1994, 1997, 2002), Litopoulou-Tzanetaki et al. (1993), Mallatou et al. (1994), Pappas et al. (1994, 1996a, 1996b), Moatsou et al. (2002, 2004), Sarantinopoulos et al. (2002), Vafopoulou et al. (1989), Vafopoulou-Mastrojiannaki et al. (1990), Valsamaki et al. (2000).

1996b). However, the majority of the reported values for hardness, fracturability, and compression at fracturability point of Feta cheese were within the ranges 2.45– 5.07 kg, 1.31–2.25 kg, and 15.4–19.8%, respectively. In addition, the rheological properties of the product are also infl uenced by the amount of goat’s milk added to the sheep’s milk. Increasing the proportion of goat’s milk in the cheese milk base alters the microstructure of the casein network by reducing the degree of porosity of the protein matrix and hence infl uencing the hardness of the cheese (Mallatou et al., 1994; Tsigkros et al., 2003). The major microbial group found during the ripening of Feta cheese (Fig. 2.9) is lactic acid bacteria that originate from the starter culture or are present as non- starter lactic acid bacteria (NSLAB). In general, the lactic acid bacteria increase at a fast rate during the pre-maturing period (Litopoulou-Tzanetaki et al., 1993; Manolopoulou et al., 2003; Sarantinopoulos et al., 2002; Tzanetakis & Liptopoulou- Tzanetaki, 1992; Vafopoulou-Mastrojiannaki et al., 1990). Moreover, the low pH condition in the cheese during the maturation stage enhances the growth of NSLAB (Manolopoulou et al., 2003; Sarantinopoulos et al., 2002). Lactobacillus species constitute the majority of NSLAB, that is, ~90% of the isolates from Feta, with Lactobacillus plantarum being the predominant species. NSLAB form also the dominant microfl ora of the brine throughout the maturation period, and the dominant species are Lb. paracasei subsp. paracasei and Lb. plantarum (Bintsis et al., 2000). The salt-tolerant group of enterococci also increases during the pre-maturing period, and the predominant species are Enterococcus faecium and Enterococcus durans. Coliforms and Escherichia coli decline after the fi rst day of maturation due to the low pH conditions and lack of sugars (Litopoulou-Tzanetaki et al., 1992; Manolopoulou et al., 2003; Sarantinopoulos et al., 2002; Tzanetakis & Litopoulou- Tzanetaki, 1992). Salt-resistant yeasts grow on the surface of the cheese, and are also present in high numbers in the brine, where Saccharomyces cerevisiae has been reported to be the dominant species (Bintsis et al., 2000; Kaminarides & Laskos, 1992; Tzanetakis et al., 1996;).

The total free fatty acids (FFA) content (C4:0–C18:2) in mature Feta cheese ranges between 1 and 10 g kg–1, and the level of FFA in the cheese is inﬂ uenced by the

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) 12 –1 10 cfu g 10 8

microbial count (log 0 020406080100120 maturation period (d)

mesophilic lactococci thermophilic lactobacilli NSLAB enterococci presumptive leuconostoc micrococci

–1 Fig. 2.9 Evolution of the means of different microbial groups (log10 cfu g cheese) during the maturation of traditional Feta manufactured in three different traditional cheesemaking plants in Peloponissos using yoghurt as a starter culture and packaged in wooden barrels. NSLAB, non-starter lactic acid bacteria. After Manolopoulou et al. (2003).

manufacturing parameters. Furthermore, the level of FFA in Feta cheese inﬂ uences the sensory characteristics of the product (Alichanidis et al., 1984; Efthymiou, 1967; Georgala et al., 1999, 2004; Katsiari et al., 2000a; Kondyli et al., 2002; Vafopoulou et al., 1989). High values of FFA in Feta cheese have been associated with: (a) using subpasteurisation heat treatment of the cheese milk, which does not result in complete inactivation of the indigenous milk lipase; (b) the starter culture blend/mixture used; (c) draining the curd at high temperature; and (d) using the traditional artisanal rennet (Georgala et al., 2005; Kandarakis et al., 2001; Moatsou et al., 2004). The characteristic FFA proﬁ le of Feta cheese is shown in Fig. 2.10, and the results can be summarised as follows:

The short-chain volatile fatty acids (C –C ) may reach one-third of the total • 4:0 8:0 FFA (C4:0–C18:2) content in traditional Feta cheese (Georgala et al., 2005). • The level of butyric acid ranges between 115 and 2200 mg kg–1 in mild and mature Feta with mild and piquant ﬂ avour, respectively (Efthymiou, 1967; Georgala et al., 1999). The concentration of butyric acid is inﬂ uenced by the use of traditional rennet because of the PGEs activity (Collins et al., 2003; Moatsou et al., 2004). • The level of acetic acid ranges between 400 and 1500 mg kg–1 in mature cheese (Alichanidis et al., 1984; Efthymiou, 1967; Georgala et al., 1999; 2004; Kondyli et al., 2002; Vafopoulou et al., 1989). This organic acid is produced in the cheese as a result of citrate and lactose fermentation, or from amino acid catabolism, or from lipolytic activity (McSweeney & Sousa, 2000).

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12000

10000

8000 cheese) -1 6000

FFA (mg kg 4000

2000

0 0 20 40 60 80 100 120 Maturation period (d)

FFA (C4:0-C18:2) Volatile FFA (C4:0-C8:0) acetic acid (C2:0) butyric acid (C4:0)

Fig. 2.10 Evolution of free fatty acids (FFA; mg kg–1 cheese) during the maturation of traditional Feta cheese made from a mixture of sheep’s and goat’s milk (in a ratio of 4:1). The milk is heated to 67°C for 15 s; traditional artisanal liquid rennet is used; yoghurt is added as a starter culture; the cheese is packaged in wooden barrels. After Georgala et al. (2005).

The extent of proteolysis during the maturation of Feta cheese follows the pattern of changes in its chemical composition and microbial fl ora (Fig. 2.11). The level of protein hydrolysis in mature Feta cheese has been reported by researchers (see Table 2.3). The facts that confi gure the evolution of proteolysis in Feta are as follows. • Fast acid development in the curd, low pH, and high moisture and salt levels in the product are very favourable conditions for the retention of chymosin (including its activity) in the cheese, and this enzyme seems to be the main proteolytic factor during the maturation of Feta. Under these conditions, the opposite seems to be true α for plasmin activity. At the end of the pre-maturing stage, 30–50% of s1-casein has been hydrolysed, but the hydrolysis of β-casein is very limited (Michaelidou et al., 2003; Moatsou et al., 2002; 2004; Valsamaki et al., 2000; Sarantinopoulos et al., 2002). Furthermore, most of the major peptides identifi ed in Feta originate α from the N-terminal half of s1-casein and very few from the C-terminal domain of β-casein, which is attributed to the action of chymosin (Michaelidou et al., 1998). However, there are strong indications that the activity of cathepsin D in this type of cheese should not be overlooked (Hurley et al., 2000). • Most medium-sized and small peptides result from the action of bacterial proteinases and peptidases, and they accumulate during the pre-maturing stage and account for almost two-thirds of the soluble nitrogen content in the cheese (Michaelidou et al., 2003; Moatsou et al., 2002; Polychroniadou, 1994; Valsamaki et al., 2000).

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20 18 16 14 12 10 8 6

Soluble N fractions (% of total N) of (% fractions Soluble N 4 2 0 0 20 40 60 80 100 120 Maturation period (d)

WSN TCA-SN PTA-SN

Fig. 2.11 Evolution of nitrogenous fractions (expressed as percentages of total nitrogen) during the maturation of traditional Feta cheese made from a mixture of sheep’s and goat’s milk (in a ratio of 4:1). The milk is heated to 67°C for 15 s; traditional artisanal liquid rennet is used; yoghurt is added as a starter culture; the cheese is packaged in wooden barrels. After Moatsou et al. (2002).

• Moisture and soluble compounds are exchanged between the cheese and brine and, therefore, a portion of the casein and whey proteins’ hydrolytic products diffuse into the brine, especially during the second phase of maturation of the cheese in the cold store (Alichanidis et al., 1984; Michaelidou et al., 2004). Therefore, the changes in the water-soluble nitrogen fraction in Feta cheese are not always a reliable maturation index (Katsiari et al., 2000b; Moatsou et al., 2002)

The total free amino acid (FAA) content increases at a very fast rate during pre- maturing, remains almost steady from 40 to 60 days, and increases thereafter up to 240 days (Katsiari et al., 2000b; Valsamaki et al., 2000). The most abundant free amino acids in mature Feta have been found to be leucine, valine, phenylalanine, lysine, arginine, alanine and γ-aminobutyric acid (Alichanidis et al., 1984; Katsiari et al., 2000b; Michaelidou et al., 2003). The total biogenic amine content in the cheese is not high. It is lower than 1339 mg kg–1 in commercial Feta samples, and follows the evolution of FAA in the product. It has been found to be 330 mg kg–1 at 60 days and 620 mg kg–1 at 120 days. Tyramine and putrescine are the main biogenic amines present in Feta cheese (Valsamaki et al., 2000).

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Table 2.3 Some reported levels of proteolysis in mature traditional Feta cheese

Nitrogen fractions, expressed as percentages of total nitrogen WSNa TCA-SNb PTA-SNc 60 d 120 d 60 d 120 d 60 d 120 d References – 11.63 – – – – Anifantakis & Kandarakis (1983) 16.60 21.50 8.73 14.52 – – Alichanidis et al. (1984) – 26.94 – 15.33 – 5.0 Vafopoulou et al. (1989) – 27.0 – 20.0 – 9.0 Vafopoulou-Mastrojiannaki et al. (1990) – 29.61 – 19.77 – 5.97 Litopoulou-Tzanetaki et al. (1993) 17.16 19.47 12.93 14.25 1.81 3.67 Katsiari & Voutsinas (1994) 16.85 18.60 13.55 14.44 2.50 3.90 Mallatou et al. (1994) 25.18 28.92 20.04 22.62 – – Pappas et al. (1994) 12.80 – – – – – Kehagias et al. (1995) 10.71 11.75 8.11 9.47 – – Kandarakis et al. (1996) 21.60 23.23 13.43 14.70 – – Pappas et al. (1996a) 16.42 18.4 11.13 11.59 – – Pappas et al. (1996b) 9.12 9.44 7.32 7.74 – – Kandarakis et al. (1999) 19.21 19.83 11.46 12.42 4.18 4.74 Katsiari et al. (2000b) 13.0 14.21 10.10 11.40 – – Valsamaki et al. (2000) 16.59 – – – – – Kandarakis et al. (2001) 17.79 20.07 13.56 16.17 3.42 3.72 Moatsou et al. (2002) 17.86 – – – – – Sarantinopoulos et al. (2002) 18.27 19.41 12.20 13.28 2.72 3.34 Michaelidou et al. (1998) 12.55 – – – – – Moatsou et al. (2004) a Water-soluble nitrogen. b Nitrogen soluble in 12% trichloroacetic acid (TCA) (medium and small peptides and amino acids). c Nitrogen soluble in 5% phosphotungstic acid (PTA) (amino acids and small peptides).

The main characteristic of the profi les of volatile compounds in Feta cheese is the appearance of elevated levels of ethanol, acetate and butan-2-ol. Other major volatile compounds that have been identifi ed are propan-1-ol, butan-2-one, pentan- 2-one, acetone, ethylacetate and acetaldehyde (Horwood et al., 1981; Kondyli et al., 2002; Sarantinopoulos et al., 2002). Accelerated ripening has been successfully achieved in Feta with heat-shocked cultures or microbial proteinases, and also the addition of minute amounts of lamb lipase to the cheese milk to keep the fl avour in balance (Vafopoulou et al., 1989). Reduced-sodium Feta of highly acceptable quality can be produced using 3:1 or 1:1 (g 100 g–1) mixtures of NaCl and KCl, respectively, without any signifi cant effect on the cheese characteristics (Katsiari et al., 1997, 2000a, 2000b). Strains of Enterococcus faecium and E. durans have been considered as appropriate adjunct cultures for Feta production (Litopoulou-Tzanetaki et al., 1993; Sarantinopoulos et al., 2002). In addition, the use of the adjunct culture, Pediococcus pentosaceus, has been found to shorten the maturation period of Feta cheese by one month (Vafopoulou-Mastrojiannaki et al., 1990). Low-fat brined cheese of acceptable quality can be manufactured from sheep’s milk containing 1.5 g fat 100 g–1 using the conventional method of manufacture, and the addition of an adjunct commercial culture can ameliorate its fl avour characteristics (Katsiari & Voutsinas, 1994; Katsiari et al., 2002; Kondyli et al., 2002; Michaelidou et al., 2003).

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2.2.6 Defects of Feta cheese There are several common defects of Feta cheese. • Early blowing – usually appears during draining or salting. The texture of Feta becomes ‘spongy’ and a large number of small holes are formed in the cheese resulting from coliform and yeast growth. This defect is associated with the use of raw cheese milk of poor quality, and manufacturing the cheese at high environmental temperatures. The use of pasteurised milk, starter cultures and good hygienic conditions should prevent this defect. • Mould growth – this affects the cheese surface when the cheese portions are not completely submerged in the brine. To avoid this problem, the cheese must be kept continuously covered by the brine and, when Feta is matured and preserved in barrels, a quality control is done every two weeks to ensure this. • Soft texture – this occurs if the cheese is not properly acidiﬁ ed and salted before it is placed in the cold stores. • Ropy appearance of the brine – this is not associated with undesirable sensory characteristics of Feta, but it affects the appearance of the product. Bacteria of the genera Lactobacillus and Alcaligenes, which are common in dairy plants, especially strains of Lb. plantarum, can intensify ropiness (Bintsis & Papademas, 2002; Samaras et al., 2003).

2.2.7 Feta cheese whey Feta cheese whey is used to a great extent for the production of different types of whey cheeses like Mizithres, Anthotiros and Manouri, usually in mixtures with whey from hard cheeses (Table 2.4). These cheeses are manufactured by heating whey that is enriched with sheep’s or goat’s milk and/or cream. Nowadays, a great part of Feta whey is further processed, into whey powder (WP), whey protein concentrates (WPC), and cooked whey powder (Philippopoulos & Papadakis, 2001). The protein fraction of Feta whey and of the WPCs produced thereof (Fig. 2.12) are characterised by the high percentage of the major whey proteins (α-lactalbumin and β-lactoglobulin), and by the high ratio of β-lactoglobulin to α-lactalbumin (Moatsou et al., 2003).

Table 2.4 Mean chemical composition (g 100 g–1) of whey from Feta and Kefalotyri (hard variety) cheeses made from sheep’s milk or mixtures of sheep’s and goat’s milk

Composition Feta whey Kefalotyri whey Dry matter 7.87 8.10 Fat 0.39 0.80 Protein 1.61 1.55 Lactose 5.33 5.25 Salts 0.60 0.50 Lactic acid 0.14 0.14 After Anifantakis (1998).

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-lactoglobulin -lactalbumin caseinomacropeptide immunoglobulins serum albumine

Fig. 2.12 Whey protein distribution (g 100 g–1 of total protein) in clariﬁ ed Feta cheese whey. After Moatsou et al. (2003).

2.3 Miscellaneous brined Greek cheeses

Apart from Feta cheese, other brined cheeses that are produced on a small scale in Greece are Sfela, Batzos and Kalathaki Limnou. These varieties have been registered as Products of Designation of Origin (PDO) (EU, 1996).

2.3.1 Sfela cheese The area of Sfela production is Southern Peloponnissos. Sfela is a semihard rindless cheese with many small holes, and is ripened in brine in wooden barrels or in tins for at least 3 months (Fig. 2.13). The maximum moisture has to be 45 g 100 g–1, and minimum FDM ~40 g 100 g–1. The cheese is manufactured from sheep’s milk, goat’s milk or a mixture. Raw or pasteurised whole milk is coagulated at 30–32°C using traditional artisanal rennet (Anonymous, 2003); the amount used is sufﬁ cient to clot the milk and have the curd ready for cutting after 40 min.

Fig. 2.13 Sfela cheese.

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Fig. 2.14 Batzos cheese.

The curd is cut into very small pieces (i.e. similar in size to a grain of rice), stirred continuously and scalded slowly to 38–40°C. Afterwards, the curd pieces are collected using a cheese cloth and then pressed. The pressed curd is cut into strips, e.g. 4–7 cm wide, and dry salted for 24 h at room temperature before transfer to barrels or tins containing brine (20 g salt 100 g–1 concentration), and stored at room temperature for one month. The cheese pieces are carefully and tightly placed side by side in rows in the container, and each row of cheese pieces is packed crosswise to the previous layer so that no spaces are left between the cheeses. After one month, the brine is changed, and the containers are sealed and transferred to the cold stores at 4–6°C. Under these conditions and providing that brine covers the cheese all the time, Sfela can be preserved for about 2 years. The yield is 17–19%, the pH is 4.74, and the mean chemical composition (g 100 g–1) is as follows: moisture 41.2, protein 21.3, FDM 46.2 and SM 10.2. One of the main characteristics of Sfela is its high salt content, which can be reduced when using pasteurised milk and starter cultures (Anifantakis, 1998).

2.3.2 Batzos cheese Batzos is a semihard to hard low-fat white brined cheese, which is slightly acidic, piquant and very salty in taste, and has many holes (Fig. 2.14). According to the Greek Codex Alimentarius (Anonymous, 2003), the maximum moisture and the minimum FDM contents of mature Batzos have to be 45 and 25 g 100 g–1, respectively. It is traditionally manufactured from sheep’s or goat’s milk, or a mixture, in Western and Central Macedonia and Thessalia. The unique characteristic stage of its manufacture is the cutting of the curd into very small pieces as soon as the coagulation occurs (~10 min after addition of the rennet). A resting period of 30 min follows to complete the coagulation. After scalding the curd/whey mixture to 45°C, the curd granules are collected with cheese cloth and drained. These processing conditions produce whey

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Fig. 2.15 Kalathaki Limnou cheese.

high in fat (>2.5 g 100 g–1), which can be used for the manufacture of traditional whey cheese known as Manouri in Greece. The drained curd is left at 16–18°C for 2 days until the appearance of gas holes. Then, it is cut into pieces and dry salted. The next day, the cheese pieces are packed in metal containers ﬁ lled with brine (10–12 g salt 100 g–1), and kept in the cold stores for at least 3 months. The yield is 20% and 14% for sheep’s and goat’s milk, respectively. The mean chemical composition (g 100 g–1) of Batzos cheese is as follows: moisture 43.4, protein 23.2, FDM 34.6 and SM 11.06. The pH ranges between 5.51 and 4.80 (Anifantakis, 1998; Nikolaou et al., 2002).

2.3.3 Kalathaki Limnou cheese This is a soft brined cheese that is cylindrical in shape and has a characteristic embossed surface (Fig. 2.15); Kalathaki means ‘small basket’. It is produced on Limnos island from sheep’s milk or from a mixture with goat’s milk. The manufacturing stages are similar to those of traditional Feta, but the draining and the acidiﬁ cation of the curd take place in special cylindrical moulds that give the cheese its characteristic shape and appearance.

2.4 Telemes (Telemea) cheese 2.4.1 Manufacturing stages Telemes is a soft rindless white cheese matured and kept in brine; it is slightly salty and acid. It originated in Romania (Chintesco et al., 1960; Davis, 1976), and spread to other Balkan countries (e.g. Greece, Bulgaria, Turkey). In Greece, this type of cheese was introduced around 1906 by the Greek refugees of East Romylia (Anifantakis, 1998; Zigouris, 1952).

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Telemes and Feta cheeses have many common characteristics, but also certain differences mainly attributed to differences in their stages of manufacture. The ﬂ a- vour of Telemes is more acidic and sometimes more intense than that of Feta, while the texture of the cheese is sometimes crumbly and harder than Feta. The colour of Feta is always ‘pure’ white, whilst Telemes can be slightly yellowish depending on the ratio of cow’s milk mixed with sheep’s milk (Zerﬁ ridis, 2001). The production stages of Telemes cheese are illustrated in Fig. 2.16. The fat content of the cheese milk can be standardised to casein:fat ratios of 0.72–0.75 for

Filtration, standardisation of the cheese milk Pasteurisation

Renneting CaCl2, Starters at 30-32°C

Cutting after 50-60 min Rest into 1-3 cm cubes for 10-15 min

Draining under pressure Moulding

Cutting of pressed curd Salting in brine

Pre-ripening in the tin Packaging in open tin with brine container and dry salting

Transfer to cold store

Fig. 2.16 Flow chart for the production of Telemes cheese in Greece. Adapted from Zerﬁ ridis et al. (1989) and Anifantakis (1998).

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sheep’s milk or to 0.76–0.80 for cow’s milk (Mallatou et al., 2003; Zerﬁ ridis, 2001). After pasteurisation, the milk is cooled to 32°C and fresh yoghurt (0.3 mL 100 mL–1) is usually used as a starter culture. In addition, mixtures of mesophilic starters (Lactococcus lactis subsp. lactis and Lactobacillus casei subsp. casei) or mixtures of mesophilic and thermophilic lactic acid bacteria (Lac. lactis subsp. lactis and Lb. delbrueckii subsp. bulgaricus) are used at a rate of 0.5–1.0 mL 100 mL–1 (Mallatou et al., 2003; Manolkidis et al., 1970a; Zerﬁ ridis et al., 1989). Other additives that

can be used are chlorophyll to whiten cow’s milk, CaCl2 to assist the coagulation process of the milk, and lipase to give a piquant taste (Anifantakis, 1998). Calf rennet is used as a coagulant at 30–32°C, and the curd is cut after 50–60 min into cubes of 1–3 cm and left for 10–15 min before transfer to the rectangular bottomless moulds that are dressed with cheese cloths (Alichanidis et al., 1981; Anifantakis, 1998; Tzanetakis et al., 1991; Zerfi ridis, 2001). There are several differences in the technology between Feta and Telemes cheeses. • Type of milk – Feta is made from sheep’s milk or from mixtures of sheep’s and goat’s milk (<30%), while Telemes is mostly manufactured from mixtures of different types of milk or from cow’s milk alone. • Colour of the cheese – Telemes made from cow’s milk has a yellowish colour and sometimes has a crumbly texture; however, the cheese made from sheep’s or goat’s milk is white in colour. Sheep’s milk Telemes has a smooth texture, whilst the product made from goat’s milk has a coarse texture. Moreover, the presence of goat’s milk in the cheese milk gives the product its piquant fl avour (Abd El-Salam & Alichanidis, 2004; Anifantakis, 1998). • Draining of the curd – After the transfer of the curd into the moulds or after a period of natural draining, a weight equal to the curd weight is applied to the mould. When the curd becomes fi rm, the mould is removed and the curd is cut into portions about 13 × 13 × 10 cm or smaller (7 cm cubes) (Fig. 2.17). Therefore, Telemes curd drains under pressure, whereas the Feta curd drains by gravity and by the surface dry salting of the curd (Anifantakis, 1998; Manolkidis et al., 1970a). • Salting – Telemes cheese portions, soon after their drainage, are salted in a brine bath (~18 g salt 100 g–1) at 15–18°C for ~20 h, and placed side by side to retain their shape (Fig. 2.18). The salting time is governed by the size of the cheese portions, the salt concentration, and the temperature of the brine. Usually, coarse dry salt (i.e. size of a grain of rice) is spread on the surface of cheese portions and, after 4 h, the portions are turned over, dry salted again on the surface, and left for an additional 16 h in the brine (Alichanidis et al., 1981; Anifantakis, 1998; Tzanetakis et al., 1991). At the end of the dry salting/brining period, the temperature in the centre of the cheese portions is ~20°C, pH ≤5, SM >2.5 g 100 g–1 and moisture 62–65 g 100 g–1 (Zerfi ridis, 2001; Zerfi ridis et al., 1989). Afterwards, the cheese portions are placed in open tin containers in layers, dry salted using coarse salt and turned every 12 h. It is evident that the method of salting of Telemes cheese is quite different to that of Feta. In the latter type of cheese, the salt penetration (or the salting procedure) is slow due to dry

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Fig. 2.17 Cutting of pressed Telemes cheese curd.

Fig. 2.18 Salting of Telemes cheese in brine.

salting for several days before the ﬁ nal packaging in brine, which contrasts with the salting method of Telemes cheese portions where they are placed in the brine straight after the pressing stage. This salting practice protects the cheese (i.e. reduces or inhibits microbial activities), especially if it is made from milk high in titratable acidity. Therefore, the lactic acid that accumulates (i.e. from the milk and the starter culture) results in high acidity of Telemes cheese, especially if the product is refrigerated soon after manufacture (Abd El-Salam & Alichanidis, 2004; Efthymiou, 1967).

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• Packaging – After 2 to 5 days, Telemes cheese is normally packaged in tin containers containing brine (7–8 g NaCl 100 mL–1), while traditional Feta is packaged in wooden barrels. The metal containers are sealed and kept at 15–16°C for about 2 weeks to complete the pre-maturing period (pH <4.8, moisture ∼54 g 100 g–1 and SM 5 g 100 g–1; Zerﬁ ridis et al., 1989). Cheeses are then transferred to the cold stores (2–8°C) in order to complete the maturation for at least 2 months after the day of manufacture; under these conditions, the product can be kept up to one year.

2.4.2 Characteristics of Telemes cheese The chemical composition of mature Telemes cheese, shown in Table 2.5, is infl uenced by the type of milk used. Lactobacillus spp. predominate throughout the maturation period of Telemes and, in particular, Lb. plantarum that is resistant to NaCl. Other predominant isolates that have been found in Telemes cheese are Lactococcus lactis subsp. lactis, Leuconostoc mesenteroides subsp. mesenteroides and, from the enterococci group, Enterococcus faecium. However, the majority of Lactococcus species are inactivated during the fi rst few days of maturing because of the inhibitory effect of the low pH and the high salt-in-moisture content (Litopoulou- Tzanetaki et al., 1992; Tzanetakis & Litopoulou-Tzanetaki, 1992). The total FFA content is generally low, ranging between 1000 and 2500 mg kg–1 cheese. The main characteristic of the volatile FFA (i.e. chromatographic profi le of Telemes cheeses) is the abundance of acetic acid, which is not the result of lipolysis, but due to microbial fermentation that take place during the maturation period (Alichanidis, 1981; Efthymiou, 1967; Horwood et al., 1981; Mallatou et al., 2003). In addition, proteolysis (Fig. 2.19) proceeds at a constant rate throughout the maturation period, in contrast to Feta where the proteolysis is more intense during the pre-maturing stage (Alichanidis et al., 1981; Manolkidis et al., 1970b). The β α hydrolysis of -casein is slower than that of s1-casein, and its hydrolytic process is similar to Feta (Alichanidis et al., 1981; Mallatou et al., 1994). However, the total FAA content of 60-day-old Telemes cheese is ~2.5 g kg–1, and it can be doubled at

Table 2.5 Mean chemical composition (g 100 g–1) and pH values of Telemes cheese made from cow’sa or sheep’sb milk

Chemical composition Type of milk Age of cheese (days) Moisture FDMc Protein SMd pH Cow’s 60 53.79 43.40 15.25 5.66 4.81 120 53.35 43.20 15.23 5.70 4.85 Sheep’s 60 52.49 17.58 6.00 4.82 90 52.27 17.66 6.10 4.76 130 52.16 17.64 6.20 4.73 a Kalogridou-Vassiliadou & Alichanidis (1984). b Alichanidis (1981). c FDM = fat-in-dry matter. d SM = salt-in-moisture.

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16 14 12 10 8 6 4 2 TCA-SN 0 WSN ow's milk c 's milk sheep ilk goat's m

Fig. 2.19 Extent of proteolysis in Telemes cheese. Age of the cheese is 60 days; data expressed as percentage of water-soluble nitrogen (WSN), and of nitrogen of medium and small peptides (TCA-SN). Data compiled from Alichanidis et al. (1981), Kalogridou-Vassiliadou & Alichanidis (1984) and Mallatou et al. (2004).

4 months of maturing; the most abundant FAA are lysine, leucine, phenylalanine, valine, arginine, glutamic acid and γ-aminobutyric acid (Alichanidis et al., 1981; Mallatou et al., 2004; Polychroniadou & Vlachos, 1979).

2.5 Some examples of Balkan brined cheeses 2.5.1 Bjalo Salamureno Sirene (white brined cheese) Bjalo Salamureno Sirene (Belo Salamureno Sirene or Bjalo Sirene or simply Sirene) is a traditional and very popular cheese in Bulgaria. It is a semihard brined cheese that has a close and smooth texture, and is mainly produced from sheep’s milk. There is also a hybrid variety made from cow’s milk or from mixtures of sheep’s and cow’s milk. The manufacturing stages are similar to those for Telemes cheese, but the salting is carried out in saturated brine. Furthermore, maturation of the cheese takes place in brine (10–12 g salt 100 mL–1) for 2–4 weeks. Mesophilic starter cultures are used, usually Lactococcus lactis subsp. lactis and Lactobacillus casei (Davis, 1976, Robinson & Wilbey, 1998). The gross chemical composition (g 100 g–1) of the mature cheese is: moisture 46–54, FDM 50–53, total protein 14–22, salt 3.5–4.5, pH 4.10–4.40, and water- soluble nitrogen 18–25 of the total nitrogen content (Abd El-Salam & Alichanidis, 2004; Efthymiou, 1967; Lloyd et al., 1979). Similar to other brined cheeses, the nitrogenous breakdown substances increase during the maturation period and, after reaching a maximum level, they decrease due to the effect of leaching to the brine. Lipolysis in sheep’s milk cheese is similar to that of Feta with regard to the butyric, caproic and caprylic acid contents, and the total FFA and acetic acid contents range

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between 1.5 and 2 g kg–1, and between 0.6 and 1 g kg–1 cheese, respectively. The most abundant volatile compound by far is ethanol followed by butan-2-ol and propan-1-ol (Efthymiou, 1967; Horwood et al., 1981; Lloyd et al., 1979).

2.5.2 Belir Sir U Kriškama (white cheese in pieces) Belir Sir U Kriškama is a Serbian white cheese produced in the countries of former Yugoslavia under the names of Srpski, Travnički and Sremski. Traditionally, these cheeses were made from sheep’s milk but, at present, cow’s milk or a mixture with ewe’s milk is also used. The cheese has an acidic and salty taste, is tender but has a fi rm texture, and has a rectangular shape (10 × 10 × 10–12 cm). Blends of mesophilic and thermophilic starter cultures are used for the acidifi cation of the milk and curd. However, considering the fl ow chart for the manufacture of Telemes cheese (Fig. 2.16), the intensity and the duration of pressing are higher for Belir Sir U Kriškama cheese, and brine containing a higher salt content (20–24 g NaCl 100 mL–1) is used. The salted cheese portions are matured in brine of 10–12 g NaCl 100 mL–1 in metal containers at 12–15°C for 4–6 weeks (Abd El-Salam & Alichanidis, 2004; Carić, 1999; Robinson & Wilbey, 1998).

2.6 Turkish brined cheeses (see also Chapter 6)

The main Turkish cheese of this group is known as Beyaz Peynir (Turkish White cheese; Peynir means cheese), and the annual volume of production corresponds to two-thirds of all the cheese produced in Turkey (Güven & Karaka, 2001). However, there is a wide range of brined cheeses in Turkey, which are produced locally and most of them share slight modiﬁ cations in their technology, such as Telemes Peynir, Civil Peynir, Orgu Peynir, Malatya Peynir, Urfa Peynir, Mihalic, and Hellim cheese – the latter is similar to Halloumi cheese (A.A. Hayaloglu, personal communication). Beyaz Peynir is a white brined cheese with a strong acidic taste and high salt content, which is normally consumed after 30 days to one year maturation (Akalin et al., 2002). According to the review by Hayaloglu et al. (2002), the cheese was originally manufactured from sheep’s or goat’s milk, but cow’s milk or a mixture of different milks is now the common practice of production. Cuboidal or rectangular portions of cheese (7 × 7 × 10 cm) are matured in brine (12–14 g NaCl 100 mL–1) (Akalin et al., 2002; Hayaloglu et al., 2002). In the traditional method of manufacture, starter culture is not added to the raw or pasteurised milk (Erkmen, 1995; Turantas et al., 1989) and, apart from its production in well-organised dairy plants, this type of cheese is also produced in small dairies, on farms or in private houses. As mentioned elsewhere, the manufacturing stages of Turkish White cheese are similar to those of Telemes cheese produced in Greece (see Fig. 2.16). The main differences are the coagulation time, salting method and maturation conditions. In brief, commercial cheese production consists of pasteurisation of the milk, cooling to 30–32°C, and

the addition of CaCl2 and starter cultures (i.e. a blend of mesophilic or thermophilic

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lactic acid bacteria (Dağdemir et al., 2003; Erkmen, 1995; Güven & Karaca, 2001; Hayaloglu et al., 2002;). Thirty minutes after adding the starter culture, commercial calf rennet (or home-made rennet extracts of young calves’, lambs’ and kids’ stomachs – used in artisanal cheesemaking) is added, and the amount is suffi cient to coagulate the milk in 90–120 min. After cutting the curd into 1–3 cm cubes and resting for a period of 5–10 min, the curd is drained in moulds lined with a cheese cloth for 25–30 min, and followed by pressing the cheese at 2–4 kg kg–1 for 3–6 h; incidentally, the pressure applied is higher than that used during the manufacture of Telemes cheese (Hayaloglu et al., 2002). The cheese blocks are salted in brine (14–16 g NaCl 100 mL–1) at 15–16°C, and then packaged in tin containers fi lled with brine (14 g NaCl 100 mL–1), and matured for 30–60 days at 12–15°C (Hayaloglu et al., 2002) or at 4°C for 90 days (Dağdemir et al., 2003; Erkmen, 1996). Therefore, a distinct pre-maturing treatment is not always carried out. Although the acid taste is the main characteristic of Turkish White cheese, the pH values may range between 4.11 and 5.65 in cheeses sold in the market (Turantas et al., 1989). In fact, in cheese made without the addition of starter cultures, there is no signifi cant change in the level of pH throughout the maturation period (Erkmen, 1995, 1996, 2001). Lactococci decline during the maturation of the cheese, while the Lactobacillus species increase, and the most predominant species are Lb. casei subsp. casei and Lb. plantarum. Furthermore, throughout the same period, the viable count of enterococci, which is the second most numerous group at the beginning of the maturation of the cheese, remains relatively constant, but the counts of coliforms, staphylococci and micrococci decrease (Hayaloglu et al., 2002). The use of raw milk, the absence of starters, and the concomitant low acid development in this cheese variety favour the survival of pathogens, such as Listeria monocytogenes, Yersinia enterocolitica and Staphylococcus aureus (Aytac & Özbas, 1992; Erkmen, 1996, 2000, 2001). It is evident, however, that due to the lack of a standard manufacturing procedure of this type of cheese, there is signifi cant variation in the chemical composition (g 100 g–1) of the product, and typical values may range between 36.3 and 47.6 for total solids, 35.7 and 68.9 for FDM, 4.3 and 9.9 for SM, and 12.1 and 19.7 for total proteins (Hayaloglu et al., 2002; Koca & Metin, 2004; Turantas et al., 1989). The maturation index expressed as water-soluble nitrogen (WSN)/total nitrogen ranges between 13.6 and 21.9 g 100 g–1 in mature cheese (Guven & Karaca, 2001; Kocak et al., 2004; Saldamli & Kaytanli, 1998). During the maturation period, a great deal α β of s1-casein is hydrolysed, while the residual -casein is high, that is, similar to Feta and Telemes cheeses (Hayaloglu et al., 2004). At the end of the same period, the total FAA content is ~4115 mg kg–1 in cow’s milk cheese and ~3858 mg kg–1 in sheep’s milk cheese; the main FAA are leucine, glutamic acid, phenylalanine, valine and lysine (Hayaloglu et al. 2002, 2004). In addition, the main biogenic amines that have been found in the cheese are putrescine, cadaverine and tyramine, but they tend to decrease when starter cultures are used (Durlu-Özkaya et al., 1999). The level of lipolysis is generally low in Turkish White cheese made from pasteurised milk, especially with regard to volatile FFA content. However, the –1 total FFA content (C4:0–C18:2) may reach 555 mg kg , and the dominant ones are

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palmitic (C16:0) and stearic (C18:1) acids (Akin et al., 2002, 2003; Aydemir et al., 2001). Compared with other white brined cheeses, acetic acid is present in high concentrations, and similar characteristics have also been found for Urfa cheese – a different brined cheese with a shorter coagulation time that drains without pressure (Ozer et al., 2002). Mihaliç Peynir is a hard cheese variety that is made predominantly from raw sheep’s milk. One of the main processing features of the manufacture of the cheese is the scalding of the ﬁ nely cut curd in boiling water. Fresh cheese portions, after draining, are salted in brine of 16 g NaCl 100 mL–1 for 2–4 days, and followed by maturation in brine (18–20 g NaCl 100 mL–1) at 10–12°C for 90 days. The cheese has a very salty taste, and the pH of market cheeses ranges between 5.42 and 6.05. The compositional quality (g 100 g–1) of the cheese ranges between 31.67 and 46.10 for moisture, 34.02 and 47.94 for FDM, 20.42 and 31.50 for protein, 11.4 and 20.9 for SM, and 27.6 and 61.9 for the ratio of WSN to total nitrogen (Özdemir et al., 2004).

Acknowledgement

We would like to thank Dr A.A. Hayaloglu for providing the literature review and useful information on Turkish brined cheeses.

References

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Anifantakis, E. & Green, M. (1980) Preparation and properties of rennets from lamb’s and kid’s abomasa. Journal of Dairy Research, 47, 221–230. Anifantakis, E.M. & Kandarakis, J.G. (1980) Contribution to the study of composition of goat’s milk. Milchwissenschaft, 35, 617–619. Anifantakis, E.M. & Kandarakis, J.G. (1983) Utilisation de la pepsine bovine en fabrication de fromage Feta à partir du lait de brebis. Le Lait, 63, 416–424. Anonymous (1953) Cheese varieties and descriptions. Agricultural Hanbook No 54, pp. 4. Laboratory of Eastern Utilization Research and Development Division, Agriculture Research Service, Washington DC. Anonymous (2003) Greek Codex Alimentarius, vol. 2. Ministry of Economics, Athens. Aydemir, S., Akin, N. & Cocak, C. (2001) Effect of lipase enzyme on the ripening of white pickled cheese. Journal of Food Lipids, 8, 205–213. Aytac, S.A. & Özbas, Z.Y. (1992) Isolation of Yersinia enterocolitica from Turkish pickled white cheese. Australian Journal of Dairy Technology, 47, 60–61. Baltadjieva, M., Veinoglou, B., Kandarakis, J., Edgaryan, M. & Stamenova, V. (1982) La composition du lait de brebis de la region de Plovdiv en Bulgarie et de Ioannina en Grèce. Le Lait, 62, 191–201. Bintsis, T. & Papademas, P (2002) Microbiological quality of white brined cheeses: a review. International Journal of Dairy Technology, 55, 113–120. Bintsis, T., Litopoulou-Tzanetaki, E., Davies, R. & Robinson, R.K. (2000) Microbiology of brines used to mature Feta cheese. International Journal of Dairy Technology, 53, 106–112. Carić, M. (1999) Ripened cheese varieties native to the Balkan countries. In: Cheese, Chemistry, Physics and Microbiology, 2nd edn (ed. P.F. Fox), vol. 2, pp. 263–279. Aspen Publishers, Gaithersburg. Chintesco, G., Toma, C. & Ionesko, I. (1960) Recherches sur le fabrication en Roumanie du fromage ‘Télémea’ de lait de brebis. Le Lait, 40, 263–273. Collins, Y.F., McSweeney, P.L.H. & Wilkinson, M.G. (2003) Lipolysis and free fatty acid catabolism in cheese: A review of current knowledge. International Dairy Journal, 13, 841–866. Courtine, R.J. (1972) Dictionnaire des fromages. Librairie Larousse, Paris. Dağdemir, E., Celik, S. & Ozdemir, S. (2003) The effects of some starter cultures on the properties of Turkish White cheese. International Journal of Dairy Technology, 56, 215–218. Davis, J.G. (1976) Cheese, vol. III, pp. 856–857. Churchill Livingstone, Edinburgh. Durlu-Ozkaya, F., Alichanidis, E., Litopoulou-Tzanetaki, E. & Tunail, N. (1999) Determination of biogenic amine content of Beyaz cheese and biogenic amine ability of some lactic acid bacteria. Milchwissenschaft, 54, 680–682. Eekhof-Stork, N. (1976) The World Atlas of Cheese. Pattington, London. Efthymiou, C. (1967) Major free fatty acids of Feta cheese. Journal of Dairy Science, 50, 20–24. Erkmen, O. (1995) Behavior of Staphylococcus aureus in Turkish Feta cheese during manufacture and ripening. Journal of Food Protection, 58, 1201–1205. Erkmen, O. (1996) Survival of virulent Yersinia enterocolitica during the manufacture and storage of Turkish feta cheese. International Journal of Food Microbiology, 33, 285–292. Erkmen, O. (2000) Inactivation kinetics of Listeria monocytogenes in Turkish White cheese during the ripening period. Journal of Food Engineering, 46, 127–131. Erkmen, O. (2001) Survival of Listeria monocytogenes during the manufacture and ripening of Turkish White cheese. Nahrung/Food, 45, 55–58. EU (1996) Commission Regulation No. 1107 – The registration of geographical indications and designations of origin under the procedure laid down in article 17 of council regulation (EEC) No. 2081/92. Ofﬁ cial Journal of European Communities, L148, 1–10. EU (2002) Commission Regulation No. 1829 – Amending to the Annex to Regulation (EC) No. 1107/96 with regard to the name “Feta”. Ofﬁ cial Journal of the European Communities, L277, 10–14. Georgala, A.K., Kandarakis, I.G., Kaminarides, S.E. & Anifantakis, E.M. (1999) Volatile free fatty acid content of feta and white-brined cheeses. Australian Journal of Dairy Technology, 54, 5–8.

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Georgala, A., Moschopoulou, E., Aktypis, A., Massouras, T., Zoidou, E., Kandarakis, I. & Anifantakis, E. (2005) Evolution of lipolysis during the ripening of traditional Feta cheese. Food Chemistry 90, 73–80. Güven, M. & Karaca, O.B. (2001) Proteolysis levels of White cheeses salted and ripened in brines prepared from various salts. International Journal of Dairy Technology, 54, 29–33. Hayaloglu, A.A., Guven, M. & Fox, P.F. (2002) Review. Microbiological, biochemical and technological properties of Turkish White cheese ‘Beyaz Peynir’. International Dairy Journal, 12, 635–648. Hayaloglu, A.A., Guven, M., Fox, P.F., Hannon, J.A. & McSweeny, P.L.H. (2004) Proteolysis in Turkish White-brined cheese made with deﬁ ned strains of Lactococcus. International Dairy Journal, 14, 599–610. Horwood, J.F., Lloyd, G.T. & Stark, W. (1981) Some ﬂ avour components of feta cheese. Australian Journal of Dairy Technology, 36, 34–37. Hurley, M.J., Larsen, L.B., Kelly, A.L. & McSweeney, P.L.H. (2000) The milk acid proteinase cathepsin D: a review. International Dairy Journal, 10, 673–681. Kalogridou-Vassiliadou, D. & Alichanidis, E. (1984) Effect of refrigerated storage of milk on the manufacture and the quality of Telemes cheese. Journal of Dairy Research, 51, 629–636. Kaminarides, S.E. & Laskos, N.S. (1992) Yeasts in factory brine of Feta cheese. Australian Journal of Dairy Technology, 47, 68–71. Kandarakis, I., Anifantakis, E. & Moschopoulou, E. (1996) Production of Feta cheese with fermentation-produced chymosin from Kluyveromyces lactis. In: Production and Utilization of Ewe and Goat Milk. Special Issue 9603, pp. 184–190. International Dairy Federation, Brussels. Kandarakis, I., Moschopoulou, E. & Anifantakis, E. (1999) Use of fermentation produced chymosin from E. coli in the manufacture of Feta cheese. Milchwissenschaft, 54, 24–26. Kandarakis, I., Moatsou, G., Georgala, A.I.K., Kaminarides, S. & Anifantakis, E. (2001) Effect of draining temperature on the biochemical characteristics of Feta cheese. Food Chemistry, 72, 369–378. Katsiari, M.C. & Voutsinas, L.P. (1994) Manufacture of low-fat Feta cheese. Food Chemistry, 49, 53–60. Katsiari, M.C., Voutsinas, L.P., Alichanidis, E. & Roussis, I.G. (1997) Reduction of sodium content in Feta cheese by partial substitution of NaCl by KCl. International Dairy Journal, 7, 465–472. Katsiari, M.C., Voutsinas, L.P., Alichanidis, E. & Roussis, I.G. (2000a) Lipolysis in reduced sodium Feta cheese made by partial substitution of NaCl by KCl. International Dairy Journal, 10, 369–373. Katsiari, M.C., Alichanidis, E., Voutsinas, L.P. & Roussis, I.G. (2000b) Proteolysis in reduced sodium Feta cheese made by partial substitution of NaCl by KCl. International Dairy Journal, 10, 635–646. Katsiari, M.C., Voutsinas, L.P., Kondyli, E. & Alichanidis, E. (2002) Flavour enhancement of low-fat Feta-type cheese using a commercial adjunct culture. Food Chemistry, 79, 193–198. Kehagias, C., Koulouris, S., Samona, A., Malliou, S. & Koumoutsos, G. (1995) Effect of various starters on the quality of cheese in brine. Food Microbiology, 12, 413–419. Koca, N. & Metin, M. (2004) Relationships between instrumental texture, composition and sensory properties of Turkish White cheese. In: Proceedings of International Dairy Symposium, May 24–28, Isparta, Turkey, pp 233–238. Kocak, C, Aydemir, S. & Seydim, Z.B. (2004) Levels of proteolysis in important types of Turkish cheese. Abstracts of IDF Symposium on Cheese, Prague (21–14 March 2004), Poster No. 054, pp. 76. International Dairy Federation, Brussels. Kondyli, E. & Katsiari, M.C. (2002a) Fatty acid composition of raw caprine milk of a native Greek breed during lactation. International Journal of Dairy Technology, 55, 57–60. Kondyli, E. & Katsiari, M.C. (2002b) Fatty acid composition of raw ewe’s milk of Boutsiko breed during lactation. Milchwissenschaft, 57, 74–76. Kondyli, E., Katsiari, M.C., Masouras, T. & Voutsinas, L.P. (2002) Free fatty acids and volatile compounds of low-fat Feta-type cheese made with a commercial adjunct culture. Food Chemistry, 79, 199–205.

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Litopoulou-Tzanetaki, E., Kalogridou-Vassiliadou, D. & Tzanetakis, N. (1992) Evolution de la fl ore microbienne au cours de la fabrication et de l’affi nage du fromage Telemes. Microbiologie-Aliments- Nutrition, 10, 283–288. Litopoulou-Tzanetaki, E., Tzanetakis, N. & Vafopoulou-Mastrojiannaki, A. (1993) Effect of lactic starter on microbiological, chemical and sensory characteristics of Feta cheese. Food Microbiology, 10, 31–41. Lloyd, G.T. & Ramshaw, E.H. (1979) The manufacture of Bulgarian-style Feta cheese – a review. Australian Journal of Dairy Technology, 34, 180–183. Mallatou, H., Pappas, C.P. & Voutsinas, L.P. (1994) Manufacture of Feta cheese from sheep’s milk, goat’s milk or mixtures of these milks. International Dairy Journal, 4, 641–664. Mallatou, H., Pappa, E. & Massouras, T. (2003) Changes in free fatty acids during the ripening of Telemes cheese made with ewes’, goats’, cows’ or mixtures of ewes’ and goats’ milk. International Dairy Journal, 13, 211–219. Mallatou, H., Pappa, E. & Boumba, V. (2004) Proteolysis in Telemes cheese made from ewes’, goats’ or a mixture of ewes’ and goats’ milk. International Dairy Journal, 14, 977–987. Manolkidis, C., Polychroniadou, A. & Alichanidis, E. (1970a) Variations dans la composition du fromage «Télémé» au cours de sa maturation. Le Lait, 50, 38–48. Manolkidis, C., Polychroniadou, A. & Alichanidis, E. (1970b) Observations suivies sur la proteolyse pendant la maturation du fromage «Télémé». Le Lait, 50, 128–136. Manolopoulou, E., Sarantinopoulos, P., Zoidou, E., Aktypis, A., Moschopoulou, E., Kandarakis, I.G. & Anifantakis, E.M. (2003) Evolution of microbial populations during traditional Feta cheese manufacture and ripening. International Journal of Food Microbiology, 82, 153–161. McSweeney, P.L.H. & Sousa, M.J. (2000) Biochemical pathways for the production of fl avour compounds in cheese during ripening. A review. Le Lait, 80, 293–324. Michaelidou, A., Alichanidis, E., Urlaub, H., Polychroniadou, A. & Zerfi ridis, G. (1998) Isolation and identifi cation of some major water-soluble peptides in Feta cheese. Journal of Dairy Science, 81, 3109–3116. Michaelidou, A., Katsiari, M.C., Kondyli, E., Voutsinas, L.P. & Alichanidis, E. (2003) Effect of a commercial adjunct culture on proteolysis in low-fat Feta-type cheese. International Dairy Journal, 13, 179–189. Michaelidou, A.-M., Alichanidis, E., Polychroniadou, A. & Zerfi ridis. G. (2004) Equilibrium of water soluble N of Feta between the cheese blocks and the brine. Abstracts of IDF Symposium on Cheese, Prague (21–24 March 2004), Poster No 052, p. 76. International Dairy Federation, Brussels. Moatsou, G., Massouras, T., Kandarakis, I. & Anifantakis, E. (2002) Evolution of proteolysis during the ripening of traditional Feta cheese. Le Lait, 82, 601–611. Moatsou, G., Hatzinaki, A., Kandarakis, I. & Anifantakis, E. (2003) Nitrogenous fractions during the manufacture of whey protein concentrates from Feta cheese whey. Food Chemistry, 81, 209–217. Moatsou, G., Moschopoulou, E., Georgala, A., Zoidou, E., Kandarakis, I., Kaminarides, S. & Anifantakis, E. (2004) Effect of artisanal liquid rennet from kids and lambs abomasa on the characteristics of Feta cheese. Food Chemistry, 88, 517–525. Morgan, F., Massouras, T., Barbosa, M., Roseiro, L., Ravasco, F., Kandarakis, I., Bonnin, V., Fiskatoris, M., Anifantakis, E., Jaubert, G. & Raynal-Ljutovac, F. (2003) Characteristics of goat milk collected from small and medium enterprises in Greece, Portugal and France. Small Ruminant Research, 47, 39–49. Moschopoulou, E. (2003) Study of the traditional rennet and of chymosin and pepsin from kid abomasums. PhD Thesis. Agricultural University of Athens, Athens. Nikolaou, E., Tzanetakis, N., Litopoulou-Tzanetaki, E. & Robinson, R.K. (2002) Changes in the microbiological and chemical characteristics of an artisanal low-fat cheese made from raw ovine milk during ripening. International Journal of Dairy Technology, 55, 12–17. Özdemir, C., Özdemir, S., Demirci, M., Çelik, Ş. & Sönmez, I. (2004) The microbiological and physicochemical properties of Mihaliç cheeses. In: Proceedings of International Dairy Symposium (Isparta, Turkey, 24–28 May 2004), pp. 243–246.

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Ozer, B., Atasoy, F. & Akin, S. (2002) Some properties of Urfa cheese (a traditional white-brined Turkish cheese) produced from bovine and ovine milks. International Journal of the Society of Dairy Technology, 55, 94–98. Pappa, H.C. & Anifantakis, E.M. (2001a) Effect of concentrated starter cultures on the manufacture of Feta cheese. Milchwissenschaft, 56, 325–329. Pappa, H.C. & Anifantakis, E.M. (2001b) Effect of different concentrated cultures on the proteolysis and organoleptic characteristics of Feta cheese. Milchwissenschaft, 56, 384–387. Pappas, C.P. & Zerﬁ ridis, G. (1989) Seminar on Milk Cheesemaking and Traditional Cheeses. Greek National Dairy Committee, Athens. Pappas, C.P., Kondyli, E., Voutsinas, L.P. & Mallatou, E. (1994) Effect of standardization of ewe’s milk for casein/fat ratio on the composition, sensory and rheological properties of feta cheese. International Dairy Journal, 4, 763–778. Pappas, C.P., Kondyli, E., Voutsinas, L.P. & Mallatou, H. (1996a) Effects of starter level, draining time and aging on the physicochemical, sensory and rheological properties of Feta cheese. Journal of the Society of Dairy Technology, 49, 73–78. Pappas, C.P., Kondyli, E., Voutsinas, L.P. & Mallatou, H. (1996b) Effects of salting method and storage time on composition and quality of feta cheese. Journal of the Society of Dairy Technology, 49, 113–118. Philippopoulos, C.D. & Papadakis, M.T. (2001) Current trends in whey processing and utilization in Greece. International Journal of Dairy Technology, 54, 14–19. Polychroniadou, A. (1994) Objective indices of maturity of Feta and Teleme cheese. Milchwissenschaft, 49, 376–379. Polychroniadou, A. & Vlachos, I. (1979) Les acides amines du fromage Télémé. Le Lait, 59, 234–243. Robinson, R.K. & Wilbey, R.A. (1998) In: Cheesemaking Practice, 3rd edn (ed. R. Scott), pp. 335–337. Aspen Publisher Inc., Gaithersburg. Saldamli, I. & Kaytanli, M. (1998) Utilization of Fromase, Maxiren and Rennilase as alternative coagulating enzymes to rennet in Turkish cheese production. Milchwissenschaft, 53, 22–25. Samaras, F.I., Kehagias, C., Arkoudelos, J.S. & Bocaris, M.I. (2003) Investigation on ropiness development by isolates of the genera Lactobacillus, Alcaligenes and Feta cheese starter cultures. Food Microbiology, 20, 503–509. Sarantinopoulos, P., Kalantzopoulos, G. & Tsakalidou, E. (2002) Effect of Enterococcus faecium on microbiological, physicochemical and sensory characteristics of Greek Feta cheese. International Journal of Food Microbiology, 76, 93–105. Simos, E., Voutsinas, L.P. & Pappas, C.P. (1991) Composition of milk of native Greek goats in the region of Metsovo. Small Ruminant Research, 4, 47–60. Tsigkros, D., Folland, E., Moate, R. & Brennan, C. S. (2003) Feta cheese texture: the effect of caprine and ovine milk concentration. International Journal of Dairy Technology, 56, 233–236. Turantas, F., Ünlütürk, A. & Götkan, D. (1989) Microbiological and compositional status of Turkish white cheese. International Journal of Food Microbiology, 8, 19–24. Tzanetakis, N. & Liptopoulou-Tzanetaki, E. (1992) Changes in numbers and kinds of lactic acid bacteria in Feta and Telemes, two Greek cheeses from ewes’ milk. Journal of Dairy Science, 75, 1389–1393. Tzanetakis, N., Litopoulou-Tzanetaki, E. & Vafopoulou-Mastrojiannaki, A. (1991) Effect of Pediococcus pentosaceus on microbiology and chemistry of Telemes cheese. Lebensmittel Wissenschaft und Technologie, 24, 173–176. Tzanetakis, N., Hatzikamari, M. & Litopoulou-Tzanetaki, E. (1996) Yeasts of the surface microﬂ ora of Feta cheese. In: Yeasts in the Dairy Industry: Positive and Negative Aspects – Proceedings of the Symposium Organized by Group F47 of the IDF, Copenhagen (2–3 September 1996), pp. 34–43. International Dairy Federation, Brussels.

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Vafopoulou, A., Alichanidis, E. & Zerfi ridis, G. (1989) Accelerated ripening of Feta cheese, with heat- shocked cultures or microbial proteinases. Journal of Dairy Research, 56, 285–296. Vafopoulou-Mastrojiannaki, A., Litopoulou-Tzanetaki, E. & Tzanetakis, N. (1990) Effect of Pediococcus pentosaceus on ripening changes of Feta cheese. Microbiologie-Aliments-Nutrition, 8, 53–62. Valsamaki, K., Michaelidou, A. & Polychroniadou, A. (2000) Biogenic amine production in Feta cheese. Food Chemistry, 71, 259–266. Voutsinas, L.P., Delegiannis, C., Katsiari, M.C. & Pappas, C. (1988) Chemical composition of Boutsiko ewe milk during lactation. Milchwissenschaft, 43, 766–771. Zerfi ridis, G.K. (2001) Soft cheeses – white cheeses in brine. In: Technology of Dairy Products, 2nd edn, pp. 155–157. Giachoudi, Thessaloniki. Zerfi ridis, G.K., Alichanidis, E. & Tzanetakis, N.M. (1989) Effect of processing parameters on the ripening of Telemes cheese. Lebensmittel Wissenschaft und Technologie, 22, 169–174. Zigouris, N. (1952) The Milk Industry, 2nd edn, pp. 391–427. Ministry of Agriculture, Athens.

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A.Y. Tamime, R.K. Robinson and G. L. J. Kiers

3.1 Background

In the mid-1980s, the production of Feta and Feta-type cheeses in 14 European countries, plus Canada, South Africa and Oceania, was ~400 000 tonnes (IDF, 1989; Tamime et al., 1991). At present, there are no available fi gures for world production of these cheeses. However, in view of the fact that the export of Feta-type cheese from Denmark to some Middle Eastern countries has fallen dramatically over the past 15 years (see Chapter 1), the local production of cheeses between 1990 and 2002 increased signifi cantly. For example, cheese production in Iran has doubled, and in Egypt has increased by ~170 000 tonnes, mainly because of local increases in milk production and a switch to self-suffi ciency rather than reliance on imported cheese (Table 3.1). As a consequence, local cheese production has replaced reliance on large imports, as was the case in the late 1980s, of Feta-type cheese to these countries. Nevertheless, factories have installed new production lines mainly using ultrafi ltration (UF) systems, and some examples of such installations are shown in Table 3.2. Although the list may not be complete enough to estimate the annual Feta-type cheese production, it is possible to suggest that, from the total capacity (L h–1) of the plants shown in Table 3.2, the production fi gures in Iran, Egypt and Saudi Arabia in 2003 were 115, 99.4 and 15 × 103 tonnes, respectively. In addition, the actual number of cheese factories in Iran using the UF technology for the manufacture of Feta-type cheese could be around 18, and the annual UF

Table 3.1 Annual milk and cheese production in two Middle Eastern countries (×1000 tonnes)

Milk Cheese Country 1990 1995 2002 1990 1995 2002 Egypt (total) 2291 3649 4059 320 349 490 Cow 970 1000 1900 Sheep 7 16 15 Goat 14 43 93 Buffalo 1300 1590 2051 Iran (total) 3900 4540 5877 115 216 228 Cow 2600 3450 4975 Sheep 535 450 302 Goat 643 500 374 Buffalo 122 140 After FAO (1991, 1997, 2003)

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Table 3.2 Reference list of Feta-type cheesemaking installations in some selected countries in the Middle East

Country/number of Annual production installationsa Year Type of UF system Total capacity (L h–1) (×1000 tonnes) Egypt One 1996 BAFb 6500 NRc One NR APV/Primodan 10 000 NR Six NR APV/Primodan 6 × 15 000 NR Four NR Techsep 25 000 (total) NR Two NR Tetra Pak 25 000 (total) NR Threed NR NR NR 10–30 (each) Sevend NR NR NR 2 (each) Fived NR NR NR 1 (each) Iran One 1997 BAF 6500 NR One 1999 BAF 10 000 NR Seven NR APV/Primodan 70 000 (total) NR One 2000 BAF 6500 NR One 2000 APV/Primodan 10 000 NR Two 2001 BAF 6500 and 10 000 NR One 2001 APV/Primodan 10 000 NR One 2002 BAF 10 000 NR Two 2003 BAF 20 000 NR One 2003 APV/Primodan 10 000 NR Saudi Arabia One 1998 BAF 6500 NR Three NR APV/Primodan 15 000 NR a The number of installations by process and capacity. b Tetra Tebel Casoﬁ ll® Bacteriologically Acidiﬁ ed Feta-type (BAF). c NR = not reported. d Installations between 1989 and 2003. The equipment supplied by APV/Primodan, Techsep and Tetra Pak is used to manufacture different Feta-type cheeses (e.g. cast, recombined and glucono-δ-lactone). After G. Kiers (unpublished data) and M. Abd El Salam (personal communication).

cheese production in 2003 ranged between 100 and 130 × 103 tonnes (H. Ghoddusi, personal communication); however, an exact ﬁ gure for total UF plants in the near future including the ones under consideration may be around 43 (F. Farahnoodi, personal communication). Over the past two decades, a wide range of mechanised systems have been developed for the manufacture of Feta-type cheeses (i.e. the cast and structured varieties); these systems have been extensively reviewed by Tamime & Kirkegaard (1991), Renner & Abd El-Salam (1991), Kyle & Hickey (1993), Cheryan (1998) and Nielsen (2000), and will not be described in this chapter. In addition, Mann (1996, 1999) regularly publishes a ‘digest’ of international dairy publications on brined cheeses including Feta and related products. Furthermore, the following are recommended for further reading regarding aspects of membrane applications in the dairy industry (Horton 1997a, 1997b; Mahaut, 1992; Maubois, 2002; Rosenberg, 1995) and/or the manufacture of the following cheeses: Teleme (Antoniou et al., 1995; Raphaelides et al., 1995; Yetismeyen et al., 2003), Domiati and Feta-type cheese (Aalund, 1997; Hoﬁ et al., 2001a, 2001b; Mehaia, 2002), Croatian Feta-type cheese (Andrea et

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al., 2001), Iranian white-brined cheese (Ziabary & Hoffmann, 2001), and fat-free Feta-type cheese (Wium et al., 2003). The importance of these cheese varieties in developing countries and the recently developed UF mechanised/automated systems for the manufacture of Feta-type cheeses is dealt with in this chapter, whilst the traditional process is detailed in Chapter 2.

3.2 The cheesemaking process

The principal stages of the manufacture of Feta-type cheese can be brieﬂ y summarised as follows: • selection of milk (raw or heat-treated); • addition of the starter cultures and ripening of the milk; • addition of the coagulant, followed by coagulation of the milk; • cutting of the coagulum and de-wheying; • matting of the curd particles and cutting into small portions; • packaging in bulk and brining/salting; and • retail packaging in brine. In the traditional method, the first five stages of the cheesemaking process take place in the cheese vat, whereas in the UF method, the cheese vat is replaced by different mechanised equipment for the production of cast and structured Feta-type cheeses, which has been reviewed by Tamime & Kirkegaard (1991). It can be argued that, in theory, the traditional and the UF methods of production are similar, in that the removal of the water and other soluble milk constituents takes place during cheesemaking; but in practice this removal is performed at different stages of manufacture. For example, in the traditional method, the water in the milk is removed after the cutting stage, whilst in the UF method the milk is concentrated and the water is removed before the formation of the curd. Hence, the properties of the coagulum produced from the UF milk are different from those produced by the traditional process, and the degree of concentration is determined by the kind of Feta-type cheese to be produced. Nevertheless, the primary objectives of the mechanisation of any cheesemaking process are well established, and have been reported by Tamime (1993); they can be summarised as follows: • increase productivity in any given factory; • reduce cost of manufacture by labour savings; • improve working conditions and reduce heavy manual work; and • improve, if possible, the quality of cheese. In addition the industrial-scale production of Feta-type cheeses in retail containers merits detailed discussion (see Fig. 3.1), covering the following aspects: (a) milk handling and preliminary treatments including ultraﬁ ltration, homogenisation and

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8 0

Pre-treatment BAF module 1

Starter Salt Rennet

Cold storage Incubation at 55 °C 5–7 °C

ORE COLD STORE

BAF module 2 BAF module 3 Filling and storage

Fig. 3.1 Flow diagram of the cheesemaking process using ultraﬁ ltered milk. Reproduced with permission of Tetra Pak Tebel B.V., Leeuwarden, The Netherlands. 116/05/2006 12:11:33 6 / 0 5 / 2 0 0 6

1 2 : 1 1 : 3 3 Industrial Manufacture of Feta-Type Cheeses 81

heat treatment; (b) the use of deﬁ ned starter cultures; (c) the production of the different Feta-type cheeses; and (d) other miscellaneous treatments depending on the method of production employed.

3.2.1 Composition and hygiene quality of raw milk In the United Kingdom (UK), the chemical composition and the microbiological quality of the raw milk can affect the quality of Feta-type cheeses (Anonymous, 2003a; Harding, 1995; MAAF 1995a, 1995b; SI, 1995), and the following facts should be noted: • Adulteration of milk (e.g. extraneous water, detergents and chemicals, neutralisers to mask developed acidity, sugar and salts to mask extraneous water, preservatives and foreign fats) has been identiﬁ ed in the past but, at present, the most common potential adulterant in milk is extraneous water. No legislation exists in the UK for permissible extraneous water in milk, but the current recommendation for freezing point depression (FDP) should be –0.530°C as compared with –0.520°C in the European Union (EU) (Harding, 1995; Tamime & Kirkegaard, 1991). The difference is due to the technique adopted to measure the FDP in °C in the EU – in the UK the Hortvet method is used, and the scale is about 0.017°C higher. Nevertheless, Harding (1995) proposed the following FDP information regarding the presence of extraneous water in milk: (a) FDP > –0.535°C, the milk is assumed free from added water; (b) FDP between –0.530°C and –0.534°C, the producer is alerted to check his plant; (c) FDP between –0.525ºC and –0.529°C, water is probably present in the milk; and (d) FDP < –0.525°C, water is present in the milk. Recently, Langridge (2004) has published a paper to clarify the principles behind the measurement of the FDP, and the differences that exist between the measurements in millidegrees Hortvet and millidegrees True. • The milk used should be free from inhibitory agents because these compounds can inhibit the growth of the starter cultures; the recommended level of penicillin in the UK is <0.004 µg mL–1 or <0.007 international units (IU) mL–1 and other inhibitory substances should be undetectable. • Milk from healthy animals should be used, because milk from an abnormal udder (i.e. one with mastitis) can inﬂ uence the quality of cheese; in the UK, the somatic cell count should be <4.0 × 105 mL–1. • The chemical composition of the milk should be high or comply with existing legal standards, for example, the fat and protein contents should be 3.5 and 3.0 g 100 g–1, respectively (Tamime & Kirkegaard, 1991); however, lower levels can affect the yield of cheese. • The current UK legal standard for total count of Brand A ex-farm milk is <10 × 104 colony forming units (cfu) mL–1.

The current speciﬁ cations for cow’s milk at reception in factories may vary from one area to another in the same country and from one country to another but, in general, the milk received at factories: (a) should be at a temperature of <10°C; (b)

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should be free from antibiotics; (c) should be unadulterated, e.g. with water (FDP > –0.535°C); (d) conform to targets for total and somatic cell counts at 15 × 103 cfu mL–1 and ~2.5 × 105 mL–1, respectively; and (e) should have fat and protein contents of >3.5 and 3.0 g 100 g–1, respectively.

3.2.2 Milk reception and storage In developing and industrialised countries, milk collection from farms is carried out in bulk using a road milk tanker. The facilities available for milk reception in a typical modern dairy have been described by Tamime & Kirkegaard (1991) and Anonymous (2003b), and are illustrated in Fig. 3.2. On reception of the bulk tanker at the factory, the milk (i.e. including samples from each individual farm) is subjected to stringent checks before being accepted. According to Muir and Tamime (2001), these tests are grouped into two main categories: (a) the intermediate quality control tests (e.g. measurement of temperature, pH or titratable acidity, freezing point depression (FPD), antibiotic residue and a check for smell – the taste of milk (optional) is carried out after it has been heated in the laboratory), and (b) the delayed quality control tests, for example, including proximate chemical composition, total viable cell count and somatic cell count. When the milk is accepted, the milk intake can either be measured by weight or by volume. In the former method, the bulk milk can be measured in one of two ways: (a) a weighbridge – the weight of the tanker is weighed before and after unloading, the difference in weight being the net weight of the milk – or (b) a tank fi tted with a load cell – the milk is pumped into the tank and the load cell measures the weight of the milk in the tank before the milk is pumped to the silo. Afterwards, there are two possible routes for milk handling at reception (see Fig. 3.2). First, the milk passes through an air eliminator, and a fi lter to remove any contaminants (e.g. straw, hairs, soil) before being cooled to <5°C and pumped to a silo. Second, with extended storage of raw milk at the factory or when collecting the milk every second day, the milk is handled as above but, after the metering stage, it is thermised in a plate heat exchanger (PHE), cooled to <5°C and fi nally stored in the silo.

Milk Heating medium Cooling medium

12 3 4 5 6

Litres

Fig. 3.2 Milk reception, handling and storage in a modern dairy factory. 1, air eliminator; 2, ﬁ lter; 3, milk meter; 4, intermediate storage tank; 5, cooling or thermisation and cooling (optional); 6, silo. Reproduced with permission of Tetra Pak A/B, Lund, Sweden.

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3.2.3 Optional preliminary treatments Although metal fi lters are commonly used in the dairy industry to clean the milk of solid particles such as hairs and straw, centrifugal clarifi ers can remove more solid impurities (e.g. straw, hairs, udder cells, leucocytes and some bacteria) that can be present in the milk. In principle, a clarifi er is similar to a centrifugal separator, but the disc stack is not equipped with vertically aligned distribution holes and, hence, it has only one outlet as compared with the two outlets in a cream separator. As the milk is introduced into the separation channels at the outer edge of the disc stack of the clarifi er, it fl ows radially inwards through these channels towards the axis of rotation and leaves through the outlet at the top of the clarifi er (Fig. 3.3). While the milk is on its way through the disc stacks, the solid material/impurities are separated and thrown back along the underside of the disc stack to the periphery of the clarifi er bowl (Anonymous, 2003b). The impurities are collected in the sediment space and, at the same time when the milk passes along the full radial width of the disc, it allows very small undesirable particles present in the milk to be separated. The solid material present in the milk varies (~10 kg 10 000 L–1), and the sediment space volume in the bowl will depend on the size of the clarifi er or cream separator, generally 10–20 L. In modern self-cleaning clarifi ers, the ejection of the undesirable solid material from the bowl of the clarifi er is carried out automatically at preset intervals (the mechanism is also known as self-desludging), normally every 30–60 min; the principle of the automatic discharge system has been detailed by Anonymous (2003b). It is well accepted in the dairy industry that milk containing high counts of thermoduric and spore-forming microorganisms is not suitable for cheesemaking (Chambers, 2002). Abdel-Fatah et al. (1998) reported that swollen Feta-type cheese

Fig. 3.3 The ﬂ ow of milk through a clariﬁ er. Reproduced with permission of Tetra Pak A/B, Lund, Sweden.

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made in a Tetra Pak Brik carton was caused by the presence of Bacillus spp. (e.g. B. fastidious, B. pumilus and B. ﬁ r m u s ), Clostridium spp. (e.g. Cl. paraputriﬁ cum and Cl. tertium), and Kluyveromyces spp. As a consequence, processes that can help to remove these bacterial contaminants from the milk before the manufacture of cheese are described below.

Bactofugation The bactofuge, which is a specially designed centrifuge, was developed a few decades ago to separate mechanically the microorganisms (i.e. spore-formers that are heat resistant) from the milk to prevent late blowing of the cheese by, for example, Clostridium spp. At present, the bactofuges available on the market are the third generation of centrifugal separators that are manufactured by Tetra Pak and GEA Westfalia and, according to te Giffel & van der Horst (2004), the factors that can affect the effi ciency of bactofugation are: • the size (0.5–7.0 µm), form (spherical to rod-shape) and/or outer surface (smooth or rough) of the microorganism; • the agglomeration process between the bacterial cells, or between the milk impurities and the bacteria; • the density of the microorganisms; • the space between the disc stack that determines their number; • the temperature of bactofugation (50–68°C), which infl uences the viscosity; • the capacity of the machine, i.e. rate of fl ow (L h–1); • speed or spin rate of the centrifuge, which determines the centrifugal force; • the bacterial quality of the milk – this may lead to chemical and physical changes; and • the design of the bactofuge, which should seek to minimise recontamination of the centrifuged milk by the bactofugate.

The efﬁ ciency of bactofugation of spores and vegetative bacteria is 94–98% and 86–92%, respectively; it is evident that the process is more effective for the removal of spores. In addition, it has been observed in the cheese industry that double bactofugation is practised to reduce effectively the load of bacterial spores of the raw milk (Anonymous, 1992a; Daamen et al., 1986; te Giffel & van der Horst, 2004; Uhl, 1990). The temperature of bactofugation of the milk (55–60°C) is similar for cream separation, and the bactofuge is normally installed in series with the centrifugal separator (either downstream or upstream) as the latter machine is used to standardise the fat content in the cheese milk (Anonymous, 2003b). Bactofuges fall into two categories: ﬁ rst, the two-phase type has two outlets at the top (i.e. one for the continuous discharge of the bactofugate via a special top disc and the other for the bacteria-reduced milk); and second, the single-phase type has only one outlet at the top of the bactofuge for the bacteria-reduced milk, whilst the bactofugate is collected as a sludge in the bowl and discharged at preset intervals

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1 2 3 4 4

Heat treatment for inactivation of spores

Milk Cream Heating medium Bactofugate Cooling medium

Fig. 3.4 Double bactofugation with two one-phase bactofuges and a steriliser. 1, pasteuriser; 2, centrifugal separator; 3, automatic fat standardisation unit; 4, one-phase bactofuge. Reproduced with permission of Tetra Pak A/B, Lund, Sweden.

through a port in the bowl body. There are around ten possible confi gurations of a bactofugation plant depending on its application (Anonymous, 2003b), but only one arrangement (i.e. two single-phase bactofuges in series) will be illustrated for its application in cheese production (Fig. 3.4). The milk is preheated in a PHE to 55–65°C, separated (i.e. ~40 g fat 100 g–1), and standardised to the desired fat content to achieve the fat-in-dry matter (FDM) content in Feta-type cheeses, which may range between <20 and 50% (IDF, 1981; Tamime et al., 1991). Incidentally, the surplus cream is utilised in the manufacture of other dairy products. The standardised milk is passed through the fi rst one-phase bactofuge, and the bactofugate (~0.15–0.2 mL 100 mL–1 of the feed) is discharged from the bowl body every 15–20 min. whilst the bacteria-reduced milk is bactofugated again in the second one-phase bactofuge. Furthermore, the bactofugates from both bactofuges are mixed together and, since they are very concentrated, part of the bacteria-reduced milk (~1.8 mL 100 mL–1 of the milk feed) is mixed with the bactofugate before it is pumped to a steriliser to be heated to 120°C for 1 min to inactivate the spore-formers. During the manufacture of any cheese variety, the heated bactofugate is cooled by remixing with the bacteria-reduced milk before being pasteurised at 70°C for 15 s, and cooled to 30°C. Alternatively, for the manufacture of Feta-type cheeses from UF milk, the processed bactofugate is cooled to 50–55°C before being ultrafi ltered.

Microfiltration (MF) An alternative method to remove spore-formers in the milk is the use of a membrane, such as in microfi ltration MF (Fig. 3.5), and the current developments of MF technology in the dairy industry have reviewed by Saboya and Maubois (2000) (see also Anonymous, 1992b; le Berre & Daufi n, 1998; Brandsma & Rizvi, 1999; Damerow, 1989; Gésan-Guiziou et al., 1999; Grangeon & Lescoche, 2000; Guerra et al., 1997; Kelly, 1997; Krabsen et al., 1994; Larsen, 1990, 1992; Morel & Cohen-Maurel, 1990; Plett, 1990; Zoon & Hup, 1993). The pore size of the microfi lter may be up to 1.4 µm, but ~0.2 µm can fi lter bacteria in the milk, and MF can eliminate up to 99.1–99.9% of the bacteria and spores in the milk (te Giffel & van der Horst, 2004). However, the fat globules and some protein particles are as large as or larger than

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the bacteria, and this results in the membrane being fouled very quickly. Hence, normally the fat is separated and MF is applied to the skimmed milk. There are many MF systems available on the market and, although the fundamental principles of bacterial separation are similar, the processing of milk differs from one supplier to another. For example, the Tetra Pak MF process could be described as follows: whole raw milk is prewarmed in a PHE to 60–63°C, separated in a cream separator followed by cooling the skimmed milk to 50°C, fed into two MF module loops under constant pressure (10–50 kPa), and fractionated into retentate (5 mL 100 mL–1 consisting of 9–10 g 100 g–1 total solids) and permeate (95 mL 100 mL–1) (Anonymous, 2003b; Muir & Tamime, 2001). The retentate (which contains all the bacteria present in the milk) from both loops is mixed with the desired amount of cream to standardise the fat content in the cheese milk, sterilised at 120–130°C for 2–4 s, and cooled to 70°C before being mixed with the permeate and, subsequently, pasteurised at 72°C for 15 s and cooled to the fermentation temperature. Furthermore, an MF plant can be designed for different capacities, and the layout of a unit handling 5000 L h–1 of raw skimmed milk in each loop is shown in Fig. 3.5. In some MF systems the retentate from the MF module is either remixed with the incoming raw milk to be separated once more and later microﬁ ltered or, alternatively, is discharged to waste (Muir & Tamime, 2001). It is evident that the efﬁ ciency of bacterial separation from the milk using the MF system is better than the bactofuge, but the choice is sometimes dictated by tradition and/or the comparative capital cost of the different equipment.

3.2.4 Standardisation of the casein-to-fat ratio The chemical composition of fresh milk (mainly the fat and protein contents) from any species of mammal varies from day to day depending on such factors as the stage of lactation, breed, age of the animal, milking intervals, nutrition, diseases of

1 2 3 Milk Cream Permeate Retentate Steam Heating medium Cooling medium

5 4 4

Fig. 3.5 Milk treatment using double-loop microﬁ lter and a steriliser for the retentates including fat separation and standardisation. 1, pasteuriser; 2, centrifugal separator; 3, automatic fat standardisation unit; 4, double- loop microﬁ ltration plant; 5, steriliser. Reproduced with permission of Tetra Pak A/B, Lund, Sweden.

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the udder and environmental conditions (Anonymous, 2003a; Tamime & Robinson, 1999). In addition, the fat and the protein components of the milk can affect the quality of any type of cheese and, in order to overcome these inherent variations in composition, the milk has to be standardised for the following aspects: (a) to comply with existing legal standards; (b) to maintain the same consistency of the cheese all year around (this is mainly affected by the level of the protein present in the milk); and (c) to optimise the yield of the cheese. Hence, the standardisation of the casein-to-fat ratio is of primary importance (Tamime, 1993; Kosikowski & Mistry, 1997; Robinson & Wilbey, 1998). A casein-to-fat ratio of 0.72 and 0.67–0.72 (optimum level 0.72) has been recommended for the manufacture of Feta and Feta-type cheeses from cow’s and sheep’s milk, respectively (Pappas et al., 1994; Sherkat et al., 1998). Since the fat content in sheep’s milk is rather high, Pappas et al. (1994) have recommended that the excess fat should be separated and removed from the milk, whereas making cheese from milk standardised to a casein-to-fat ratio of 0.67 requires the addition of cream. However, in cow’s milk the same approaches could be applied, but the current practice in the cheese industry is to concentrate the protein in milk to achieve the desired casein-to-fat ratio before the manufacture of the cheese.

3.2.5 Tetra Tebel process The full name of this process is known as Tetra Tebel Casoﬁ ll® Bacteriologically Acidiﬁ ed Feta-type (BAF) (Kiers, 2001), which is suitable for the manufacture of brined cheeses (i.e. Feta-type), Queso Fresco and cream cheese (Bredahl et al., 1995). As shown in Fig. 3.1, the process line consists of the following.

Pretreatment The raw milk is prewarmed to ~60°C, separated, and the skimmed milk is microfi l- terd (MF) or bactofugated (optional treatment). The retentate from the MF and/or the bactofugate containing the bacteria could discharge to waste depending on the process confi guration that has been installed, and the permeate (i.e. the bulk of the skimmed milk) is standardised automatically to give a fat-to-protein ratio of 1:1. The principle of the in-line direct standardisation system (i.e. two streams – one for the skimmed milk and the other for the cream containing ~40 g fat 100 g–1) consists of control valves, fl ow density meters and a computerised control loop to adjust the fat content in the skimmed milk to a desired value. Descriptions of the in-line fat standardisation systems available on the market have been given by Tamime & Robinson (1999), Muir & Tamime (2001), Tamime et al. (2001), and Anonymous (2003b). Alternatively, recombined skimmed milk could be used instead of raw milk, but melted anhydrous milk fat (AMF) could either be added during the rehydration stage of the process or metered into the retentate before the homogenisation stage (Anonymous, 2003b). Afterwards, the standardised milk is pasteurised at 75°C for 15 s to ensure the inactivation of pathogenic microorganisms, cooled to 5–7°C and stored for further processing.

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Module 1 The cold stored processed milk is prewarmed to 50°C and pumped to the UF module to concentrate the milk total solids (TS) to ~38.5 g 100 g–1 (i.e. crude protein 16.40, fat 17.12, lactose 3.22 and ash 1.67 – this is equivalent to a 5.5-fold concentration of the milk solids); the permeate may be discarded (optional). The UF plant (e.g. Tetra Alcross® US/UC) could be supplied with spiral wound or ceramic membranes (see Fig. 3.6). The capacity of such UF modules ranges between 5 000 and 10 000 L h–1. In addition, the permeate is pumped into the regeneration section of the PHE to heat the incoming cold milk from 5–7°C to the UF temperature. If the permeate is not discarded, it is cooled to <7°C for further processing, for example, the manufacture of drinking-type fermented milks or concentrated using the reverse osmosis (RO) technique, while the retentate is added to the UF retentate in order to increase the cheese yield.

Module 2 In this section of the BAF process (Fig. 3.7), the concentrated milk is heated to 75–80°C for 30 s, homogenised using a two-stage homogeniser at 4.5 and 0.5 MPa, respectively, and cooled to the incubation temperature of the starter culture. The primary objectives of the heat treatment and the homogenisation of the UF cheese

Fig. 3.6 On-site view of an ultraﬁ ltration plant – module 1. Reprodueced with permission of Tetra Pak Tebel B.V., Leeuwarden, The Netherlands.

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Fig. 3.7 Heat treatment and homogenisation equipment – module 2. Reproduced with permission of Tetra Pak Tebel B.V., Leeuwarden, The Netherlands.

milk are: (a) to provide a stable fat-in-water emulsion of the milk fat; (b) to induce physicochemical changes in the milk; and (c) to inactivate certain microorganisms present in the milk. In addition, high heat treatment (e.g. 90°C) and high homogenisation pressure (i.e. >18 MPa) of the retentate, as previously reported by Tamime and Kirkegaard (1991), are not applied in the BAF process and, as a consequence, the possible physicochemical changes that may be induced in the milk are shown in Table 3.3. Nevertheless, the retentate may be heated at ~150°C for a few seconds for ultra-high-temperature (UHT) sterilisation during the manufacture of Queso Fresco cheeses (i.e. not salted), which are very popular in the Iberian Peninsula and South America.

Module 3 In this part of the production line (see Fig. 3.8), the processed milk is cooled to 30°C, and inoculated with a mesophilic starter culture (i.e. direct-to-vat inoculation (DVI) or direct-to-vat set (DVS) type). Typical examples are cultures R-703 or R- 704, which can be obtained from Chr. Hansen A/S, Hørsholm. These are blends of Lactococcus lactis subsp. lactis and Lactococcus lactis subsp. cremoris that do not

produce CO2, categorised as fast acid-producers, and inoculated at a rate of 1000 units 10 000 L–1 of retentate. The inoculated milk is fermented at between 31 and 37.8°C in an intermediate tank for 12–15 h or until pH reaches <5.0. Incidentally, dry salt

11405124601_4_003.indd405124601_4_003.indd 8989 116/05/20066/05/2006 12:11:3712:11:37 11405124601_4_003.indd 90 4 0 5 1 2 4 6 0 1 _ 4 _ 0 90 0 3 . Chapter 3 i n Table 3.3 The effects of different treatments, and physicochemical changes in the milk using the Bacteriologically Acidiﬁ ed Feta-type (BAF) system and their relevance d d

in the manufacture of Feta-type cheeses

9 0 Treatment Induced changes Consequences for Feta-type cheese 1. Clarifi cation and fat Removes undesirable impurities present in the milk Improves the quality of the cheese standardisation Adjusts the fat-to-casein ratio 2. Microfi ltration/ Reduces the bacteriological count in milk including the spore-formers Ensures public safety bactofugation Only a small fraction of the milk is subjected to high heat treatment/ Minimises quality defects sterilisation Improves the quality of the product Does not affect the coagulation process of the milk 3. Homogenisation Reduces the diameter of the fat globule to <0.2 µm Improves retention of moisture in the cheese due to increases in the number Prevents cluster formation and the tendency of the fat to rise to the of fat globules surface Improves texture and smoothness of the cheese May increase the viscosity of the milk due to the reduction in the fat The cheese appears slightly whiter in colour because of the enhanced light globule size and increased adsorption onto the casein micellea refl ectance and scattering resulting from increased number of fat globules May cause partial denaturation of the whey proteins and limited If lipase is added, the enzymatic activity increases, which contributes to the interaction with the casein particles fl avour of the cheese (i.e. slight rancid taste) In recombined milk cheese, ensures proper rehydration of the powder and proper mixing with the AMF Pumping of the skimmed milk may cause foaming due to the increase of the phospholipid content in the milk phase that originates from the fat globule membrane 4. Heat treatment Pasteurisation ensures destruction of most bacterial contaminant Ensures consumer safety of the product present in the milk Minimises quality defects Slight destruction of some water-soluble vitamins Inactivation of some naturally occurring enzymes present in the milk Reduction in the level of dissolved gases No denaturation of the bulk of the whey proteins occurs 5. Ultrafi ltration Causes ‘partial’ homogenisation of the fat due to pumping and fl ow of Same as some factors listed in 3 and 4 above milk through restricted pathways and valves The use of UF modules in series can minimise the shearing force, which Pumping of the retentates may lead to some casein–fat interaction and may infl uence the texture of the cheese some whey protein denaturation If air is trapped in the retentates, this leads to a spongy texture Increases the buffering capacity of the milk; highly active starter cultures should be used in order to produce the desired change in the pH aThe effect is limited due to the low homogenisation pressure applied – see text.

116/05/2006 12:11:40 Adapted from Tamime & Kirkegaard (1991). 6 / 0 5 / 2 0 0 6

1 2 : 1 1 : 4 0 Industrial Manufacture of Feta-Type Cheeses 91

Fig. 3.8 Fermentation, salting and heating of the retentate – module 3. Reproduced with permission of Tetra Pak Tebel B.V., Leeuwarden, The Netherlands.

(2–3 g 100 mL–1), which is metered into the retentate, is added at two stages; ﬁ rstly, 0.5 g salt 100 mL–1 is added with the starter culture before the incubation period, and secondly, the remainder of the salt (i.e. 1.5–2.5 g 100 mL–1) is added to the fermentate at pH <5.0, and the time required to mix the bulk of the salt in the fermentate is ~90 min. Afterwards, the fermentate is heated to 45–50°C, mixed with the coagulant (e.g. Chy-Max® (rennet powder) from Chr. Hansen A/S – 2080 international milk clotting units (IMCU) g–1, which is rehydrated at a rate of 1.5–2.5 g L–1 of good potable water free from chlorine – this corresponds to 3120–5200 IMCU L–1), and metered in-line to the fermented retentate at a rate of 1 mL 100 mL–1 at the point of ﬁ lling into the retail container (see Fig. 3.1). Alternatively, Standard Rennet (i.e. before dilution with water) could be used at a rate of 20–30 mL 100 kg–1 of retentate (E. Høeier, personal communication). The coagulation time is within 15–20 min, and the containers are stored at ambient temperature (~25°C) overnight before they are transferred to the cold store (5–7°C). The cheese can be consumed directly after cooling or can be stored for up to 12 months with refrigeration. Other coagulants that can be used during the manufacture of Feta-type cheese have been reported by many researchers. Saldamli and Kaytanli (1998) concluded that Maxiren® 50 (from Kluyveromycece lactis by recombinant technology) was more suited to Turkish white cheese than parallel products made with Fromase® 46T (from Mucor miehei) or Rennilase® 150 L (from Rhizomucor miehei), and the quality of the cheese was similar to those made with standard rennet. Kadarakis et

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al. (1999) concluded that the quality and yield of Feta cheese made with Chymax® (from Escherichia coli) were similar to those of the product made with Ha-La® (from calf rennet) (see also Alichanidis et al., 1984; Anifantakis & Kandarakis, 1983).

Packaging A Tetra Brik aseptic machine (models TBA/8 and TBA/19) is used to fi ll the fermentate, including the added salt and the coagulant, and the packaging throughput ranges between 6 000 and 7 000 packs per hour depending on the capacity of the container (e.g. 250 or 500 mL). Technical information regarding the formation of the packaging container, sterilisation of the packaging material and fi lling procedure has been reported by Tamime & Robinson (1999) and Muir & Tamime (2001). The viscosity of the UF fermentate is greater than milk and, as a consequence, a large diameter nozzle on the fi lling head should be used to facilitate easy fi lling of the cartons (Fig. 3.9).

3.2.6 Tetra Tebel Casofill® glucono-δ-lactone (GDL) For the manufacture of Feta-type cheese using the GDL method, the stages of manufacture/processing of the milk until the heat treatment and homogenisation are similar to those described for the BAF process, but with very slight changes, namely heating to 85°C for 30 s and using a single-stage homogeniser at 7.5 MPa. The differences in the subsequent stages of production are as follows:

Fig. 3.9 Feta-type cheese made by the Bacteriologically Acidiﬁ ed Feta-type (BAF) system. Reproduced with permission of Tetra Pak Tebel B.V., Leeuwarden, The Netherlands.

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• Since the GDL is added as a dried ingredient (~3 g 100 g–1), the milk retentate is concentrated to 36.0 g TS 100 g–1 rather than 38.5 g TS 100 g–1 (see Section 3.2.5), and the ﬁ nal total solids content of the cheese will be ~39.0 g 100 g–1; the processed retentate is cooled to 40°C. • Rather than having an intermediate tank for preliminary fermentation of the retentate, what is required is two salt mixing tanks, and the dry salt is metered in-line directly into the retentate using a salt dosing unit, which is positioned adjacent to the mixing tanks; the time for the salt addition is 1 h. As soon as all the salt is added and well mixed/dissolved into the retentate, the subsequent processing stage may start. • The salted retentate is pumped to the GDL mixing plant, which consists of two 300 L enclosed stainless steel tanks mounted on top of each other; the upper tank is used for mixing the GDL, which is added manually through the manhole of the tank; the lower tank is used to feed the packaging machine. • The coagulant is metered in-line to the retentate before the in-feed of the packaging machine, and the retentate coagulates within 20 min depending on the ﬁ lling temperature, and the strength and amount of the coagulant used. • The pallets containing the cartons are stored for 24 h at ~25°C before the cheese is transferred to the cold store (6–8°C); the cheese is ready for consumption 1 week after manufacture.

Alternatively, the GDL could be rehydrated in water (i.e. a mixture of 1:1 water and GDL) and added to the retentate at a rate of 4 mL 100 mL–1 (Hansen, 1985); this seems a high dosage rate, but it is likely that the strength of the GDL was rather low due to dilution. However, inoculation of GDL (at a rate of 2 g 100 g–1) has been used to acidify the milk (16 g total solids 100 g–1) to pH 4.5 at 42°C for ~3 h to produce a yoghurt-type product (Tamime et al., 2000), whereas 3.6 g GDL 100 g–1 UF retentates (~39 g total solids 100 g–1) required 16 h to reduce the pH to 4.6 at 30°C (Wium & Qvist, 1998a, 1998b). The use of GDL in Feta-type and other related cheeses has been reported by Bayoumi & Reuter (1989). In a model experiment by Wium & Qvist (1998a, 1998b) and Wium et al. (1998), the retentate (~39 g total solids 100 g–1) was mixed with GDL (3.6 g 100 kg–1), salt (30 g kg–1) and the coagulant at ﬁ ve different rates (7.72 mg to 0.56 g kg–1; Standard Rennet – Chr. Hansen A/S at 165 IMCU mL–1; 65% of the total enzyme activity originated from chymosin, whilst 35% was from pepsin) at different intervals to make Feta-type cheese as follows: (a) the GDL, salt and rennet were added to the retentate at the same time; (b) the GDL was added to the retentate and, after 15 min, the salt and the rennet were added; (c) the GDL and the salt were added together to the retentate while the rennet was added after 180 min; and (d) the rennet was replaced with water. The amount of added rennet affected the clotting time including the salt contact of the retentate, and the physical and proteolysis properties of the cheese (Wium et al., 1998). In addition, in the cheese made with no added rennet, the retentate coagulated at pH 4.8 due to the acidic effect of the GDL, but the action of the rennet-like native milk enzyme (e.g. cathepsin D) should not be overlooked regarding the degree of proteolysis in the cheese (Larsen et al., 2000).

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3.2.7 Tetra Tebel Casofill® cast Feta-type This type of cheese is made in a similar manner as described for the BAF process, but the product is not made in a Tetra Brik container. Instead, the processed retentate (i.e. after the heat treatment and the homogenisation stages) is mixed with the starter culture and preacidifi ed to pH 6.3. Afterwards, the retentate is mixed with the coagulant, packaged in plastic cups (i.e. without the lid in place), and coagulated in the container for 20 min using a large conveyor belt. The plastic cups are returned to the fi lling machine, where a parchment paper is placed on top of the coagulated milk and dry salt is added followed by sealing of the container, turning it upside down and allowing the ‘milk’ to acidify to pH 4.8 overnight at 25–27°C (i.e. for ~12 h). During the acidifi cation period, some whey is expelled from the coagulum, thus dissolving the salt to form the brine in the plastic cup/container. After 20 days at 5°C, the cheese will be properly salted and ready for retailing. It is evident that each of the processes described above require, in part, different processing equipment, and the use of different acidifi cation methods can affect the quality of the fi nal product; a summary is shown in Table 3.4.

Table 3.4 Variations in the process parameters and quality of the Feta-type cheese made using the different Tetra Pak Tebel methods of production

Method of production Comments Bacteriologically Acidifi ed Feta-type (BAF) Acidifi cation of the milk by using starter cultures Only natural ingredients are used The product is similar in taste to the traditional product The chemical composition of the pre-cheese is similar to the fi nal product Yield of the cheese (1.0 kg cheese 5.27 kg–1 milk) is lower than the GDL method Packaging, e.g., in a TBA3 fi lling machine Glucono-δ-lactone (GDL) Chemical acidifi cation of the milk The product has a slight chemical fl avour The chemical composition of the pre-cheese is similar to the fi nal product Yield of the cheese is higher (1.0 kg cheese 4.57 kg–1 milk) due to the replacement of the milk solids by the GDL Packaging, e.g., in a TBA3 fi lling machine Cast Feta-type Acidifi cation of the milk by using starter cultures The cheese has the best fl avour and taste Yield of cheese is the lowest mainly due to de-wheying and the formation of the brine The cheese requires ripening or maturation High risk of contamination with moulds during the acidifi cation of the milk in the plastic cup Different packaging machine is required If the product is made in metal cans (i.e. in bulk), repackaging of the cheese in retail containers is required

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3.3 Miscellaneous additives and treatments related to Feta-type cheeses

Different treatments are performed and additives added to the UF retentates during the production of Feta-type cheeses, and these may include the addition of calcium

chloride (CaCl2), decolourising agents, lipase enzyme preparations, preservatives and/or processing the fat at high temperature.

3.3.1 Starter cultures Mesophilic and thermophilic lactic acid bacteria, and combinations of these have been used for the production of Feta and related cheeses (i.e. traditional and UF). The review by Tamime & Kirkegaard (1991) suggested that these cheeses can be produced using different strains of Lactococcus spp. and the yoghurt organisms (Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus, and in some instances Leuconostoc mesenteroides subsp. cremoris is also added with these cultures. The recommended rate of starter culture inoculation can vary in relation to: (a) the blend of microorganisms used; (b) the rate of acid development during the manufacture of the cheeses; (c) the degree of fl avour development in the end-product; and (d) the type of the starter used, for example, liquid or DVI/DVS. However, Table 3.5 illustrates some examples of Feta-type cheeses that can be produced using different strains of lactic acid bacteria. The effi cacy of the microbial blend(s) of the starter cultures could have originated from the experience of making the cheese from raw milk (i.e. relying on the indigenous lactic acid bacteria present in the milk). However, as Feta-type cheeses are currently produced in large centralised factories, it is evident that the use of different blends of starter cultures including the adjunct organisms (see Table 3.5) can affect the quality of the end product, and the cheeses produced may have different characteristics from the traditional product. Although research work on traditional Feta cheese (i.e. made from ewe’s or goat’s milk, or a blend of both) is well advanced (Moatsou et al., 2002), some other white brined cheeses, for example the Turkish varieties, require more research to characterise the changes in the microfl ora, biochemistry and texture during the maturation of these cheeses so that these effects on the quality of the product are better understood (Gağdemir et al., 2003; Hayaloglu et al., 2002, 2004; see also Chapters 2, 5 and 6). As a consequence, the appropriate blend(s) of the starter organisms can be developed for any variety of Feta-type cheese – a view that has been recently reported by Benkerroum & Tamime (2004) for starter culture development in Morocco.

3.3.2 Calcium chloride During the ultraﬁ ltration of the skimmed milk, the concentration of Ca2+ ions (i.e. soluble fraction) is reduced in the UF retentate because some of these ions are lost in the permeate, whilst the remainder of these ions will be partly bound to the protein (Glover, 1985) and concentrated to the same factor as the protein content in the

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9 6

Table 3.5 Some examples of combinations of starter culture organisms used for the production of Feta-type cheeses

Blends of starter organismsa Comments References P. pentosaceus + lactic starter Feta was made using ewe’s milk, and the adjunct culture Vafopoulou-Mastrojiannaki et al. (1990) (see also reduced the maturation period of the cheese by one month Tzanetakis & Litopoulou-Tzanetaki, 1989 Lac. lactis subsp. lactis + Lb. casei The taste and aroma of white-brined cheese was of good G’osheva et al. (1991) (see also Çakamkçi & Kurt, quality with Smetana-like consistency, and inﬂ uenced by 1993a, 1993b) the starter culture used Lac. lactis subsp. lactis + Lb. casei + E. durans + The cheese had higher sensory scores than the one made Tzanetakis et al. (1995) (see also Pappa & Leu. mesenteroides subsp. cremoris or with the yoghurt organisms, and the product contained Anyfantakis, 2001; Manolopoulou et al., 2003) S. thermophlis + Lb. delbrueckii subsp. bulgaricus higher levels of phosphotungstic acid soluble-N due to the high counts of the mesophilic lactic acid bacteria and the enterococci Lac. lactis subsp. lactis + Lac. lactis subsp. lactis bv. The cultures were blended at 45:45:10 ratio to produce the Karakuş & Alperden (1995) (see also Karakuş, 1994, diacetylactis + Lb. casei best cheese; in another blend, Lb. plantarum was also used 1995) S. thermophilis + Lb. delbrueckii subsp. bulgaricus Heat-shocked cells were used to ripen Iranian brined cheese, Azarnia et al. (1998) and organoleptic scores were higher than the control product E. faecium The strain was used as an adjunct culture that enhanced the Sarantinopoulos et al. (2002) growth of mesophilic cocci and thermophilic bacilli and affected the growth of non-starter lactic acid bacteria Adjunct culture CR-213 containing Lac. lactis subsp. The effect on the proteolysis (PAGE)b and reverse phase Michaelidou et al. (2003) lactis + Lac. lactis subsp. cremoris HPLCc of the cheese was marginal, but the levels of soluble nitrogen and free amino acids were signiﬁ cantly higher than those of the control cheese Lb. delbrueckii subsp. bulgaricus and Lb. helveticus Freeze-shocked lactic strains were used in low-fat white Gursel et al. (2003) pickled cheese production; proteolysis was enhanced especially with Lb. helveticus a P. = Pediococcus; Lac. = Lactococcus; Leu. = Leuconostoc; Lb. = Lactobacillus; S. = Streptococcus; E. = Enterococcus. b PAGE = polyacrylamide gel electrophoresis. c HPLC = high-pressure liquid chromatography. 116/05/2006 12:11:44 6 / 0 5 / 2 0 0 6

1 2 : 1 1 : 4 4 Industrial Manufacture of Feta-Type Cheeses 97

milk (Mistry & Maubois, 1993). As a consequence, the buffering capacity of the UF retentates will increase, and subsequently affect the cheesemaking process, such as the acidifi cation kinetics of the starter culture, level of pH, kinetics of the coagulant to gel the milk and rheological properties of the curd, activity of the ripening enzymes, survival and growth rate of pathogens, and water-holding capacity of the cheese curd during the maturation period (Mistry & Maubois, 1993). Alternatively, the addition of NaCl to the skimmed milk before UF helps to reduce the buffering effect of the retentates (Voutsinas et al., 1995a, 1995b). The reduction in the amount of soluble Ca2+ ions can affect the rate of the enzymatic reaction during the coagulation/gelation of the milk. Thus, the addition of Ca2+ to milk accelerates the clotting process of the aggregation stage of the reaction (Dalgleish, 1993). In addition, if the same amount of coagulant is added to equal volumes of milk or UF retentates, the coagulant clotting time is not affected by the increase in the protein level, but the time from clotting of the milk to cutting of the coagulum is reduced (Mistry & Maubois, 1993). Although the optimum curd fi rmness would be achieved by the addition of calcium chloride, this aspect is important during the manufacture of Feta-type varieties where some de-wheying takes place, but in the BAF process the added Ca2+ may ensure curd fi rmness when the UF milk is clotted in the retail carton. Different amounts of calcium chloride have been reported during the manufacture of Feta-type cheeses (Tamime & Kirkegaard, 1991). A level –1 of 20 g [CaCl2.H2O] 100 L milk can be used without causing any ‘off’ taste in the product (Harboe & Budtz, 1999), whilst in Canada a rate of 0.02 g 100 g–1 of milk has been recommended (http://www.canlii.org/ca/reg/crc870/secb.08.033.html).

3.3.3 Decolourising agents The cream or yellowish colour of cow’s milk as compared with sheep’s and goat’s milk is possibly due to the level of carotene present in the milks: ~20 µg 100 g–1 in cow’s milk, and only trace amounts in sheep’s and goat’s milk (Roe et al., 2002). Thus, Feta cheese made from sheep’s or goat’s milk or a mixture of both, tend to be brighter and whiter than similar Feta-type cheeses manufactured from cow’s milk. According to Tamime & Kirkegaard (1991), the different methods that have been used in the industry for the decolorisation of cow’s milk fat include: • The addition of dyes to milk, mainly of the blue-green type (e.g. chlorophyll- copper complex, such as Blego and Komplementa, Patent Blue or Brilliant Blue). In Canada, the amount of residual Brilliant Blue, which is permitted only in Feta-type cheese, should not exceed 0.1 µg 100 g–1 (http://www.canlii. org/ca/reg/crc870/secb.08.033.html). The use of higher doses of these dyes can affect the ﬁ nal colour of the milk, i.e. it becomes greenish. • The use of bleaching agents (e.g. clay or active carbon) or treatment with benzoyl peroxide to decolorise the cream followed by deodorisation to remove the off- ﬂ avours, which are oxidative in origin; the use of benzoyl peroxide in Feta-type cheesemaking is regulated by existing legal standards, and the compound is illegal in many countries. In the USA the maximum permitted amount of Novadelox

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(containing ~24 g 100 g–1 benzoyl peroxide as an active agent) is 0.002 g 100 g–1 (Kosikowski & Mistry, 1997); it is added to the milk or cream (preferably raw), heated to 63°C or more for 60–120 min and followed by processing of the cheese milk. • Treatment with titanium oxide (i.e. whitening agent) helps to mask the yellowish colour of cow’s milk, and its addition to the cheese milk may be preferable if the other decolorising agents cannot be used legally. • High heat treatment of the separated cream/butteroil helps to decolourise cow’s milk (i.e. physical decolourisation process). For example, the cream is separated twice (e.g. fi rst to 40 g fat 100 g–1 and then to 99.6 g butteroil 100 g–1) to remove the surplus aqueous phase, heated to 250°C for 3 min, and deodorised in a vacuum dryer to remove any off-fl avours or remaining moisture; it is then blended with the skimmed milk, homogenised at 60°C and 12–15 MPa and followed by ultrafi ltration. Nielsen et al. (1996) suggested that bleaching of the butteroil/AMF from cow’s milk during the manufacture of Feta-type cheese should be performed at 220°C in order to prevent cholesterol oxidation. In addition, the disadvantage of using such a process is the high capital investment required in a butteroil/AMF processing line. Alternatively, the butteroil can be replaced with vegetable fat (palm-seed oil) to produce a whiter Feta-type cheese (see also El-Malek & El-Khair, 2002).

No data are available on the possible mechanism(s) of the decolourising agents when added to milk or cream, and it is most likely, for example, that benzoyl peroxide either chemically modiﬁ es the β-carotene in some way, so breaking the long chain of the conjugated polyene chromophore (H. Deeth, personal communication), or it encourages an oxidation reaction. Alternatively, some of the decolourising agents may initiate the oxidation of β-carotene by attacking the cyclohexenes, so causing the ring to open. A secondary oxidation occurs at the hyperperoxide sites, which leads to a less conjugated chain and, as a consequence, the milk appears whiter. However, the addition of titanium oxide (0.02–0.05 g 100 g–1) to the cheese milk physically masks the yellow colour of the β-carotene (i.e. does not destroy it) by enhancing the light dispersion and giving the impression of whiteness (Kosikowski & Mistry, 1997). Incidentally, titanium oxide is commonly used as a white pigment during the manufacture of toothpastes and white paints (D. Godfrey, personal communication). In traditional cheesemaking the titanium oxide may precipitate during the renneting stage. However, if the titanium oxide is added to the UF retentate, it should be homogenised into the ﬂ ow, which can affect the wear and tear of the homogenising head.

3.3.4 Lipase A wide range of lipase enzymes (e.g. animal, lamb, kid, fungal or mixtures) have been added to cow’s milk retentate to partly hydrolyse the milk fat and enhance the sharp or ‘rancid’ taste in Feta-type cheeses (Tamime & Kirkegaard, 1991). The enzyme is normally added to the milk before the coagulant; however, the amount of added enzyme that can be used varies with the source/type, and cheesemakers

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should follow the instructions of the supplier. A typical example is to use Chr. Hansen lipase at a rate of 5 g 1000 kg–1 retentate depending on the desired level of lipolysis required in the cheese (E. Høeier, personal communication). Few data are available on the use of lipase enzymes in brined cheeses, but the use of Palatase A 750 L (derived from Aspergillus niger) signiﬁ cantly (P < 0.01) increased the soluble nitrogen, ripening index and acid degree value of Tulum cheese. The organoleptic properties of the product were not improved, and the lipase was not recommended as a means of accelerating the maturation of Tulum cheese (Koçak et al., 1995). A commercial preparation of pregastric lipase enzyme (2–6 g 100 L–1) accelerated the development of free fatty acids (FFA) and volatile FFA in Turkish white brined cheese, and the recommended level of addition to milk was 4 g 100 L–1 (Akin et al., 2003; Aydemir et al., 2001).

3.3.5 Preservatives The growth of spore-forming bacteria in Feta and other related products made in bulk in metal tins (ca. 20 kg) can cause gas production, which may lead to blowing of the containers, but the addition of potassium nitrate (0.2 g kg–1; also known as saltpetre) or sodium nitrate (5 g 100 kg–1) to the cheese milk tends to suppress the growth of these microorganisms. Alternatively, other preservative compounds (e.g. Nisin or potassium sorbate) could be added to the brine during the production of UF Feta-type cheeses (Tamime & Kirkegaard, 1991; Welch, 1985). The use of these preservatives in Feta-type cheeses in many countries is regulated by existing legal standards and, in some instances, they are prohibited. However, the permitted residual amount of potassium nitrate, sodium nitrate or a combination of both should not exceed 50 µg 100 g–1 in Canadian cheeses (http://www.canlii.org/ca/reg/crc870/ secb.08.033.html; see also El-Gendy et al., 1989; Magdoub et al., 1988). Sodium benzoate solution (30 g kg–1) can be added as a thin layer on top of cast Feta-type cheese before sealing the metal container and storage at 5°C (Wium & Qvist, 1998a), but the use of sodium benzoate as a preservative in brined cheeses is, in many countries, regulated by existing legal standards. The addition of potassium sorbate (up to 0.3 g 100 g–1) to milk before the manufacture of Turkish white pickled cheese reduced the starter culture activity and inhibited the growth of coliforms, faecal streptococci, yeasts and moulds, but not the lactobacilli, staphylococci or micrococci (Doğruer et al., 1996).

3.4 Recombined Feta-type cheeses 3.4.1 Introduction In countries where milk production is low or underdeveloped, recombined dried dairy ingredients are used for the manufacture of a wide range of milk products including cheese. The International Dairy Federation (IDF, 1979, 1982, 1990, 1999) has published bulletins and monographs to cover a wide range of technical aspects in this ﬁ eld.

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Table 3.6 Proximate compositional quality (g 100 g–1) of different powders used for the manufacture of Feta-type cheeses

Constituent Powder Type Protein Fat Lactose Whole milk powder (WMP) Commercial 26 26 39 Retentatea 42 42 9 Skimmed milk powder (SMP) Commercial 39 0.6 53 Retentatea 42–85b 1.0–1.6 1.0–46.0 a Ultraﬁ ltration and diaﬁ ltration processing were used to reduce the lactose level in the retentates before evaporation and drying. b Range of different powders. Data adapted from Tamime & Marshall (1997), Tamime & Robinson (1999) and http://www.doitwithdairy.com

A wide range of milk powders (e.g. whole milk powder (WMP), skimmed milk powder (SMP), WMP-retentate or SMP-retentate) are available on the market, which are suitable for the manufacture of different cheeses, and the compositional quality of such powders is shown in Table 3.6. It is evident that the choice of milk powders is based on their physical, chemical and microbiological specifi cations, and detailed aspects of these criteria that can affect the quality of Feta-type cheeses have been reported by Sjollema (1988) and Kjaergaard-Jensen (1990); the specifi cation for powders is published by the American Dairy Products Institute (ADPI, 1990; this organisation was previously known as the American Dry Milk Institute – ADMI). Some specifi c requirements of SMP to be used for recombination in cheesemaking have been reported by Wilcek (1990) and include the following: • whey protein nitrogen index, >6 mg undenatured whey protein nitrogen per gram powder; • cystein number, 31–38; • thiol number, <7.5; and • heat number <80. These specifi cations classify the powder(s) as low heat, which is ideal for the manufacture of cheeses. The powders should be free from any inhibitory agents as their presence will inhibit the growth of the starter culture; however, other specifi cations for powders, which could benefi t cheesemakers, are shown in Table 3.7.

3.4.2 Recombination of powders Dairy powders are recombined in water at ca. 40–50°C, cooled to 10°C and, to hydrate properly (i.e. allow the protein to stabilise), the milk should be allowed to stand for at least 6 h. In some instances, the recombined milk is left until the following day, but the microbiological quality of the water is highly critical. The cheese milk is handled in a manner similar to that described elsewhere (i.e. pasteurisation, cooling and cheesemaking), and it is recommended that the calcium content is adjusted to ~0.2 kg 1000 kg–1 of milk when the coagulant is added (Tamime & Kirkegaard, 1991).

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Table 3.7 Some general speciﬁ cations of skimmed milk powdera

Constituent/miscellaneous tests Sjollema (1988) ADPI (1990) Chemical composition Fat (g 100 g–1) 1.00 1.25 Moisture (g 100 g–1 4.00 4.00 Lactic acid + lactates (mg 100 g–1) 0.15 0.15 Physical measurements Scorched particles Bb or better B or better Insolubility index (mL) 0.5 1.25 Insolubility high-heat powder (mL) 1.2 2.0 –1 c NO3 (mg kg ) 30.0 NR Sensory Flavour and appearance Normal Normal Microbiological counts (cfu g–1) Total viable count (37°C) 50 × 103 50 × 103 Plate count (55°C) 10 × 103 NR Themoduric spores 1 × 103 NR Enterobacteriaceae 10 NR Salmonella Absentd NR Staphylococcus aureus 10 NR Clostridiae 50 NR Bacillus cereus 100 NR Yeasts and moulds 100 NR a All specifi cations are for maximum observations. b Disc B (15.0 mg). c Not reported. d The count in 25 g. e Sulphur dioxide-reducing strains. Specifi cations for contaminants, such as afl atoxin, pesticides, polychlorbuphenyls and heavy metals are detailed by Sjollema (1988) but not in ADPI (1990).

Batch or continuous methods are available on the market for the recombination of powders depending on the scale of daily production, and some of these systems have been reported by Tamime & Robinson (1999) and Anonymous (2003b). At present, recombination units that hydrate the powders under vacuum without the incorporation of air have become very popular, and details of such systems have been reviewed in a separate book (Fermented Milks) to be published within this Technical Series prepared on behalf of the Society of Dairy Technology (SDT) in the UK (Tamime, 2006). Nevertheless, some examples of recombination methods that can be used for Feta-type cheeses have been reviewed by Tamime & Kirkegaard (1991), and it is highly recommended that the cold recombined milk is left to hydrate properly. Some recently developed methods for recombined cheese manufacture are as follows.

3.4.3 Mimic the traditional method of production Recombined skimmed milk powder (e.g. 8.5–9.0 g solids 100 g–1; aged for 6 h) is prewarmed to ~40°C, and pumped through a duplex ﬁ lter to remove any residual undissolved or scorched particles before it is blended with AMF. Afterwards, the

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milk is warmed to 60°C, homogenised, heat treated and cooled to 30°C for production of the cheese (see also Dokhani, 1993, 1998). In some cases, the melted AMF (~60°C) is metered into the recombined milk just before the homogenisation stage. Nevertheless, this method of manufacture will not be detailed as it is not widely used at the present time.

3.4.4 Ultrafiltration of recombined powders An alternative method of manufacturing Feta-type cheeses in developing countries is to UF the recombined skimmed milk. The powder is rehydrated to 14–16 g solids 100 g–1 and processed in a similar manner to that described in Section 3.2.5. Since the powder may contain high counts of spore-formers, it is highly recommended that the milk is microfi ltered or bactofugated before the manufacture of cheese. In some countries where the availability of fresh milk is limited, SMP is recombined in the milk to 14–16 g solids 100 g–1, ultrafi ltered and made into cheese as described elsewhere. In doing so, the cheese yield is improved due to the retention of higher levels of lactose in the processed milk, and the yield can be even further increased by adding a reverse osmosis (RO) retentate of the UF permeate to the fat-standardised cheese milk to boost the lactose content. Alternatively, Moroccan Jben (i.e. brined-type) was made successfully from fresh milk, recombined milks (9 g SNF 100 g–1 plus 3.5 g AMF 100 g–1 or 18 g SNF 100 g–1 plus 7 g AMF 100 g–1) or blends of fresh milk and recombined milks at ratios of 25:75 or 50:50. The quality of the products was good, but the Jben made from recombined milks containing the highest level of total solids had the lowest moisture content, higher pH and fi rmer and rubber-like texture when compared with other cheeses (Zahar et al., 1997; see also Hamama et al., 1998, 2003).

3.4.5 Miscellaneous recombination methods Casein (acid and rennet) and caseinates (calcium, potassium and sodium) have been used to manufacture laboratory-scale Sudanese Gibna Baida (Ali & Robinson, 1990, 1992). The casein products were not suitable due to diffi culty in recombination and the low pH of the acid casein; however, cheeses made with the caseinates were far better, but the type of caseinate infl uenced the structure and the coarseness of the product. High-protein skimmed milk powders (ca. 73.5 g 100 g–1) can be recombined for the manufacture of Halloumi cheese, and the powder characteristics (i.e. by decreasing the heat treatment of the liquid skimmed milk before drying) can infl uence the stretch and melt properties of the product (Lelievre et al., 1991); such powder may be suitable for the manufacture of Feta-type cheeses. Kuo and Harper (2003) used commercially available skimmed milk protein concentrate powders (ca. 56, 69 or 83 g 100 g–1) for recombination with sweet and unsalted butter for cast Feta-type production, and concluded the following: (a) the rehydration time did not affect the quality of the product; (b) the cheese made with the lowest level of protein had more defi ned irregular structure characteristics and was harder compared with the rest of

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the cheeses, whilst the cheese made with high-protein powder (83 g 100 g–1) had more void spaces, a spongy structure, and a very soft texture – such ‘faults’ could be minimised with the addition of lactose to the recombined milk; and (c) powders up to 83 g protein 100 g–1 could be used successfully for cast Feta-type cheeses. Alternatively, a similar powder (ca. 48.6 g protein 100 g–1) was blended with whole milk for the manufacture of Feta-type cheese; the product had similar qualities to the control cheese, but a better yield was obtained from the experimental product (de Block et al., 1996). In a model experiment, skimmed milk powder (36 g protein 100 g–1), retentate powder (82.3 g protein 100 g–1) and AMF were recombined to make Turkish white- brined cheese containing 12.5, 14.0, 15.5 or 17.0 g protein 100 g–1; all the cheeses were similar, but the higher protein contents in the product affected proteolysis (Avsar et al., 2001, 2002).

3.5 Plant specification

As the scale of Feta-type cheese production increases, the use of mechanisation to receive the milk, and handle and process the milk (e.g. UF retentate, recombined milk and/or GDL method) to make the cheese becomes inevitable. A wide range of equipment is available for the manufacture of UF Feta-type cheeses (see Tamime & Kirkegaard, 1991), but the ﬁ nal choice is primarily governed by the overall capital cost, the method or process adopted, and the quality parameters of the product. Table 3.8 lists the major equipment that might be required for the production of Feta-type cheese using the BAF method from UF milk, including the recombination of dairy ingredients. Most of the equipment required for the production of the cheeses is broadly similar, but different equipment is required for handling the liquid milk and the recombined milk.

3.6 Implementation of a hazard appraisal (analysis) critical control points (HACCP) system

In theory, the only way of ensuring that every carton of Feta-type cheese from, for example, a BAF production line, is safe (i.e. from a chemical and microbiological standpoint) is to test every carton – clearly such a suggestion is ludicrous and unacceptable. Instead, a representative number of cartons are withdrawn according to a sampling plan appropriate for the product and the batch of production. Such an approach may be essential to conﬁ rm that preset standards of hygiene are being met and that potential contaminants are at a low level or absent, but the procedure is never 100% foolproof and can never prevent some spoiled cartons from reaching the consumer. Nevertheless, the emphasis within quality assurance has turned to the avoidance of problems, a concept that forms the basis the HACCP system (Tamime & Robinson, 1999). Thus, the adaptation of an HACCP system for Feta-type cheese will involve

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1 a –1

0 Table 3.8 Simplifi ed plant specifi cation of the Tetra Tebel Casofi ll® BAF production lines to manufacture Feta-type cheese; capacity 100 000 L d of fresh milk 4

Production function Number required Liquid milk Number required Recombinedb Milk/powder 2 Silos (2 × 50 000 L) 1 or 2 Storage area for powder and anhydrous milk fat reception 1 of each Air eliminator, fi lter, metering unit, intermediate (AMF) storage, balance tank, PHEc (see Fig. 3.2) 1 Unloading bay 3 Pumps 1 Fork-lift truck 1 Vacuum mixing unit and vessel fi lled with water 2 Silo tanks for powder 3 Circulation tanks 1 Circulation pump Pretreatment 1 Balance tank Similar equipment to that for liquid milk 2–3 Pumps pretreatment (fat separator is not required) 1 PHE/cooling – 10 000 L h–1 1 Filter unit (see text) 1 Microfi ltration or bactofugation plantb 3 Rehydration storage tanks 1 Fat separator – 10 000 L h–1 1 Melting tank for the AMF 1 Fat standardisation unit 1 Metering unit for dosing the AMF into the milk }

Cheese production

BAF module 1 1 Intermediate storage tank (10 000 L) 1 PHE (10 000 L h–1) 1 Ultraﬁ ltration plant (6 500 L h–1) BAF module 2 1 Balance tank 1 PHE (3 000 L h–1) 1 Homogeniser (10 000 L h–1) BAF module 3 2 Fermentation tanks (10 000 L each); different tanks are used for the glucono-δ-lactone (GDL) (see text) 116/05/2006 12:11:47 6 / 0 5 / 2 0 0 6

1 2 : 1 1 : 4 7 11405124601_4_003.indd 105 4 0 5 1 2 4 6 0 1 _ 4 _ 0 0 3 . i n d d

–1 1 1 Dry salt dosing unit (0.5–5.0 kg min ) 0 5 1 PHE (3000 L h–1) Packaging and 1 Rennet dilution tank (60 L) storage 1 Rennet dosing unit (15–45 L h–1) 1 Tetra Brik Aseptic (TBA/8 – 3 000 L h–1 for 500 mL capacity; TBA/19 – 1500 L h–1 for 200 mL capacity) 1 Storage at ambient temperature (~20 m2 or enough for 16 (Euro) pallets per batch of 10 tonnes of UF Feta) 1 Cold store at 5–7°C (area suffi cient for approximately for 1 week’s production) CIPd system 3 Detergent tanks (depending on total plant throughput; volume of each tank may range between 5000 and 10 000 L) 1 PHE (3 000 L h–1) Miscellaneous – Control panels depending on degree of automation – Stainless steel valves, fi ttings and pipes required in each of the sections mentioned above 1 Boiler to generate hot water and steam (1500 kg h–1 at 0.3 MPa at peak requirement) 1 Water treatment plant (~80 000 L d–1) 1 Effl uent treatment plant (~60 000 L d–1) 1 Compressed air (15 L min–1 at 2°C and 0.6 MPa) 1 Chilled water (5000 L h–1 at <2°C and 0.3 MPa) 1 Electricity supply

aBAF = Bacteriologically Acidiﬁ ed Feta. Industrial ManufactureofFeta-Type Cheeses bRefer to Anonymous (2003b) for further details regarding plant speciﬁ cations for recombination of powder. cPHE = plate heat exchanger, to cool the milk; thermisation is optional. dCIP = cleaning-in-place. 105 116/05/2006 12:11:47 6 / 0 5 / 2 0 0 6

1 2 : 1 1 : 4 7 106 Chapter 3

top management and their support for the dairy operatives who are charged with running the monitoring procedures on a day-to-day basis. Detailed specifi cations (e.g. chemical, physical, microbiological, organoleptic and storage conditions) of the raw milk at reception, other ingredients (powders, AMF, additives; see Section 3.3) and packaging materials, processing of the milk, production of the cheese and the fi nal product have to be drafted. A fl ow-diagram of the overall BAF process for the production of Feta-type cheese and annotating it with indications of the likely control points (CP) will help to identify the steps that might be considered as critical (i.e. CCP). Figure 3.10 shows the relative importance of the identifi ed CPs within the BAF process, which helps in the establishment of the HACCP system as part of total quality management within a food production organisation. In addition, other aspects, such as human factors, services, equipment, analytical methodologies

Reception and storage of raw materials1 CP2, 3, 4, 5 & 6

Preliminary treatment of milk (pre-heating, fat separation and standardisation, and spores removal) CP3 & 4

Microfiltration CP3 & 4

Processing, homogenisation, heat treatment7, fermentation, salting and heating CP3 & 4

Renetting, packaging and ambient storage CP3, 4 & 5

Cold storage 5-7ºC, maturation and dispatch CP3, 4, 5 & 6

Fig. 3.10 Typical Hazard Appraisal Critical Control Points (HACCP) scheme for the production of Feta-type cheese using the Bacteriologically Acidiﬁ ed Feta-type (BAF) method. Key: 1Raw materials (e.g. liquid milk, powders, AMF, added ingredients (see text) and packaging materials). 2Control points (CP). 3Physicochemical. 4Microbiological. 5Visual. 6Organoleptic. 7Critical control point (CCP).

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and possible interactions, should be also detailed, and a chart that highlights the records that are required in the cheese factory also helps during the establishment of the HACCP system. Illustrations of such ﬂ ow diagrams for yoghurt production encompassing the HACCP system have been described by Tamime & Robinson (1999), and these can be adapted and/or modiﬁ ed for the production of UF Feta-type cheese (see also Mauropoulos & Arvanitoyannis, 1999).

3.7 Conclusion and future development(s)

The UF method of cheesemaking may have some disadvantages, such as: • greater reliance on mechanisation and automation, especially in industrialised countries; • a high initial capital investment is required; • highly trained dairy operatives/cheesemakers are required; • there is greater need for more effective sanitation, good manufacturing practice (GMP) and the hazard appraisal (analysis) critical control points (HACCP) system; and • the ancient craft/art of cheesemaking could be lost for ever. It is evident that, over the past two decades, UF technology has been adapted successfully for the manufacture of Feta-type cheeses in large industrial-scale operations (Tamime & Kirkegaard, 1991). The present trend is for the Tetra Tebel Casofi ll® BAF method to be more widely used; however, future development(s) will focus on more technological advances including automation and mechanisation. Microfi ltration of the milk is becoming widely used in many Middle Eastern countries not only for cheesemaking, but also for the preliminary treatment of market milk because of high microbial counts in the raw milk (~1–10 × 106 cfu mL–1). The choice of this method to remove bacteria from raw milk is primarily based on its better effi ciency when compared with the bactofuge. Nevertheless, the current method of making brined cheese varieties offers several advantages including: • centralisation of cheesemaking with greater reliance on highly mechanised/automated and continuous production lines; • saving in manpower, less requirement for coagulant, and a better recovery of milk solids that helps to increase the yield of the cheese; • lower overall energy consumption and reduction in whey disposal problems (but not the permeate); • smaller fl oor area is required, because some of the cheesemaking equipment (i.e. vat or tanks) has become obsolete; • the compositional quality of the product has become easier to control (Tamime & Kirkegaard, 1991).

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Future developments in UF Feta-type cheesemaking might include the following: • the use of wider blends of microorganisms in the starter culture including the capsule-producing strains (Kehagias et al., 1995; Elsborg, 1997; Hassan et al., 2002); • production of low-fat or fat-free cheeses (Gursel et al., 2003; Hassan et al., 2002; Katsiari & Voutsinas, 1994; Katsiari et al., 2002 Kondyli et al., 2002; Michaelidou et al., 2003; Volikakis et al., 2004; Wium et al., 2003); • probiotic cheese (El-Kholy et al., 2003; Ghoddusi & Robinson, 1996; Mehanna et al., 2002; Psomas et al., 2001; Yilmaztekin et al., 2004); release of CO from Feta-type cheese (Vivier et al., 1996); • 2 • reduction in sodium content (Abdel-Rafee et al., 2003; Katsiari et al., 1997, 2000a, 2000b 2002; Kondyli et al., 2002); and • replacement of the milk fat with fat substitutes (El-Sheikh et al., 2001; Romeih et al., 2002; Sipahioglu et al., 1999) or the use of different salts (Güven & Karaca, 2001).

In view of the fact that labour costs in the majority of developing countries are low, mechanisation and/or automation of certain parts of the cheesemaking production line, for example, the packaging of cartons in cardboard trays, overwrapping with plastic sheeting and stacking onto pallets, may not be installed at the present time, but could merit some consideration in the future. It is of interest to report that the current consumer trend is for smaller portions of Feta-type cheese (i.e. reduction of size from 500 mL to 200–250 mL). Although this trend may be governed by the smaller number of persons per household in Western countries, in Iran also, for example, consumers are demanding more convenient packs. As a consequence, more packaging machines are required on the production line(s), and the reliance on automation will increase in order to enhance the efﬁ ciency of the dairy operative. The current capacity of most production units of UF Feta-type cheese in Middle Eastern countries is ~10 tonnes h–1, and there is no evidence that this capacity is going to increase in the near future. However, three underlying strategic trends in countries producing UF Feta-type cheeses can be discerned. • To improve the utilisation of the permeate in fruit juice production. However, the daily volume is rather small per unit of operation and it may not be eco- nomically feasible to invest in permeate processing equipment unless different production units pool together to develop and utilise the permeate; this approach is environmentally friendly. • To install more membrane ﬁ ltration units to recover the waste water for reuse. • To reduce the manufacturing cost of UF Feta-type cheese. It is possible to fore- cast that in some developing countries, the use of fresh milk in cheesemaking will be replaced by cheaper ingredient(s), for example retentate powders, and the fresh milk could be utilised to produce higher value products.

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P. Papademas

4.1 Historical background

Halloumi (χαλλούμι) is the traditional cheese of Cyprus and, according to legend and published data, it has been produced on the island for hundreds of years (Economides, 2004). The name Halloumi may have originated from the Arabic word ‘helime’ for cheese. Most of the words of the Cypriot dialect that have (-ούμι) as their last syllable are of Arabic origin. It has also been suggested that the name ‘Halloumi’ could have been derived from the ancient Greek word meaning salt, or from the Italian word ‘salamoia’, which means brine (Anonymous, 1999a). It is alleged that the cheese was introduced to Cyprus by Arab mercenaries from Syria and Palestine, who settled on the island during the Frankish rule (AD 1192– 1489). The ﬁ rst references that link Halloumi with Cyprus date back to 1554, when Florio Bustron refers to the sheep and goats of Cyprus, and a cheese named Halloumi (in Italian, ‘calumi’) made from a mixture of sheep’s and goat’s milk (Economides, 2004). Also in 1643, Monk Agapios in his book ‘Agronomics’ mentions a recipe from Cyprus on how to make Halloumi cheese; further, in 1788, Kyprianos of the Cyprus Church, in his historical review, describes Halloumi cheese as ‘delicious’ and that ‘quantities were sold abroad’.

4.2 The importance of Halloumi cheese to the Cypriot economy

As shown in Table 4.1, Halloumi cheese production in Cyprus has increased over the last few years from 4730 tonnes in 1999 to 6600 tonnes in 2002. This promising trend reﬂ ects the positive picture of the total Halloumi cheese exports. Gibbs et al. (2004) reported that Halloumi cheese accounts for 27% of the processed

Table 4.1 Cheese production in Cyprus (tonnes)

Year Cheese milk 1999 2000 2001 2002 Cow 680 820 990 800 Goat 2750 2870 3450 4000 Sheep 1300 1330 1600 1800 Total 4730 5020 6040 6600 Data compiled from FAO Statistics in 2004 (www.faostat.com).

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agricultural products exported, and is the largest sector. Exports worldwide have shown a dramatic increase, from just under 3000 tonnes in 2001 to around 4000 in 2003. As shown in Table 4.2, important markets for Halloumi cheese in 2003 were the UK (972 tonnes), Greece (601 tonnes), Germany (430 tonnes), Kuwait (401 tonnes), United Arab Emirates (UAE) (364 tonnes) and Saudi Arabia (265 tonnes). The European market accounted for 60% of the total exports in 2003, whereas the fi gure for the Arab markets for the same year was 31%. The corresponding fi gures for the US market were 157 tonnes in 2001 compared with 224 tonnes in 2003, representing an increase of 30%. Looking at the 1999 fi gure of 151 tonnes, imports to the USA have nearly doubled in fi ve years. The same trend is observed in the Australian market, where in 1999 56 tonnes were exported compared with 109 tonnes in 2003. According to the Cyprus Statistical Department, the export value of Halloumi cheese in 2003 was CY£10.5 million compared with CY£6 million in 1999. The above data show that Halloumi cheese production is very important for both the domestic and the export markets.

4.3 Forecasts on the future of Halloumi cheese

Halloumi cheese has gained collective trademarks in Greece in 2000, at EU level in 2002 as well as in the USA in 1999. The local authorities have recently applied for Protected Designation of Origin (PDO) labelling of Halloumi cheese in the EU. The PDO labelling of Halloumi cheese will prove to be a powerful marketing tool as no other country will attempt to produce a similar cheese and name it Halloumi. The above developments together with the fact that Cyprus is a full European Union (EU) member state and that the market of Halloumi cheese is not fully exploited have led to new major domestic competitors. Recently, the newest and largest dairy company on the island processing only fresh milk announced that it was planning to enter the Halloumi cheese market in the early part of 2005.

4.4 Raw materials used for the production of Halloumi cheese 4.4.1 Milk Milk from sheep and goats is mainly produced in countries situated in the Mediterranean basin, and is almost exclusively used for producing cheese. These milks are considered important for the dairy industry of the Mediterranean countries and also for the Middle East. In Cyprus, for example, goat’s and sheep’s milk represents 30% of the total milk production (see Table 4.3). Milk from sheep and goats is utilised in the production of traditional dairy products, such as Halloumi, and yoghurt. More recently, two large dairies placed pasteurised goat’s milk on the market. In Cyprus, goat’s milk is produced, to a large extent, by the imported Damascus breed, the cross-bred population of Paphos goats, the local breed of Macheras and, more recently, by the imported French Alpine breed. Moreover, in Greece the great majority (85%) of cheeses and about 95% of whey cheeses

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1 1 9

Table 4.2 Export of Halloumi cheese (volume and value) to different countries

1999 2000 2001 2002 2003 Country Tonnes CY £ (× 1000) Tonnes CY £ (× 1000) Tonnes CY £ (× 1000) Tonnes CY £ (× 1000) Tonnes CY £ (x 1000) Europe (EU) UK 597 1411 656 1556 786 1910 889 2230 972 2547 Greece 273 639 379 897 424 1084 384 988 601 1610 Germany 111 249 192 438 188 461 310 772 430 1161 Others 281 647 284 658 335 802 341 827 392 1027 Total EU 1262 2946 1511 3549 1733 4257 1924 4817 2395 6345 Middle East (ME) Lebanon 186 458 106 285 112 302 102 275 92 246 Kuwait 286 673 363 950 297 784 309 816 401 988 United Arab Emirates 312 730 389 1058 299 791 343 911 364 886 Saudi Arabia 194 450 215 564 190 494 205 530 265 681 Others 68 141 75 164 100 255 83 203 116 256 Total ME 1046 2452 1148 3021 998 2626 1042 2735 1238 3057 Rest of the world USA 151 471 202 696 157 534 164 803 224 747 Australia 56 168 81 253 59 181 59 182 109 302

Others 7 16 17 42 30 66 6 18 10 29 Halloumi Cheese Total rest of the world 214 655 300 991 246 781 229 1003 343 1078 Total exports 2522 6053 2959 7561 2977 7664 3195 8555 3976 10480 After Anonymous (2004). 119 116/05/2006 12:16:30 6 / 0 5 / 2 0 0 6

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Table 4.3 Milk production in Cyprus (1000 tonnes)

Year Type of milk 1999 2000 2001 2002 2003 Cow 132.5 146.6 141.5 144.0 149.0 Goat 28.5 29.2 36.1 40.0 40.0 Sheep 17.1 18.0 21.8 23.5 24.0 Data compiled from FAO Statistics in 2004 (www.faostat.com).

(Mitzithra, Manouri) and over 65% of yoghurt are made from goat’s and sheep’s milk (Alichanidis & Polychroniadou, 1996). All the sheep ﬂ ocks in Cyprus belong to the same breed, originating from the Greek island of Chios. The local breed (i.e. fat-tailed sheep) is limited to 500–600 animals, and a project is underway to increase their number. The typical chemical composition of sheep’s milk from Paphos and Nicosia is approximately the same: the fat contents were 5.86 g and 6.30 g 100 mL–1, respectively; while the protein contents were 5.45 g 100 mL–1 for milk from Paphos and 5.40 g 100 mL–1 for the Nicosia milk (Anonymous, 2000). Approximately the same data have been reported by Economides (2004) (see Table 4.4). Variations in milk composition are evident within breeds of sheep, goats and cows. For example, the average fat content of milk is 9.05 and 6.20 g 100 g–1, and protein content 6.52 and 5.40 g 100 g–1, respectively, for the Vlachiki (Greece) and Welsh Mountain breeds of sheep (Bencini & Pulina 1997). Also the milk from goats differs within breeds. The Epirus (Greece) goat produces milk with fat and protein contents of 5.18 and 3.56 g 100 mL–1, respectively, while French Alpine goats produce milk of 3.45 g fat 100 mL–1 and 2.94 g protein 100 mL–1 (Alichanidis & Polychroniadou, 1996). Similar differences are also reported for different breeds of cows. For example, Jersey and Guernsey breeds produce, on average, exceptionally high-fat milk (5.75 and 5.0 g 100 g–1, respectively) having casein contents of 3.0 and 2.7 g 100 g–1. In addition, Friesian and Ayrshire dairy cattle will produce milk of 4.0 and 3.85 g 100 g–1 fat, and casein of 2.6 and 2.5 g 100 g–1, respectively. Cow’s milk

Table 4.4 Chemical composition (g 100 g–1) of different mammalian milks used in Halloumi cheesemaking

Constituent Sheep’s Goat’s Cow’s Mixture (sheep’s & goat’s) Total solids 16.84 13.22 11.33 14.96 Fat 6.20 4.33 3.34 5.26 Protein 5.50 3.75 2.86 4.57 Calcium 0.18 0.11 0.11 0.15 Ash 0.90 0.83 0.77 0.84 Casein 4.25 2.97 2.04 3.64 Lactic acid (mL 100 mL–1) 0.14 0.14 0.12 0.14 pH 6.67 6.61 6.66 6.61 After Economides (2004).

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production in Cyprus is utilised for market milk and the manufacture of different dairy products, and it is almost exclusively produced by Friesian dairy cattle. Sheep’s and goat’s milk is whiter than cow’s milk owing to the lower content of β-carotene (Alichanidis & Polychroniadou, 1996; Jandal, 1996). There are signifi cant differences in the composition of cow’s, goat’s and sheep’s milk. The differences are refl ected in the gross chemical composition (i.e. fat, protein, lactose, minerals), and also in the amounts of free fatty acids (FFA) (Papademas, 2000). In addition, goat’s milk has a piquant, peppery fl avour due to the signifi cant amounts of caproic, caprylic and capric acid produced by the action of the indigenous lipoprotein lipase (LPL) on the milk fat (Deeth & Fitz-Gerald, 1995). Sheep’s milk has a rich taste and a special odour, probably related to the fatty acid composition with its increased amount of capric acid. Goat’s milk is also different from both sheep’s and cow’s milk because of its greater amount of medium-chain fatty acids (see also Chapter 1). Overall, short- and medium-chain fatty acids in goat’s and sheep’s milk represent 10–12 g 100 g–1 of the total fatty acids compared with 3–4 g 100 g–1 in cow’s milk (Alichanidis & Polychroniadou, 1996). Butyric acid is an FFA with a pronounced fl avour of its own, so infl uencing the fl avour of cheese. Sheep’s milk contains a greater proportion of butyric acid than the other two types of milk – a probable explanation for the superior fl avour of cheeses made with sheep’s milk. Some of the factors that might affect the quality of milk and, hence, the cheese include the breed, the lactation period, feeding regime (Papademas & Robinson, 2002) and the general management of the fl ock (Frenaritou, 1998). The Cyprus Milk Industry Organisation (CMIO) together with the Veterinary Services of Cyprus is responsible for monitoring the quality of milk distributed to dairies. The tests that are carried out daily consist of total viable counts (TVC), somatic cell counts (SCC), antibiotics (presence/absence) in accordance with the European Union (EU) Directive on the Hygiene of Milk and Milk Products (EU, 1992).

4.4.2 Salt Salt is considered an integral part of the manufacture of Halloumi cheese as it contributes to the taste of fresh Halloumi cheese, and controls the multiplication of pathogens and/or spoilage microorganisms. Salt is also important in the maturation of Halloumi because the fresh cheese is immersed in whey brine of 12 g NaCl 100 mL–1, until it is matured.

4.4.3 Mint The Mentha genus comprises 25 variable species of aromatic perennials that belong to the family of Labiatae/Lamiaceae. Mentha viridis is a sweetly scented perennial with bright-green, ovate, wrinkled leaves (Bown, 1995). The bright-green M. viridis has been used as culinary mint since Roman times. Its essential oil (D-carvone) is less pungent than spearmint oil, and is nonirritant. Menthol is one of the major

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fl avour compounds of Mentha × piperita (Rohloff, 1999). Menthol-rich mints are only used with sweet foods (chocolate, ice cream and confectionery). Mint (M. viridis) is usually added to Halloumi cheese during the dry salting stage. Since the addition of mint is not standardised or compulsory, the dairies follow different regimes. However, the impact of mint on the fl avour of Halloumi cheese has been studied by Papademas (2000), and the results show that fl avour compounds, such as limonene and D-carvone, can impart fruity citrus-like and mint fl avour notes to the product.

4.4.4 Coagulant At present the coagulant that is extensively used for Halloumi cheese production is of non-animal origin (e.g. Formax) allowing it to be labelled ‘suitable for vegetar- ians’ whereas smaller dairy factories use commercial animal rennets. The amount of rennet used is ~1 mL 100 mL–1 to provide a ﬁ rm coagulum in about 60 min.

4.4.5 Starter cultures In Cyprus, Halloumi cheese production is made without the addition of starter cultures, but they can be used to ripen the milk in some Middle Eastern countries or elsewhere in Europe to produce Halloumi-type cheese (Robinson, 1991); the subsequent heating (i.e. the cooking stage at 90°C for 30 min) will destroy most of the living cells. The use of salt-resistant, acid-resistant, probiotic microorganisms (i.e. Lactobacillus casei subsp. casei) added in the whey brine could prove a promising development (Gobbetti, 2000).

4.5 Manufacturing methods 4.5.1 Outline of the traditional process Traditional Halloumi cheese is made from raw sheep’s milk or a mixture of sheep’s and goat’s milk. No commercial or natural starter cultures are used, and changes in the fl avour, and probably the texture, depend solely on the indigenous microfl ora of the milk. During the maturation stage, the yeasts present in the salted whey used for storage, and non-starter lactic acid bacteria originating from the dairy’s environment, are also important in the evolution of fl avour. After coagulation of the milk with animal coagulant in a 500 L vat, the curd is cut manually into small cubes that will be left to rest and precipitate for a few minutes. The curd is then collected, and transferred to small plastic perforated conical moulds (11 cm in height, 10 cm upper diameter, 8 cm lower diameter, and with a capacity of 350 g of curd) (Fig. 4.1). Without applying any pressure, the curd is left to drain for about 1 h, and the whey is collected to be used for the preparation of the brine. As the curd is left to drain, the collected whey is transferred to a cooking vat where it is heated to 90–95°C under continuous stirring. This causes denaturation of the whey proteins, which consequently fl oat to the surface of the vat. Using a

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Fig. 4.1 Plastic perforated moulds used in traditional and industrial Halloumi cheese manufacture.

ladle, the soft denatured whey proteins are collected and placed in plastic perforated moulds (straw moulds were used in the old times), and left to drain. This is called Anari cheese, an analogue to Ricotta – a soft whey cheese variety. Anari can be consumed fresh and unsalted within 2 days of manufacture, or salted in whey brine and dried – shelf-life exceeds 1 year. The next step during the manufacture of the cheese involves cooking the cheese blocks in the hot whey at 90°C for at least 30 min. This is a crucial step because it will determine the plasticisation of the curd. Moreover, half-cooked curds will give an irregular colour in the centre of the block (Papademas & Robinson, 1998); properly cooked cheese blocks will ﬂ oat to the surface of the hot whey. After cooking, the cheese blocks are dry salted and sprinkled with dry crushed leaves of mint (M. viridis) before being folded crossways and left to chill for a few hours (Figs 4.2 & 4.3). Afterwards, the cheese blocks are placed in containers varying in size between 1 and 5 kg, and ﬁ lled with salted whey (i.e. prepared from the whey used for boiling plus 12 g NaCl 100 mL–1) to cover all the cheese blocks. Fresh Halloumi cheese is the commercial product marketed directly after manufacture, that is, 24 h after production (Anonymous, 1985a); whereas mature Halloumi cheese is the commercial product marketed at least 40 days after manufacture (the cheese matures in salted whey – Anonymous, 1985b).

4.5.2 Outline of the industrial process and comparison with the traditional method The production of Halloumi cheese in modern dairies has been almost fully mechanised through the invention and construction of customised machinery made entirely

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Fig. 4.2 Sprinkling cooked Halloumi cheese pieces with salt and dry crushed mint leaves.

Fig. 4.3 Manual folding of cooked Halloumi cheese pieces.

in Cyprus. Pasteurised sheep’s milk is usually the main component, with mixtures of sheep’s and goat’s milk used much less. Although modern dairies also produce small quantities of cheese made exclusively from a mixture of sheep’s and goat’s milk, milk standardization is necessary to achieve the correct casein-to-fat ratio (i.e. ~0.7). After coagulating the milk with non-animal rennet in cheese vats of 3500 L capacity each, the curd is cut (1 cm3 cubes) using rotating horizontal and vertical stainless steel knives. The curd particles are left to rest and precipitate in the vat for few minutes in order to expel whey. A ﬁ rm coagulum and subsequent ﬁ ne cut-

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ting of the matted curd particles are very important in order to avoid fat loss into the whey. The curd particles are covered with a perforated stainless steel sheet, and pressure (0.35–0.4 MPa) is applied to fuse the curd particles and expel more whey (Figs 4.4 & 4.5). This step is not included in the traditional method of manufacture since the use of sheep’s milk produces a ﬁ rm coagulum that requires less draining than the cow’s–sheep’s/goat’s milk analogue. The pressed curd is then mechanically trans-

Fig. 4.4 Stainless steel perforated baskets used in industrial-scale Halloumi cheese manufacture.

Fig. 4.5 Stainless steel perforated baskets with rectangular moulds for manufacture of industrial Halloumi cheese.

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Fig. 4.6 Cheese vat with automatic lid for cooking Halloumi cheese in industrial-scale manufacture.

ferred to the cooking vat (Fig. 4.6) where it is cooked at temperatures of ~90°C for at least 30 min. The way in which the cheese is salted also differs in the industrial production of Halloumi cheese; the fresh product is not dry salted at all, but left to cool on a cheese table under controlled temperature conditions, and directly placed in 100 kg containers (Fig. 4.7) containing cool pasteurised whey with added salt (12 g NaCl 100 mL–1). Halloumi blocks will remain in the whey brine at 3–5°C for ~18 h, which is the time required for the cheese to reach the desired salt level (see Table 4.5). Finally, individual 300 g pieces of Halloumi cheese are removed from the whey brine, sprinkled with dry sterilised mint (120°C for 60 min), individually packed under vacuum, and stored in refrigerated stores at 2–4°C until distribution. However, mature Halloumi is packed in 1–5 kg plastic containers containing whey brine for at least 40 days at 15–20°C (Figs 4.8 & 4.9).

4.5.3 Experimental production of Halloumi-type cheese using ultrafiltration (UF) technology The review by Papademas & Robinson (1998) detailed the use of UF technology to produce a Halloumi-type cheese. The use of high-protein skimmed milk powder (HPSMP) (i.e. made from UF retentate of skimmed milk) in Halloumi cheesemaking produced a product of comparable chemical properties to the control cheese. The main differences were attributed to the physical properties of the cheese; the stretchability and meltability were negatively affected by the high level of calcium in the powder. Better results were obtained when UF powders derived from acidiﬁ ed milk were used.

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Fig. 4.7 Brining tank of Halloumi cheese.

Fig. 4.8 Halloumi cheese in retail stores.

4.6 Types of Halloumi cheeses 4.6.1 Fresh Halloumi cheese Fresh Halloumi cheese is semi-hard, elastic and has no obvious skin or rind. The texture is close with no holes and it is easily sliced. The colour of the cheese varies from white (when a mixture of sheep’s and goat’s milk is used) to yellowish (when the product is made completely from cow’s milk).

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Fig. 4.9 Halloumi cheese in retail stores packed both as individual pieces and in plastic containers ﬁ lled with whey brine.

Fresh Halloumi has a distinct aroma and a mild milky and creamy ﬂ avour. It is moderately salty and the dried Mentha leaves are added to the cheese during dry salting to give the product a ‘minty’ ﬂ avour. The cheese can be consumed directly, for example, served with fruit or vegetables, but it is usually grilled, fried or grated over a hot dish.

4.6.2 Mature Halloumi cheese As mentioned elsewhere, Halloumi is matured for at least 40 days, and the cheese blocks are kept usually at room temperature immersed in whey brine (10–12 g NaCl 100 mL–1) in plastic containers. During the maturation period, some perceived changes in texture and ﬂ avour take place. A typical textural change is easily detected in the hardness of the product and, in some, the cheese becomes very hard if kept in the whey brine for a prolonged period of time. This change is accounted for by the exudation of the serum from the cheese blocks to the whey brine because of the salt gradient. As a consequence, this results in a reduction of moisture content and a concomitant increase of salt content in the product. Mature Halloumi cheese has a close texture and tough body. Changes in the ﬂ avour of the cheese during the maturation period are detailed in Section 4.8.1.

4.6.3 Low-fat Halloumi cheese In Cyprus, low-fat Halloumi cheese is marketed by two large dairies under the brand names of Lite and Slim. A study by Papademas et al. (2000) has shown that the low-fat (19 g 100 g–1) and reduced-fat (11 g 100 g–1) Halloumi cheeses made from cow’s milk were

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harder and with a higher degree of fracturability than the full-fat product. Unlike the chemical and physical properties of the cheeses, the sensory characteristics of these products did not change considerably as the results showed that the taste panel (11 English nationals) equally accepted all three types of Halloumi, that is, full-, low- and reduced-fat. The tentative conclusion would be that a major market for low-fat Halloumi would be generated within the hotel, tourist or export markets. Moreover, as people are nowadays more health conscious, low-fat Halloumi, together with Anari (whey cheese) may be attractive options.

4.7 Chemical composition and microbiological quality of the cheese 4.7.1 Chemical composition The gross chemical composition of the fresh and mature Halloumi cheeses made from different milks and methods of manufacture is shown in Table 4.5 (see also Kaminarides et al., 2000; Papademas, 2000). The fat and total nitrogen (TN) contents, as well as the pH and lactic acid values of the fresh samples of Halloumi cheese were signiﬁ cantly different, but the moisture and salt contents were similar. The differences in the TN and fat contents can be attributed to the different types of milk

Table 4.5 Gross chemical compositions (g 100 g–1) of commercial samples traditional and industrial of Halloumi cheeses (fresh and matured)

Fresh cheese Matured cheese Constituents Cypriot standards Traditional† Industrial‡ Traditional† Industrial‡ Moisture Fresh <46 and 47.5 ± 2.5ns 46.6 ± 0.2ns 34.9 ± 0.5d 35.3 ± 0.1f mature <37 Fat N/A 26.1 ± 0.6a 24.4 ± 1.4c 31.9 ± 1.2d 28.6 ± 2.7f Total nitrogen (TN) N/A 3.2 ± 0.2ac 3.5 ± 0.2ac 3.6 ± 0.1d 4.5 ± 0.5f Protein (TN × 6.38) N/A 20.2 ± 1.2a 22.3 ± 1.4c 22.84 ± 0.6d 28.5 ± 2.9f Salt Fresh <3 and 2.7 ± 0.53ns 3.0 ± 0.3ns 3.8 ± 0.1d 4.0 ± 0.2f mature <6 pH N/A§ 5.9 ± 0.1a 6.2 ± 0.1c 4.9 ± 0.2ns 4.8 ± 0.1ns Lactic acid N/A 0.52 ± 0.04a 0.21 ± 0.01c 1.39 ± 0.03d 1.11 ± (mL 100 mL–1) 0.01f Fat-in-dry matter Fresh >43 and 49.7 45.7 49.0 44.2 (FDM) mature >40 Moisture-in-fat-free N/A 64.3 61.6 51.2 49.4 cheese (MFFC) Salt-in-moisture (SM) N/A 5.7 6.4 10.9 11.3 The results are means of six determinations (three blocks of cheese analysed in duplicate) Different superscripts indicate signiﬁ cant differences (P < 0.05) between brands when fresh and after maturation; ns = not signiﬁ cant. † Sheep’s and goat’s milk as the major type of milks used. ‡ Mainly cow’s milk is used. § Not applicable. Data compiled from Papademas (2000).

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used for the production of the cheeses, while the similarities of the moisture and salt contents indicate that the methods of manufacture were broadly the same. The signifi cant differences in pH and lactic acid (determined by Gas chromatography/Flame Ionization Detector – GC/FID), where the sheep’s traditional cheeses had lower pH values and higher lactic acid contents than the industrial counterparts, may be linked to the fact that the original sheep’s milk had a more active and varied microfl ora of lactic acid bacteria. After maturation of the cheeses, the chemical composition of the products changed dramatically, and the moisture contents dropped while the salt contents increased. The total nitrogen and fat contents increased, probably due to the increase in total solids. The fermentation of lactose by the non-starter microfl ora is largely responsible for the developed acidity in mature Halloumi cheese, which, in turn, causes a drop in pH. Furthermore, the overall compositional quality indices, such as moisture- in-fat-free cheese (MFFC) and salt-in-moisture (SM), are critical factors in cheese quality, since both of them affect the rate of proteolysis in a cheese. Lawrence et al. (1993) report that, for Cheddar cheese, the rate of protein breakdown increased when the MFFC percentage was high. The SM ratio is also very important because it can determine the rate of bacterial growth and the proteolytic activity of chymosin (note: non-animal rennet is used in making Halloumi cheese intended for export to some Arab countries), plasmin and starter proteases. For example, an SM concentration of 6 g 100 g–1 will inhibit the activity of all strains of Lactococcus lactis subsp. cremoris. For Cheddar cheese, the SM range proposed for fi rst grade cheese is 4.7–5.7. The SM ratio in matured Halloumi cheese is quite high, i.e. 11 (see Table 4.5), probably explaining the fact that proteolysis during cheese maturation is limited (Papademas, 2000). The fat-in- dry matter (FDM) content of Halloumi samples gives an indication of the fat content of the milk used for cheese manufacture. Traditional products made from sheep’s milk have higher values of FDM than the industrial cheese (see Table 4.5).

4.7.2 Microbiological quality Papademas and Robinson (2000) reported that the microbiological quality of commercial Halloumi cheeses (fresh and matured) was different, mainly due to the type and age of the product. The major difference between the fresh samples of Halloumi cheese was the apparent absence of lactic acid bacteria (LAB) in the industrial samples. As only thermoduric microorganisms from the original milk are likely to survive the cheesemaking procedure (Poullet et al., 1993), it was not unexpected that Enterococcus faecium was the dominant Gram-positive coccus in the traditional cheeses – as a contaminant when the processing equipment is not cleaned properly. Enterococcus spp. have been isolated from many traditional dairy products (Giraffa, 2000). However, the lactic acid microﬂ ora of all the samples of Halloumi changed with maturation, and Gram-positive catalase-negative rods became dominant; such changes in microﬂ ora with maturation were reported by McSweeny et al. (1993) and Haddadin (1986), who found that lactobacilli were the predominant non-starter lactic acid bacteria in Cheddar and Domiati cheeses, respectively.

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The species Lactobacillus brevis, Lactobacillus pentosus and Lactobacillus plantarum were present in mature cheeses. Lb. brevis has been reported as a weakly proteolytic microorganism (Teixeira 2000) but, being heterofermentative, it can produce acetic acid as well as ethanol. Acetic acid is considered as an important fl avour compound for white brined cheeses (Georgalla et al., 1999), while ethanol can react with fatty acids to produce the ethyl esters responsible for fruity aromas in the product (Law, 1999; Moio & Addeo, 1998). In addition, Bintsis et al. (2003) studied the protease, peptidase and esterase activities of lactobacilli and yeast isolates from Feta cheese brine, and concluded that Debaromyces hansenii as well as Lactobacillus paracasei subsp. paracasei possessed the necessary enzymatic activities required for Feta cheese fl avour development. Lb. plantarum, which was isolated from mature Halloumi cheese, is a dominant bacterium of the non-starter fl ora in mature cheeses (Law, 1999). Kok and de Vos (1994) have reported that Lb. plantarum possesses both cell-wall-bound proteinase, and a carboxypeptidase (a peptidase that attacks substrates from their C-terminal end). An esterase of Lb. plantarum has also been purifi ed by Fox et al. (1995). The proteolytic and lipolytic activities and the wide occurrence of this bacterium have probably led researchers to investigate its possible addition as a selected strain in fl avour diversifi cation applications (Law, 1999). Yeasts isolated from fresh cheeses, such as D. hansenii and Candida parapsilosis, have probably originated from the dairy’s environment and/or from the whey brines used to immerse the cheese blocks for a short period before they are packaged under vacuum and sold as fresh product. Yeast species, namely Pichia membranaefaciens, Candida boidinii and Candida versatilis were also isolated from mature Halloumi cheeses (Bintsis & Papademas, 2002). In addition D. hansenii has also been isolated from both Feta cheese brines and the surface of Feta cheese (Bintsis et al., 2000). The yeasts isolated from the commercial samples of fresh and mature Halloumi cheeses did not have any adverse effects on the fl avour or produce visible defects. A new lactobacillus strain has been isolated from mature Halloumi cheese made in Cyprus, which suggests that this organism is resistant to high salt concentrations and low pH. According to Lawson et al. (2001), it has been classifi ed as a new species known as Lactobacillus cypricasei. The microbial cells are Gram-positive, catalase- and oxidase-negative, non-spore-forming and rod-shaped, occurring as single cells, in pairs or in short chains. Rods are 0.6–0.8 µm wide to 3–5 µm long, with rounded ends. When grown on MRS agar, the colonies are small, entire and creamy in colour. Lb. cypricasei is facultatively anaerobic and, since no gas is produced from glucose, the bacterium is considered to be homofermentative. Lb. cypricasei possesses a wide range of enzymatic activities, amongst them leucine and valine aminopeptidases, which might be useful in accelerating the proteolysis of cheese as it matures, leading to the formation of fl avour compounds or precursors of fl avour components (e.g. amino acids). Further research work is required on the properties of Lb. cypricasei with regards to its microbial activity/role in the cheese matrix during the production of mature Halloumi, before suggesting the use of this strain as an adjunct culture in the whey brine.

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4.8 Sensory profiling and rheological properties of the cheese 4.8.1 Flavour and taste Halloumi cheese, as with all cheeses, has a unique fl avour and taste. A connoisseur can easily distinguish Halloumi made from different milk mixtures or manufactured in different areas of Cyprus. It is also true that many Cypriots prefer the goat’s/sheep’s milk mixture for Halloumi cheese and, in particular, the product from the Paphos area rather than an equivalent product made around Nicosia. Moreover, traditional Halloumi cheese (i.e. made from a mixture of goat’s and sheep’s milk) is preferred over the industrial cheese made from cow’s milk as the major milk type (Papademas & Robinson, 2001). A study by Papademas & Robinson (2000) showed that the organoleptic characteristics of Halloumi cheese change dramatically with maturation, and it becomes hard in texture, and salty and acidic in taste, while fl avour notes such as ‘creamy’ and ‘milky’ decrease (see Section 4.8.3). The major differences observed with maturation were the formation of esters, and an increase in the aldehyde, alcohol and acid contents. Other changes included a general decrease of methyl ketones, and lactones increased for traditional cheeses, whereas they seemed to decrease for industrial cheese. Some of the native compounds (α- and β-pinene, β-caryophyllene) seemed to increase with maturity. Phenols (p-cresol) were also formed as the cheese matured. The biochemistry of cheese during maturation is governed by complex reactions, such as proteolysis, lipolysis and glycolysis. The microfl ora of the cheese and/or brine will bring about fl avour changes through these reactions, while the reducing conditions prevailing in the cheese with maturation can contribute to the formation of specifi c fl avour compounds. The fruity fl avours of short-chain esters may contribute to cheese aroma by smoothing the sharper, pungent fl avour notes of acids (de Frutos et al., 1991). Overall, the study of the fl avour compounds of Halloumi cheese has revealed great differences both with age and between samples. The major fl avour compounds representing this volatile fraction were probably formed by the action of heat (lactones and methyl ketones in fresh cheese), lipolysis and other chemical reactions, including reductions and oxidations (esters, secondary alcohols, acids and lactones in mature samples). The degradation of proteins during maturation did not seem to produce many volatile compounds that could infl uence the fl avour of Halloumi cheese (Papademas, 2000). Short-chain organic acids (i.e. ethanoic, propanoic) may contribute to the fl avour of cheeses with low levels of proteolysis and lipolysis (de Llano et al., 1996), while the branch-chain fatty acids (BCFA) are considered important fl avour constituents due to their ‘cheesy’ fl avour notes (Brennand et al., 1989). The free volatile fatty acids (FVFA) identifi ed in different types of Halloumi cheese are shown in Table 4.6. Papademas & Robinson (2000) reported that these compounds were present in the cheese at concentrations above their corresponding threshold values. Therefore, it can be suggested that the acidic component of the water-soluble fraction of Halloumi cheese is important in characterising its fl avour. In addition ethanoic acid is an important FVFA for white-brined cheeses, and it can

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Table 4.6 The free volatile fatty acids (FVFA) identiﬁ ed in Halloumi cheese

International Union of Pure and Applied Chemistry (IUPAC) Trivial name Odour, descriptors Thresholds (mg kg–1) Ethanoic acid Acetic acid Acetic, sour 22.0–54.0 ﬂ avour,100 aroma Propanoic acid Propionic acid Pungent, sour 40.3 aroma 2-Methylpropanoic acid Isobutyric acid Cheese, rancid butter 5.3 aroma Butanoic acid Butyric acid Cheese, rancid, sour 0.4–6.8 ﬂ avour, 1.1–4.8 aroma 3-Methylbutanoic acid Isovaleric acid Cheese rind, rancid 0.07–0.13 aroma Pentanoic acid Valeric acid Stable, sweaty, sheep, goat 1.1–6.5 aroma Data compiled from Brennand et al. (1989), Moio & Addeo (1998) and Papademas (2000).

be readily formed by the degradation of lactose by the microfl ora present in the whey brine and/or cheese during maturation. Lb. brevis, a heterofermentative LAB, which can produce both lactic and acetic acids from lactose, was isolated from three mature Cypriot cheeses made industrially (i.e. one sample) and traditionally (i.e. two samples). Ethanoic acid represented ∼87% of the total FVFA in the mature industrial cheese, and ∼81% and ∼69% in the two traditional cheese samples. The ethanoic acid content of Domiati cheese (a white cheese that also matures in whey brine) represented 85% of the total FVFA fraction (Abd El-Salam & Alichanidis, 2004). Georgalla et al. (1999) have reported values of ethanoic acid in sheep’s Greek Feta in the range of 1223–2095 mg kg–1. In a study by Piggott et al. (1998), the volatile fraction of fresh commercial Halloumi cheeses was studied by headspace chromatography. The 26 volatile compounds included an unidentifi ed lactone, alcohols, phenol, nonanone and acids. Compounds arising from the added mint included pulegone, carvone and a ‘mint terpene’. The above results underestimate the signifi cance of lactones and methyl ketones in the fl avour of fresh Halloumi cheese. The choice of a headspace analysis may have been a limiting factor in recovering these compounds. However, Papademas and Robinson (2002) studied the volatile plant compounds in fresh commercial traditional (goat’s/sheep’s milk mixture) and industrial (bovine milk as major ingredient) Halloumi cheeses. The results showed that a greater number of native fl avour compounds (e.g. α-pinene, β-caryophyllene, δ-cadinine, thymol, β-cubebene) were isolated from the traditional product where the animals grazed in the mountains compared with the industrial product where the cows are fed hay. The authors concluded that the terpenoids present in the cheeses were suffi ciently different to suggest a defi nite correlation between composition and the diet of the milk-producing animals. It is also likely that a similar correlation exists between the presence of volatile terpenes and cheese fl avour.

4.8.2 Texture The texture of fresh and mature Halloumi cheese has been studied extensively, and the results showed that the most pronounced effect of maturation was the signiﬁ cant

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increase of hardness, detected in all samples. The fracturability, as perhaps expected, also increased during maturation. Differences were noted between samples of fresh Halloumi; the industrial Halloumi cheese (bovine milk as the major constituent) was the hardest, the most chewy and least fracturable, and the traditional product (mixture of sheep’s and goat’s milk) was the least hard, least chewy and most easily fractured. The fresh samples did not differ signiﬁ cantly as far as springiness and cohesiveness were concerned (Papademas, 2000). The increase in hardness during maturation of the cheese is probably a direct impact of the penetration of salt into the product from the whey brine, and the concomitant loss of water into the whey brine. It has also been proposed by Walstra et al. (1999) that the quantities of water lost and amount of salt uptake are strongly positively correlated with the duration of brining and the salt content of the brine. In addition, Kaminarides & Anifantakis (1985) reported a loss in weight during the maturation of Halloumi cheese. The chemical composition data of the commercial Halloumi samples (see Table 4.5) reveal a relationship between the texture of the cheeses and maturation, as the moisture content decreased while the salt content increased.

4.8.3 Sensory profiling Papademas and Robinson (2001) studied the sensory characteristics of both fresh and mature Halloumi cheese. The infl uence of the panellists’ age on the reported sensory characteristics of Halloumi cheese was also noted. The study revealed that the product changed markedly with maturation. Young panellists (average age 21) assessed the cheese and noticed signifi cant changes for the texture attributes; the moist and springy fresh Halloumi cheese became hard and with a close tough body after 40 days in the whey brine. Moreover, the taste and fl avour of the cheese was affected by maturation, and the attributes of salty, acidic and bitter scored higher than in the fresh counterpart. Moreover, the milky and creamy fl avour notes scored lower for the mature product. Generally the young panellists preferred the fresh Halloumi cheese because the hedonic response dropped for the mature product. There was also a signifi cant preference for the traditional products over the industrial sample. When the older panellists (average age 46) assessed the same cheeses, differences were noted, with the most signifi cant one being the fact that they liked both fresh and mature samples of Halloumi equally; they gave higher scores for fl avour intensity as the cheese matured.

4.9 Quality and safety of dairy products

Quality and safety management systems, such as International Organisation for Standardisation (ISO, 2001) and the Hazard Appraisal (Analysis) Critical Control Points (HACCP), are now being implemented, and the latter is compulsory in all dairy factories in Cyprus.

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Recent food scares, such as bovine spongiform encephalopathy (BSE) and diox- ins in milk, plus the free movement of foodstuffs in EU countries have rendered HACCP essential in order to increase internal controls and minimise risks in dairy products. The introduction of ISO 22000 (i.e. ISO/DIS 22000 standard is under development) as a universal food safety system aims to harmonise the food sector specifi c standards, and is crafted with a structure compatible with other management system standards. ISO/DIS 22000 will defi ne the requirements of a food safety management system covering all organisations in the food chain from farmers to catering, including packaging. The percentage of milk mixtures in Halloumi production is also of concern as consumer protection (labelling) is of primary importance. Papademas (2000) has shown that capillary electrophoresis can be successfully used to distinguish milk mixtures, and especially the presence of cow’s milk in a Halloumi cheese labelled as sheep/goat. This can be achieved because the cow’s, sheep’s and goat’s casein fractions have different migration times due to their different net charge. Moatsou et al. (2004) have also studied the presence of goat’s casein in sheep’s Halloumi cheese. By law, the manufacture of cow’s Halloumi cheese is prohibited in Cyprus (Anonymous, 1985a, 1985b), but it can be mixed with goat’s and sheep’s milk; however, the exact level is not defi ned under existing legislation. Nevertheless, cow’s milk is widely used elsewhere in Europe and the Middle East to produce a Halloumi-type product.

4.10 Nutritional value of Halloumi cheese

Halloumi cheese is considered a rich source of calcium (approximately 700– 794 mg 100 g–1), which is comparable with Edam and Gouda cheeses (795 and 773 mg 100 g–1, respectively). The estimated average requirement (EAR) of calcium for adults (age between 19 and 50 years old) is 525 mg d–1 (Anonymous, 1995). Moreover, Halloumi cheese is a good source of protein, with values around 22 g 100 g–1 (see Table 4.5). However, 70 g 100 g–1 of the fat is saturated in Halloumi cheese, and it has cholesterol values in the range 90–100 mg 100 g–1; hence, it must be enjoyed with caution. Therefore, the ‘slim’ and ‘light’ Halloumi cheeses containing 62 and 43 mg 100 g–1 of cholesterol, respectively, which are marketed by large dairies, could offer a healthier alternative (Anonymous, 1999b).

4.11 Conclusion

The study of cheese is a very demanding but fascinating sector of the wider fi eld of dairy science, and the nature of cheese is such that, in order to construct a characteristic profi le of a specifi c variety, several properties must be examined. Halloumi is certainly a very popular cheese in the Eastern Mediterranean and in other European countries where Cypriot communities exist. It probably owes

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its success to the fact that it is very versatile, making it both a delicious table and cooking cheese. The importance of Halloumi cheese to the Cypriot economy is well established, and the relevant government bodies are committed to ‘protect- ing’ the cheese by applying for Collective Trademarks and, more recently, the EU PDO labelling. In Cyprus, farm hygiene and, thus, raw material quality, can still improve considerably in order to guarantee that the end-products are of the highest quality possible. Hence, the rigorous ofﬁ cial controls on: (a) hygiene of raw materials and ﬁ nal products, and (b) product labelling are essential and must be continued, ensuring that the product abides by the Cyprus Standards and meets the EU regulations.

Acknowledgement

The author wishes to thank G. & I. Keses Dairy Products Ltd., and AGMfoodtech Ltd. for providing the requested technical information.

References

Abd El-Salam, M.H. & Alichanidis, E. (2004) Varieties ripened under brine. In: Cheese, Chemistry, Physics and Microbiology, 3rd edn (eds P.F Fox, P.L.H McSweeney, T.M. Cogan & T.M. Guinee), vol. 2, pp. 227–251. Elsevier Science and Technology, London. Alichanidis, E. & Polychroniadou, A. (1996) Special features of dairy products from ewe and goat milk from the physicochemical and organoleptic point of view. In: Production and Utilisation of Ewe and Goat Milk: Proceedings of the IDF Seminar held in Greece (Crete), pp. 21–44. International Dairy Federation, Belgium. Anonymous (1985a) CYS 94 Part 1: Standard for the Fresh Halloumi Cheese, pp. 1–3. Cyprus Organisation for Standards and Control of Quality, Nicosia. Anonymous (1985b) CYS 94 Part 2: Standard for the Mature Halloumi Cheese, pp. 1–3. Cyprus Organisation for Standards and Control of Quality, Nicosia. Anonymous (1995) Dietary Reference values for Food Energy and Nutrients for the United Kingdom, No. 41, pp. 136–145. Department of Health, London. Anonymous (1999a) Provenance of the Cyprus word Halloumi. Newspaper Politis, Nicosia. Anonymous (1999b) Cyprus Food Composition Tables, 2nd edn. State General Laboratory, Ministry of Health, Nicosia. Anonymous (2000) Data on Ovine Milk Composition, Cyprus Milk Industry Organisation, Nicosia. (http://myweb.cytanet.com.cy/cmio/cmiop.html). Anonymous (2004) Statistics and Research Department, Nicosia. (www.pio.gov.cy/dsr/index.html). Bencini, A. & Pulina, G. (1997) The quality of sheep milk: a review. Australian Journal of Experimental Agriculture, 37, 485–504. Bintsis, T. & Papademas, P. (2002) Microbiological quality of white-brined cheeses: a review. International Journal of Dairy Technology, 55, 113–121. Bintsis, T., Litopoulou-Tzanetaki, E., Davies, R. & Robinson, R.K. (2000) Microbiology of brines used to mature feta cheese. International Journal of Dairy Technology, 53, 106–112. Bintsis, T., Vafopoulou-Mastroyiannaki, A., Litopoulou Tzanetaki, E. & Robinson, R.K. (2003) Protease, peptidase and esterase activities by lactobacilli and yeast isolates from Feta cheese brine. Journal of Applied Microbiology, 95, 68–77.

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Bown, D. (1995) Encyclopaedia of Herbs and Their Uses. Dorling Kindersley, London. Brennand, C.P., Ha, J.K. & Linsay, R.C. (1989) Aroma properties and thresholds of some branched- chain and other minor volatile fatty acids occurring in milkfat and meat lipids. Journal of Sensory Studies, 4, 105–120. Deeth, H.C. & Fitz-Gerald, C.H. (1995) Lipolytic enzymes and hydrolytic rancidity in milk and milk products. In: Advanced Dairy Chemistry 2nd edn (ed. P.F. Fox), vol. 2, pp. 247–308. Chapman and Hall, London. de Llano, D.G., Rodriguez, A. & Cuesta, P. (1996) Effect of lactic starter cultures on the organic acid composition of milk and cheese during ripening-analysis by HPLC. Journal of Applied Bacteriology, 80, 570–576. Economides, S. (2004) Milk and Milk Products of Cyprus – Special Reference to Halloumi Cheese. Cyprus Milk Industry Organisation (CMIO), Nicosia. EU (1992) Council Directive 92/46/EEC of 16 June 1992 laying down the health rules for the production and placing on the market of raw milk, heat-treated milk and milk-based products. Offi cial Journal of the European Commission, L268, 1–40. Fox, P.F., Singh, T.K. & McSweeny, P.L.H. (1995) Biogenesis of fl avour compounds in cheese. In: Chemistry of Structure-Function Relationships in Cheese, 1st edn (eds E.L. Malin & M.H. Tunick), pp. 59–98. Plenum Press, New York. Frenaritou, H. (1998) Halloumi – the traditional Cyprus cheese – current situation and future perspectives. Diploma project, Mediterranean Institute of Management (MIM), Nicosia. de Frutos, M., Sanz, J. & Martinez-Castro, I. (1991) Characterisation of artisanal cheeses by GC and GC/MS analysis of their medium volatility (SDE) fraction. Journal of Agricultural Food Chemistry, 39, 524–530. Georgalla, A.K., Kandarakis, I.G., Kaminarides, S.E. & Anifantakis, E.M. (1999) Volatile free fatty acid content of Feta and white-brined cheeses. Australian Journal of Dairy Technology, 54, 5–8. Gibbs, P., Morphitou Nicoletti, R. & Savva, G. (2004) The development of the dairy industry (Halloumi) in Cyprus. British Food Journal, 105, 569–576. Giraffa, G. (2000) Enterococcus. In: Encyclopedia of Food Microbiology (eds R.K. Robinson, C.A. Batt & P.D. Patel), vol. 1, pp. 617–624. Academic Press, London. Gobbetti, M. (2000) Lactobacillus casei. In: Encyclopedia of Food Microbiology (eds R.K. Robinson, C.A. Batt & P.D. Patel), vol. 2, pp. 1157–1164. Academic Press, London. Haddadin, M.S.Y. (1986) Microbiology of white-brined cheeses. In: Developments in Microbiology, (ed. R.K. Robinson), vol. 2, pp. 67–89. Elsevier Applied Sciences, London. ISO (2001) Quality Management, ISO 9000:2001, 10th edn, pp. 1–23. International Organization for Standardization, Switzerland. Jandal, J.M. (1996) Comparative aspects of goat and sheep milk. Small Ruminant Research, 22, 177–185. Kaminarides, S.E. & Anifantakis, E.M. (1985) Changes in the microbiological burden and the quality of Halloumi cheese kept in brine 10% at 4°C and 20°C. In: Modern Technology and Quality Control, Proceedings of the First Panhellenic Food Conference, pp. 384–395. Thessaloniki University of Agriculture, Thessaloniki. Kaminarides, S.E., Rogoti, E. & Mallatou, H. (2000) Comparison of the characteristics of Halloumi cheese made from ovine milk, caprine milk or mixtures of these milks. International Journal of Dairy Technology, 53, 100–105. Kok, J. & de Vos, W.M. (1994) The proteolytic system of lactic acid bacteria. In: Genetics and Biotechnology of Lactic Acid Bacteria, 1st edn (eds M.J. Gasson & W.M. de Vos), pp. 169–210. Blackie Academic and Professional, London. Law, B.A. (1999) Cheese ripening and cheese fl avour technology. In: Technology of Cheesemaking, (ed. B.A. Law), pp. 163–192. Sheffi eld Academic Press, Sheffi eld.

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Lawrence, R.C., Gilles, J. & Creamer, L. K. (1993) Cheddar cheese and related dry-salted cheese varieties. In Cheese: Chemistry, Physics and Microbiology, Vol. 2, 2nd edn., Ed P.F. Fox, pp. 1–39, Chapman and Hall, London. Lawson, P.A., Papademas. P., Wacher, C., Falsen, E., Robinson, R.K. & Collins, M.D. (2001) Lactobacillus cypricasei sp. nov., isolated from Halloumi cheese. International Journal of Systematic and Evolutionary Microbiology, 51, 45–59. McSweeney, P.L.H., Fox, P.F., Lucey, J.A., Jordan, K.N. & Cogan, T.M. (1993) Contribution of the indigenous microﬂ ora to the maturation of Cheddar cheese. International Dairy Journal, 3, 613–634. Moatsou, G., Hatzinaki, A., Psathas, G. & Anifantakis, E. (2004) Detection of caprine casein in ovine Halloumi cheese. International Dairy Journal, 14, 219–226. Moio, L. & Addeo, F. (1998) Grana Padano cheese aroma. Journal of Dairy Research, 65, 317–333. Papademas, P. (2000) Halloumi cheese: the product and its characteristics. PhD Thesis, School of Food Biosciences, University of Reading, Reading. Papademas, P. & Robinson, R.K. (1998) Halloumi cheese: the product and its characteristics. International Journal of Dairy Technology, 51, 98–103. Papademas, P. & Robinson, R.K. (2000) A comparison of the chemical, microbiological and sensory characteristics of different types of Halloumi cheese. International Dairy Journal, 10, 761–768. Papademas, P. & Robinson, R.K. (2001) The sensory characteristics of different types of Halloumi cheese as perceived by tasters of different ages. International Journal of Dairy Technology, 54, 94–99. Papademas, P. & Robinson, R.K. (2002) Some volatile plant compounds in Halloumi cheeses made from ovine or bovine milk. Lebensmittel-Wissenschaft und Technologie, 35, 512–516. Papademas, P., Norman, J. & Robinson, R.K. (2000) Some properties of full-fat, less fat and reduced- fat Halloumi cheese made from bovine milk. Australian Dairy Foods, October, 30–32. Piggott, J.R., Margomenou, A., Withers, S.J. & Conner, J.M. (1998) Sensory characterisation of Halloumi cheese and relationship with headspace composition. In: Food Flavours: Formation, Analysis and Packaging Inﬂ uences, Proceedings of the 9th International Flavour Conference (eds E.T. Contis, C-T. Ho & C.J. Mussinan), pp. 385–391. TH Elsevier, Amsterdam. Poullet, B., Huertas, M. Sanchez, A., Caceres, P. & Larriba, G. (1993) Main lactic acid bacteria isolated during ripening of Casar de Caceres cheese. Journal of Dairy Research, 60, 123–127. Rohloff, J. (1999) Monoterpene composition of essential oil from Peppermint (Mentha x piperita L.) with regard to leaf position using solid phase microextraction and Gas Chrmatography.Mass Spectrometry analysis. Journal of Agricultural Food Chemistry 47, 3782–3786. Robinson, R.K. (1991) Halloumi cheese – the product and its manufacture. In: Feta and Related Cheeses (eds R.K. Robinson & A.Y. Tamime), pp. 144–159. Ellis Horwood, Chichester. Teixeira, P.C.M. (2000) Lactobacillus brevis. In: Encyclopaedia of Food Microbiology (eds R.K. Robinson, C.A. Batt & P.D. Patel), vol. 1, pp. 26–33. Academic Press, London. Walstra, P., Geurts, P., Noomen, A., Jellema, A. & van Boekel, M.A.J.S. (1999) Dairy Technology – Principles of Milk Properties and Processes. Marcel Dekker, New York.

11405124601_4_004.indd405124601_4_004.indd 113838 116/05/20066/05/2006 12:16:4012:16:40 Brined Cheeses Edited by Dr Adnan Tamime Copyright © 2006 by Blackwell Publishing Ltd 5 North African Brined Cheeses

M. Abd-El Salam and N. Benkerroum

5.1 Background

North African countries have an ancient tradition in the production and consumption of dairy products. In fact, milk and its related products have long been key foods, which contributed to food security in these countries to a point that they were considered holy by many people in rural communities. Due to the highly perishable character of milk, there has been a need to develop appropriate methods to allow its conservation for longer periods. Many traditional techniques, based on milk fermentation, were originally developed to ensure the availability of safe and nutritious foods throughout the year, and to prevent shortage of dairy products to consumers. Among these products, cheese was the most popular dairy product in the region, and some cheese varieties could be preserved for several months or even years. In addition, the fermentation of milk, drying and salting of the curd, and/or addition of herbs and spices were common practices to extend the shelf-life of dairy products as much as possible. A combination of these techniques was an empirical application of the synergistic effect of different barriers to microbial growth, now designated ‘the multiple hurdles technology’. Salting was probably the most common and reliable traditional method used in combination with lactic acid fermentation for the production and preservation of cheese. It was achieved by adding salt to milk before fermentation, sprinkling of dry salt on the surface of the cheese after moulding and/or dipping the cheese in a brine (pickling). One typical pickled cheese variety now being produced on an industrial scale and commercialised worldwide is the Greek Feta cheese (see Chapter 2). In African countries, especially those of the Mediterranean basin, numerous traditional brined cheeses made from cow’s, goat’s, sheep’s or buffalo’s milk have long been known and highly appreciated by consumers. Among these cheeses, white soft cheese varieties with relatively short shelf-life (3 to 15 days) were the most common and, despite the variations in their composition, structure and methods of manufacture, they were collectively called Jben, Jibneh Gibna, Gibneh (meaning ‘cheese’ in Arabic) or Gjibna Bayda (meaning ‘white cheese’ in Arabic). Nonetheless, some semihard brined cheese varieties with a longer shelf-life are also known. In Egypt, pickled cheeses represent a major sector of the dairy industry, and it is estimated that 36% of total milk production is utilised in the manufacture of these products (Anonymous, 2002). The types of pickled cheeses produced in Egypt have changed markedly over the past two decades. In addition to the traditional cheese varieties, the production of ultraﬁ ltered (UF) Feta-type cheese has grown dramati-

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cally in recent years (see Chapter 3 for further details). However, Egypt was one of the leading Feta cheese importing countries in the 1980s, reaching a maximum of 29 000 tonnes in 1990. At present, the situation has changed due to the establishment of UF Feta-type cheese factories locally and, as a consequence, the importation of Feta-type cheese decreased to less than 1000 tonnes in 2002. Incidentally, one of the Egyptian dairy companies was rated among the largest worldwide producers of Feta-type cheese in cartons in 2002. Also, consumer preference for low-salt pickled soft cheeses boosted the production of this type of product. At present, it is diffi cult to obtain an exact breakdown of pickled cheese varieties produced in Egypt; however, Domiati cheese is still considered as the major cheese variety produced. Nevertheless, the annual production of pickled cheeses has increased from 171 000 tonnes in 1981 to 293 000 tonnes in 2000; this corresponds to a steady increase of 7 000 tonnes per year (Anonymous, 2002). In addition, most of the pickled cheese produced in Egypt is consumed locally, and only ∼11 000 tonnes was exported annually during 1998–2000 (Anonymous, 2002). The per capita consumption of cheese was 4.2 kg in 1981 and had increased slightly to 4.4 kg by 2000. Also during the last two decades, the packaging materials of the cheese have been changed dramatically. Traditionally, pickled cheeses were packaged in metal containers of 20 kg capacity but, increasingly, these have been replaced with plastic containers of different capacities (e.g. 2–14 kg). In addition, retail packages of pickled cheeses are, at present, made out of plastics (500 g and/or 1 kg) and cartons (200–500 g). One of the drawbacks of the storage of Domiati cheese in metal containers is the incidence of ‘blowing’, especially in the summer season. This has been attributed to electrolytic corrosion by the high salt (i.e. sodium chloride, NaCl) content and the developed acidity during the maturation period (Abo Elnaga, 1971). The storage of Domiati cheese in polystyrene containers has been recommended by Atia (2001) as it has little effect on the chemical, microbiological and sensory properties of the cheese. Traditionally, Domiati cheese has been made from mixtures of buffalo’s and cow’s milk, which imparts the characteristic white colour of the product. However, cow’s milk is now increasingly used in the manufacture of pickled cheeses, causing the product to become yellowish in colour, a feature that is not accepted by the consumer. Therefore, cow’s milk fat is partially replaced by vegetable oils, such as coconut or palm, to give the cheese a whiter colour, and also to reduce the production costs. Also, imported ‘fi lled’ milk powder (i.e. made from skimmed milk and vegetable oils) is now utilised in the manufacture of pickled cheeses in Egypt. Rennet extracts of calf abomasum have been used in the production of pickled cheeses for years and, in some parts of Egypt (Fayoum), rennet paste is used in the manufacture of sharp-fl avoured Domiati cheese (Abd El-Ghani et al., 1998). However, microbial rennet substitutes and recombinant chymosin are now used in addition to calf rennet. Heat treatment of the cheese milk and addition of starter cultures were not practised in the past during the manufacture of Egyptian pickled cheeses. However, when heat treatment of the cheese milk became an obligatory step (Anonymous, 2001), it necessitated the use of starter cultures in the processed milk in order to develop the

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characteristic ﬂ avour in the product. Also, the size of cheese factories has changed; most of the Domiati cheese has been produced in small factories processing less than 2 t milk day–1 (Hassan, 1990). However, large-scale production facilities for pickled cheese have developed markedly over the past two decades. This chapter reviews the latest developments of brined cheeses produced in Egypt and other North African countries.

5.2 Production and consumption of dairy products in North African countries

In North African countries, milk is produced from different species of mammals, such as the cow, goat, ewe, buffalo or dromedary (i.e. the camel), depending on the extent of adaptation of the speciﬁ c animal to the climatic conditions that prevail in a given region. Cow’s and ewe’s milk are predominantly produced in the ﬂ at and plateau areas with high rainfall, whilst goat’s milk is mainly produced in the forested mountainous regions. In the dry and semiarid lands, milk is essentially produced by dromedaries. Table 5.1 summarises the mean production of milk from different animals in North African countries during the years 2000–2003. Despite the long tradition of milk and dairy products in North Africa, the apparent consumption of dairy products remains generally low (Table 5.2). With the exception of Mauritania and Sudan, the apparent consumption of dairy products is far below the basal level of 100 milk-equivalents per capita per year recommended by the World Health Organisation (WHO) of the United Nations (FAO, 1995). This situation may be explained by the unfavourable climatic conditions prevailing in most of these countries and the continuing reliance on traditional management systems of livestock characterised by low productivity. Moreover, most of the dairy products consumed in these countries consists of liquid milk (heated, pasteurised or UHT), whilst the consumption of fermented milks with higher nutritive value is low. The average consumption of cheese is generally below 1.9 kg per capita per year, with

Table 5.1 Mean production of milk (×1000 tonnes) from different species of mammals in North African countries during the period 2000–2003

Mammalian species Country Cow Ewe Goat Camel Buffalo Total Algeria 1173.3 200.0 155.0 8.0 NAa 1536.3 Egypt 1890.0 93.0 15.1 NA 2068.2 4066.3 Ethiopia 1450.0 28.6 17.1 22.5 NPb 1518.2 Libya 137.7 55.8 15.4 2.0 NP 210.9 Mauritania 118.8 92.1 107.0 21.5 NP 339.4 Morocco 1238.0 27.0 34.0 3.8 NP 1303.8 Sudan 3200.0 463.0 1280.0 82.2 NP 5025.2 Tunisia 947.0 17.0 12.2 1.0 NP 977.2 a NA = not available. b NP = not produced. After FAOSTAT (http://faostat.fao.org/faostat/collections?version=ext&hasbulk=0&subset=agriculture).

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Table 5.2 Consumption (per head per annum) of milk and cheese in North African countries

Milk (L) Cheese (kg) Country 2001 2002 2001 2002 Algeria 81.0 74.1 0.6 0.7 Egypt 15.3 15.2 7.2 7.1 Ethiopia 16.2 15.9 0.1 0.1 Libya 56.5 57.2 1.9 1.6 Mauritania 126.1 129.6 0.8 0.8 Morocco 10.0 12.0 0.4 0.4 Sudan 115.5 115.3 4.7 4.6 Tunisia 80.4 84.9 1.7 1.7 After FAOSTAT (http://faostat.fao.org/faostat/collections?version=ext&hasbulk=0&subset=agriculture).

the exception of Egypt and Sudan, where it is 7.1 and 4.6, respectively. In developed countries this value exceeds 25 kg per capita per year (Benkerroum, 2003).

5.3 Egyptian pickled cheeses

Many different pickled cheese varieties are traditionally produced in Egypt, and the review by Abou Donia (1991) is recommended for further reading regarding methods of manufacture, microbiological quality, sensory proﬁ ling and sensory properties.

5.3.1 Domiati cheese Technological aspects The traditional method for the manufacture of Domiati cheese was fi rst described by Fahmi and Sharara (1950), and can be summarised as follows. • Raw milk (usually a mixture of buffalo’s and cow’s milk) is standardised to different fat contents depending on the required fat level in the fi nal product. • One-third of the standardised milk is heated to 80°C, while table salt is added to the remaining two-thirds of the milk in order to give 10–15 g NaCl 100 mL–1 in the cheese milk when the two portions are combined together; the salted milk is transferred to a double-jacketed vat, and the temperature is adjusted to 40°C. • Liquid rennet solution is added (e.g. single strength – 60 ml 100 kg–1), and the salted milk is left to coagulate within 2–3 h. • The coagulum is scooped into wooden frames (the height of the frame is suffi - cient to give a cheese block ∼10 cm thick after pressing) lined with cheesecloth and placed over the draining table. The top layer of the coagulum (rich in fat) is taken off fi rst and evenly distributed when fi lling the moulds. The curd is covered with the free sides of the cheesecloth and pressed with a suitable weight (about half the weight of the milk used).

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• Whey drainage is allowed for 12–24 h depending on several factors, but usually a shorter time is adopted during the summer season. • The following day, the pressed cheese is removed from the wooden frame, cut into small blocks ∼0.5 kg in weight, and placed in 20 kg metal containers in layers (total weight of 14–16 kg); salted whey (i.e. collected from the same batch of cheese) is added and the container is soldered (rarely practised now) or tightly closed with a press-on-lid. • The cheese is retailed directly as a fresh product or kept at room temperature for ≥3 months before being marketed as matured cheese.

Several modifi cations have been suggested to improve and standardise the traditional method for making Domiati cheese including heat treatment, homogenisation and addition of starter cultures, which have been reviewed extensively by Abd El-Salam et al. (1976) and Abou Donia (1991). However, in large factories, the traditional method of manufacturing Domiati cheese has been scaled-up over the years with some modifi cations, the most important being pasteurisation of the milk and the addition of starter cultures. In view of the shortage of fresh milk in Egypt, dairy factories have been encouraged to utilise reconstituted milk powder and/or recombined milk in Domiati cheese milk. In order to avoid the deleterious effect of the high NaCl level on the weak coagulum made from reconstituted or recombined milk, the total solids content of the fresh milk is fortifi ed with skimmed milk powder (SMP), reconstituted or recombination milk to 20–25 g 100 g–1 (El-Koussy, 1982).

Coagulants The type of coagulant used is an important factor in determining the characteristic quality of Domiati cheese made in different parts of Egypt. Locally prepared liquid calf rennet extract is preferred by manufacturers of traditional Domiati cheese in Damietta Governorate. This source of rennet is characterised by low milk clotting activity (i.e. less than 0.5 strength (Soxhlet unit) and poor bacteriological quality), and thought to be responsible for major defects observed in Domiati cheese (Naguib et al., 1975). Attempts have been made to standardise the preparation of rennet extracts from calves (Fahmi & Amer, 1962), sheep (Girgis et al., 1983), adult animals (cows and buffaloes – Fahmi et al., 1979), and camels (El-Batawy et al., 1987), which improved markedly the quality of Domiati cheese. In Fayoum Governorate, cheese manufacturers prefer the use of a rennet paste prepared by storing the calf abomasum with its content (coagulated milk) layered with sodium chloride in soldered metal containers for almost one year before use. The rennet paste is characterised by being thick and viscous/pasty in texture, white in colour, and having a pleasant smell, high proteolytic and lipolytic activities, and acceptable bacteriological quality (Abd El-Ghani et al., 1998). In addition, the locally made rennet paste is thought to be responsible for the pungent ﬂ avour of traditional Domiati cheese produced in this part of Egypt.

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Imported rennet powder, microbial rennet and recombinant chymosin are now used for the industrial production of Domiati cheese. These different types of rennet slightly affect the yield, the maturation of the cheese and texture of the product (Abdou et al., 1976; Mehanna et al., 2002).

Starter cultures Traditionally, Domiati cheese was made from raw milk. The maturation of the cheese was governed by the natural microfl ora present in the milk, selectively controlled by the added sodium chloride to develop the fl avour typical of this cheese variety. However, the use of pasteurised milk in the industrial manufacture of Domiati cheese requires the addition of suitable starter organisms in order to obtain a product of similar quality to that made from raw milk. Two trends have been followed to achieve this objective: • Firstly, the addition of ‘traditional’ cheese starter cultures consisting of mesophilic and thermophilic lactic acid bacteria (LAB) to pasteurised milk. Incidentally, the milk is left to allow the growth of the added organisms before the addition of sodium chloride and onset of cheesemaking (Abou Donia, 1981; Naguib et al., 1974a; Sharara, 1962). • Secondly, the selection of salt-tolerant organisms to be added to the salted milk before cheesemaking. A mixed culture of Pediococcus cerevisiae (see Simpson & Taguchi (1995) for the nomenclature of this organism) and Enterococcus faecalis were recommended for making Domiati cheese from pasteurised milk containing up to 10 g NaCl 100 mL–1 (Naghmoush et al., 1983). El-Gendy et al. (1983) used a blend of Pediococcus spp. 452 and Leuconostoc paramesenteroides in Domiati cheese packaged in pouches. El-Soda and Abd El-Salam (2002) reported that the use of E. faecium and a combination of mesophilic and thermophilic lactobacilli develops the characteristic fl avour of Domiati cheese made from pasteurised milk. A special starter culture is now produced by Chr. Hansen Laboratories S/S, Hørsholm, which has been used in the manufacture of Domiati cheese from pasteurised milk in several factories. The cheese has the same fl avour characteristics of Domiati cheese made from raw milk.

Cheese yield The yield of Domiati cheese has been researched extensively, mainly to determine the economy of its production. Generally, the fresh yield of Domiati cheese is markedly higher than the yield of other brined cheeses. Several factors were reported to affect the yield of Domiati cheese, and have been summarised in Table 5.3. However, the high salt content added to the milk can be considered a major factor in determining the yield of the fresh cheese. The old data available on the yield of Domiati cheese, which were developed by Teama (1967) as a function of added salt, have been recalculated based on a standardised moisture content of 60 g 100 g–1 (Table 5.4). For example, an increase of 1 g of added NaCl to the milk can increase the fresh cheese yield by 0.75–1.0 g 100 g–1. However, differences in the yield of cheese with

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Table 5.3 Effect of different factors on the yield of Domiati cheese

Factor Effect Extent References Type of milk Variable Hamed (1955), Mehaia (1993) Salt content Increase +++ Fahmi & Sharara (1950), Teama (1967) Heat treatment Increase + Sharara (1962), El-Koussy (1966) Homogenisation Increase + Ahmed et al. (1972), Abd El-Salam & El-Shibiny (1982) Acidity Decrease + El-Koussy et al. (1975) Type of coagulant Variable + Abdou et al. (1976), El-Safty & El-Shibiny (1980) Additives Variable + El-Abbassy et al. (1991)

Table 5.4 Effect of added salt (g 100 g–1) to the milk on the yield (kg 100 kg–1 milk) of Domiati cheese

Age of the cheese (months) Salt content Fresh 1 2 3 4 7 28.06 23.60 21.60 21.38 20.35 10 30.32 23.59 22.92 21.65 21.36 13 33.34 23.85 22.95 24.10 23.67 The calculated yield of cheese was standardised at 60 g moisture 100 g–1. Data calculated from Teama (1967).

different salt contents became less pronounced during the storage period. In addition to its direct effect on the yield of cheese, the Na+ ions replace some of the Ca2+ ions of the casein micelles (Sharara, 1958), and the rennet-coagulated salted milk gives rise to a gel of mixed calcium and sodium paracaseinate of higher water-holding capacity (Fahmi & Sharara, 1950). Domiati cheese may lose ∼25–35% of its fresh weight during the storage period (Abd El-Salam et al., 1976; Abou Donia, 1991), and most of the weight losses occur during the ﬁ rst month of storage. Several factors have been identiﬁ ed as responsible for cheese weight losses during storage, but the developed acidity and changes in pH are considered the main factors. As the pH of cheese decreases, the net charge of the cheese matrix decreases, and the developed acidity partially solubilises the calcium phosphate that stabilises the gel matrix (Ahmed et al., 1972). This enhances the shrinkage of the cheese matrix and exudation of part of the aqueous phase in the cheese to the brine and, thus, decreases the weight of the product.

Compositional changes during the storage period of the cheese in brine The Egyptian Standard (Anonymous, 2001) classiﬁ es Domiati cheese according to the type of milk used, maturation stage, and fat-in-dry matter (FDM) and moisture contents of the product (see Table 5.5). In addition, the same standard speciﬁ es that the lactose and sodium chloride contents of Domiati cheese should not exceed 4.5 and 9 g 100 g–1, respectively, and the protein content should not be less than 10 g 100 g–1. It is evident, however, that continuous changes in the chemical composition and other properties of Domiati cheese can be seen as long as the cheese is stored in brine. These changes are governed mainly by the following factors.

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Table 5.5 Egyptian Standards for Domiati cheese.

Level of fat Constituent (g 100 g-1) Age of the cheesea Type of milk Full Three-quarters Half Low Fat-in-dry matter (FDM) Fresh/matured Buffalo/sheep ≥45 ≥35 ≥25 ≥10 Moisture Cow/goat/others ≥40 ≥30 ≥20 ≥10 Fresh All milks ≤62 ≤62 ≤65 ≤65 Matured All milks ≤58 ≤60 ≤60 ≤62 a Age of mature cheese is >3 months. After Anonymous (2001).

• Domiati cheese made from buffalo’s milk has higher FDM, less moisture and lower acidity than similar products made from cow’s or goat’s milk (Hamed, 1955; Kandeel et al., 1991). The use of reconstituted or recombined milks reduces the moisture content of the cheese (Hagrass, 1971). • High salt contents of the cheese and the brine selectively enhance the growth and activity of salt-tolerant microorganisms in the product (Helmy, 1960; Naguib et al., 1974b). However, as the percentage of NaCl added to the milk is increased, the changes in the chemical composition of the cheese during the storage period will slow down (Zaki et al., 1974). • High lactose content of the cheese and the salted whey used as a brine continuously supplies an energy source for the growth and activity of the microﬂ ora present in the product. This carbohydrate has been found in Domiati cheese even after 6 months of storage (Tawab et al., 1975). The use of brine with reduced lactose content retarded acid development in the cheese (El-Abd et al., 1975). • High retention of milk-clotting enzymes in the cheese matrix, which arises from using a high concentration of coagulants during the manufacture of the cheese, can contribute to higher protein hydrolysis during the maturation stage (Abdou et al., α 1976; Fahmi & Sharara, 1950). These enzymes hydrolyse s1-casein rapidly, whilst β-casein resists hydrolysis (Abd El-Salam & El-Shibiny, 1972; Abd El-Salam et al., 1983; El-Shibiny & Abd El-Salam, 1974; Mehanna et al., 1983). Matured Domiati β α cheese has a high ratio of - to s1-casein, which may partly explain the soft body and texture of the product (Abd El-Salam et al., 1983). Analysis of soluble nitrogen constituents of Domiati cheese by gel permeation chromatography showed that they are mainly low molecular weight components (i.e. amino acids and small peptides) (Abd El-Salam & El-Shibiny, 1972). The use of milk-clotting enzymes other than calf rennet altered the pattern of protein hydrolysis in Domiati cheese (Abdou et al., 1976, Abdel-Kader, 2003). In addition, Domiati cheese contains very low concentrations of biogenic amines, e.g. tyramine (the principal amine), histamine, tryptamine, phenylethylamine and putrescine (Mehanna et al., 1989). • Storage of the cheese at ambient temperature accelerates the chemical and biochemical changes (Abou Dawood, 1964; Teama, 1967). • Continuous partition of soluble constituents between the cheese and the brine has been reported by Teama (1967) and Ahmed et al. (1972), and this would encourage continuous biochemical changes to attain equilibrium between the product and the salt solution.

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Most of the chemical (i.e. gross composition) and biochemical changes in Domiati cheese occur during the fi rst month of storage, which coincides with the rapid development of acidity or changes in the pH in the product. For example, the content of volatile acids of Domiati cheese increases markedly during the same period, which is due to the optimal microbial activity (Naguib et al., 1974a, 1974b; Shehata et al., 1984), and acetic acid was found to constitute the major part of the volatile acids in the product (El-Shibiny et al., 1974). In addition to the volatile fatty acids, several other volatile components have been identifi ed in Domiati cheese by dynamic headspace gas chromatography-mass spectroscopy (GC-MS), and Collin et al. (1993) reported 44 compounds, most of which were present after 2 months of maturation. The quality of matured Domiati cheese was found to be associated with the level of several esters, such as ethyl propionate, propyl acetate, ethyl butyrate, propyl propionate and propyl butyrate, alcohols (namely propan-1-ol and butan-2-ol), a ketone (i.e. butan-2-one), acrolin and pentane. However, the presence of high concentrations of sulphur-containing compounds impaired the quality of the cheese (Collin et al., 1993). The milk fat undergoes nonspecifi c lipolysis during the storage of the cheese, as is apparent from the pattern of the free fatty acids (Ramos et al., 1988) and glycerides (Precht & Abd El-Salam, 1985), and the addition of starter cultures and cheese slurry during the manufacture of Domiati cheese from pasteurised milk enhanced the formation of free fatty acids in the product (Kebary et al., 1991). Limited data on the vitamin content in Domiati cheese have been reported

(Khattab & Zaki, 1986; Sabry & Guerrant, 1958). The levels of biotin, vitamin B2 and folic acid remained unchanged during storage, while changes in riboﬂ avin and niacin were dependent on the storage conditions (Sabry & Guerrant, 1958).

Texture and microstructure of the cheese Fresh Domiati cheese has a soft texture, but becomes fi rmer when stored in brine. The cheese has a close texture and, as ripening progresses, it becomes brittle when broken. The textural parameters (elasticity, hardness, brittleness, adhesiveness, chewiness and gumminess) of fresh Domiati are affected by several factors (El- Zeny, 1991; Zaki, 1990): • the chemical constituents and pH of the cheese affect the textural parameters in the following order: pH > NaCl > protein > fat > moisture; • the values of the textural parameters increase signifi cantly with increasing rennet concentration, renneting temperature and addition of CaCl2 to the milk; • decreasing the pH and increasing the amount of added NaCl decrease signifi cantly the values of all textural parameters; and • the optimal values for textural parameters were obtained by using milk of pH 6.6, renneting at 39°C, with a rennet concentration of 0.09 mL 100 mL–1, and –1 CaCl2 at 0.02 g 100 g .

The values of the textural parameters of Domiati cheese increase during the early maturation period followed by a decrease after 3 months of storage in brine (Gomaa,

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1990). It seems that the increase in these measurements is related to the decrease in moisture and pH leading to fi rmer texture, while the decrease in the textural parameters in latter stages is attributed to changes in the protein matrix due to proteolysis and losses of Ca2+. Also the method used to store the cheese can affect the textural properties of the product; for example, cheese stored in plastic laminates (i.e. pouches) without any brine was signifi cantly harder and more cohesive and gummy than cheese stored in brine (Gomaa, 1990). Electron microscopic examination of ultra-thin sections of Domiati cheese indicates that the internal structure of the fresh product is made up of a framework of spherical casein aggregates held together by bridges, and that the fat globules are embedded within these aggregates (Abd El-Salam & El-Shibiny, 1973; Hofi et al., 2001). During storage of the cheese in brine, the casein aggregates dissociate into smaller spherical particles forming a loose structure. Micrographs obtained using scanning electron microscopy (SEM) illustrate that the high salt content has little effect on the surface characteristics of Domiati cheese (Kerr et al., 1981).

Microbiological quality Predominant microflora During the early maturation stages of Domiati cheese, Lactococcus spp. are predominant, but Lactobacillus spp. become dominant in the latter stages (Naguib et al., 1974a,b; Shehata et al., 1984). Isolated cocci from mature Domiati cheese are mainly salt-tolerant enterococci (Hemati et al., 1998), but other organisms that have been found in the product include Enterococcus faecalis, Enterococcus faecium, Lactococcus lactis subsp. lactis, Lactococcus lactis subsp. cremoris, Lactobacillus casei subsp. casei, Lactobacillus plantarum, Lactobacillus brevis, Lactobacillus delbrueckii subsp. lactis, Lactobacillus alimentarius, Leuconostoc mesenteroides subsp. cremoris, Brevibacterium linens and Propionibacterium jensenii (El-Zayat et al., 1995; Naguib, 1965; Shehata et al., 1984). Also, yeasts belonging to the genera Triechospora, Saccharomyces, Pichia, Debrayomyces, Hansenula, Torulopsis, Endomycopsis and Cryptococcus have been found in Domiati cheese (Ghoniem, 1968; Seham et al., 1982).

Changes in the microflora during the maturation of the cheese The total bacterial and lactococcal counts increase rapidly to a maximum after a week of storage, and then decline; the Lactococcus spp. disappear after 2–3 months of storage. However, the counts of lactobacilli reach a maximum after 2–4 weeks and then decrease gradually (Helmy, 1960; Naguib et al., 1974a). During the ﬁ rst month of storage, Domiati cheese made from raw milk generally has higher bacterial total counts than cheese made from pasteurised milk, but both cheeses have similar counts thereafter (Naguib et al., 1974b). In addition, a high salt content in the cheese milk reduces the total bacterial and other microbial counts (Shehata et al., 1984), and micrococci and lactobacilli share predominance in Domiati cheese with a high salt content (Helmy, 1960).

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Survival of harmful microorganisms The survival of coliforms in Domiati cheese is affected by the level of NaCl added to the cheese milk, and the addition of salt >9.5 g 100 mL–1 is necessary to suppress the growth of coliforms in the product, especially in cheeses made from raw milk (Hegazi, 1972). The presence of Campylobacter spp., but not Campylobacter jejuni, has been detected in Domiati cheese (El-Nokrashy et al., 1998), whilst the viability of Listeria monocytogenes in Domiati cheese was dependent on the pH level, NaCl content and storage temperature (Tawﬁ k, 1993). Aeromonas caviae, Aeromonas hydrophila and Aeromonas sobria have been found in retail samples of Domiati cheese sold in different markets (Effat et al., 2000). Coryneforuis spp. are the most prevalent microorganisms associated with the slimy surface defect of white pickled cheese (Abou Elnaga, 1974). Clostridium spp. have been found in Domiati cheese, even in samples with high acidity and salt content (Fahmy & Youssef, 1974), and the predominant species isolated were Clostridium tyrobutricum and Clostridium perfringens (Naguib & Shauman, 1973). Bacillus cereus has been isolated from Domiati cheese (El-Nawawy et al., 1981), and Salmonella typhi can survive for up to 16 days in cheese made from milk containing 10 g NaCl 100 mL–1 (Naguib et al., 1979). Staphylococcus aureus can tolerate up to 15 g NaCl 100 mL–1, but its enterotoxin has not been detected in the product (Ahmed et al., 1983).

Microbial defects in cheese Early blowing is the principal defect in Domiati cheese, particularly in products made from raw milk. The cheese develops a spongy texture due to the formation of gas holes and, subsequently, there is blowing of the metal containers. Several microorganisms and other factors have been reported to be responsible for this defect including: (a) the presence of coliforms, particularly Aerobacter aerogenes (Hegazi, 1972); (b) the presence of Saccharomyces spp. (El-Shibiny et al., 1988); and (c) electrolytic corrosion of the metal container by NaCl and developed acidity in the cheese (Abo Elnaga, 1971).

5.3.2 UF Domiati cheese Introduction Success in the use of ultrafi ltration (UF) in the production of Feta-type cheeses has encouraged the development of UF Domiati cheese. Abd El-Salam et al. (1981) were the fi rst researchers to manufacture UF Domiati cheese from buffalo’s milk; the milk was ultrafi ltered and sodium chloride was added to the retentate before coagulation. Al-Khamy (1988) reported that the texture and fl avour of UF Domiati cheese can be manipulated by changing the homogenisation pressure, heat treatment of the milk and rate of acid development by the starter culture. The industrial production of UF Domiati cheese was fi rst exploited through a fi eld study by Abd El-Salam et al, (1994), and an increase in the yield of cheese by 20–25% was reported. However, Chapter 3 reviews the latest development in the manufacture of UF brined cheeses similar to Domiati.

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Technical aspects At present, UF Domiati cheese is produced in small- and large-scale factories using similar methods of manufacture. In small-scale production units, the milk is pasteurised, and batch ultrafi ltered (i.e. concentration factor of 4.0–4.5 depending on the chemical composition of the milk used). The retentate is heated to 80°C, homogenised at 5–8 MPa, cooled to 40°C, and inoculated with 0.5 mL 100 mL–1 starter culture. After 30–60 min, sodium chloride (3–5 g 100 mL–1) is added to the retentate, which is then distributed in stainless steel trays (50 × 50 × 10 cm) lined with plastic sheet. Rennet (3 g 100 kg–1 milk) is dissolved in water, added to the salted retentate, and mixed thoroughly; the trays are covered, left at 40°C for 1–2 h, and then left overnight in a cool place. The cheese block is removed from the tray, cut into portions (about 0.5 kg), wrapped in a plastic sheet, and then packaged in 1–2 kg plastic containers (consumer package) or in 10–20 kg metal or plastic containers. In both cases, the cheese portions are covered with 5 g 100 mL–1 brine solution. For the large-scale production of UF Domiati cheese, continuous ultrafi ltration of the milk is carried out, and the manufacturing stages of the cheese are similar to those used in small-scale plants. In some factories, the renneted retentate is packaged directly in consumer plastic packaging containers (0.5–1 kg), placed on a moving conveyor belt, and the speed adjusted to ensure complete coagulation before discharge. Afterwards, each package is dosed with brine or dried salt, heat sealed with aluminium foil laminate, and fi nally covered with a press-on plastic lid.

Compositional quality and yield of the cheese The yield of UF Domiati cheese has been reported to be higher than that of a traditional product, in particular when made from cow’s milk (Al-Khamy, 1988); during the storage period, the UF product retains this higher yield compared with a traditional Domiati cheese (Table 5.6). The UF product is normally stored and marketed at low temperature, due to its low salt content and relatively high pH. It has a shelf-life of one month, and is usually consumed fresh. However, changes in the total solids and FDM contents of UF Domiati cheese during storage are much less than those

Table 5.6 The yield and chemical composition of traditional and ultraﬁ lterd (UF) Domiati cheese made from cow’s and buffalo’s milk

Yield Total solids Fat-in-dry matter (kg 100 kg–1 milk) (g 100 g–1) (FDM) (g 100 g–1)pH Type of cheese Fresh 60 days Fresh 60 days Fresh 60 days Fresh 60 days Traditional – cow’s 20.00 12.81 38.49 48.77 40.86 47.11 5.93 4.30 milk UF – cow’s milk 23.72 22.23 40.74 41.56 41.24 43.32 5.90 4.90 Traditional 29.67 20.46 39.59 51.71 46.08 53.00 5.96 4.29 – buffalo’s milk UF – buffalo’s milk 30.89 29.74 42.47 42.97 45.60 46.94 5.90 4.81 Adapted from Al-Khamy (1988).

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observed for the traditional product, even when stored at room temperature (Table 5.6). Also, changes in the pH are much slower in UF Domiati cheese, and this has been attributed to its high protein content and increased buffering capacity.

Texture and microstructure of the cheese The textural properties of UF Domiati cheese can be controlled by changing the processing parameters (Al-Khamy, 1988). Increasing the homogenisation pressure, heat treatment of the milk and decreasing the pH of the pre-cheese will result in increased hardness of fresh UF Domiati cheese (Al-Khamy, 1988). The UF product was found to be less elastic than the traditional Domiati cheese (Gomaa, 1990), and an increase in the textural parameters of UF Domiati was found to be due to losses in cheese moisture during the early stages of maturation. However, a marked decrease in these parameters occurs later, which can be attributed to the hydrolysis of the proteins and loss in Ca2+ from the cheese matrix. With regard to the microstructure of traditional and UF Domiati cheeses, differences were reported by Hoﬁ et al. (2001). The protein matrix of UF Domiati cheese is denser and made of larger protein aggregates, and the whey proteins are also included in the matrix.

Packaging of the cheese Storage of the cheese without brine in plastic pouches sealed under vacuum has had a marked effect on the changes during the maturation period and quality of UF Domiati cheese, and Gomaa (1990) concluded the following: (a) it improved the yield and accelerated ripening of the cheese; (b) the compositional quality (i.e. total solids, protein, fat, lactose and ash contents) was better than in cheese matured in brine; (c) in UF cheese, an increase in proteolysis (i.e. soluble nitrogen fractions and free amino acids) and free fatty acids was evident in the product; (d) the product had signiﬁ cantly higher measurements for the structural parameters; and (e) the UF cheese developed a more yellowish colour compared with a similar product stored in brine.

5.3.3 Tallaga cheese Tallaga (meaning ‘refrigerated’ in Arabic) cheese is a product closely related to Domiati cheese, and mainly matured and stored in metal containers without brine under refrigeration for up to 9 months before consumption. The speciﬁ c features of this type of cheese are: • It is prepared from high-heat-treated milk, but the heating conditions are not standardised. • The cheese is made from milk with a high fat content. • The salt content is lower than traditional Domiati cheese. • It has a clean, slightly acid ﬂ avour, and smooth creamy body and texture.

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Hoﬁ et al. (1979) analysed market samples of Tallaga cheese, and grouped the samples according to their sensory properties as good, medium and fair. The same authors also observed that a good-quality Tallaga cheese contained a high fat content. In addition, a product stored at 4°C rather than at 8 or 12°C had the best sensory

attributes (Awad et al., 2002), and the addition of CO2 to the milk improved the quality of Tallaga cheese (Mehanna & Rashed, 1990). The breakdown of the casein occurs very quickly in the cheese during the fi rst month of storage in a pattern typical of chymosin action on casein. The hardness, cohesiveness, springiness, consistency and stress relaxation of Tallaga cheese decrease with advanced storage, being more pronounced for product stored at 12°C rather than at 4°C (Awad et al., 2002). Mixed cultures of Lac. lactis subsp. cremoris and Lb. casei subsp. casei at a ratio of 1:1 have been recommended for the manufacture of Tallaga cheese (El-Abd et al., 2003), and the best quality was obtained using 3 g NaCl 100 mL–1. The total bacterial and LAB counts in the cheese reached a maximum after 30 days of storage and decreased thereafter (El-Abd et al., 2003). Recently, Lactobacillus acidophilus and Bifi dobacterium animalis subsp. lactis have been used in the manufacture of probiotic Tallaga cheese (El-Zayat & Osman, 2001); the sensory profi le scores of the cheese were high, and the counts of the probiotic organisms were >106 colony- forming units (cfu) g–1 during the storage period.

5.3.4 Mish cheese Mish cheese has always been considered as a staple food in the rural areas, and it is the oldest indigenous milk product in Egypt. The origin(s) of Mish cheese is not well known, but it is a brined cheese, and stored and matured in earthenware pots; similar pots were found in the tombs of King Horaha of the ﬁ rst dynasty (3200 BC). Traditionally matured Mish consists of Mish cheese and Mish slurry (concentrated pickling medium), and both are consumed. The colour of the product is yellowish- brown, and has a sharp, pungent ﬂ avour. Mish is traditionally prepared by farmers following a simple method of manufacture. However, an industrial method has been developed for large-scale production of Mish cheese. The Egyptian Standards (Anonymous, 2003) specify that the farmhouse product consists of ‘pieces of cheese in their original size mixed with a pasty brining medium’, whilst the industrially produced Mish cheese is a ‘homogenate which may contain very small pieces of cheese particles’.

Technical aspects The traditional method for making Mish cheese is based on brining Karish cheese – i.e. skimmed milk, acid coagulated (e.g. natural acid development), and mixed with variable amounts of sour milk, buttermilk, Morta (residues from the manufacture of butter oil, known locally as Samna/Ghee) by the boiling off method. The mixture is ﬂ avoured with different types of pepper (e.g. green, red, hot, paprika are the most common ﬂ avouring additives), table salt and a portion of an old Mish, which acts as a starter culture. Mish cheese is stored in porous earthenware jars that permit

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water to seep through or evaporate, and concentrate the brining medium, which, in turn, with extended storage converts the mixture into a paste (El-Gendy, 1983). The Mish container is kept closed in a warm place for maturation. As part of matured Mish is consumed, a new portion of various ingredients is added and mixed with the remaining content of the container. There is no limit for the maturation of Mish as the container is kept charged continuously, that is, on-going fermentation. For the industrial production of Mish, residual cheese curd, broken portions/ pieces of Domiati and Karish cheeses, trimmings of portioned hard cheese, yoghurt (not suitable for marketing), Morta, emulsifying salt (5 g 100 g–1), table salt (∼10–15 g 100 g–1), hot pepper and old traditional Mish (2.5 g 100 g–1) are mixed well and stored in an air tight container until mature (∼1 year). The contents are then cooked at 70°C with continuous stirring in a stainless steel vat to produce a homogeneous paste, and packaged hot in suitable containers (0.5 kg glass or plastic containers).

Compositional quality and general characteristics of the cheese Wide variations have been found in the composition of market samples of Mish cheese as shown in Table 5.7 (Abou Donia & El-Soda, 1986; El-Erian et al., 1975; Nassib & El-Gendy, 1974; Zaki & Shokry, 1988). These variations could be attributed to the lack of standardised ingredients employed during the manufacture of the product. In general, Mish cheese contains low fat and high salt contents. During the maturation stage, the total solids contents of Mish cheese and the brining medium increase mainly due to evaporation from the porous container. However, the extent of this increase depends on the chemical composition of the ingredients and brining medium used, and the conditions as inﬂ uenced by time and temperature. The pickling medium (Mish slurry) acquires a pasty texture with advanced storage, and both the matured Mish cheese and the slurry develop a yellow-brown colour, which probably arises from the Maillard reactions. Mish cheese undergoes extensive proteolysis and lipolysis during the maturation period, which is apparent from the high nonprotein and amino acid nitrogen (Nassib & El-Gendy, 1974), and volatile fatty acids and butyric acid contents (Taha & Abdel- Samie, 1961b; Zaki & Shokry, 1988). An increase in the reducing substances in Mish cheese and slurry has been reported by Zaki & Shokry (1988), and attributed to sulphydryl compounds, but it is more likely to arise from Maillard reactions. Table

Table 5.7 Maximum and minimum contents of gross chemical composition (g 100 g–1) of Mish cheese

Constituent Minimum Maximum Moisture 54.76 75.68 Fat 0.50 4.60 Protein 6.90 13.13 Ash 11.13 19.79 NaCl 10.00 15.00 After Nassib & El-Gendy (1974) and El-Erian et al. (1975).

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Table 5.8 Changes in the chemical composition (g 100 g-1) of Mish cheese and slurry during the maturation period

Cheese Slurry Constituent Fresh 10 months Fresh 10 months Moisture 71.64 53.350 84.60 68.40 pH 4.45 5.20 5.80 4.70 Titratable acidity 2.50 3.36 0.78 2.95 Total volatile fatty acids (TVFA)a 26.00 77.30 29.90 76.00 NaCl 2.61 9.74 9.80 12.59 Total nitrogen (TN)b 7.71 9.57 5.79 12.66 Soluble nitrogen (SN)b 0.79 2.97 2.47 3.12 Amino acid nitrogen (AAN)b 0.19 2.96 0.54 1.69 Soluble tyrosine 0.29 1.96 0.39 1.59 Reducing substancesc 37.20 90.20 42.10 78.30 Ash 3.02 11.50 8.20 14.32 a mL 0.1N NaOH 100 g-1. b Calculated as a percentage of dry matter (DM). c Milligrams ferrocyanide 100 g-1. Data compiled from Zaki & Shokry (1988).

5.8 summarises the changes in the composition of Mish cheese and slurry during the maturation period. In addition, Neamat Allah (1997) analysed 50 samples of commercial Mish cheeses, and reported that the histamine and tyramine contents averaged 9.9 and 29.2 mg kg–1, respectively, and these compounds were found in 50–66% of the samples tested. Incidentally, the tyramine value is rather high.

Microbiological quality The total bacterial count of Mish cheese ranges between 105 and 106 cfu g–1 (El- Erian & El-Gendy, 1975; Nassib & El-Gendy, 1974; Zaki & Shokry, 1988). The counts of proteolytic and lipolytic bacteria are generally less than the total count, and Mish samples are free of coliforms (Abou Donia & El-Soda, 1986). During the maturation period, the microbial counts of most bacteria decrease except for spore-formers, which show an increase (see Table 5.9). However, micrococci, bacilli and arthrobacteria have been found in Mish (El-Erian & El-Gendy, 1975; Nassib & El-Gendy, 1974), and Taha & Abdel-Samie (1961a) identiﬁ ed two new species of clostridia, namely Clostridium mishii and Clostridium mishami, which were isolated from market Mish samples.

5.4 North African brined cheeses 5.4.1 Traditional technology and properties of the cheeses Despite the diversity of traditional technologies for producing brined cheese from cow’s, goat’s or sheep’s milk in North African countries, four basic steps are common to the manufacturing of any cheese variety: (a) milk preparation, (b) milk

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Table 5.9 Changes in bacterial counts (cfu g–1) of Mish cheese and slurry during the maturation period

Cheese Slurry Bacterial counts Fresh 10 months Fresh 10 months Total viable count 4.0 × 108 4.0 × 105 6.2 × 107 1.2 × 103 Micrococci 1.0 × 106 2.0 × 103 3.3 × 107 2.5 × 103 Lactic acid bacteria (LAB) 1.8 × 108 3.2 × 104 9.2 × 106 5.4 × 104 Pediococci 1.8 × 108 2.6 × 105 2.0 × 107 1.8 × 105 Proteolytic 2.0 × 107 5.6 × 103 4.3 × 107 2.0 × 102 Lipolytic 1.3 × 106 2.2 × 102 6.5 × 105 1.2 × 102 Aerobic spore-formers 4.0 × 102 1.2 × 103 5.3 × 103 1.8 × 103 Data compiled from Zaki & Shokry (1988).

Table 5.10 Common manufacturing steps of brined cheeses

Product Processing stage Operations Raw milk Preparation of the Sieving milk Adjust temperature of the milk (heating to 37°C) Pasteurise the milk (optional) Standardise the fat content (optional – allow the milk to settle and remove some of the fatty layer from the surface) Cheese milk Coagulation of the Add rennet (commercial, animal or vegetable type) milk Acidify the milk: (a) spontaneous, (b) addition of starter cultures (mesophilic lactic acid bacteria or a yoghurt culture), and (c) addition of acids, e.g. lemon juice or vinegar

Addition of calcium chloride (CaCl2) (optional and only used in industrialised cheeses) Handling of the Draining of the whey Cutting of the coagulum coagulum Removal of the whey – e.g. (a) spontaneous drainage, (b) application of pressure, i.e. manual squeezing of the curd or the use of weights Cooking of the curd in the whey (optional), either applied directly or by the addition of hot water or whey Handling of the curd Pre-cheese Addition of dry salt (optional) Stretching of the curd (only used during the manufacture of Pasta Filata type cheeses) Moulding of the curd using traditional moulds, baskets, wooden frames, plastic moulds, cheesecloth Pressed/moulded Maturation De-moulding of the pressed curd curd Brining of the cheese in saline solution, salted skimmed milk, salted sour milk or salted whey Mature the cheese in the brine or in the open air in ripening rooms (optional)

coagulation, (c) handling of the curd including brining, and (d) maturation. Table 5.10 summarises the main steps and the corresponding operations used to obtain different traditional North African brined-type cheeses.

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Milk preparation Prior to cheesemaking, the milk should undergo some preparative steps to optimise the quality of the cheese. Three different measures are usually taken.

(1) Sieving of raw milk by passing it through a strainer to remove the animal hair and the gross debris that are usually present after milking. For some cheese varieties, the milk is heated or boiled to remove all the undesirable microorganisms; however, in this case, an alternative means to ensure the acidiﬁ cation of the milk is usually necessary. This can be achieved by blending a portion of a previous day’s fermented milk as a lactic starter culture (i.e. back-slopping) or by adding acid solutions, such as lemon juice, citric acid or vinegar. (2) In traditional cheesemaking methods, the freshly drawn milk can be directly used for processing as its temperature is close to 37°C, which is optimal for the growth of most bacteria present in the milk, especially the mesophilic group. In addition, this temperature is also optimal for the action of the milk-clotting enzyme/preparation. However, if cheese production is delayed after milking and the milk is allowed to cool, it should be prewarmed to about 37–40°C prior to processing, depending on the cheese variety. (3) Reduction of the fat content may be necessary as it is usually higher than required. Standardisation of the milk fat content during the manufacture of cheese is normally carried out by mixing whole milk with partly or totally skimmed milk, mixing skimmed milk with cream, or separating part of the fat in whole milk to get the desired level. However, due to the fact that traditional cheese in North Africa is essentially made at the household level with very simple tools, none of these standardisation techniques may be affordable or technically feasible (i.e. purchase and maintenance of small-scale separators, fat testing equipment, and availability of skilled operators to determine the right proportion of whole milk and skimmed milk to be mixed together). Therefore, standardisation of the fat content is rarely practised and, when slight reduction of the fat content is required (e.g. Ethiopian Scamorsa cheese), the milk is allowed to settle until the fat layer rises to the surface of the milk, and part of the cream is removed.

Milk coagulation Milk coagulation is a crucial step in any cheesemaking procedure, and it consists mainly in destabilisation of the casein micelles and their precipitation with subsequent serum extrusion. It is well established that such destabilisation is achieved by hydrolysis of κ-casein, or by acidiﬁ cation of milk to a pH below the isoelectric point of casein (4.6 at 20°C). To hydrolyse the casein, proteolytic enzyme preparations from animal or plant origin have been used successfully for centuries. With the current developments in biotechnology and microbiology, coagulants obtained from bacteria and fungi are being increasingly used, even in traditional cheesemaking technologies. In general,

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the acidiﬁ cation of the milk relies on spontaneous lactic fermentation carried out by the naturally occurring lactic acid bacteria in milk, whilst in some cheese varieties where the milk is heated before the coagulation stage and no lactic starter cultures are subsequently added, acidiﬁ cation is achieved by the addition of vinegar or lemon juice.

The use of coagulants of animal origin Historically, coagulation of the milk by rennet action in traditional cheesemaking was achieved by fi lling a calf stomach (i.e. thoroughly cleaned and tied up at one end) with freshly drawn milk; this was kept at room temperature until coagulation occurred. In such a way, the stomach was used both as a container for cheesemaking and as a source of the coagulant (i.e. rennet). Moreover, the resident microfl ora of the stomach lining tissues contributed to the milk fermentation by providing a natural inoculum of lactic cultures. However, due to increased cheese production and the concomitant reduced supply of calf’s stomachs, the practice has been abandoned in North African countries. Nowadays, rennet is extracted from the fourth stomach (abomasum) of a calf, kid or lamb. The stomach is cut into strips and subsequently dried in the shade then stored in the dark until needed. To extend the shelf-life of the dried stomach and prevent its microbial alteration, the strips are salted or rubbed with cinnamon (Fig. 5.1). Cinnamon has a potent antimicrobial activity (Bartine & Tantauoui-Elaraki, 1997; Sebti & Tantaoui-Elaraki, 1994) and effectively prevents microbial contaminants or growth (mainly moulds) on the dried stomach. To make a rennet solution, the dried stomach strips are generally soaked in water or in a saline solution (12–20 g salt 100 mL–1). This infusion is allowed to settle for 1–3 days, and then repeatedly sieved through a strainer until a clear fi ltrate is obtained (i.e. crude rennet). The crude rennet may be stored for more than 30 days without signifi cant loss of activity if protected from light and microbial contamination. In

Fig. 5.1 Strips of dried calf’s stomach (abomasum) coated with cinnamon ready for rennet extraction.

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many instances, however, it is more convenient to store the dried stomach strips than the rennet solution and, hence, the crude rennet is prepared for milk coagulation during cheesemaking. For example, in Moroccan brined Jben manufacture, a piece of dried calf stomach (ca. 10 g) is soaked in water (ca. 100 mL) for 1 to 2 h, and then sieved to be used for clotting the cheese milk. This preparation coagulates 20–30 L of milk in 20–30 min. Upon whey syneresis, part of the extruded whey is collected and used for another infusion of the same piece of dried calf stomach to exhaustively extract the remaining enzymes to coagulate another batch of milk. It should be noted, however, that this traditional method of rennet extraction from ruminant stomachs is being gradually substituted by commercial rennet preparations. These are readily available in pharmacies and drug stores as solutions or tablets, and they give predictable and reliable performance in cheesemaking compared with the traditionally extracted calf rennet. However, this change may affect the sensory attributes of the cheese and, hence, its authenticity, as the calf stomach extract contains not only the rennet but also lipases that may play an important role during the maturation of the cheese and ﬂ avour development.

The use of coagulants of plant origin Although calf rennet is, by far, the most widely used coagulant in North African countries, other coagulants of plant origin are also commonly employed and may be exclusively utilised in some cheese varieties. The latex of a freshly harvested immature fi g tree has long been used at the household level and by shepherds to produce traditional cheeses. The fi g latex is rich in fi cin, which hydrolyses the casein effi ciently causing milk to clot in the same manner as the rennet; one drop of the latex may coagulate more than 1 L of milk within 10 min at ambient temperature. Nonetheless, excessive use of the fi g latex in cheesemaking usually leads to bitterness of the product. Another coagulant of plant origin that is commonly used in milk coagulation in North African countries (e.g. Morocco, Algeria and Tunisia as well as other Mediterranean countries such as Portugal and Spain), is derived from the fl owers of wild thistles including Silybum marianum (milk thistle) and Cynara cardunculus (cardoon) (Fig. 5.2). These plants belong to the same family (Asteraceae) as the globe artichoke. In Northern Africa, thistles grow abundantly during spring and early summer (i.e. March through July). A typical scheme for the utilisation of these plants in milk coagulation consists of collecting the thistle fl ower (stylets and stigma), and drying them in the shade. The dried fl owers should be stored in a dark, dry place. For use in cheesemaking, the dried fl owers are placed in a muslin cloth and dipped in warmed milk; the cloth acts as a strainer and the enzymes diffuse into the milk over several minutes. Despite the extreme variability in the activity of the plant extract – due to such factors as plant variety, its stage of maturity, the drying procedure and the conditions of storage after drying – the clotting activity is generally relatively high (ca. 3 g of the dried fl ower coagulates up to 15 L of milk in less than 15 min at 35–37°C). Alternatively, an aqueous extract from the fl ower could be prepared and directly added to the cheese milk as is the case for the crude rennet preparation; however, this method of plant extraction is mainly practised in

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(a) (b)

Fig. 5.2 Wild Cynara cardunculus L. (Compositae), used to coagulate milk in some brined cheese varieties. (a) The whole plant and (b) the ﬂ ower used to extract the milk coagulant. Courtesy of Pietro Pavone, Multimedia Botanical Garden, Ministry of University and Scientiﬁ c and Technological Research, Botanical Department, University of Catania (http://www.dipbot.unict.it/orto/boga.html).

Northern Mediterranean countries, namely Spain and Portugal (Sousa & Malcata, 2002), but is rarely used in North African countries. As regards the mechanism of milk clotting by the infusion of thistle, the ﬂ ower of the plant was reported to

contain an acid proteinase called cardosin that cleaves the Phe105-Met106 bond in bovine κ-casein (Faro et al., 1992) in a similar manner to commercial rennet (Fox & McSweeney, 1997; for further information refer to Chapter 1), but with the notable exception of that produced by the mould (e.g. Endothia parasitica), which κ hydrolyses the Ser104-Phe105 bond of the -casein (Fox, 2002). Another coagulant of plant origin, extracted from the leaves of Calotropis procera (Fig. 5.3), which grows in West African countries including Mauritania, is used to prepare a speciﬁ c brined cheese called Wagashi. This extract contains a proteinase called calotropain, which appears to act in the same manner as papain to clot milk. Alternatively, crushed stems of Bryophyllum sp., a succulent plant, can be used instead of C. procera to prepare Wagashi cheese, but the putative protease(s) involved and the precise mode of action remain to be elucidated, because, in practice, the extract coagulates the milk after being boiled.

Draining and moulding of the curd After clotting of the milk, the coagulum is cut into pieces and sometimes stirred to accelerate whey drainage, followed by transfer of the curd to the moulds for further whey draining. In some soft cheese varieties, especially when small quantities of cheese are made, the coagulum is directly transferred to the mould without prior cutting or stirring. Many types of utensils and containers are used for moulding and draining of the whey depending on the region, locality and country. In most coun-

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(a) (b)

Fig. 5.3 Calotropis procera, used to coagulate Wagashi cheese in Mauritania and other West African countries. (a) The whole bush and (b) Flowers and leaves showing droplets of the latex that coagulates milk. Refer to (http://www.chateaudebrou.com/niger/page_06.htm).

tries, these utensils have evolved with time and with socioeconomic changes. The fabric, bamboo and other hand-made baskets have been largely replaced by plastic and metal containers. However, in some regions, traditional utensils to drain the whey are regarded as essential tools to conserve the authenticity and uniqueness of traditional cheeses. For example, in the Northern region of Morocco, some villages located in the Maâmora forest of cork trees use utensils that have been inherited through generations and are still used to make the traditional brined cheese known as Djibna. Figure 5.4a,b illustrates this traditional equipment, which consists of a circular piece of bark (~30 cm in diameter) with grooves cut in the cork surface to facilitate whey drainage (Fig. 5.4a). For moulding, a handcrafted belt (~1 m long and 10 cm wide; Fig. 5.4c) is made from the sawn leaves of palmetto (Serenoa repens L.), folded lengthways and mounted on the cork piece in such a way as to make a cylinder of adjustable volume depending on the desired size of the cheese block. The cylinder is ﬁ lled with the curd and left to drain at ambient temperature for 1–2 h (Fig. 5.4d).

Salting and preservation of the cheese After whey drainage, the fresh cheese block is placed in a brine solution for maturation and preservation. In some cases, the fresh cheese is presalted in a brine solution 4–6 g salt 100 mL–1 for ~24 h, and then dry salted on the surface of the cheese before being transferred to another brine solution with a higher salt concentration. The brine is usually prepared by dissolving table salt in water to different concentrations ranging from 4 g salt 100 mL–1 to saturation (~30 g salt 100 mL–1) depending on the cheese variety; however, in some cheese types (e.g. Egyptian Mish or Sudanese Gibna Bayda), the brine is prepared by dissolving salt in whey, buttermilk, fermented skimmed milk (Laban), skimmed milk or diluted milk.

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(a) (b)

Fig. 5.4 Traditional Moroccan utensils for moulding and draining white brined cheeses. (a) A piece of bark, which is used as a support for moulding and whey draining of Jben Malah, showing the upper face with grooves and (b) the plain bottom side. (c) A belt made from sawn palmetto leaves and used for cheese moulding. It is folded so as to make a cylinder ~10 cm high and of variable diameter depending on the amount of curd to be drained. (d) A complete assembly for moulding of the curd and whey drainage.

For many producers, the primary role of maturation of the cheese, beside the fl avour development and acquisition of the salty taste, is preservation of the fresh cheese during the storage period, because the product is made under poor hygiene conditions and without facilities to control the temperature of storage. Therefore, the brining stage of soft cheese can be interrupted at any time for retailing and consumption. As a consequence, the brining period may vary from 1 day to more than 2 weeks, which can ultimately result in inconsistencies in the chemical composition, microbiological quality, structure and sensory properties of the cheese. Hence, the brine provides an adequate medium for the storage of the product. In addition, salting promotes syneresis, increases the hardness and adhesiveness of the cheese (Pastorino et al., 2003), and selects the microorganisms that may survive and/or grow during the maturation/storage period. Salt-tolerant or halophilic microorganisms are favoured and, in turn, govern the fl avour development thereby affecting the chemical composition and the sensory properties of the fi nal product. Microorganisms able to grow in salty conditions were reported to possess a wide range of hydrolytic enzymes, including lipases and proteases, which are the main enzymes involved in cheese ripening (Wouters et al., 2002).

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Maturation of the cheese In many traditional North African brined cheeses, especially the soft types, maturation of the product is optional, and is only considered if the cheese is to be sold in the cities or stored for relatively long periods. In this case, the cheese blocks are placed in a variety of earthenware, plastic, bamboo or plant ﬁ bre containers. Otherwise, they remain in the brine until consumption. However, in some brined cheese types, maturation of the product is part of the manufacturing stage, and should be properly completed. A typical example is the Sudanese Gibna Bayda (white cheese) and Mudafara, which are normally pickled and matured in closed metal containers so that maturation takes place under anaerobic conditions similar to those for Domiati cheese.

Quality appraisal of the cheeses Due to the variations in the chemical composition of milk during the lactation period, the inconsistencies of the cheesemaking methods, and the poor hygiene conditions where the product is made, the properties of North African cheeses vary greatly among regions, localities, and even within the same farm on a day-to-day basis. A similar situation exists in traditional fermented foods (Holzapfel, 2002); however, some key parameters should vary within speciﬁ c limits to maintain the authenticity of the product.

Compositional quality Variability in the chemical composition of North African cheeses is common regard- less of whether or not they are pickled as their manufacture is usually an artisanal (Benkerroum & Tamime, 2004). Table 5.11 shows variations of the gross chemical composition of some North African brined cheeses. It is evident that the salt content is the most variable parameter owing to the inconsistencies in the brine preparation, the maturation time, and the age of the brine before a fresh batch is prepared. In practice, the salt concentration in the brine is usually approximate, as the amount of added salt is not always weighed or the volume of water measured. Furthermore,

Table 5.11 Typical chemical composition (g 100 g–1) of some North African brined cheeses

Soft cheeses Semihard cheeses Constituent Minimum Maximum Minimum Maximum Moisture 50 65 40 49 Fat 15.8 27.5 18 33 Protein 17 29 24 30 Salt 1.0 2.7 1.8 2.5a pH 3.5 4.5 4.5 5.5 a In some cheese varieties where the dry salt is added to milk or to the curd, the salt content may vary between 8 and 15 g 100 g–1 (e.g. Sudanese Gibna Bayda, Mudaffara or Braided cheese). Data compiled from Osman (1987), Moens & O’Connor (1992), O’Connor (2003), Barraoui (2003) and Hamama (1997), and from http://www.fao. org/ag/aga/Publication/apah85/160.htm

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the maturation period of the cheese may vary from 1 to 45 days or even longer for some cheese varieties. These conditions can have a direct impact on the fi nal salt concentration in the cheese. As a consequence, the salt content in the majority of well-known cheeses may vary between 1.0 and 2.7 g salt 100 mL–1, whilst in some varieties the salt level could reach as high as 15 g salt 100 mL–1. In the latter case, however, dry salt should be added at different stages during the manufacture of the cheese (e.g. in the milk, in curd and/or during the maturation period). One of the most obvious effects of increased salt concentration in freshly salted cheese is the promotion of syneresis with a concomitant decrease of the moisture content. In this regard, an increase of salt content from 0.1 to 2.7 g salt 100 mL–1 resulted in a moisture decrease from 41 to 38 g 100 mL–1, and with subsequent variations in the contents of other constituents, especially those of the dry matter (e.g. the proteins, carbohydrate, fat and ash) (Pastorino et al., 2003). Apart from the impact of salt content on the gross chemical composition, it affects also the functional and structural properties of the cheese. Increased salt concentrations in the cheese have been shown to increase the hardness, adhesiveness and initial rate of fl ow of the product, and can cause a decrease in cohesiveness of the cheese (Pastorino et al. 2003). In addition, the salt content infl uences the main parameters that determine the quality of the cheese, such as the salt-in-moisture (SM) content, and the moisture-in-fat free cheese (MFFC) (i.e. the ratio of moisture to protein content). In fact, these parameters are used to grade the quality of some cheese varieties. For example, the SM provides a good indicator for projecting Cheddar cheese quality, and values ranging between 4.0 and 6.0 g 100 g–1 have been associated with premium quality cheese; values outside the range <2.5 and >6.0 g 100 g–1 are more likely to lead to fl avour defects (e.g. bitterness) during the maturation period (Singh et al. 2003). The Greek Regulatory Standards set a minimum SM value of 4.3 g 100 g–1 for Feta cheese (Anifantakis, 1998). Similarly, the MFFC values for a good quality Cheddar cheese should range between 52 and 56 g 100 g–1 (Fox, 2002). While such grading aspects may not be applicable to traditional North African brined cheeses due to the wide variations in their chemical composition, including the sensory attributes and consumers’ perception of ‘best’ quality cheeses, these aspects may be considered as a useful yardstick if the manufacturing methods are going to be standardised in the future.

Microbiological quality Some of the North African brined cheeses have been poorly researched, and data regarding the microbiology of these products are scarce. A sound knowledge of the microbiology of North African brined cheeses is of paramount importance to the understanding of the technological aspects of manufacturing methods, safety and keeping quality of the cheeses. From a technological point of view, it is well recognised that the natural microfl ora of raw milk plays a crucial role in milk coagulation as well as in the maturation of the cheese if the milk is not heat treated. Spontaneous acidifi cation of raw milk by the natural microfl ora contributes to its coagulation along with the action of added clotting enzymes. In some cheeses, it is the only means for milk clotting (i.e. acid

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coagulated cheese). The microbial acidifi cation results from the breakdown of lactose by LAB into lactic acid as a major end-product (homolactic fermentation) or with other constituents including aromatic substances (heterolactic fermentation) (McSweeney & Sousa, 2000). LAB bacteria are normal inhabitants of raw milk, and their initial count may vary between 102 and 105 cfu mL–1 (Tantaoui-Elaraki et al., 1983) depending on many environmental factors, such as the type of feeding and management system, and the hygienic practices adopted in milk production, handling and collection. During the fermentation period of the cheese milk, the LAB may increase to overgrow the other indigenous microorganisms and, if the count exceeds 108 cfu mL–1, as may be the case in normal lactic acid fermentation processes (i.e. the addition of a starter culture), this can lead to a safe product. The main species of LAB involved in dairy fermentations belong to genera Lactococcus, Streptococcus, Lactobacillus, Leuconostoc and Enterococcus (Holzapfel, 2002). However, the relative importance of each LAB group and the degree of its implica- tion in the fermentation and maturation of the cheese may vary greatly depending on the microbiological quality of raw milk, the cheese variety, the technological parameters and other ecological factors. Furthermore, the quantity and the nature of LAB undergo signifi cant changes during production, maturation and storage. Current research on LAB during cheesemaking shows that lactococci, enterococci and leuconostocs predominate in the early stages of fermentation, whilst lactobacilli and enterococci are the most abundant groups in the later stages of maturation and storage (Piredda et al., 1998; Wouters et al., 2002). Although in North African brined cheeses these genera are mostly represented by mesophilic species, few studies have been done to identify and characterise the specifi c species or strains involved in the fermentation and maturation in each cheese variety. According to Hamama (1997), the main species of LAB in surface-salted traditional Moroccan fresh cheese (i.e. Jben) were Lac. lactis subsp. lactis, Leuconostoc mesenteroides subsp. lactis and Lb. casei subsp. casei. However, the Italian Fiore Sardo brined cheese, which is very similar to some North African brined cheeses, contained, at least in the early stages of manufacture, lactococci and enterococci as the main LAB involved. Enterococcus spp. played a major role during the fermentation or maturation of Fiore Sardo and, as the counts of Lac. lactis subsp. lactis decreased during the maturation period and eventually disappeared, E. faecium and E. faecalis came to predominate; their counts were maintained >107 cfu g–1 during all the manufacturing stages (Piredda et al. 1998). Likewise, the enterococci species appear to play a major role in North African brined cheeses. For example, in commercial Moroccan brined cheese, their counts were in excess of 105 cfu g–1, and E. faecium and E. faecalis species were the most frequently isolated (Ghalfi , 2001). The predominance of enterococci among other LAB and their persistence in high counts throughout the whole processing period of brined cheese may be explained by their halotolerance, and their ability to grow well alongside LAB. Furthermore, the presence of E. faecium and E. faecalis in the cheeses is a reassuring factor with regards to the safety of the product. These species were the least incriminated organisms in food intoxications and infections within the genus, and their probiotic properties have been widely acknowledged in recent years (Salminen et al., 1998). Therefore, these species are

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considered as potential candidates to be approved in commercial starter cultures or in probiotic preparations. In addition to LAB, yeasts seem to play an important role in cheese fl avour and nutritional quality especially in the ripened cheese types. Yeasts are commonly present in different North African brined cheese in excess of 106 cfu g–1, and may signifi cantly contribute to the enhancement of the nutritional and sensory properties of these products. Yeasts are known to produce valuable nutrients (vitamins, essential amino acids) and various aromatic compounds, such as diacetyl, acetaldehyde, methylketones and ethanol (Jacobsen & Narvhus, 1996) or antimicrobial substances (Bakalinsky, 2000). Although traditional brined cheeses have a long history of safe consumption, and their contribution to food security is undeniable, they rarely meet international standards. Coliforms and faecal enterococci (considered as indicators of faecal contamination) are usually in excess of 104 cfu g–1 (Berraoui, 2003). Moreover, many pathogens of public health concern, such as Salmonella spp., coagulase-positive and enterotoxinogenic Staphylococcus aureus, Yersinia enterocolitica, Escherichia coli O157:H7, Listeria monocytogenes, Brucella abortus and Mycobacterium bovis, have been frequently isolated from North African brined cheeses (El Marrakchi, 1993; Benkerroum et al., 2004a). Other food-borne pathogens of concern may also be present, but a comprehensive survey has yet to be carried out. Although many sources of contamination, including the dairy operatives, the utensils and the brine, may be the possible causes of cheese contamination, raw milk remains the primary vehicle of such pathogens. The poor hygiene quality of raw milk in developing countries in general is well documented (Giangiacomo, 2003), and North African brined cheeses rely primarily on natural protective hurdles to inhibit the undesirable microorganisms originating from raw milk and to prevent contamination during or after cheesemaking. The precautions are mainly the promotion of growth of LAB, and the salt concentration in the brine and in the cheese. Lactic acid fermentation was historically used as a preservation method for perishable foods including milk. In fact, it is considered to be the oldest preservation method and the most signifi cant innovation in food technology known to mankind (Ross et al., 2002). In appropriate fermentation conditions, LAB overgrow the other microbial groups present in raw milk, especially those of health or spoilage signifi cance, shifting the balance towards a safer and more stable product. These bacteria possess many features that provide them with ecological advantages over the other groups of microorganisms living in the same ecosystem. The production of organic acids by the lactic microfl ora with the subsequent pH decrease is an antibiosis mechanism common to all LAB. According to Jay (1986), all pathogenic bacteria are normally inhibited when pH is lower than 4.0, and this value is higher when the pH decrease is induced by an organic acid, namely lactic acid. However, adaptation of bacterial pathogens to low pH values is a frequent phenomenon in foods (Benkerroum et al., 2002). In addition, LAB produce a variety of inhibitory substances that interfere with the growth of microbial competitors. These include hydrogen peroxide, diacetyl, carbon dioxide, ethanol and bacteriocins (for further reviews see Adams & Nicolaides, 1997; Caplice & Fitzerald, 1999). High frequencies

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of bacteriocin-producing LAB in traditional dairy products have been extensively reported by Benkerroum et al. (2000) and Rodríguez et al. (2000). Lactic acid fermentation and the dominance of LAB alone do not guarantee absolute protection against the growth of pathogenic and spoilage microorganisms. Pickling has, therefore, long been used as an additional method to ensure the production of stable and safe cheese. The salt concentration of the brine protects the cheese from early surface alteration by reducing enzyme activities, and hence the microbial growth either on the surface or within the cheese block, thereby extending its shelf-life. However, increased salt content will not stop the growth of microorganisms in the cheese, but rather change their composition. Halophilic and/or halotolerant microorganisms will have greater opportunity to survive and/or grow during the maturation period or storage and will, therefore, determine the sensory properties of the ﬁ nal product. This may explain the predominance of enterococci in some North African brined cheeses as well as the closely related Italian Fiore Sardo. Nonetheless, many spoilage and pathogenic bacteria, such as Pseudomonas spp., Salmonella spp. and many other members of the Enterobacteriaceae that are sensitive to salt, will be inhibited. However, the brine itself may be a vehicle of salt-tolerant or halophilic microorganisms of spoilage and/or health signiﬁ cance (e.g. S. aureus, Vibrio spp., Micrococcus spp. and L. monocytogenes) depending on the hygiene standards prevailing during its preparation and on the microbiological quality of the water used (see Chapter 9 for further details). L. monocytogenes was shown to be able to survive for more than 259 days in brine with a salt concentration as high as 24.7 g 100 mL–1 (Larson et al. 1999). In North African countries, the brine is often prepared in poor sanitary conditions and with water of doubtful hygienic quality.

5.4.2 Some examples of North and East African brined cheeses Table 5.12 shows the general characteristics of some popular brined cheese varieties produced in North African countries. These cheeses fall within the soft and semihard cheese types. Other cheese varieties may exist, especially of the soft cheese type, but they are unknown as their production is restricted to small communities or even a small number of families, and they have no speciﬁ c designation other than ‘white cheese’ or simply ‘cheese’. An exhaustive survey of brined cheeses in the region seems worthwhile to acknowledge some endangered indigenous cheese varieties, and eventually to protect them from loss due to their cultural signiﬁ cance and the role they may play in the diet and food security of communities. Selected North and East African brined cheese varieties are discussed below.

Soft-type brined cheeses Scamorsa This is a Pasta Filata-type cheese (i.e. similar to Mozzarella) that is produced by smallholders in Ethiopia and other East African countries, such as Tanzania and Kenya. It is made from cow’s milk either whole or standardised to ~3.3 g fat

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Table 5.12 Some of the main characteristics of brined North and East African cheeses

Country Name of the cheese Cheese variety Type of milk used General characteristics Morocco Jben Malah Soft Cow’s, goat’s, Cylindrical in shape (e.g. sheep’s or blends 250–400 g), white in colour, and mild to salty in taste Mauritania Wagashi Soft Cow’s Ball shaped, and white or orange to light brown in colour Ethiopia Scamorsa Soft Cow’s Ball shaped (~400 g) and coated with a layer of batter Tunisia Kashkaval Semiharda Sheep’s Homogeneous body and a smooth rind Sudan Gibna Bayda Semihard Cow’s, goat’s, Acidic and salty in taste; sheep’s or blends the cheese (i.e. cubes of 5–8 cm) is submerged in brine, and it is consumed with broad beans mainly at breakfast Sudan Mudaffara/Braided Semiharda Cow’s, goat’s, The curd is braided, and the cheese sheep’s or blends cheese is acidic and salty in taste a Pasta Filata-type cheeses.

100 g–1 by allowing the milk to settle for about an hour and skimming off the fatty layer from the surface. In cheesemaking (Fig. 5.5), milk coagulation is normally achieved by the combined action of commercial rennet and natural lactic fermentation; however, a yoghurt starter culture is added to accelerate the fermentation when the cheese is made on a semi-industrial scale. After coagulation, the gel is cut into cubes (~1 cm3), and gently stirred while heating to increase the temperature gradually at a rate of 1°C every 5 min from 36 to 42°C. The temperature should be maintained at 42°C to allow good acidiﬁ cation and, hence, a good whey/curd separation. This is achieved by removing intermittently part of the whey (i.e. in total ~60 mL 100 mL–1), and replacing it with the same amount of hot whey. The curd is then separated from the whey and dipped in boiling water to cook. After an appropriate elasticity development, the curd is folded into balls (~400 g), placed in moulds, and allowed to cool in a cold water bath (10–12°C). The fresh cheese is then demoulded, pickled in brine (15 g salt 100 mL–1) for 3 h, and allowed to mature in the store at ambient temperature for about one month. Before maturing the cheese, the surface of the product may be coated with a thin layer of butter to enhance the physical appearance and reduce the evaporation of moisture, thereby increasing the yield of the cheese. According to Moens and O’Connor (1992) the yield of Scamorsa cheese varies from 7.5 to 11 kg 100 L–1 depending on the fat content in the milk and on the maturation period (Table 5.13).

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Whole milk

Standardisation (3-3.5 g fat 100 g-1) Temperature adjustment (36°C) Yogurt starter culture addition (2 mL 100 mL-1) Ripening (30-40 min. to reach 0.02 g lactic acid 100 mL-1)

Cheesemilk

Renneting (use commercial rennet at 36°C for 30-40 min.)

Coagulum/curd

Cutting (1 cm3) Stirring and heating from 36 to 42°C (i.e. 1°C increase every 5 min.) Whey drainage (60 mL 100 mL-1 off) Maturation of coagulum (pH 5.3 or 0.35 g lactic acid 100 mL-1) Hot water addition (80-85°C) Stretching Moulding and cooling (water bath 10-12°C)

Pre-cheese

Salting/brining (15 g salt 100 mL-1)

Fresh cheese

Maturation (0 to 4 weeks at ambient temperature)

Mature Scamorsa cheese

Fig. 5.5 The stages in Scamorsa cheesemaking on a semi-industrial scale. Adapted from Moens & O’Connor (1992).

Gibna Bayda There are many cheese types called Gibna Bayda in North Africa and some Middle Eastern countries. Gibna Bayda is a generic term meaning ‘white cheese’ in Arabic, and includes fresh, ripened, salted or unsalted cheese varieties. For example in Sudan, Gibna Bayda refers to a white soft cheese (moisture content 55–63 g 100 g–1) pickled in brine, and was introduced to Sudan by early Greek immigrants (Osman, 1987); this product resembles Greek Feta and Egyptian Domiati cheese in appearance, texture and ﬂ avour. It is produced in large quantities by local Sudanese pastoral- ists either for home consumption or for sale in local markets. Gibna Bayda has a

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Table 5.13 Scamorsa cheese yields (kg cheese 100 L–1 ± SD) as function of the milk fat content and the period of maturation

Fat content (g 100 g–1) Maturation time (weeks) 2.12 2.97 4.45 Fresh 9.7 ± 0.4 10.0 ± 0.6 11.1 ± 0.3 1 8.7 ± 0.5 9.0 ± 0.6 9.7 ± 0.1 2 8.2 ± 0.5 8.5 ± 0.6 9.2 ± 0.3 3 7.8 ± 0.5 8.1 ± 0.5 8.8 ± 0.3 4 7.5 ± 0.5 7.8 ± 0.5 8.5 ± 0.3 After Moens & O'Connor (1992).

pronounced acidic and salty taste (i.e. owing to its pH of 3.5–4.2), high salt content (8–15 g 100 mL–1), and is consumed as a staple food with broad beans mainly at breakfast. To make Sudanese Gibna Bayda, 8–10 g salt 100 mL–1 is added to the milk (cow’s, goat’s, sheep’s, or their blends) after it has been warmed to ∼37°C, and left to ripen by natural souring for 1–2 h. The cheese milk is then coagulated with calf rennet solution, and the coagulum is transferred to large wooden moulds lined with a cheese cloth and pressed overnight to allow the whey to drain. After whey drainage, the curd is cut into 10 cm cubes and transferred to metal containers ﬁ lled with brine made from whey (~15–20 g 100 mL–1). This cheese variety is now produced in Sudan on a small industrial scale according to the same traditional procedure except that tablets of commercial rennet are used (one tablet dissolved in 1 L of water for 100 L of milk) instead of locally extracted rennet.

Wagashi/Wabasha This is a soft brine-pickled cheese originating from the Sahelian countries including Mauritania, Mali, Niger and Burkina Faso, where it is still very popular amongst nomadic tribes. The cheese has a creamy to white appearance with small eyeholes. It has a slightly sour and salty taste, and is occasionally coloured (i.e. orange to light brown). For Wagashi cheesemaking, fresh milk is boiled for 3–5 min., cooled to ∼37°C, and coagulated by the addition of a plant coagulant extracted from C. procera leaves or Bryophylum spp. stems. Neither acid addition nor microbial fermentation is practised during the manufacture of the cheese, and the enzymes extracted from the plant juice are the only means used to coagulate the milk. The plant juice can be extracted in two different ways: (a) the leaves (C. procera) or stems (Bryophillum spp.) are ﬁ nely chopped and mixed with warm water (~5 g 100 mL–1) for ∼5 min. The juice is sieved through a clean cloth, and the clear ﬁ ltrate is directly added to the cheese milk (5–6 L); or (b) leaves/stems are crushed and placed in a piece of muslin, and swirled in the milk for a few minutes. The milk is then heated slowly until boiling and coagulation. Aside from technological considerations in the Wagashi cheesemaking process, the heat treatment after the addition of the plant extract appears to be necessary to reduce toxicity as the plant is known to contain toxic substances. These toxins are heat labile (inactivated at 95°C), and should be

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destroyed for human health and safety reasons. After coagulation, a sweet curd is obtained, which can be consumed fresh within the same day due to its highly perishable character; this product is known as Wara cheese. Otherwise, the Wara is used to make Wagashi cheese by moulding it in a clean cheesecloth and draining the whey by manual squeezing until a ﬁ rm ball is obtained. The cheese balls are subsequently salted and placed in brine (20–25 g salt 100 mL–1) for 12–15 h. Due to the absence of lactic acid fermentation during cheesemaking as a protective measure against rapid spoilage, the shelf-life of Wagashi does not exceed 3 days outside the brine. However, if the cheese is kept in the brine, it can be stored for up to 14 days at ambient temperature. Occasionally, Wagashi cheese is dipped for few seconds in a hot solution of the stems and leaves of red sorghum to acquire an orange to light-brown colour. The salt content of the cheese varies between 1.0 and 1.7 g 100 g–1 depending on the period of storage in the brine, and its moisture content is ∼60–65 g 100 g–1 (O’Connor, 2003). Wagashi cheese is usually fried before consumption, and used as a protein source in soup and stew dishes. As matter of fact, despite the popularity of this product as a cheese, the lack of fermentation poses a question regarding its conformity to the legal deﬁ nition of a ‘cheese’.

Jben Malah Moroccan salted Jben (or Jben Malah, which means ‘salted cheese’ in Arabic) is a very common white soft cheese in the Northern Jbala region in Morocco, but it can also be made in other regions. It is essentially made at the household level for home consumption or for sale in open markets or by street vendors. Although the cheese was originally made exclusively from goat’s or sheep’s milk, it is now made from cow’s, sheep’s or goat’s milk or their mixtures due to the shortage of goat’s milk in Morocco and the increasing demand for Jben Malah by consumers. Although Moroccan Jben Malah is made by different methods, a typical procedure consists of the following stages. • Raw milk is ﬁ ltered and warmed to ∼37°C or freshly drawn milk is directly used after sieving. • Rennet extract (animal- or plant-type; see Section 5.4.1) is used to coagulate the milk. No starter culture is added, and the acidiﬁ cation of the milk takes place by spontaneous lactic fermentation. • After coagulation (30–60 min), the coagulum is moulded in traditional moulds (Fig. 5.4), and left to drain for 6–8 h; while draining, the curd is turned two or three times. Other plastic and/or metal containers or bamboo baskets may be used for moulding the curd and draining the whey. • The fresh cheese is placed in brine (15–18 g salt 100 mL–1) at ambient temperature for maturation and preservation for a period varying from 12 h to 15 days. Out of the brine, the cheese may be kept for 5–7 days at ambient temperature or 10–15 days in cold storage.

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Semi-hard brined cheese For semi-hard cheese types, the milk is usually acidiﬁ ed prior to enzymatic coagulation, and the acidiﬁ cation relies on microbial activity (either the indigenous LAB in the raw milk or commercial starter cultures). After cutting, the curd may be cooked and the whey is removed. Some examples of the best known North African semihard brined cheeses follow.

Mudaffara or Braided cheeses Mudaffara (meaning ‘braided’ in Arabic) is a semi-hard cow’s milk cheese originating from the Middle East, and now widely produced in Sudan (see also Chapter 6). It has a slightly salty taste and, on average, contains 40 g 100 g–1 moisture and 28 g 100 g–1 FDM. During the manufacture of the cheese, cow’s milk is warmed to ~37°C before adding rennet for coagulation. Acidiﬁ cation occurs naturally by metabolic activities of the microorganisms present in the raw milk. The coagulum is heated in boiling water to develop the elasticity, and is then stretched into long thick threads, plaited and stored in brine (8–16 g 100 mL–1) in metal containers at room temperature. Another popular plait-shaped cheese variety, which is produced in the Eastern and Western provinces of Sudan, is Braided cheese made from whole cow’s, goat’s or sheep’s milk. The cheese milk is prepared and coagulated in a similar manner as for Mudaffara cheese; however, salt (10–15 g 100 mL–1) and black cumin are added to the curd, which is then cooked by direct heating at low temperature to develop the elasticity. The curd is stretched into strips (5 × 15 cm), and the remaining manufacturing stages proceed as for Mudaffara cheese.

Kashkaval This is a semi-hard cheese belonging to the Pasta Filata-type, which is made from sheep’s milk. It originated from Bulgaria, and its manufacture spread to Mediterranean countries, including Tunisia, in the 16th century. Incidentally, this cheese is also known as Balkani, referring to its origin in the Balkan countries. Kashkaval cheese is cylindrical with a homogeneous curd (i.e. without eyeholes) and a smooth rind usually coated with wax. Its moisture and FDM contents vary in the ranges 40–45 and 45–55 g 100 g–1, respectively. The salt content ranges between 1.8 and 2.5 g 100 g–1. During the manufacture of Kashkaval, whole sheep’s milk is ﬁ rst ripened for 15–30 min, coagulated by a combined action of commercial rennet (~40 ml rennet 100 kg–1 milk), and an inoculated mesophilic starter culture. Calcium chloride (10–15 g 100 L–1 milk) may be added to accelerate milk clotting. Whey drainage is enhanced by cutting the curd into small pieces (0.5 cm cubes), vigorous stirring of the curd/whey mixture for 15–20 min while heating to raise the temperature from 37 to 42°C, and then pressing the curd for 1–2 h. The fresh cheese is allowed to pre-mature for 2–10 h at room temperature until the pH reaches 5.2 (i.e. similar to Cheddar cheese), and subsequently cut into pieces (0.5 cm thick); these are dipped in hot brine (72–75°C; 5–7 g NaCl 100 mL–1) for 3–5 min to develop the elasticity.

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The curd is squeezed and hot moulded before cooling to 12–18°C within 12–24 h. Thereafter, the cheese surface is dry salted every two days for 16–18 days, and coated with wax. Kashkaval may be further cured for 50 to 60 days at a room temperature.

Camel’s milk brined cheeses Introduction In North African countries, especially in Saharan and sub-Saharan zones, camel’s milk contributes signifi cantly to the diet and food security of many communities and, in some periods of the year, it may even be the only food available for the nomadic people in these regions. Camel’s milk production is characterised by a marked seasonality with a dramatic shortage in the dry period and an excess in the rainy season (June to August). In such situations, humans have learned to transform milk into stable products that can be preserved for months or years as a means to prevent food shortage and to have foods with high nutritional values. However, camel’s milk has rarely been processed into cheese, basically due to the fact that it is diffi cult to coagulate compared with milk from other domestic animals. The milk is consumed fresh or as a cultured drink, such as Frik and Shubat, obtained by natural souring in a skin bag or a wooden tub for 24–48 h at room temperature. Occasionally, the soured milk is shaken to separate the fat from the fermented drink. Nonetheless, a traditional dried cheese called Tchoukou is popular in Sahelan and North African countries, but it is only produced in very limited quantities. This product is manufactured by acidifi cation and heating of the milk for the separation of the proteins. Subsequently, it may be air- and sun-dried to increase its solid content to ~93.5 g 100 g–1 thereby extending its shelf-life for several months (Gast et al., 1969; Yagil, 1982). Incidentally, the dried product may not come under the standard defi nition of ‘cheese’, which should normally be the result of the combined action of a milk-clotting enzyme and microbial fermentation (Ramet, 1985). In fact, there has been a debate regarding the feasibility of camel’s milk transformation into cheese based on the observation that the Touareg (Saharan nomads) with a long history of camel raising have no record of cheesemaking. Furthermore, some scientists consider that the only way to make cheese from camel’s milk is to mix it with milk from the cow, sheep or goat (Gast et al., 1969). Others argue that it is possible to overcome the technical problem(s) providing that some adjustments are made (Yagil, 1982), for example, by increasing the rennet concentration, adding calcium salts and inoculating the raw milk with an appropriate starter culture. Recently, researchers have done a series of experiments to develop different types of cheeses (soft, semihard and/or hard) from camel’s milk in Saudi Arabia, South Tunisia and Mauritania, and the research fi ndings have been published in a manual of the Food and Agriculture Organisation of the United Nations (FAO) (Ramet, 2001). Therefore, promotion of cheesemaking from camel’s milk would be a good opportunity to make a healthy food available in the arid and subarid zone of North African countries, especially as camel cheese has been shown to be high in vitamins (notably vitamin C), low in cholesterol, and low in lactose (Bengoumi et al., 1998; Farah, 1993; Sawaya et al., 1984) making

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it nutritious and suitable for people who are allergic to other dairy products or at risk of cardiovascular diseases. Other therapeutic and health beneﬁ ts are often claimed by the nomads, but they have yet to be demonstrated scientiﬁ cally.

Specifications of camel’s milk with regards to cheesemaking There is a general agreement that the limiting factor in cheesemaking from camel’s milk is the diffi culty in achieving a successful coagulation after renneting. It is now well established that this diffi culty is essentially related to the molecular composition of the proteins, as the gross chemical composition of camel’s milk (Table 5.14) does not differ signifi cantly from that of other mammals. However, variability within the same species depends on the stage of lactation, season of the year, genetic breed, age of the animal and the management system. The main differences that have a direct impact on the gelation properties of camel’s milk are those at the molecular level of the protein composition. The casein content of camel’s milk, expressed as a proportion of the crude proteins, is generally lower than that of cow’s milk (64–77 g 100 g–1 vs. 77–82 g 100 g–1, respectively), and the casein fractions are very different. The camel’s κ-casein fraction, which is responsible for milk clotting by rennet action, represents only 5 g 100 g–1 of the total casein as compared with 13.6 g 100 g–1 in cow’s casein. Conversely, α -caseins (i.e. α and α s s1 s2) are quantitatively more important in camel’s milk (Table 5.15). Also, due to the high level of nonprotein nitrogen in camel’s milk as compared with cow’s milk, the casein number (i.e. percentage of casein in the total nitrogen) is lower, which is an additional negative factor for making cheese from camel’s milk. Furthermore, the size distribution of casein particles in camel’s milk is signifi cantly broader than in cow’s milk, and their mean size (280–321 nm) is at least twice that of cow’s milk

Table 5.14 Chemical composition (g 100 g–1) of camel’s milk from camels in their natural biotope (i.e. limited access to water)

Constituent Minimum Maximum Average Moisture 85.5 91.2 87.37 Dry matter (DM) 8.0 15.0 12.63 Lactose 2.5 6.2 4.62 Crude protein 2.29 4.6 3.45 Fat 1.1 5.6 3.70 Ash 0.35 0.95 0.74 Adapted from Ramet (2001) and Bengoumi et al. (1998).

Table 5.15 Comparison of casein fractions of camel’s and cow’s milk

Casein fraction (g 100 g–1) of total caseinb Mammalian Casein content (g 100 g–1) a α βκ milk of crude protein s Camel 64–77 63 28 5 Cow 77–82 46 34 13 a Mehaia et al. (1995). b Ramet (1991).

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(Farah, 1993; Farah & Rüegg, 1989; Larsson-Raznikiewicz & Ali, 1986; Sawaya et al., 1984; Scher, 1988). The large-sized micelles are known to be lower in calcium than the smaller ones (Scher, 1988), and the content of colloidal calcium bound to the micelles in camel’s milk has, indeed, been shown to be much lower than that of cow’s milk (35 g 100 g–1 vs. 65 g 100 g–1 of the total calcium) (Yagil & Etzion, 1980). Although there is a general agreement that camel’s milk micelles are signiﬁ cantly larger than those of cow’s milk, Ali and Robinson (1985) reported an average size of casein particles of camel’s milk of ~160 nm as determined by electron micrographs of ultrathin sections. The difference in the size could be attributed to the method used or to the breed of camels from which the milk samples were obtained. According to Farah and Rüegg (1989), a freeze-fracture technique in electron microscopy studies provides better counting and sizing of the casein micelles and, hence, would give a more realistic appraisal of the size distribution of the casein micelles.

Manufacturing methods of cheesemaking Although there are no known traditional brined cheese varieties made from camel’s milk in North African countries, at least two brined cheese varieties are now produced on an industrial scale in Mauritania based on the procedure developed by Ramet (2001). The changes introduced to cheesemaking method(s) using camel’s milk as compared with the classical procedures consist essentially in adjusting the coagulation conditions, the type and concentration of the clotting enzyme, improvement in the salt balance, and the addition of a suitable starter culture. With regards to the type of clotting enzyme, bovine pepsin has proven more appropriate for clotting camel’s milk than calf rennet, microbial proteinases extracted from Mucor miehei and Endothia parasitica, or chymosin of genetically modiﬁ ed origin (Ramet, 2001). However, for optimum performance, bovine pepsin should be added at a concentration 50 to 100 times higher than that usually used for clotting cow’s milk because camel’s milk coagulates three to four times slower than bovine milk. In addition, parts of the stomachs of the desert rabbit or an adult camel have been traditionally used by some nomads in the Sahara and Sinai as clotting agents to accelerate camel’s milk coagulation (Yagil, 1982). The stomachs of both animals contain pepsin as the predominant digestive proteinase (El-Abassy, 1987). The proportions of pepsin in the rennet extracted from adult animals vary greatly depending on the age and feeding. For example, the rennet extracted from the stomach of a young calf contains 88–94% chymosin and about 6–12% pepsin while the extracts from an adult bovine contain 90–94% pepsin and 6–10% chymosin (O’Connor, 1993). Therefore, rennet of an adult bovine may be suitable for cheesemaking from camel’s milk and this option is worth considering. To improve the clotting properties of camel’s milk, many researchers have suggested the addition of calcium salts (e.g. calcium chloride/phosphate) in order to increase the calcium concentration in the milk, and to enhance the mineralisation of caseins. While the addition of calcium salts is optional for cow’s milk coagulation, it appears to play a crucial role with camel’s milk. Controlled enrichment of camel’s milk with ionic calcium was shown to reduce signiﬁ cantly the clotting time and to reinforce the gel strength (Farah & Bachmann, 1987). However, excessive addition of calcium salts may

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lead to fl avour defects (e.g. bitterness). Sodium chloride addition at 0.3–0.6 g 100 mL–1 to the milk before the rennet addition was also suggested to improve pepsin activity and the clotting properties of camel’s milk (Ramet et al., 1982). Another measure that has been reported by researchers to improve the clotting properties of camel’s milk, is the addition of appropriate starter cultures to accelerate the acid formation in the milk. Natural acidifi cation and rates of acid development of camel’s milk throughout the fermentation period were shown to be signifi cantly slower than those of cow’s milk (Ramet, 1985). When fresh raw milk is allowed to sour, a bacteriostatic period is observed for the fi rst few hours after milking. This lag phase is greater in camel’s milk (4–6 h) than in cow’s milk (2–3 h) (El Agamy et al., 1992). The greater buffering capacity of camel’s milk compared with cow’s milk may account for this greater lag phase. In addition, raw camel’s milk was reported to contain several antimicrobial agents including lysozyme, lactoferrins, lactoperoxidase and immunoglobulins, and in greater amounts than the milk from other lactating animals; these may limit microbial growth to some degree. The inhibitory activity of camel’s milk is well documented (Ahmed & Kanwal, 2004; Barbour et al., 1984; Benkerroum et al., 2004b; Duhaiman, 1988; de Valdez et al., 1988). Therefore, inoculation of camel’s milk with a selected starter culture(s), which is capable of growth in the milk to accelerate acid development thereby improving the pepsin activity, is highly recommended. Providing appropriate corrective treatments for camel’s milk were introduced, Ramet (2001) was able to make at least three types of brined cheeses; for example, a surface smear soft cheese, baby Gouda and Gibna, and Figs 5.6, 5.7 and 5.8 detail the manufacturing stages of these cheeses. However, from the main physicochemical characteristics of camel’s milk (see Table 5.14), it is evident that the yield of cheese made from camel’s milk is rather low, depending mainly on the content of milk solids and the type of cheese produced. The moisture content in camel’s milk varies greatly (Table 5.16) depending on the availability of drinking water. During the dry period, water deprivation induces an increase in moisture content in the milk without affecting the daily milk production. Cheese manufacture from milk with low dry matter content results in low yields due to low recovery of milk solids. Furthermore, the level of recovery of milk solids varies according to the type of cheese made and the treatments used in cheese milk preparation. In general, the recovery of dry matter in fresh cheese is higher than in semihard cheese as more whey solids are retained in the curd. However, corrective treatments including milk pasteurisation, addition of adequate milk-clotting enzyme, and calcium salt were shown to improve signifi cantly the recovery of solids and, hence, the cheese yield (Ramet, 1987). Also, enrichment of camel’s milk with sheep’s or goat’s (30 or 50 mL 100 mL–1) increased the yield greatly.

5.5 Conclusion

North African countries, including Egypt, have a long and rich tradition in cheesemaking based on the many traditional cheese varieties produced in each region or

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Milk preparation Sieving Fat adjustment (Optional) Heat treatment (62-65°C for 1 min or 72-75°C for 1 min)

Cheese milk

Coagulation (Predominantly enzymatic) Clotting additives o Calcium chloride or phosphate addition (10-15 g 100 kg-1 milk) o Mesophilic lactic starter culture (1-3 mL 100 mL-1) Renneting o Clotting preparation concentration (4-8 g 100 kg-1 milk) o Acidity (0.16-0.25 mL lactic acid 100 mL-1 or pH 6.2-6.8) Temperature (28-35°C)

Coagulum

Whey drainage (Spontaneous or by gentle mechanical action) Cutting (1-4 cm3) Keeping in whey for 30-90 min (30-50 mL 100 mL-1 whey off) Gentle stirring (periodic for 60 s every 10 min) Moulding Draining o Pressing by hand or by gentle mechanical action (26-28°C for 4-6 h or 16-22°C for 18-20 h) o Turn moulds 3-5 times during draining

Curd Salting Surface salting (1.5-1.8 g salt 100 mL-1) Brining (10-30 min)

Fresh cheese

Maturation Inoculation with surface microflora o Moulds (Penicillium spp., Geotrichum spp.) o Bacteria and yeasts (Brevibacterium linens, Micrococcus spp., Kluyveromyces marxianus var. marxianus, Candida krusei) Temperature (12-14°C)

Mature soft cheese

Fig. 5.6 Processing stages for the manufacture of soft smear or mould-ripened cheese made from camel’s milk. Adapted from Ramet (2001).

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Milk Preparation Ripening (slight acidification) Fat adjustment (optional) Heat treatment (62-65°C for 1 min or 72-75°C for 1 min)

Cheesemilk

Coagulation (essentially lactic acid) Additives o Calcium chloride or phosphate addition (10-15 g 100 kg-1 milk) o Mesophilic lactic starter culture (0.5-1 mL 100 mL-1) Renneting o Clotting preparation (4-8 g 100 kg-1 milk) o Acidity (0.15-0.20 mL lactic acid 100 mL-1 or pH 6.4-6.8) Temperature (30-33°C) Clotting time (6-20 min)

Coagulum

Whey drainage Cutting (0.5-1.0 cm3) Pitching after 15-30 min to harden the curd grains Periodic stirring ( for 60 s every 10 min for 30-45 min) De-lactosing (replacing 20-60 mL whey 100 mL-1 with tap water at 30-33°C) Pre-pressing in wooden or metallic frames for 10-20 min Moulding (cheese-cloth or moulds) Pressing (apply pressure or weight for 2-6 h at 22-26°C)

Curd

Salting Surface salting (1.5-2.5 g salt 100 g-1) Brining (20-25 g salt 100 mL-1 for 10-30 min)

Fresh cheese

Maturation Temperature (12-16°C) Relative humidity (90-95 g 100 mL-1) Time (15-45 d)

Mature baby Gouda cheese

Fig. 5.7 Main processing stages for the production of lactose-free semihard cheese (baby Gouda) from camel’s milk. Adapted from Ramet (2001).

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Milk

Cheesemilk Same as baby Gouda cheese made from camel’s milk (see Figure 5.7)

Coagulum

Curd

Salting Surface salting (1.5-2.5 g salt 100 g-1) Soaking in brine or salted whey (8-18 g 100 mL-1) for 10-30 min

Fresh cheese

Packaging (in earthenware jars or metal containers) Maturation Slow ripening in brine or oil bath outdoors or in air conditioned rooms Temperature (15-40°C) Time (30-180 d)

Camel semi-hard cheese (i.e. Gibna)

Fig. 5.8 Main processing stages for the manufacture of semihard cheese (Gibna) from camel’s milk. Adapted from Ramet (2001).

locality, or each tribe. Although these products have long contributed to food security, they have been essentially produced at the household level to meet domestic needs and their hygiene quality is doubtful. At present, and in the light of changing culinary habits, there is an urgent need to revive interest in traditional products as a part of cultural conservation and to strengthen the contribution these products can make to food security at the quantitative as well as at the qualitative level. Although such products are generally known for their good nutritional quality, they have been associated with food intoxications and other gastroenteritic ailments. One of the options proposed to improve this situation is the transfer of the traditional technology to an industrial and/or semi-industrial scale. However, such transfers should be

11405124601_4_005.indd405124601_4_005.indd 117878 116/05/20066/05/2006 15:40:0815:40:08 11405124601_4_005.indd 179 4 0 5 1 2 4 6 0 1 _ 4 _ 0 0 5 . i n d d

1 7 9

Table 5.16 Cheese varieties experimentally made from camel’s milk and their main physicochemical characteristics

Chemical composition (g 100 g–1) Physical characteristics Type of Yield (kg cheese Name of cheese cheese Dry matter (DM) Fat 100 L–1) when fresh Taste Shape Weight (g) Appearance Gouda (baby) Semihard 34–45 10–30 6–10.0 Acidic Oblong 50–800 Smooth texture without and salty portions holes, and a thin crust Gibna Bayda Semihard 44–46 10–30 6–10.0 Neutral to Cylindrical 1000–2000 Smooth texture slightly (large acidic diameter) NRa Soft 40–50 10–30 6–10.5 NR Cylindrical 150–300 Uniform paste, some (large holes, and evidence of

diameter) surface microﬂ ora North AfricanBrinedCheeses a Not reported. Adapted from Ramet (2001). 179 116/05/2006 15:40:08 6 / 0 5 / 2 0 0 6

1 5 : 4 0 : 0 8 180 Chapter 5

done on a sound basis and taking account of many prerequisites in order to maintain the authenticity of the products while improving their hygiene quality and market share (Benkerroum & Tamime, 2004). Nevertheless, in Egypt, there have been great developments in cheesemaking technology where the traditional method(s) have been replaced, in part, with new technologies such as the use of UF and the addition of well-deﬁ ned starter cultures. It could be that similar developments may take place in adjacent countries to improve the quality of cheeses, in particular the brined varieties, in the future. In addition, the use of well-deﬁ ned starter cultures, mainly isolated from traditional cheeses, may help to conserve the main characteristics and authenticity of the products.

Acknowledgement

One of us (N.B.) wishes to thank M.M. Noureddine Habbat, Mohamed Douabi and Said Lamsaoub for their valuable help in surveying the traditional technology of brined cheeses in the Northern region of Morocco.

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I. Toufeili and B. Özer

6.1 Introduction

The conversion of milk into cheese and storage of the product in brine has been practised for thousands of years in the Middle East. The process provides a practical means for preserving milk nutrients in a form that can be safely stored for extended periods of time at high ambient temperatures. White brined cheeses have been traditionally produced from sheep’s and goat’s milk. However, the more readily available cow’s milk is used by large-scale dairy processors to meet the growing demands for these cheeses in the Middle East and export markets. A large number of white brined cheese varieties exist, with the range including Feta (in Greece), Halloumi including Halloumi-type, Akkawi, Braided (Mujaddal), Double Crème and Nabulsi (in many Middle Eastern countries and Cyprus) and Domiati (in Egypt). The production and characterisation of these cheeses are reviewed in Chapters 2, 4 and 5, respectively. In this chapter, the characteristics of common white brined cheeses produced in the Middle Eastern countries including Turkey will be reviewed.

6.2 Middle Eastern cheeses 6.2.1 Cheese specifications, standards and chemical composition Middle Eastern brined cheeses, such as Akkawi and Nabulsi, have been classiﬁ ed as semihard (Tannous, 1991), whilst Halloumi cheese is a semihard to hard variety (Robinson, 1991) and Braided or Mujaddal is a hard cheese (Tannous, 1991). According to Lebanese Standards (LS, 2001) and Jordanian Standards (JS, 2003), these cheeses are grouped into different categories based on their fat-in-dry matter (FDM) (see Table 6.1).

6.2.2 Technology of manufacture General aspects The production of white brined cheeses indigenous to the Middle East has been described by Tannous (1991), Yamani et al. (1998) and Abd El-Salam (2003). In general, starter cultures are not normally used in the production of Middle Eastern brined cheeses. The cheeses are chalky white in colour, possess strong salty and acid tastes and very mild odours.

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Table 6.1 Compositional speciﬁ cations (g 100 g–1) of some Middle Eastern brined cheeses

Akkawi Halloumi Nabulsi Double Crème Braided/Mujaddal Fat category Moisture FDMa Moisture FDM Moisture FDM Moisture FDM Moisture FDM Full-fat 56 ≥40 50 ≥40 NRb 45–60 64 ≥33 44 ≥40 Medium- 57 25–40 53 25–40 NR 25–40 NR NR 45 25–40 fat Low-fat 61 10–25 59 10–25 NR 10–25 65 10–33 NR NR No-fat 63 <10 63 <10 NR <10 66 <10 NR NR a Fat-in-dry matter. b NR = not reported or not speciﬁ ed. Data compiled from Lebanese Standards (LS, 2001) and Jordanian Standards (JS, 2003).

Raw or pasteurised milk is treated with calcium chloride (CaCl2), coagulated with rennet, and the coagulum is cut into small cubes and allowed to drain in cheese moulds. During the manufacture of Akkawi cheese, the moulded curd is pressed to expel more whey and stored in brine (10 g NaCl 100 mL–1). For Nabulsi cheese, the curd is boiled in brine (15–20 g NaCl 100 mL–1) for 5–10 min, but a cheesecloth containing mahaleb (Prunus mahaleb) and mastic (Pistacia lentiscus) is sometimes added to the brine; however, for the production of Halloumi-type cheese, the pressed curd is boiled in deproteinated whey for 20–50 min prior to storage in brine (15–20 g NaCl 100 mL–1). In addition to Akkawi, Nabulsi and Halloumi-type cheeses, Double Crème and Braided cheeses are produced in different countries of the Middle East. For the production of Double Crème cheese, the whey obtained during cheesemaking, with optional addition of liquid milk, is heated at 90–95°C in the presence of citric acid (0.1 g 100 mL–1) and the ﬂ occulate that forms at the surface is skimmed off. Afterwards, the ﬂ occulated material is placed in cheesecloth, pressed for about 1 h and stored in brine (10 g NaCl 100 mL–1).

Mujaddal or Braided cheese Braided cheese production involves intensive manual handling during the manufacturing stages, and requires skilful manipulation of the curd by the cheesemaker. This –1 type of cheese is made by warming the milk to 40°C, adding CaCl2 (0.2 g 100 mL ), renneting, cutting the coagulum into small cubes and straining in a cheesecloth. The drained curd is allowed to ferment at 45°C until the pH drops to 5.0–5.2, relying on the indigenous microﬂ ora in the raw milk, and, as a consequence, the curd pieces fuse into a continuous mass. The fused curd is cut into portions (3 × 3 × 2 cm) and scalded in boiling water; this process transforms the fused curd particles into a plastic mass amenable to stretching by the cheesemaker. Afterwards, the plasticised curd is removed from the boiling water, stretched and shaped into a loop (i.e. at ~70–75°C); the loop is either split into thin or thick strands, and knotted at one end to form the ﬁ nal cheese (Fig. 6.1). The cheese is then placed in cold water, stored at refrigera-

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(a) (b)

Fig. 6.1 Some manufacturing stages of Braided or Mujaddal cheese. The curd is shaped into a loop (a), split into strands (b) and given its ﬁ nal shape as thin Braided cheese (c) or thick Braided cheese (d).

tion temperature overnight to consolidate its form or shape and to control the rate of acid development, and ﬁ nally stored in brine (15 g NaCl 100 mL–1). Few data are available on the microbiology, rheology, storage-in-brine induced changes and sensory properties of Akkawi cheese. Published data on Middle Eastern cheese varieties have largely dealt with the production of Nabulsi cheese only.

Nabulsi cheese For the production of this cheese variety, raw cow’s, goat’s or sheep’s milk is used (Fig. 6.2). However, milk is normally pasteurised at 63–65°C for 30 min in large- scale dairies due to public health concerns, and to achieve relatively better process

control. The raw/pasteurised milk is warmed/cooled to 32–37°C, fortiﬁ ed with CaCl2 (0.02 g 100 mL–1) and rennet is added to achieve coagulation within 30–60 min. The resulting curd is cut into cubes (i.e. 1–2 cm3) and left to drain for 20–30 min. The curd and whey are then transferred into stainless steel moulds (5 × 37 × 40 cm) lined with cheesecloth and, after a period of ‘free’ whey drainage (i.e. without applying any pressure), the cheese blocks are pressed at 0.4 MPa for 30 min and then at 0.8 MPa for 2 h. The cheese blocks are cut into portions (5 × 4 × 2 cm or 10 × 10

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Raw cow’s, goat’s or sheep’s milk 1

Warm to 32–37oC

Add CaCl2 (0.02 g 100 mL–1)

Add rennet (Achieve coagulation within 30–60 min)

Cut curd (1–2 cm3 )

Rest for 20–30 min

Place in a stainless steel mould lined with a cheese cloth

Press at 0.4 MPa for 30 min and then at 0.8 MPa for 2 h

Cut into portions (5×4×2 cm or 10×10×3 cm)

Sprinkle with salt

Hold at 5oC overnight

Place in brine (15–20 g NaCl 100 mL–1)2

Boil (5–10 min)

Store in boiled brine in glass jars or metal containers Fig. 6.2 Schematic illustration of Nabulsi cheesemaking. 1In some instances the milk is pasteurised at 63–65°C for 30 min. 2A cheesecloth containing mahaleb (Prunus mahaleb) and mastic (Pistacia lentiscus) is sometimes incorporated into the brine.

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× 3 cm), sprinkled with coarse salt and stored at 5°C overnight. On the following day, the portions of cheese are boiled in brine (15–20 g NaCl 100 mL–1) until a thin layer of melted cheese forms on the surface (i.e. within 5–10 min), and stored in the boiled brine in metal (for bulk packaging) or glass (for retail packaging) containers (http://www.khayma.com/tagthia/nabulsicheese.htm). The chemical composition of Nabulsi cheese is governed by the method of manufacture, type of milk used and seasonal variations in milk composition. The compositional quality (g 100 g–1) of Nabulsi cheese made from sheep’s milk under laboratory conditions were: total solids (54.8), protein (17.7), fat (24.2), ash (11.5), salt (10.8), nitrogen-free extract (1.4) and titratable acidity as lactic acid (0.21) (Humeid et al., 1990; see also Haddadin et al., 1995a). The fat content in milk is not normally standardised during the manufacture of Nabulsi, which is believed to be responsible, at least in part, for fl uctuations in the product’s quality. Nabulsi cheese made from milk with different casein-to-fat (C:F) ratios exhibited variations in the chemical composition of the product, and the yield of the cheese (i.e. expressed as kg cheese kg–1 of fat in the milk) showed a linear relationship with the C:F ratio (Table 6.2). Sensory profi ling of the product indicated a preference for the cheese made from milk with a C:F ratio of 0.7; whilst Nabulsi cheese made from milks with C:F ratios of 0.5 and 1.0 were rated as poor due to an excessively soft or leathery texture, respectively (Haddadin et al., 1995b). The keeping quality of Nabulsi cheese is largely determined by the boiling process, and the salt concentration of the brine (~15–20 g NaCl 100 mL–1) used for storage. However, the relatively high pH of the brine (>6.0) might allow for growth of spoilage microorganisms with subsequent losses to dairy processors. In addition to the high pH, Nabulsi cheese made from pasteurised milk has a relatively bland fl avour as compared with the product made from raw milk. These shortcomings might be alleviated through the use of milk’s indigenous microfl ora, as starter cultures, to lower the pH and mimic the much appreciated fl avour of the product made from raw milk. Within this framework, salt-tolerant lactic acid bacteria were isolated from cow’s and sheep’s milk, and tested for their acidifi cation rate and their suitability to produce a Nabulsi cheese that had similar sensory properties of the traditional product (Yamani et al., 1998). The microbial species isolated were predominantly enterococci, with lactobacilli and lactococci being less frequent. Cheeses made

Table 6.2 Effect of different casein-to-fat (C:F) ratios on the chemical composition (g 100 g–1) and yield (kg kg–1 of fat in milk) of Nabulsi cheese made from sheep’s milka

C:F Yield Protein Fat Moisture Salt Lactose Titratable acidity 0.5 1.8 15.8 27.6 51.2 8.8 0.5 0.29 0.6 2.2 15.8 28.9 47.3 8.5 0.5 0.31 0.7 2.5 17.7 29.9 44.5 7.6 0.5 0.30 0.8 2.8 17.3 29.3 43.5 7.5 0.5 0.32 0.9 3.0 19.7 28.9 42.5 6.4 0.4 0.32 1.0 3.2 19.9 29.7 39.3 6.3 0.5 0.31 a After one month storage in brine (15 g NaCl 100 mL–1) Adapted from Haddadin et al. (1995b).

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Table 6.3 Changes in the pH of Nabulsi cheese and the brine, and sensory proﬁ ling of the product made with different lactic acid bacteria

Cheese Brinea After After 7 After After 7 Sensory Microorganism After cutting boiling days boiling days scoreb Lactobacillus paracasei 6.2 5.8 5.8 6.6 5.5 6.7 Lactobacillus rhamnosus 6.2 5.8 5.7 6.5 5.1 6.8 Lactococcus lactis subsp. lactis 5.8 5.3 5.3 5.7 5.1 6.3 Enterococcus faecalis 5.8 5.6 5.5 6.3 5.2 6.7 Enterococcus faecium 6.1 6.0 5.8 6.3 5.6 7.3 Enterococcus durans 6.1 6.1 5.9 6.1 5.3 7.5 Controlc 6.4 6.4 6.1 6.7 5.7 7.5 a Concentration of salt in the brine: 15 g NaCl 100 mL–1. b The cheeses were stored in brine for 2 weeks before tasting; a nine-point Hedonic rating scale was used (i.e. ranging from dislike very much ‘1’ to like very much ‘9’). c Control cheese made without starter culture. Adapted from Yamani et al. (1998).

with starter cultures of the isolated lactic acid bacteria exhibited lower pH values than the product made without a starter. In addition, the starters brought about a decrease in the pH of the brines, with Lactobacillus rhamnosus and Lactococcus lactis subsp. lactis being particularly active (Table 6.3). Apart from Nabulsi cheese made with Lac. lactis subsp. lactis, which was rated as being less liked than the control, the products made with other starter cultures had comparable degrees of liking to the control. The ability of certain strains of lactobacilli to bring about the needed protection against the growth of spoilage microorganisms, to develop the balanced and desirable sensory properties in the product, and the absence of antibiotic-resistant strains may allow their use as potential starter cultures during the manufacture of Nabulsi cheese. Manual handling in shaping the cheese portions after boiling and placing in the brine is a major source of contamination in Nabulsi cheesemaking. Furthermore, storage of Nabulsi cheese in large containers (e.g. 10–20 kg capacity) is impractical for retail purposes, especially as repeated opening of containers leads to contamination with spoilage organisms. These routes of contamination were effectively curtailed by boiling Nabulsi cheese in the retail packages. Humeid et al. (1990) reported that heating Nabulsi cheese (i.e. made from raw sheep’s milk) in retortable packages made from polyethylene (PE) and polyvinylidene chloride (PVDC) laminate at temperatures between 70 and 90°C for 3, 8 or 11 min reduced the viable plate count from 2.7 × 108 colony-forming units (cfu) g–1 to 1.3 × 106, 1.5 × 105 and 5.0 × 103 cfu g–1, respectively, when fresh; after 12 months’ storage, the counts were reduced to 2.5 × 104, <102 and <102 cfu g–1, respectively. The original coliform, and yeast and mould counts, were 5 × 105 and 4.2 × 104 cfu g–1, respectively, and these were reduced to <102 cfu g–1 directly after the heating stage and remained the same during the 12-month storage period. Incidentally, the experimental cheeses were stored at 22 ± 5°C, and all the products remained acceptable after storage for 9 months; a deterioration in

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quality was observed after 12 months, and this was attributed to lipid oxidation due to the relatively high oxygen permeability of the packaging laminate. Development of rancidity in the fat phase of Nabulsi cheese is primarily associated with lipolysis of triglycerides or oxidation of the fatty acid constituents during processing and storage, which might lead to the formation of off-fl avours with deleterious effects on the sensory quality of the product. Furthermore, oxidation of cholesterol and the subsequent formation of cholesterol oxides might be of public health concern, where these products possess atherogenic, carcinogenic and cytotoxic effects (Guardiola et al., 1996). The free fatty acid content increased from 2.9 to 12 g kg–1 of fat and the peroxide value increased from nondetectable levels to 5.2 meq oxygen kg–1 of fat in 9-month-old Nabulsi cheese (Al-Ismail & Humeid, 2003). The relatively slight increase of the peroxide value of the stored cheese was attributed to the low levels of dissolved oxygen in the nearly saturated brine solution (15–20 g NaCl 100 mL–1). The progress of lipolysis and oxidative rancidity in the fat phase was not accompanied by changes in sensory properties, as noted by the absence of off-fl avours in the stored cheeses, possibly due to the masking of rancid fl avours by the high saltiness of samples. The concentration of 7-ketocholesterol increased from 1.2 to 5.2 µg g–1 of fat during 9 months of storage, thereby warranting a determination of the contribution of Nabulsi cheese to daily intakes of cholesterol oxides, and the establishment of tolerance levels for the formation of these compounds during storage.

Comparative compositional quality of brined cheeses The compositional quality of brined cheeses is inﬂ uenced by many factors, such as the method of processing, type of milk used and seasonal variation in milk composition. The composition of some selected brined cheeses produced in the Middle East is shown in Table 6.4.

6.3 Traditional Turkish cheeses

In Turkey, the manufacture of cheese dates back thousands of years. At present, more than 150 local cheese varieties are known, and the processing methods of

Table 6.4 Composition (g 100 g–1) of some selected Middle Eastern brined cheeses

Constituent Akkawia Halloumia Nabulsib Double Crèmea Moisture 55.1 48.2 45.2 60.3 Protein 17.3 22.6 17.7 4.1 Fat 18.3 22.3 24.2 19.4 Ash 4.9 4.9 11.5 10.9 N-free extract 4.5 2.0 1.4 5.3 a Mean of six commercial samples of each cheese variety made in Lebanon from cow’s milk (Abu Jawdeh et al., unpublished data). b Laboratory-made cheese from sheep’s milk (Humeid et al., 1990).

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these varieties vary from one region to another (Unsal, 1997). Since methods of manufacturing show large diversity with locality, it is rather diffi cult to classify local cheeses according to production practices (Ozer, 1999). Turkey’s total milk production is around 10.5 million tonnes per annum, and 83% of the total volume of milk is produced from cows, followed by sheep (12%), goats (3%) and buffaloes (2%) (Anonymous, 2001). In 2000, cheese production was in excess of 313 000 tonnes, and since 1990 cheese production has increased by around 104 000 tonnes (Demirbas et al., 2002). Originally, the production of traditional Turkish cheeses was limited to small- scale units, which made standardisation of the gross chemical composition and other properties of these products very diffi cult. Mechanisation and automation in cheesemaking have enabled much progress in the marketing of local cheese varieties. Modern technologies have replaced old-fashioned techniques in milk handling and the manufacture of cheese, including ripening the milk with starter cultures, coagulation, cutting the coagulum and drainage of the whey (Ozer, 1999). Cheese varieties of the most industrial importance are the classical Turkish white (original name is Beyaz peynir), Urfa (scalded white cheese matured in brine), Tulum (dry- salted white cheese matured in animal skin bags or in plastic containers) and Kasar (similar to Kashkaval or Kasseri cheese). Although some of the Turkish brined cheeses have been briefl y reviewed in Chapter 2, the technology, microbiology and composition of Turkish white brined cheese (both classical and Urfa-type) will be discussed hereafter in greater detail.

6.3.1 Technology of cheesemaking Turkish White cheese is matured in brine (~12–14 g NaCl 100 g–1). The classical product is generally cubical or rectangular in shape, while Urfa-type white cheese is conical in shape and weighs ~250–300 g (Hayaloglu et al., 2002; Ozer et al., 2002). The cheese is characterised as having no rind, a white colour, close texture and a salty acid taste. Although no specifi c defi nition of White cheese is available in the existing Turkish Standards (TS) based on its moisture content, some researchers have defi ned the product as a semihard cheese (Turantas et al., 1989; Turhan & Kaletunç, 1992) or semisoft cheese (Erkmen, 2001). Urfa-type white brined cheese is a semihard variety (Ozer et al., 2003). According to the present Turkish Standards (TS, 1995), White cheese is divided into four groups based on the fat-in-dry matter (FDM) content: • full-fat cheese (minimum 45 g 100 g–1 FDM); • semi-fat cheese (30–44 g 100 g–1 FDM); • low-fat cheese (20–29 g 100 g–1 FDM); and • non-fat cheese (<20 g 100 g–1 FDM). The production of both White and Urfa-type white brined cheeses shows similarity to Feta cheesemaking with the exception that, in Urfa cheese production, whey drainage is achieved by leaving the curd hanging in special cheesecloth (known locally as ‘parzin’; see Figs 6.3 & 6.4). In addition, Urfa-type white cheese is usually

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Raw cow’s or sheep’s milk

Traditional method UF (60% volume reduction) (at 45–50°C)

Casein-to-fat standardisation (0.8:1)

Homogenisation (optional) at 14.71 MPa at 55°C

Heat Treatment (65°C for 30 min or at 72°C for 15 s)

Cooling to 30–32°C

–1 –1 Adding CaCl2 (0.02 mL 100 mL ) (concentration of solution is 40 g 100 mL )

Inoculation with mixed mesophilic cheese starter cultures at 1.0–2.0 mL 100 mL–1

Renneting (at 30–32°C with amount enough to coagulate milk within 90–100 min)

Cutting the coagulum (~2–3 cm3)

De-whey by pressing the curd (20–40 kg weight 100 L–1 of milk)

Portioning (7×7×7 cm or 7×7×10 cm)

Pre-brining (15-16 g NaCl 100 mL–1 at 14–16°C for 12–18 h)

Mature in the brine (12–13 g NaCl 100 mL–1 at 10–12°C for 90 d)

Fig. 6.3 Schematic illustration of traditional and UF Turkish White cheesemaking.

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Raw sheep’s or cow’s milk1

Traditional method UF (60% volume reduction) (at 45-50°C)

Renneting (at 30-32°C with amount enough to coagulate milk within 45-60 min)

Cutting the coagulum (~1 cm3)

De-whey by gravity (hanging the curd in special cheese cloth called ‘parzin’ at room temperature for 12 h)

Dry salting (overnight at room temperature)

Scalding in cheese whey (90°C for 3 min)

Mature in the brine (15.0 g NaCl 100 mL-1 and pasteurise the brine at 85°C for 20 min before use)

Store (<10°C for at least 90 d)

Fig. 6.4 Schematic illustration of traditional and UF Urfa cheesemaking. 1In some cases the milk is –1 pasteurised at 68°C for 30 min or at 75°C for 5 min; 0.015 g CaCl2 100 mL is added to the milk in order to restore the calcium balance after the heat treatment of the milk; thermophilic starter culture (Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus, 1:1) is used.

scalded in the whey at 85–90°C for 3 min before brining (Ozer et al., 2004a), and it is traditionally made from sheep’s milk or a mixture of sheep’s and goat’s milk (e.g. in proportions of 30:70, respectively). However, in the production of classical White brined cheeses, sheep’s, cow’s or goat’s milk, or appropriate mixtures of these milks, are used (Ozer et al., 2002). It is also reported by the same researchers

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that traditional Urfa-type cheese made from sheep’s milk matured much faster than ones made from cow’s milk. Similar fi ndings were reported by Gencer (2003), who studied the development of proteolysis in White brined cheeses made from ultrafi ltered (UF) sheep’s and/or goat’s milk. The average yield of White cheese from sheep’s milk was reported to be 26–28 kg 100 kg–1 of milk, whilst the yield of the same product made from goat’s and cow’s milk was 15–16 kg 100 kg–1 (Hayaloglu et al., 2002). In classical White cheesemaking, raw milk was widely used but, in some parts of Turkey where hot climatic conditions prevail, the product is made from heat-treated milk (e.g. 65–68°C for 5–30 min or 80°C for 1–2 min) (Turantas et al., 1989). By contrast, industrial-scale cheesemaking has largely replaced the use of raw milk by pasteurised milk (72°C for 15 s). Although standardisation of the casein-to-fat (C:F) ratio is not usually employed in classical cheesemaking, it is a common practice in large cheese factories. Aksoydan (1996) reported that an 0.8–0.9 C:F ratio was optimum for the production of high- quality White brined cheese and for better yield. Furthermore, concentration of total solids (TS) content of the milk prior to classical White cheesemaking was not a common practice; however, at present, UF of the milk to increase its TS content is becoming more popular at the industrial level for cheese production. Yetismeyen (1987) found out that the water-soluble nitrogen (WSN), nonprotein nitrogen (NPN) and proteose-peptone nitrogen (PPN) concentrations of the classical White cheese were higher than those of UF cheese, indicating that the degree of proteolysis in the latter product was lower than in the classical product. By contrast, no difference in the level of protein hydrolysis was observed between UF and classical Urfa-type white cheese (Ozer et al., 2003). The maturation temperature had a signifi cant α β effect on the rate of degradation of s- and -casein in UF White cheese (Renner & Omeroglu, 1981); for example, below 10–12°C, the degradation of the caseins to smaller molecular weight peptides was slow. It was also reported that the volume reduction by UF (ca. 70%) affected the organoleptic properties of both White and Urfa-type white cheeses (Ozer et al., 2003; Yetismeyen, 1987). However, the same cheeses made with UF milk (i.e. to >70% volume reduction) formed a curd that had a very fi rm texture, and was diffi cult to handle. Similar observations were reported by Yaygin and Uysal (1990). The coagulation of milk used in the production of White cheese is mostly achieved by commercial calf rennet. However, the increase in cheese consumption has led to an increase in rennet demand while there has been a decrease in the number of young animals available for slaughtering to produce the enzyme extract (Saldamli & Kaytanli, 1998). Therefore, other suitable coagulants, including proteinases from microorganisms, are becoming more popular in the manufacture of White cheese. Yesilyurt (1992) compared White cheeses made using animal or microbial coagulants (Fromase and Rennilase from Rizomucor miehi) and, she found that, while microbial coagulants had no signifi cant effect on the yield, total acidity, dry matter, fat and salt levels of the cheeses, the rate of proteolysis was faster. Similarly, Yetismeyen et al. (1998) concluded that proteolysis developed much faster (ripening index of 24.0%) in the cheese made with microbial coagulant (from R. miehei) than the cheese made with calf rennet (ripening index of 16.2%), and the sensory profi le of the product

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made with calf rennet was superior to a cheese made with the microbial coagulant. Saldamli and Kaytanli (1998) used Fromase 46T (from M. miehei), Rennilase 150L type t (from R. miehei), Maxiren 50 (from Kluyveromyces marxianus var. lactis by recombinant DNA technology) and liquid commercial rennet (90% chymosin and 10% pepsin) in the production of White cheese. Different coagulants had signifi cant effects on the acidity, dry matter, fat and protein contents of the cheeses, and the highest value of ripening index was obtained from the cheese made with Fromase followed by Rennilase, calf rennet and Maxiren, respectively. The use of chicken pepsin or mixtures of chicken pepsin and calf rennet (at a ratio of 50:50 or 70:30) during the manufacture of White cheese did not affect the overall chemical composition and sensory properties of the products (Uysal et al., 1996). Salting is another factor infl uencing the composition of White cheeses. In general, the higher the level of NaCl in brine solution, the lower the rate of proteolysis in both classical White and Urfa-type white brined cheeses (Ozer et al., 2004a). By increasing the NaCl concentration from 12.5 to 17.5 g 100 mL–1, the concentration β α of - and s1-casein degradation products declined gradually in 90-day-old Urfa-type white cheese, as studied by urea gel electrophoresis (Ozer et al., 2004a). Akbulut et al. (1996) investigated alternative salting methods (i.e. adding salt to the milk or the curd before pressing) in classical White cheesemaking, and they proposed that 2 or 3 g NaCl 100 g–1 milk or curd could be used for the purpose of salting the cheese. The temperature of brining and the size of the cheese blocks also had direct effects on salt penetration from the brine into the cheese. Diffusion coeffi cients of salt in classical White cheese at 4°C, 12°C and 20°C were 0.21 × 10–9, 0.31 × 109 and 0.39 × 109 m2 s–1, respectively (i.e. the brine concentration was 15 g NaCl 100 mL–1) (Turhan & Kaletunç, 1992). In recent years, interest in the consumption of reduced-salt foods has grown rapidly; therefore, studies on producing white brined cheeses with a low salt content have been intensifi ed. Methods of reducing the sodium content in these products include simply lowering the NaCl concentration in the brine and/or partially sub- stituting NaCl with other salts, such as KCl. Guven and Karaca (2001) studied the

effects of partial replacement of the NaCl by KCl, CaCl2 or MgCl2 at a ratio of 1:1 (molar basis) on the proteolysis of traditional White cheese, and they reported that

these salts had no effect on the degradation of caseins. In addition, the use of CaCl2 led to an atypical fl avour and increased fi rmness of the cheese, that is, the body and texture of the product became very fi rm (Guven et al., 2001). Scalding of dry-salted cheese blocks before brining is an important technological step in Urfa-type cheesemaking. Ozer et al. (2000) reported that scalding caused an increase in the total solids content of the product made from sheep’s or cow’s milk, but the yields of the fi nal products were lower than the unscalded cheeses. Also, the rate of proteolysis was slower after scalding the curd, and therefore it is recommended that starter cultures of high proteolytic activity should be used during the manufacture of Urfa-type white cheese from pasteurised milk (Ozer et al., 2004a). Alternatively, coagulants of microbial origin can be used as they have higher proteolytic activity than animal rennet.

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According to Turkish Standards (TS, 1995), traditional White cheese made from pasteurised milk should be matured in the brine for >90 days at 10–12°C. In some cases, manufacturers tend to market the cheese after 30–45 days of storage, and the product should be labelled properly indicating that it has been produced from pasteurised milk and is ‘fresh’.

6.3.2 Microbiological quality Starter cultures (lactic acid bacteria, LAB, and non-starter lactic acid bacteria, NSLAB) The production of White brined cheese depends on the hydrolysis of lactose by lactic acid bacteria to produce lactic acid. The selection, maintenance and use of starter cultures are, perhaps, the most important aspects of cheesemaking, particularly in the context of a modern mechanised process(es) for which predictability and consistency are essential (Bintsis & Papademas, 2002; Ozer, 1999). The fact that classical White cheese is often produced traditionally without the addition of starter cultures frequently leads to indifferent quality of the product. The microbiological quality of cheese is closely related to the method of manufacture and, as unpasteurised milk is widely used in the manufacture of traditional White brined cheese, the initial microbiological load of the milk determines the quality of the fi nal product. On the positive side, non-starter bacteria may contribute to the formation of fl avour(s) in Turkish White cheeses by affecting the levels of soluble nitrogen and peptides and the pH of the product; they can also alter the sensory and textural properties of the cheeses. On the other hand, some non-starter bacteria may cause spoilage of the product. Lactic acid bacteria (LAB) are predominant in White cheeses made in Turkey, and the main isolates were Lactococcus lactis subsp. lactis, Lactococcus lactis subsp. cremoris, Lactobacillus casei, Enterococcus faecalis var. liquefaciens and Leuconostoc paramesenteroides; however, Lac. lactis subsp. lactis, at 2.6 × 106 colony-forming units (cfu) g–1, was the dominant species among the LAB isolates (Hosono et al., 1992). With prolonged maturation of the product, the numbers of lactococci decrease and different species of lactobacilli become dominant in the white pickled cheeses. Similar results were reported for Feta cheese by Tzanetakis and Litopoulou-Tzanetaki (1992). Many different starter organisms have been used in the manufacture of classical White cheeses, and many combinations have been tested to assess the best microbial blend(s) taking into account the typical characteristics of specifi c varieties of cheeses (Gursoy et al., 2001). Determination of the microbiological properties of the natural fl ora of cheese is important in selection of a balanced combination of starter bacteria to obtain the optimum rheological properties of the product in terms of body and texture, and fl avour and aroma. The enzymatic activities of NSLAB should be the prime criterion in deciding which blend of starter bacteria is to be used in cheesemaking. Durlu-Ozkaya et al. (2001) isolated dominant LAB in mature White cheeses made from sheep’s milk, and evaluated their properties; they concluded that whole cells of Lac. lactis subsp. lactis and enterococci showed different lipolytic and proteolytic activities. Strains differed in terms of their acidifying and caseinolytic activity.

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Most of the enterococci isolates showed tyrosine decarboxylase activity, whilst lactobacilli exhibited weak antibacterial activities against food-borne pathogens. Similarly, Karakus (1994) found that the acidifying activity of Lac. lactis subsp. lactis and Lac. lactis subsp. lactis bv. diacetylactis isolated from White cheese was high in both species. On the contrary, the acid-producing capacity of Lb. casei and Lb. plantarum isolated from the same cheese samples was weak. Furthermore, the same researchers also noted that the proteolytic activities of Lactobacillus species were lower than those of lactococci. Starter culture blends that have been used in the production of White cheese are shown in Table 6.5. A slightly crumbly body is required in classical Turkish White brined cheeses including Urfa-type, and a fast acid-producing starter culture should be employed. In this context, a typical starter culture blend consisting of Lac. lactis subsp. lactis and Lac. lactis subsp. cremoris (1:1 ratio) or yoghurt culture (1:1 ratio of lactobacilli to streptococci) is able to very quickly hydrolyse enough lactose to lactic acid during cheesemaking, which leads to a crumbly body of the product (Atasoy, 2004; Gursel et al., 1987). Some strains of Lac. lactis subsp. lactis and Lac. lactis subsp. cremoris are salt-tolerant, and possess high proteolytic activity and/or acid- forming capacity. Yoghurt starter bacteria and most species of lactococci die out early in the maturation stage of White cheese. Similar ﬁ ndings were reported for Feta cheese (Tzanetakis & Litopoulou-Tzanetaki, 1992) and Domiati cheese (Shehata et al., 1975). Atasoy (2004) studied the performances of thermophilic (Streptococcus thermophilus and Lb. delbrueckii subsp. bulgaricus – code YC-350) and mesophilic (Lac. lactis subsp. lactis and Lac. lactis subsp. cremoris – code R-707) cultures

Table 6.5 Starter organisms used in the production of Turkish White cheese

Inoculation rate Blends of organismsa (mL 100 mL–1) E. durans 41770 + Lb. delbrueckii subsp. bulgaricus CH2 1.0 Lac. lactis subsp. lactis + Lac. lactis subsp. cremoris + Leu. mesenteroides subsp. cremoris NRb Lac. lactis subsp. lactis + Lac. lactis subsp. cremoris + Lb. sake 1.0 Lac. lactis subsp. lactis + Lac. lactis subsp. cremoris + Lb. plantarum 1–2.0 Lb. delbrueckii subsp. bulgaricus + S. thermophilus (1:1) 0.5–1.0 Lac. lactis subsp. lactis + Lac. lactis subsp. cremoris 2.0 Lac. lactis subsp. lactis + Lac. lactis subsp. lactis bv. diacetylactis + Lb. casei (1:1:1) 2.0 Lb. casei + Lac. lactis subsp. lactis (1:1) 0.5–2.0 Lac. lactis subsp. lactis S1 + Lb. plantarum L8 + E. durans C2O NR Lac. lactis subsp. lactis CH + E. durans CH + E. faecalis CH + Lb. delbrueckii subsp. NR lactis CH Lac. lactis subsp. cremoris + Lac. lactis subsp. lactis (R707) + Lb. helveticus LH100c + Lb. NR delbrueckii subsp. bulgaricus LB12c Lac. lactis subsp. cremoris + Lac. lactis subsp. lactis + Lb. casei 2.0 Lac. lactis subsp. lactis + Lac. lactis subsp. cremoris + B. biﬁ dum BB12 + Lb. acidophilus 1.0 LA5 a E. = Enterococcus, Lac. = Lactococcus, Leu. = Leuconostoc, Lb. = Lactobacillus, S. = Streptococcus, B. = Biﬁ dobacterium. b NR = not reported. c Used as heat-shocked culture at a rate of 2 g 100 mL–1.

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during the manufacture of Urfa-type white brined cheeses made from cow’s, goat’s or sheep’s milks, and they concluded the following: (a) as long as the inoculum rate did not exceed 0.5 mL 100 mL–1, the thermophilic starter bacteria were more suitable for the production of this cheese variety and obtaining the desired textural and aroma/fl avour properties in the product when compared with mesophilic starter cultures; and (b) higher inoculation rates of the thermophilic starter culture led to a yoghurt-like aroma and fl avour, and a weaker-bodied Urfa-type cheese. However, a starter culture blend consisting of Lac. lactis subsp. lactis S1, Lb. plantarum L8 and Enterococcus durans C20 also gave satisfactory results for the aroma and fl avour of the cheese (Gursel et al., 1994). Heat-shocked (65°C for 20 min) (Gursoy et al., 2001) or freeze-shocked (Gursel et al., 2003) cultures of Lb. helveticus LH100 and Lb. delbrueckii subsp. bulgaricus LB12 (inoculation rate 0.5 g 100 g–1) were assessed as adjunct cultures in the production of reduced-fat White cheeses to accelerate the maturation of the product. Both the freeze-shocked and heat-shocked adjunct cultures had no effect on the maturation profi le of the cheeses, but impaired the sensory properties of the experimental products. Recently, Yilmaztekin et al. (2004) studied the survival of probiotic bacteria, Bifi dobacterium bifi dum BB12 and Lb. acidophilus LA5, in classical White cheese as adjunct cultures, and observed viable probiotic counts >106 cfu g–1 in the product. Similarly, Kasimoglu et al. (2004) monitored the survival and metabolic activities of Lb. acidophilus 593N in vacuum- or brine-packed White cheeses. In vacuum-packed cheese (i.e. packed after salting), the count of Lb. acidophilus 593N was >107 cfu g–1, which is high enough to provide positive effects on health. Vacuum-packed probiotic White cheese had a higher degree of proteolysis and better sensory scores than the brine-packed product. As a consequence, Lb. acidophilus could be used for the manufacture of probiotic vacuum-packed White cheese with short maturation periods; this form of packaging is also preferred for retailing the product. Furthermore, Akgun (1997) used Lb. sake LS-9, in combination with Lac. lactis subsp. lactis and Lac. lactis subsp. cremoris, to produce a good-quality White brined cheese successfully. Up to 5.0 mL 100 mL–1 inoculation rate of Lb. sake LS-9 did not affect the organoleptic and physical properties of the product but, at higher inoculation rates, unacceptable fl avour and textural properties were evident. The types and concentrations of amino acids are considered to be an important criterion in monitoring degrees of proteolysis, and in deciding the suitability of starter cultures in White cheesemaking (Hayaloglu et al., 2002). Kaymaz (1982) profi led the amino acid (AA) contents in White cheese produced with or without starter culture, and only fi ve amino acids (i.e. leucine, phenylalanine, arginine, isoleucine and methionine) were identifi ed from mature cheeses. On the contrary, Ucuncu (1981) found more free amino acids (FAA) in White cheeses made from heated or raw cow’s and sheep’s milk with or without starter culture (Table 6.6). The concentrations of all FAA present in all cheeses (i.e. cow’s or sheep’s) increased throughout the 120-day maturation period, and the levels of glutamic acid, leucine, phenylalanine, valine and serine were the highest. Although high lipolytic activity in White cheese is not a characteristic property, the use of slightly weak lipolytic strains of the lactic acid bacteria is desirable. Akalin

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Table 6.6 Free amino acid (FAA) contents (mg 100 g–1 of cheese) of Turkish White cheese made from cow’s or sheep’s milk

Age (d) of cow’s cheesea Age (d) of sheep’s cheesea FAA Fresh 60 120 Fresh 60 120 Alanine 1.25 20.05 38.55 1.44 16.21 47.66 Arginine 1.50 4.95 4.65 0.95 5.60 5.81 Aspartic acid 0.90 4.05 12.40 0.16 9.00 18.20 Cysteine 0.92 10.55 18.40 0.90 9.20 10.62 Glutamic acid 5.68 58.40 107.60 8.80 68.75 141.60 Glycine 0.43 6.10 10.95 0.18 2.98 10.18 Histidine 1.03 5.85 19.60 2.20 7.70 11.62 Isoleucine 1.11 20.50 37.35 1.16 14.22 40.30 Lysine 2.55 20.75 48.00 0.56 6.72 58.72 Leucine 3.36 96.20 120.95 1.17 108.40 192.60 Methionine 0.75 16.45 28.55 1.40 14.65 28.22 Phenylalanine 1.49 40.10 54.00 2.26 29.66 67.00 Proline 2.13 12.00 20.55 1.70 12.30 29.45 Serineb 3.26 49.40 78.85 1.48 21.20 87.48 Threonine 0.59 9.15 14.85 1.42 12.20 17.47 Tyrosine 3.63 12.75 16.05 2.00 7.82 9.88 Valine 1.23 24.30 66.85 2.26 39.26 76.27 Total 31.81 411.55 698.15 30.04 385.87 853.08 a The cheeses were made from heat-treated milk and starter culure. b Values shown are the summation of the following FAA: serine + asparagine + glutamine. Data compiled from Ucuncu (1981).

et al. (1998) proﬁ led the free fatty acid (FFA) content of commercial cheese samples

(n = 22), and found that the myristic (C14), palmitic (C16), stearic (C18) and oleic (C18:1) acids were dominant in the products. The role of pregastric lipase enzyme added to the cheese milk at various levels (i.e. 0.5, 8.0 and 11.0 g 100 L–1 of milk) on the maturation of White cheese was reported by Aydemir et al. (2001). Volatile and FFA contents in the cheeses were affected by pregastric lipase, and the amounts increased signifi cantly during 90-day storage. In particular, cheese made with a high –1 dose of pregastric lipase (e.g. 11 g 100 L ) had high concentrations of butyric (C4), caproic (C6) and caprylic acids (C8), and the relative amounts of volatile FA varied with storage time and the amount of lipase added to the milk. Atasoy (2004) found no signifi cant difference between mesophilic and thermophilic starter cultures with regards to fat hydrolysis in Urfa-type white cheeses, but products made from raw milk had remarkably higher concentrations of volatile FA (14.55 mL NaOH 100 g–1 cheese) than the cheeses made from pasteurised milk (2.90 mL NaOH 100 g–1 cheese) (see also Kocak et al., 1987). The use of Piccantase A (from M. miehei) in White cheesemaking increased the total FFA content, but the fl avour intensity was lacking in the product (Dinkci & Gonc, 2000). Hence, the same researchers suggested that, when using Piccantase A in cheesemaking, a proteinase should be used in conjunction with the lipase in order to obtain a slightly piquant fl avour in the product.

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Microbial contaminants The counts of psychrotrophic bacteria tend to increase in White cheeses during the fi rst few weeks of maturation, and then their numbers fl uctuate depending on the initial microbial load in the milk or degree of contamination during the production stages. Pseudomonas spp., Aeromonas spp. and Acinetobacter spp. are among the genera of psychrotrophs most frequently found in White cheese (Ozer, 1999). Coliforms are often present in high numbers during the early stages of maturation, especially when using unpasteurised milk and/or poor sanitary conditions during cheesemaking. Kivanc (1990) enumerated the microbiological quality of Turkish products (n = 75) from three different dairies; 36.8% of the samples analysed were contaminated with Escherichia coli and 20.8% of the samples contained Enterobacter aerogenes. Also, Kivanc (1990) noted the presence of the enterobac- teria species (mainly Enterobacter cloacae), Citrobacterium spp. and Klebsiella spp. in the cheeses examined. Ozer et al. (2004b) studied the survival of six pathogens (Staphylococcus aureus, Bacillus cereus, Yersinia enterocolitica RSKK734, Shigella fl exneri RSKK184, E. coli O157:H7 and Salmonella enteritidis) in scalded and unscalded Urfa-type cheeses stored in brines of different salt concentrations, varying from 12.5 to 17.5 g 100 mL–1. The same researchers noted that scalding at 90°C for 3 min was effective enough to inactivate Y. enterocolitica RSKK734, S. flexneri RSKK184 and E. coli O157:H7, whereas S. aureus, S. enteritidis and B. cereus were able to survive under these conditions for over 90 days in all the brines. The presence of Listeria monocytogenes (Gonc & Kilic, 2002), E. faecalis (Ozer, 1999), Y. enterocolitica (Akbulut et al., 1993), E. coli (Turantas et al., 1989), Salmonella typhimurium (Akbulut et al., 1993) and Brucella abortus (Ozer et al., 2004b) in White cheeses has been reported because the products were made from raw milk. In addition, cheese-borne listeriosis, brucellosis and salmonellosis are common in some parts of Turkey where hot climatic conditions are prevalent. Durlu-Ozkaya and Tunail (2000) reported that the presence of E. durans E9 in white cheese produced biogenic amines, such as phenylethylamine, cadaverine, putrescine, histamine, tyramine and spermidine, and Mehenktas and Metin (2000) observed that increasing the level of NaCl in the brine led to a decrease in the tyramine level in the product.

6.3.3 Development of texture and microstructure of White cheese Texture is one of the important parameters determining the overall acceptability of cheese, and it is inﬂ uenced by many factors, such as the method of manufacture, handling of the curd and type of milk used. Limited data are available on the microstructure and textural properties of classical White brined cheeses. However, Ozer et al. (2003) extensively investigated the role of brining, scalding and UF of milk on the physical and microstructural characteristics of Urfa-type cheese. The Texture Proﬁ le Analyses (TPA) of Urfa-type cheeses are summarised in Table 6.7. Cheese made from UF milk had a harder body than traditionally made cheese; similarly,

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Table 6.7 Texture proﬁ les of traditional and UF Urfa-type brined cheeses with or without scaldinga

Hardnessb Springinessc Cohesivenessc Chewinessc Adhesivenessc Gumminessc Sample Ad 1086.0 0.833 0.594 537.4 69.0 645.1 Sample Be 1294.0 0.859 0.609 676.9 97.0 788.1 Sample Cf 1243.0 0.899 0.609 672.7 94.0 757.0 Sample Dg 1396.0 0.899 0.618 775.6 99.0 862.7 a Cheeses were 90 days old and brine concentration was 15.0% NaCl. b Unit of measurement is grams. c Dimensionless. d Unscalded traditional Urfa cheese. e Scalded (90°C for 3 min) traditional Urfa-type cheese. f Unscalded UF Urfa-type cheese (volume reduction was 65%). g Scalded (90°C for 3 min) UF Urfa-type cheese.

the scalded product had a fi rmer body than its unscalded counterpart. The cheese matrix is made up of interacting protein molecules, and a fi rmer curd is anticipated in the presence of higher protein content (Ozer et al., 1998, 1999). In addition, the protein voluminosity plays a key role in determining the rheological properties of the product, and an increase in the protein concentration per unit area causes an increase in milk viscosity leading to a fi rmer-bodied cheese (Hallstrom & Dejmek, 1988). Together with the increased casein concentration, the modifi ed calcium equilibrium is certainly a major cause of the increased fi rmness of the curds obtained from UF retentates. Similar to the fi rmness, the cohesiveness and springiness values of the cheese made from UF milk were higher than those of cheeses made from unconcentrated milk. Scalded cheeses were also springier than the unscalded samples. Scanning electron micrographs of UF cheeses reported by Ozer et al. (2003) revealed a more compact structure than the cheese manufactured from unconcentrated milk (Fig. 6.5). On the other hand, a fi ner and more continuous structure was evident in the classical Urfa-type cheese, whilst scalding seemed to result in a more homogeneous structure in both classical and UF Urfa-type cheeses. The same researchers concluded that, in the UF process of Urfa-type cheesemaking, the scalding step could be eliminated from the manufacturing stages.

6.4 Concluding remarks

White brined cheeses are well established products in the diet of Middle Eastern populations. However, relatively little is known and/or reported on the structure, rheology, induced changes due to storage of the product in brine and sensory properties of these varieties. Apart from their pivotal role in optimising production and quality of the traditional product, investigation and documentation of these parameters would allow systematic approaches aimed at developing low-salt, reduced-fat and prebiotic-enriched analogues of brined cheeses. Furthermore, with the increased availability and rapid spread of refrigeration facilities, the traditional practice of storing brined cheeses in metal or glass containers and their display in brine-ﬁ lled

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a b

c d

Fig. 6.5 Microstructure of different types of Urfa cheeses. Cheeses were made from unconcentrated milk (a), UF milk (b), unconcentrated milk and then scalded (c), and UF milk and then scalded (d). Bar: 50 µm. After Özer et al. (2003). Reproduced by permission of International Journal of Dairy Technology.

containers in retail outlets will become obsolete. This warrants the search for alternative methods of packaging and distributing the products. Although a number of studies have been undertaken to characterise Turkish White cheeses, there are still many areas that need to be investigated further. • The identiﬁ cation and characterisation of microorganisms present in White cheese made from raw or pasteurised milk should be studied in more detail, and the use of new starter culture combinations including salt-tolerant strains should be developed. Novel technologies, such as microencapsulation of starter bacteria, can be applied to improve the salt tolerance of starter cultures used in the manufacture of White brined cheese. Also, incorporation of non-starter lactic acid bacteria in the manufacture of this variety should be considered as a way to improve the aroma/ﬂ avour and texture of the cheese. • Brining conditions, including salt concentration, pH and temperature of brine, should be optimised. The kinetics of salt absorption and diffusion during the

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maturation of the cheese needs to be fully understood in order to standardise the salting conditions. • The isolation and identiﬁ cation of peptides, amino acid sequencing and characterisation of volatile compounds in the cheese may be helpful in fully explaining the extent of proteolysis and lipolysis during maturation. This is of particular importance in the selection of starter culture combination(s).

Also, future technological developments regarding automation and mechanisation of the manufacture of Middle Eastern and Turkish brined cheeses should be considered; the development of UF technique(s) in cheesemaking should not be overlooked, especially in large production units. These developments are important to control the various stages of production and, eventually, to produce cheeses with minimum variation in chemical composition, microbial quality, yield and consumer acceptability.

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Durlu-Ozkaya, F. & Tunail, N. (2000) Beyaz peynirlerde biyojenik amin riski. VI. Sut ve Sut Urunleri Sempozyumu Bildiriler Kitabi, 21–22 May, pp. 146–153. Trakya University Press, Tekirdag. Durlu-Ozkaya, F., Xanthopoulos, V., Tunail, N. & Litopoulou-Tzanetaki, E. (2001) Technologically important properties of lactic acid bacteria isolates from Beyaz cheese made from raw ewes’ milk. Journal of Applied Microbiology, 91, 861–870. Erkmen, O. (2001) Survival of Listeria monocytogenes during the manufacture and ripening of Turkish White chese. Nahrung, 45, 55–58. Gencer, N. (2003) The effect of enzymes on some characteristics of ultrafi ltered sheep and goat milk and their curds. PhD thesis, Ankara University, Ankara. Gonc, S. & Kilic, S. (2002) Beyaz peynirde L. monocytogenes patojeninin aranmasi üzerine bir arastirma. Gida, 27, 425–429. Guardiola, F., Codony, R., Addis, P.B., Rafecas, M. & Boatella, J. (1996) Biological effects of oxys- terols: Current status. Food and Chemical Toxicology, 34, 193–211. Gursel, A., Ergul, E., Gursoy, A. & Erdogdu, N.G. (1987) Kalsiyum klorürün taze beyaz peynirlerin bazı nitelikleri üzerine etkileri. Gida, 12, 293–298. Gursel, A., Tunail, N., Gursoy, A., Ergul, E. & Aydar, L.Y. (1994) Yerli ve ithal fekal ve laktik grup streptokoklar ile yerli ve laktobasil iceren starter kombinasyonlarinin beyaz peynir uretiminde kullanilmasi. Kukem Dergisi, 17, 1–14. Gursel, A., Gursoy, A., Senel, E., Deveci, O. & Karademir, E. (2003) The use of freeze-shocked lactic starters in low-fat white pickled cheese. Milchwissenschaft, 58, 279–282. Gursoy, A., Gursel, A., Senel, E., Deveci, O. & Karademir, E. (2001) Yag icerigi azaltilmis beyaz peynir uretiminde isil islem uygulanan Lactobacillus helveticus ve Lactobacillus delbrueckii subsp. bulgaricus kulturlerinin kullanimi. In: GAP II. Tarim Kongresi Bildiriler Kitabi, October 24–26, pp. 269–278. Harran University Publications, Sanliurfa. . Guven, M. & Karaca, O.B. (2001) Proteolysis levels of White cheeses salted and ripened in brines prepared from various salts. International Journal of Dairy Technology, 54, 29–33. Guven, M., Karaca, O.B. & Hayaloglu, A. (2001) Farklı tuzlardan hazırlanan salamuralarda tuzlanan ve olgunlaştırılan beyaz peynirlerin özellikleri. In: GAP II. Tarim Kongresi Bildiriler Kitabi, October 24–26, pp. 401–410. Harran University Publications, Sanliurfa. Haddadin, M.S., Shahin, R.M.A. & Robinson, R.K. (1995a) Nabulsi: a Jordanian cheese. Dairy Industries International, 60(7), 34–35. Haddadin, M.S., Shahin, R.M.A. & Robinson, R.K. (1995b) The infl uence of casein:fat ratio in sheep’s milk on the chemical composition and sensory properties of Nabulsi cheese. Journal of the Society of Dairy Technology, 48, 71–75. Hallstrom, M. & Dejmek, P. (1988). Rheological properties of ultrafi ltered skim milk. II. Protein voluminosity. Milchwissenschaft, 43, 95–97. Hayaloglu, A., Guven, M. & Fox, P.F. (2002) Microbiological, biochemical and technological properties of Turkish White cheese ‘Beyaz Peynir’. International Dairy Journal, 12, 635–648. Hosono, A., Isek, Y., Otani, H. & Takahashi, F. (1992) Identifi cation of lactic acid bacteria in ‘Beyaz Peynir’ a traditional cheese in Turkey. Animal Science and Technology, 63, 712–714. Humeid, M.A., Tukan, S.K. and Yamani, M.I. (1990) In-bag steaming of white brined cheese as a method for preservation. Milchwissenschaft, 45, 513–516. JS (2003) Boiled White Cheeses Standard, No. 796A/2003. Jordanian Institute of Standards and Meteorology, Amman, Jordan. Karakus, M. (1994) Beyaz peynirlerden izole edilen laktik asit bakterilerinin asit olusturma ve pro- teolitik aktiviteleri. Gida, 19, 237–241. Kasimoglu, A., Goncuoglu, M. & Akgun, S. (2004) Probiotic white cheese with Lactobacillus acidophilus. International Dairy Journal, 14, 1067–1073. Kaymaz, S. (1982). İnek sütü ile yapılan starterli ve startersiz beyaz peynirlerin olgunlaşma süreleri sırasında bazı serbest aminoasitlerin (Arginine, Isoleucine, Leucine, Methionine, Phenylalanine,

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Tryptophane) miktarları üzerinde araştırma. Ankara Universitesi Ziraat Fakultesi Dergisi, 27, 545–560. Kivanc, M. (1990) Peynirlerden izole edilen koliform grubu bakterilerin tanimlanmasi. Gida, 15, 93–99. Kocak, C., Gursel, A., Ergul, E. & Gursoy, A. (1987) Farkli tuzlama yontemlerinin beyaz peynirde ucucu yağ asitleri olusumuna etkisi. Gida, 12, 179–184. LS (2001) Brined Cheeses Standards, Nos. 222:2001, 223:2001, 225:2001, 226:2001. Lebanese Institute for Norms and Standards, Beirut. Mehenktas, C. & Metin, M. (2000) Beyaz peynirin olgunlasmasi sirasinda farkli tuz konsantrasyon- larinin tiramin olusumuna etkisi. VI. Sut ve Sut Urunleri Sempozyumu Bildiriler Kitabi, 21–22 May, pp. 337–345. Trakya University Publications, Tekirdag. Ozer, B.H. (1999) Microbiology of white-brined cheeses. In: Encyclopedia of Food Microbiology (eds R.K. Robinson, P. Patel & C. Batt), pp. 397–402. Academic Press, London. Ozer, B.H., Bell, A.E., Grandison, A.S. & Robinson, R.K. (1998) Rheological properties of concentrated yoghurt (Labneh). Journal of Texture Studies, 29, 67–79. Ozer, B.H., Stenning, R., Grandison, A.S. & Robinson, R.K. (1999) Rheology and microstructure of Labneh (concentrated yoghurt). Journal of Dairy Science, 82, 682–689. Ozer, B.H., Atasoy, A.F. & Akin, M.S. (2000) Pastorizasyon ve haslama islemlerinin geleneksel Urfa peynirlerinin mikrobiyolojik ve kimyasal nitelikleri uzerine etkileri. VI. Sut ve Sut Urunleri Sempozyumu Bildiriler Kitabi, 21–22 May, pp. 517–523. Trakya University Publications, Tekirdag. Ozer, B.H., Atasoy, A.F. & Akin, M.S. (2002) Some properties of Urfa cheese (a traditional Turkish cheese) produced from bovine and ovine milks. International Journal of Dairy Technology, 55, 94–99. Ozer, B.H., Robinson, R.K. & Grandison, A.S. (2003) Textural and microstructural properties of Urfa cheese (a white brined Turkish cheese). International Journal of Dairy Technology, 56, 171–176. Ozer, B.H., Atasoy, A.F., Yetismeyen, A. & Deveci, O. (2004a) Development of proteolysis in ultra- ﬁ ltered Turkish White-brined cheese (Urfa type) – effect of brine concentration. Milchwissenschaft, 59, 146–149. Ozer, B.H., Uraz, G., Beyzi-Yilmaz, E. & Atasoy, A.F. (2004b) The effects of brine concentration and scalding on survival of some pathogens in Urfa cheese: a traditional white-brined Turkish cheese. International Journal of Food Science and Technology, 39, 727–735. Renner, E. & Omeroglu, S. (1981) Herstellung von Weisskase aus ultrafiltrierter Milch. Milchwissenschaft, 36, 334–338. Robinson, R.K. (1991) Halloumi cheese – the product and its manufacture. In: Feta and Related Cheeses (eds R.K. Robinson & A.Y. Tamime), pp. 114–159. Ellis Horwood, Chichester. Saldamli, I. & Kaytanli, M. (1998) Utilization of Fromase, Maxiren and Rennilase as alternative coagulating enzymes to rennet in Turkish White cheese. Milchwissenschaft, 53, 22–25. Shehata, A.E., El-Gadek, G.M., Khalafalla, S.M. & El-Magroub, M.J.N. (1975) Effet of pasteurization and hydrogen peroxide-catalase treatment of milk on lactic acid bacteria in domiati cheese. Egyptian Journal of Dairy Science, 3, 139–142. Tannous, R.I. (1991) Miscellaneous white brined cheeses. In: Feta and Related Cheeses (eds R.K. Robinson & A.Y. Tamime), pp. 209–228. Ellis Horwood, Chichester. TS (1995) White Cheese Standard (TS 591). Turkish Standards Institution Publications, Ankara. Turantas, F., Unluturk, A. & Goktan, D. (1989) Microbiological and compositional status of Turkish White cheese. International Journal of Food Microbiology, 8, 19–24. Turhan, M. & Kaletunc, G. (1992) Modelling of salt diffusion in white cheese during long term brining. Journal of Food Science, 57, 1082–1085. Tzanetakis, N. & Litopoulou-Tzanetaki, E. (1992) Changes in numbers and kinds of lactic acid bacteria in Feta and Teleme, two Greek cheeses from ewe’s milk. Journal of Dairy Science, 75, 1389–1393.

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Ucuncu, M. (1981) Inek ve koyun sutunden imal edilen beyaz peynirlerde olgunlasma surecinde serbest aminoasit birikiminin belirlenmesi. Ege Universitesi Ziraat Fakultesi Dergisi, 2, 1–36. Unsal, A. (1997) Sut Uyuyunca, Yapi Kredi Yayinlari, Ankara. Uysal, H.R., Kinik, O. & Akbulut, N. (1996) Research on the possibilities of the use of chicken pepsine for the manufacture of white-brined cheese. Ege Universitesi Ziraat Fakultesi Dergisi, 33, 99–106. Yamani, M.I., Al-Nabulsi, A.A., Haddadin, M.S. & Robinson, R.K. (1998). The isolation of salt-tolerant lactic acid bacteria from ovine and bovine milks for use in the production of Nabulsi cheese. International Journal of Dairy Technology, 51, 86–89. Yaygin, H. & Uysal, H.R. (1990) Ultrafi ltrasyonla koyulastirilmis sutlerden yapilan beyaz peynirlerin özellikleri. Gida, 15, 89–92. Yesilyurt, S. (1992) Studies on the use of Fromase and Rennilase from Rhizomuchor miehei in White cheese. PhD thesis, University of Ege, Izmir, Turkey. Yetismeyen, A. (1987) Ultrafi ltre sutten beyaz peynir uretiminin arastirilmasi. Gida, 12, 13–17. Yetismeyen, A., Cimer, A., Ozer, M., Odabasi, S. & Deveci, O. (1998) Ultrafi ltrasyon teknigi ile sala- mura beyaz peynir uretiminde kalite uzerine degisik maya enzimlerinin etkisi. Gida, 23, 3–9. Yilmaztekin, M., Ozer, B.H. & Atasoy, A.F. (2004) Survival of Lactobacillus acidophilus LA-5 and Bifi dobacterium bifi dum BB-02 in white-brined cheese. International Journal of Food Sciences and Nutrition, 55, 53–60.

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M.N. Oliveira and C. Brito

7.1 Background

In 2003, South American countries produced ~46 232 million tonnes of milk, corresponding to 31.6% of the milk produced in all the Americas. Brazil is responsible for 50% of the milk produced, followed by Argentina (16.6%), Colombia (13.1%), Ecuador (4.9%) and Chile (4.7%) (EMBRAPA, 2004). However, the price of the milk is very low; according to the United Nations Food and Agriculture Organization (FAO, 2004), the mean price of the milk produced in Brazil and in Chile in 2003 was US$ 0.15 L–1, being fi ve and two times lower than that in Japan and France, respectively. In 2004, the Foreign Agriculture Service, Commodity Marketing Programs, Dairy, Livestock and Poultry Division (FAS/CMP/DLP) in the USA estimated cheese production in South America as utilising 830 million tonnes of milk, 5.4 and 6.7 times lower than that in North America and the European Union, respectively. In addition, liquid milk consumption is very low when compared with that in North American and European Union countries. The consumption of cheese per capita per year in Argentina, Venezuela and Brazil averaged 8.52, 2.84 and 2.67 kg, respectively (EMBRAPA, 2004). The apparent cheese consumption in Chile, which for many years remained at a very low level (i.e. ~2 kg per capita per year in the 1970s), has currently reached ~4.35 kg; this fi gure for cheese consumption is still quite low when compared with 20 kg per capita per year in countries such as France or Greece (Caro & Ortega, 2002; Dirven & Ortega, 2001; Esnaola, 2003). Although there are specifi c variations in the manufacturing process of different types of cheeses, in general the essential procedures include the selection and pasteurisation of milk, renneting, cutting of the coagulum, whey expulsion, moulding, salting, maturation and storage. Within the different procedures of salting, brining could be used. It is a process in which the cheese is immersed in a salt solution at a defi ned temperature for a variable time established as a function of the weight and height of the cheese. The reutilisation of brine in the cheese industries, especially in Brazil, is a cause for concern as it might introduce undesirable substances to the cheeses that could change their physicochemical composition, such as: • the pH of the brine is lowered due to the diffusion of lactic acid from the cheese to the brine, seepage of the whey during brining and/or microbial activity in the brine;

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• the build-up of nitrogenous components in the brine can act as a buffer during its utilisation; • the NaCl concentration will decrease due to dilution by the whey and penetration of the salt into the cheese during brining; and • brine without any treatment(s) will contain high viable counts of different microorganisms, some of which may be undesirable (Amaral et al., 1992; Lourenço Neto, 1996a, 1996b; see also Chapter 9).

This chapter will review the historical background, deﬁ nition, some economic and technological aspects, and properties of the main brined cheeses manufactured in Brazil and Chile, emphasising traditional production methods, direct acidiﬁ cation techniques and membrane processing.

7.2 Main brined cheeses produced in Brazil 7.2.1 Introduction Brazil sprawls across the broadest region of the South American continent, with a reputation largely built on coffee, carnival and football. The milk chain is one of the most important of the Brazilian agro-industrial complex. It is valued at around US$10 billion annually, employs three million people of whom one million are milk producers, and produces around 23 billion litres of milk annually; 14 billion litres is produced under Federal Inspection. The dairy sector has great potential to furnish dairy products to the internal and external markets (EMBRAPA, 2004). Brazil is the sixth largest milk producer in the world after the European Union, India, USA, Russian Federation and Pakistan (FAO, 2004). In the early 1970s, the productivity of the dairy cattle was less than 700 L per cow per year; this production fi gure had doubled by the late 1990s. Nowadays, it is possible to fi nd farms where the annual productivity is fi ve times higher than 25 years earlier. The actual productivity average is around 1177 L per cow per year (EMBRAPA, 2004). Few dairy cows (i.e. 19 195 million in 2003) are milked, and how often depends on their calving date, their milk production and the price of the milk. Some of the big cattle breeders prefer importing cows from the USA or from Europe. The well- bred imported animals are well cared for, unlike those on ordinary dairy farms that are not well-bred; the former type produce 4 200 kg per lactation every year, whilst the latter produce less than 2 800 kg per lactation (EMBRAP, 2004). In 2003, milk produced in Brazil under the supervision of the Federal Inspection Service (SIF) of the Ministry of Agriculture reached 14.022 billion litres. Liquid milk sales represent 41.1% of the total volume of raw milk produced in the country, with predominance of ultra-high temperature (UHT) milk processing (74%), and milk of ‘grades’ A, B and C. Milk C was produced in the highest volume. Considering the total raw milk normally produced in Brazil, the main manufactured products are cheese (27.6%), milk powder including condensed milk (25%), yoghurts (3.7%)

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and others (2.7%) (Associação Brasileira das Indústrias de Queijos, São Paulo, pers. comm.). When both the milk produced with (formal production) and without (informal production) the supervision of the SIF is considered, total milk production in Brazil reached 22.891 billion litres in 2003 (Fig. 7.1). From the total volume of raw milk informally produced, liquid milk processes represented 34.7%, cheese 34%, milk powder including condensed milk 15.3%, and others including yoghurt 16% (Associação Brasileira das Indústrias de Queijos, São Paulo, pers. comm.). In general, Brazil’s milk production is increasing annually by 10%. The South East Region produces 43.4% of the national total, and the other Regions (i.e. South, Centre East, North East and North) produce 24.8%, 15.6%, 10.9% and 5.3%, respectively (Fig. 7.2). The milk trade in Brazil also includes imported milk (83 547 tonnes in 2003), and 44 444 tonnes was exported in 2003 according to data reported by the MDCI/ EMPRAPA. Total milk consumption had reached 36 billion litres in 2000, when the last census was carried out. In fact, to meet the demand for dairy products by the Brazilian population, local milk production has to be higher than 36.089 billion litres per year according to a statistical report by MS/IBGE (EMBRAPA, 2004). Nevertheless, the dairy industry in Brazil produces 23% of all the agricultural food industries, which is around 820 000 tonnes of dairy products, of which 52% is cheese (Associação Brasileira das Indústrias de Queijos, São Paulo, pers. comm.). Cheese was ﬁ rst made in the Southern East Region of Brazil, mainly in Minas Gerais State, as a homemade product. Nowadays, cheese is manufactured all over

25.0 450.0

400.0

20.0 350.0

300.0

15.0 250.0

200.0 10.0 Cheese (tonnes) Milk (billion of L) (billion Milk 150.0

100.0 5.0

50.0

0.0 0.0 1990 1991 1992 1993 1994 195 1996 1997 1998 1999 2000 2001 2002 2003 Year

Milk Cheese

Fig. 7.1 Patterns of milk and cheese production in Brazil. After Associação Brasileira das Indústrias de Queijos, São Paulo, personal communication.

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North (5.3%) North East (10.9%)

Centre East (15.6%)

Southern East (43.4%)

South (24.8%)

Fig. 7.2 Geographical location of milk production in Brazil.

the country, and the main producers are in the following Regions: Southern East (43.4%), South (24.8%) and Centre East (15.6%). However, cheese production in the North East and North Regions amounts to 10.9% and 5.3%, respectively. The main producer states are: Minas Gerais (MG, 30.4%); Goiás (GO, 10.8%), Rio Grande do Sul (RS, 10.4%), São Paulo (SP, 10%) and Paraná (PR, 9%) (Fig. 7.2). Actually, Brazil does not have any offi cial data concerning cheese production due to the confi guration of the market: there are many mini-dairy plants that work regionally, and outside the competence of the SIF. Data shown in Table 7.1 and in Fig. 7.1 are estimates based on market data (desk research), data from the research institutes (ad hoc) and press reports. It is important to note that these cheese production data are obtained from dairy plants registered with the SIF, which corresponds, according to analysts, to only 60% of the total production fi gures (Associação Brasileira das Indústrias de Queijos, São Paulo, pers. comm.). Milk utilisation for cheese production increased between 2001 and 2003, and reached an average of 407 million tonnes (offi cial data), but the volume estimated by FAS/CMP/DLP for 2004 was 470 million tons. The main types of cheese produced in Brazil are Mozzarella (33.3%), Prato (23.6%), Minas Frescal and Padrão (9.1%), processed cheese spread (11.9%) and Parmesan (5.6%) (Table 7.1). These cheeses can be classifi ed into two groups: the common varieties and the special/speciality varieties. The former group includes cheeses like Mozzarella, Minas Frescal and Prato, which correspond to 96.7% of Brazilian cheese production. The special cheese varieties include products like Gorgonzola, Gouda and Cream cheese, and these account for only 3.3% of the Brazilian cheese production (Associação Brasileira das Indústrias de Queijos, São Paulo, personal communication).

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Table 7.1 Main cheeses manufactured in Brazil

Cheese variety Volume of production (tonnes) Percentage (%) Most common varieties Estepe 2 013 0.49 Fundido 981 0.24 Minas Frescal 31 258 0.68 Minas Padrão 5 642 1.39 Mussarela 13 561 33.33 Parmesan 22 915 5.63 Pasteurised 7 335 1.80 Petit Suisse 22 568 5.55 Prato 96 022 23.60 Provolone 7 106 1.75 Reino/Edam 3 158 0.78 Pot Cheese 48 466 11.91 Ricota 7 671 1.89 Montanhês 3 021 0.74 Total 393 772 96.78 Speciality varieties Brie 391 0.10 Batavo 195 0.05 Caccio/Cavallo/Provola 354 0.09 Camembert 542 0.13 Cottage 493 0.12 Gorgonzola 1 844 0.45 Gouda 1 488 0.37 Gruyère 1 184 0.29 Limburgo 13 0.00 Pecorino 32 0.01 Quark 213 0.05 Quartirolo 379 0.09 Queijo Cremoso 1 462 0.36 St Paulin 225 0.06 Sansoe 54 0.01 Tilsit 3 858 0.95 Others 677 0.17 Total 13 114 3.30 Overall total 406 887 100.00 After Associação Brasileira das Indústrias de Queijos, São Paulo, personal communication.

7.2.2 Minas cheese (fresh and matured) Minas cheese is a very popular product with great acceptability among the Brazilian population. The processing method was ﬁ rst brought to Brazil by the Portuguese colonialists. Since the beginning of cheese production, some of the milk produced was designated for the manufacture of a fresh cheese called Serra da Estrela. During the gold exploration in Minas Gerais Region, where cattle were predominant in the second part of the 17th century, the evolution of Minas cheese began. Nowadays, this cheese variety is manufactured in many states of Brazil.

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Minas Frescal is deﬁ ned as a fresh cheese ready to be consumed after its manufacture, or as a matured product that has undergone the biochemical and physical changes necessary for it to be considered as a different variety, according to Brazilian Standards (BS, 1996a, 1996b). The matured cheese varieties include the product known as Minas Padrão, and the Canastra cheese that is a regional product made in the Serra da Canastra in Minas Gerais. Minas cheeses can be classiﬁ ed as: (a) very high moisture content, or soft cheeses (≥55 g moisture 100 g–1); (b) high moisture content, or smooth cheeses (46.0–54.9 g moisture 100 g–1); and (c) low moisture content, or semihard cheeses (36.0–45.9 g moisture 100 g–1). Examples are Minas Frescal, Canastra and Padrão cheeses, respectively (BS, 1996b).

Minas Frescal This variety of cheese is made at home, on small farms and in dairy plants. Its manufacture employs conventional technology using microbial fermentation of the milk (i.e. not direct acidifi cation), and also it is manufactured by ultrafi ltration (UF). Minas Frescal cheese could be considered a very simple product to make, resulting in good yield and good quality when adequate raw materials and good manufacturing practices (GMP) are employed. Milk of good quality with acidity ranging between 15 and 18°D (i.e. equivalent to between 0.16 and 0.18 mL lactic acid 100 mL–1) is normally recommended for cheesemaking, and the fat content of the milk is standardised to 3.0–3.2 g 100 g–1 and pasteurised at 72°C for 15 s or 65°C for 30 min. Nonstandardised whole-fat milk could be used, but the cheese may be smooth and have a glutinous consistency, which is a fault. Calcium chloride is added to the milk at a rate of 20 g 100 L–1 or 40 mL 100 L–1 of a 50 g 100 mL–1 solution, which can be obtained from many commercial outlets. The addition of calcium chloride improves the coagulation process of the milk (see Chapter 1) due to the poor solubilisation of the calcium salts as a result of heating the milk, i.e. pasteurisation. Hence, the curd properties are better and the loss of whey constituents during the cutting stage is lowered. Figure 7.3 details the manufacturing stages of Minas Frescal cheese. After milk selection, standardisation and pasteurisation, two alternative methods of production can be employed: fi rst, direct acidifi cation or chemical acidifi cation, and second, the addition of starter cultures. In general, the former method is employed more when the cheese is homemade, or in some commercial dairy plants in order to reduce the cost of production. Industrial lactic acid (85 mL 100 mL–1) is used at a rate of 25 mL 100 L–1 of milk. It should be diluted into 2 L of water, and added slowly to the milk. The cheese produced by this method should have an acid fresh fl avour. If a more acidic cheese is desired, a starter culture can also be employed, but this procedure (i.e. the combined effect of chemical and microbial acidifi cation of the milk) can affect the texture of the product. Mesophilic lactic acid bacteria (LAB) are commonly used as starter cultures, and the most popular blend is the ‘O’ culture consisting of Lactococcus lactis subsp.

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Milk selection & standardisation (3.0–3.2 g fat 100 g–1) Addition of salt (2.0-2.5 g Pasteurisation 100 mL–1)* (72°C for 15 s or 65°C 30 min)

CaCl (20 g 100 L–1)

Addition of lactic acid Addition of starter culture (25 mL 100 L–1) (0.5 mL 100 mL–1)

Renneting (40–42ºC) Renneting (35–37ºC)

Cutting

Agitation (20–30 min)

Whey expelling

Moulding Salting* (0.7 g 100 g–1) Turning Brining* (2 × 10–20 min; 3 × 60 min) (20 g NaCl 100 mL–1 at 10–12°C for a time depending on the Storage weight and shape of the (10-12°C for 24 h) cheese)

Packaging

Dispatch (4ºC)

Fig. 7.3 Manufacturing stages of traditional Minas Frescal cheese using chemical acidiﬁ cation or starter cultures. *Salt addition, salting or brining is optional.

lactis and Lactococcus lactis subsp. cremoris or a thermophilic culture; the starter organisms are inoculated at a rate of 0.5 mL 100 mL–1. However, in order to obtain a smoothly textured cheese, lactic acid and a starter culture should not be used together. The use of a starter culture increases whey syneresis and, as a consequence, lowers

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the cheese yield. In addition, due to high acid development for a few days post- production, the shelf-life of the cheese will be reduced. These factors are reduced or minimised when the starter culture is substituted with the addition of lactic acid (i.e. chemical acidifi cation of the milk). Coagulation of the milk must occur within 30–40 min at 35–37°C after the addition of rennet at recommended doses. When the direct acidifi cation method is used, coagulation of the milk is performed at 40–42°C. Renneting affects the texture of Minas Frescal cheese and should be optimised (Oliveira et al., 1997). The coagulum is cut slowly using a lyre, which is a harp-shaped knife. Vertical and horizontal movements during the cutting stage should be performed resulting in grains of 1.5–2.0 cm in size. The titratable acidity of the whey should be equivalent to two-thirds of the initial acidity of the milk; for example, if the milk was 18°D (0.18 mL 100 mL–1 lactic acid), the acidity of the whey should be 12°D (0.12 mL 100mL–1 lactic acid) straight after cutting. In addition, the curd should be slowly agitated in the whey after cutting the coagulum using a special instrument, followed by 3–4 repeats of agitation and resting sequences (i.e. the duration of each sequence is 2 min). Afterwards, the curd/whey mixture is stirred continuously for about 20–30 min, which is just enough to ensure the desired degree of fi rmness of the curd grains. At this stage of cheese production, the overall curd mass characteristic varies according to the desired moisture content of the fi nal product. In general, it is observed that when the curd mass drains easily into the mould and without retaining any whey, the grains have a more rounded shape. After draining most of the whey, moulding is done by collecting the curd mass using special moulds or putting the curd into the moulds using a perforated metal sheet. The moulds are characteristic for Minas Frescal cheese, and must be completely fi lled in order to give the adequate height and weight to the product. After 10–20 min, the cheeses should be turned in the moulds to give a better outer appearance to the product. This procedure should be repeated twice every hour, but pressing of the moulded curd is not done during the manufacture of Minas Frescal cheese, as the weight of the curd mass and gravity are suffi cient to compact the curd grains together. After this, the cheeses are stored in a cold chamber for 24 h at 10–12°C to complete the drainage of the whey. Salting of Minas Frescal cheese can be done by employing one of the following approaches: (a) the addition of salt directly into the milk, (b) by applying salt solution directly on the surfaces of the cheeses (i.e. wet brine), or (c) immersing the cheeses in brine solution. The choice of procedure for salting the cheese is optional, and based entirely on the preference of each manufacturer. When the fi rst method of salting is employed, salt is added to the milk at a rate of 2–2.5 g NaCl 100 mL–1 of the milk. This salting method means that the salt is well distributed in the cheese, but a large amount of the salt is lost during the drainage of the whey. The salted whey is not suitable to be used as a by-product or as a feed for animals. However, if the second option is used, each side of the cheese block is smeared with wet brine (containing 0.7 g salt 100 mL–1) during the turning stages of the cheese blocks. Incidentally, this salting method affects the salt distribution in the

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cheese. The third, immersion method is the most common method of salting in the industrial manufacture of Minas Frescal cheese. The salt concentration of the brine is 20 g 100 mL–1, and the duration of brining depends on the weight of the cheese. For example, 500 g and 1 kg cheeses are immersed in the brine at 10–12°C for 90 min and 3–4 h, respectively. In general, the cheeses are immersed in the brine almost 12–18 h after moulding. Afterwards, the brined cheeses are stored in a cold chamber at 10–12°C for 8–12 h for drying the cheese portions. Packaging is done using plastic fi lm laminates. After this phase, the cheeses can be retailed for direct consumption or stored at 2–4°C. The shelf-life of Minas Frescal cheese is very short, averaging around 20 days, depending on the technology applied during the manufacture of the cheese. Minas Frescal cheese is cylindrical and the weight varies between 500 g and 3 kg. It has a white colour, closed or open texture with few mechanical eyeholes, a soft consistency and a fl avour ranging from smooth to acid (Fig. 7.4). The yield is typically 1 kg of cheese from 5–7 L milk. The chemical composition of Minas Frescal cheese is shown in Table 7.2. Although Minas Frescal is a fresh cheese variety, the biochemical and enzymatic changes in the product are due to action of direct acidifi cation and/or use of lactic cultures; the latter cause proteolysis affecting the texture of the cheese (González et al., 1998). During the past 30 years, the use of ultrafi ltered (UF) milk for cheesemaking has attracted considerable attention throughout the world. The ‘pre-cheese’ technology known as the Maubois, Mocquot and Vassal (MMV) process is used in many dairy plants to produce different cheese varieties (Maubois & Mocquot, 1975; Maubois et al., 1969; Mehaia, 2002). In 1986, the manufacture of Minas Frescal cheese using

Fig. 7.4 Illustration of cheeses produced in Brazil. (1) Traditional Minas Frescal, (2) ultraﬁ ltered Minas Frescal, (3) Minas Meia Cura, (4) Minas Padrão, (5) Rennet.Reproduced in colour as Plate 1, after page 236.

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2 2 0

Table 7.2 Chemical composition (g 100 g–1) of some selected cheeses produced in Brazil

Minas Frescal cheese Brazilian Ultrafi ltration Constituent specifi cation (UF) Traditional Minas Padrão cheese Rennet cheese Prato cheese Zero Low Light Mineirão Traditional Light Traditional Traditional Moisture 55–60 77.00 66.44 70.00 67.50 63.00 46.67 49.09 47.92 42.60 Protein 16.90 23.33 14.00 14.30 14.30 18.83 21.21 24.86 25.85 Fat 17–20 0.10 2.85 9.40 11.40 17.00 27.91 17.91 21.62 26.15 Carbohydrates 3.20 2.37 1.86 1.90 3.58 7.38 3.80 3.80 2.80 Salt (NaCl) 1.4–1.6 1.4–1.6 0.6–2.5 0.7–2.0 pH Microbial 5.0–5.2 5.7–6.3 5.7–6.0 fermentation 5.0–5.2; chemical acidifi cation 6.1–6.3 Energy (k cal g-1) 81 133 156 175 221 336 276 301 345 After BS (1996a) and Anonymous (2004a). 117/05/2006 12:05:06 7 / 0 5 / 2 0 0 6

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UF technology started in Brazil. After milk selection, standardisation and pasteurisation, the milk is concentrated by UF. Following direct acidifi cation, the manufacturing procedure follows stages similar to those of conventional cheesemaking. However, the processing conditions of UF Minas Frescal cheese are commercially confi dential and no published data are available. The product is packaged in plastic cups as shown in Fig. 7.4. In unmatured Minas Frescal cheese, decreased proteolysis and prevention of post-production acidifi cation have been achieved using UF technology, so that the lactose content in the milk is reduced and the shelf-life of the cheese is increased. Furthermore, in the UF cheesemaking method, the yield of the product is increased and the texture of the cheese is improved, especially when using skimmed milk (Cunha et al., 2002a, 2002b). The Minas cheeses manufactured using the UF technology and found in the Brazilian market are made in four different types: traditional, light, zero-fat and ‘Mineirão’. The light-type has 33% less energy, and it contains 37 g fat 100 g–1, lower than the traditional-type, whilst the zero-fat Minas Frescal, fi rst made in Brazil only recently, contains no fat and so has 58% less calories than the traditional cheese. Finally, the ‘Mineirão’ is a light cheese, and it contains added Cheddar cheese in order to enhance the fl avour of the product. The chemical composition of these UF cheeses is shown in Table 7.2.

Minas Padrão This variety of cheese is of Brazilian origin, is made in many States and was ﬁ rst produced in the early part of the 19th century in Minas Gerais. This cheese is known in two varieties: as Minas Curado (matured) and as Minas Padrão (standardised). These cheeses have characteristics similar to other home-made cheeses using raw milk, such as Serro, Coalho and Catiara cheeses. Another variant of Minas Padrão, known as Minas Meia Cura, is a semimatured cheese with different characteristics; although well accepted by consumers, it cannot be considered a true Minas Padrão cheese. A Minas Padrão cheese is cylindrical and weighs between 800 and 1200 g. Its crust is thin to thick, yellowish in colour, and it has an open texture with few mechanical eyeholes. The consistency of the product is similar to semihard cheeses, with a tendency to be smooth and, when broken, the interior of the cheese is white-creamy in colour and the ﬂ avour is slightly acidic. The cheese yield is normally 1 kg from 8.0–8.5 L of milk. The manufacturing stages of Minas Padrão cheese are very similar to those of Minas Frescal. Milk of good quality, for example, acidity ranging between 15 and 18°D (0.16–0.18 mL lactic acid 100 mL–1) is recommended for cheesemaking. The fat content in the milk is standardised to 3.3–3.5 g 100 g–1, and the milk is pasteurised at 72°C for 15 s or 65°C for 30 min. Milk of lower quality can be used, but the cheese may have faults, such as a smooth texture and glutinous consistency. In addition, calcium chloride is added at a rate of 20 g 100 L–1 of milk, or by using 40 mL 100 L–1 of a 50 g 100 mL–1 solution, which can be easily obtained from dif-

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ferent retail outlets in Brazil. The addition of calcium chloride improves coagulation as the naturally occurring calcium salts in the milk become insoluble due to the application of heat during pasteurisation. Hence, the curd properties are better, and the amount of curd fi nes lost in the whey is reduced. The mesophilic ‘O’ type starter culture (Lac. lactis subsp. lactis and Lac. lactis subsp. cremoris) is added at a rate of 1 mL 100 mL–1. When concentrated starter cultures are used, the doses employed are recommended by the manufacturer. It is the normal practice in cheesemaking to use starter cultures to ensure a slight acid fl avour, a weak body and a crumbly texture to the cheese. The added rennet should coagulate the milk in 30–40 min, and the dose used depends on its strength and the recommendations of the supplier. The rennet may be liquid or powder, which requires dilution in chlorine-free water, and should be added slowly to the milk. A lyre is used to cut the coagulum slowly along the length of the cheese tank followed by horizontal cutting. The grains should be ~1.0–1.5 cm in size, and the titratable acidity of the whey is equivalent to two-thirds of the initial acidity of the milk. After cutting, the curd should be slowly stirred/rested in repeated sequences as described above for Minas Frescal cheese. After 20 min of stirring, the curd and whey mixture is slowly heated (i.e. 1°C every 2–3 min) to 36–37°C under continuous agitation. Forty to fi fty minutes after completion of cutting the coagulum, the curd mass should be slightly wet and soft. The curd is prepressed immediately in a whey drainage press for the production of close-textured cheese. Alternatively, for an open-textured cheese, the curd mass should be triturated (i.e. rubbed), cooled and then prepressed; the pressure applied should be equivalent to twice the weight of the curd or 0.28–0.35 MPa in the drain press for a duration of 15–20 min. Afterwards, the mass of pressed curd is cut into 1.0–1.2 kg portions, transferred to cylindrical moulds fi tted with a follower to facilitate whey drainage or lined with a cheesecloth. The fi lled moulds are prepressed again at 0.14 MPa for 30 min, which is equivalent to ten times the weight of the moulded curd. Later, the cheese is turned upside down inside the mould, and pressed again at 0.21 MPa for 90 min. In the case of a manually operated press, the pressing time should be 10–18 h at 0.28 MPa or 20 times the weight of the cheese. At the end of pressing, when the pH reaches 5.1–5.2, the cheeses are removed from the press, demoulded, the cheesecloth is removed, and the cheeses are then pressed again for 15 min followed by brining (20 g NaCl 100 mL–1) at 10–12°C for 24 h. Subsequently, the cheeses are dried in a cold chamber (i.e. 70% relative humidity (RH) at 10–12°C for 24–48 h). Maturation of the cheese takes place in a cold chamber at 10–12°C and 85% RH and, during the fi rst 10 days, the cheeses are turned daily. During the same period, the cheeses are washed and dried and, afterwards, they are packed using plastic laminates. Maturation of the cheese continues for a further 20 days at 10–12°C in order to develop the desired fl avour and consistency in the product. The cheeses are then retailed or stored at 2–4°C. An illustration of Minas Padrão cheese is shown in Fig. 7.4, whilst the compositional quality of the traditional or light variants is shown in Table 7.2.

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Meia Cura Meia Cura cheese is a hybrid variety that has characteristics between the Minas Padrão and Prato cheeses (see Fig. 7.4). It does not have any Brazilian legal defi nition, and it is recognised by many producers as Minas Padrão cheese. Each cheese is cylindrical and weighs between 0.5 and 1.2 kg. It has a slightly thick, yellowish crust, a smooth consistency, white-creamy colour and a fl avour that ranges from slightly acidic to mild. The cheese yield is similar to Minas Padrão cheese, as are the manufacturing stages, but the coagulation of the milk is at 32°C for 35–45 min. After cutting the coagulum, the curd is stirred slowly for a short time, followed by the stirring/resting sequences as described earlier for Minas Frescal cheese. After 20 min of stirring, 20–25% of the whey is removed (i.e. equivalent to the volume of milk used) and replaced slowly with an equal amount of water at 75–80°C. The curd/diluted whey mixture is heated to 38–39°C, increasing by 1°C every 2–3 min, and stirring is continued for 50–60 min after the end of the cutting stage. This method of handling the curd allows the cheese to have a smooth fl avour. Subsequently, the curd is prepressed, moulded, pressed again, brined, matured, packaged and stored following the same method of manufacture of Minas Padrão cheese.

7.2.3 Prato cheese Traditional process The fi rst Brazilian dairy industry was established in 1888 in Mantiqueira, Minas Gerais. It was a doctor, Carlos Pereira de Sá Fortes, who imported from Germany and Holland the industrial equipment needed to construct a dairy factory, with the aim of making a semicooked Dutch-type cheese (González, 1999). Hence, Prato cheese originally developed within the dairy industry; moreover, the curd needs to be partially cooked or scalded, which is diffi cult for ‘home’ manufacture (Oliveira, 1987). According to the MERCOSUR, which approves the technical specifi cations, identity and quality of Prato cheese, the product is a matured variety of cheese and produced by coagulating the milk by means of rennet and/or other enzymes, and acidifi cation of the milk by the action of specifi c lactic acid bacteria (MERCOSUR, 1996). The manufacture of Prato cheese includes the preparation of a semicooked curd by partially replacing the whey to control the level of acid development in the product, and washing the curd with hot water; the curd mass is prepressed in the whey, moulded, pressed, brined and fi nally matured. The maturation period should be at least 25 days. Prato cheese has a great commercial value in Brazil, and the method of manufacture is well established and standardised (Oliveira, 1987). Although this type of cheese has been adapted from European technologies, variants of Prato cheeses are evident in Brazil. For example, the product may be designated in accordance with its form and weight. The best-known variants are the Cobocó, which is cylindrical in shape, and Lanche, which is loaf shaped and suitable for sandwiches. There are also other variants known as Esférico or Bola. The different variants of Prato cheeses can be made in different sizes, generally weighing 0.4–3.0 kg according to

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Fig. 7.5 Different variants of Brazilian Prato cheeses. (1) Prato Lanche or sandwich variety, (2 and 3) Prato Cobocó.

the variety (Albuquerque, 1994a, 1994b; Oliveira, 1987). The Lanche and Cobocó variants of Prato cheeses are shown in Fig. 7.5. The cheese is produced by enzymatic coagulation of the milk with the addition of a yellow colour (Urucum), which gives the cheese its typical colour (Furtado & Lourenço Neto, 1994). In addition, Prato cheese has a soft texture and smooth ﬂ avour due to the method used to make the product; the ability to slice the cheese is another characteristic of the product – in Brazil, this type of cheese is mainly consumed in sandwiches. The yield of cheese is about 1 kg from 9.0–9.5 L of milk, and the manufacturing stages of Prato cheese are illustrated in Fig. 7.6. Two different pasteurisation processes for the milk are widely used in Brazil during the manufacture of Prato cheese. However, the use of a plate heat exchanger (PHE) for heating the milk indirectly is more commonly used in large dairy factories, whilst the use of steam injection into the milk is only practised in small dairy plants (Ventura et al., 1984). Pasteurised milk (i.e. fat content between 3.4 and 3.6 g 100 g–1) is cooled to 36°C and coagulated after the addition of NaCl solution (e.g. 50 g 100 mL–1) at a rate of 0.4–0.5 mL L–1. Urucum extract (0.05–0.1 mL L–1), and potassium or sodium nitrate are also added before coagulating the milk. The latter compounds are used as a preservative, and can be used in Prato cheesemaking at a maximum amount of 50 mg kg–1 of cheese according to the Brazilian Standard (BS, 1998). Although nitrate is used widely in the industry to avoid cheese blowing, lowering the pH to 5.6 by using lactic starter cultures and employing Good Manufacturing Practice (GMP) during the production, storage and retailing of the cheese are adequate measures to preserve the product without the addition of a preservative.

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Milk selection & standardisation (3.4–3.6 g fat 100 g –1)

Pasteurisation (72ºC for 15 s)

Milk setting (32ºC)

CaCl2 NaCl (0.4–0.5 mL L–1 50% conc.) Starter culture (0.5 mL 100 mL–1) Urucum extract (0.05–01 mL L–1) Rennet Potassium nitrate (50 mg kg–1 cheese)

Milk ripening

Renneting (32–35ºC for 30–40 min)

Cutting

1º agitation (15 min)

Whey off (30–40%)

Cooking (winter:39–40ºC; summer: 40–41ºC)

2º agitation (20–30 min)

Prepress (15–20 min) Brining Moulding (20 g NaCl 100 mL–1 at 10–12°C for 24 h)

1st pressing (30 min at 0.21–0.41 MPa) Drying nd 2 pressing (24 h) (90 min at 0.21–0.28 MPa)

Maturation (12–14ºC for 60 d)

Fig. 7.6 General scheme illustrating the different stages of manufacture of Prato cheese.

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The addition of a starter culture is carried out after the preparation of the milk for cheesemaking. Starter cultures are used at different inoculation rates, ranging between 0.5 and 2 mL 100 mL–1 of milk. The starters (e.g. blends of Lac. lactis subsp. cremoris, Lac. lactis subsp. lactis, Leuconostoc mesenteroides subsp. cremoris, Lactococcus lactis subsp. lactis bv. diacetylactis) should be homogeneous to allow uniform distribution in the milk, and they are normally added to the milk while fi lling the cheese vats/tanks (Furtado & Lourenço Neto, 1994). The rennet is added to the milk at 32–35°C after slight development of acidity, and should coagulate the milk within 40–45 min, followed by cutting the coagulum. The titratable acidity of the whey should correspond to two-thirds of the milk acidity at the moment of coagulation. The coagulum is cut into cubes of 0.4 to 0.5 cm – similar to a grain of corn (maize). After cutting, the curd particles are allowed to rest to induce particle contraction and whey expulsion. After 15 min, the curd/whey mixture is stirred slowly for a short duration to minimise the coalescence of the curd particles, followed by replacing 30–40% of the whey with water at 70–80°C. Fast agitation of the curd/diluted whey mixture is performed when the hot water is added, and the volume of water used is 15–20% of the milk used for cheesemaking. Afterwards, the curd is scalded to 39–40°C in winter or to 40–41°C in the summer. If necessary, indirect heating should be used to reach the desired temperature, for example steam injection into the water jacket of the cheese vat. Stirring is continued for 60–80 min after cutting the coagulum to ensure proper dryness and fi rmness of the curd particles. At this stage of production, the characteristic of the curd mass varies depending on the desired fi nal moisture content of the cheese. This aspect will, as expected, infl uence the yield of the cheese. Another factor that can also infl uence the desired characteristic of the curd mass is the texture of the cheese in relation to consumer preferences as to how the cheese is consumed (sliced, grated or cut at the table). The texture of the cheese can be manipulated by the brining time, duration of maturation and storage period of the cheese before consumption (Anonymous, 1993). The curd mass is prepressed in the whey for 15–20 min, followed by mould fi lling using perforated plastic moulds and pressing for a duration of 30 min at 0.14–0.21 MPa to promote further whey drainage. The cheeses are turned in the moulds, and the second pressing commences for 90 min at 0.21–0.28 MPa. The cheeses can be left in the moulds until the next day or until the pH reaches 5.5–5.7, which should be 6–8 h after the addition of the starter culture to the milk. Then, the fresh cheeses are immersed in the brine solution (containing about 20 g NaCl 100 mL–1) at 10–12°C. The duration of brining varies depending on the shape and the weight of the cheese; for example, a product weighing 3 kg may be brined for 48 h, but the industrial practice is to keep the cheese in the brine for 24 h. After brining, the cheeses are dried for 24 h in a cold chamber, packed into thermo- formed plastic pouches and matured at 12–14°C for ~60 days in order to develop the textural and fl avour characteristics of the cheese. In practice, the cheeses are sold very young, that is, a few weeks after production, and such products may be considered as ‘mild’ Prato because maturation is incomplete. Table 7.2 illustrates the typical chemical composition of Prato cheese produced in Brazil.

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Ultrafiltration (UF) process In Brazil, Prato cheese is not yet produced from UF milk. Although the advantages of using the MMV method for making certain cheese varieties have been well documented by Maubois et al. (1969), it is technically difﬁ cult to concentrate the milk by UF to the degree required for the production of hard and, to a lesser degree, semihard cheeses. The use of milk partially concentrated by ultraﬁ ltration in the manufacture of semihard cheese, for example Prato, resulted in lower yields than by MMV (i.e. the chemical composition of the concentrated milk is similar to the cheese), but higher than using unconcentrated milk (Spadoti et al., 2003). Prato cheese made from UF milk was high in acidity, moisture and total protein, but had a lower fat content when compared with a product made using the traditional process (Narimatsu et al., 2003).

7.2.4 Rennet cheese The availability of milk and the manufacture of analogue products, especially cheese, are of great economic importance to small producers in the North Eastern States of Brazil (e.g. Ceará, Pernambuco, Paraiba, Bahia and Rio Grande do Norte). Low- income families on small farms usually manufacture this type of cheese, whilst the small and medium producers dominate milk production. Family enterprises consist of milk production units where 97% of the total volume of the milk produced is made into cheese in Pernambuco, and each unit produces <700 L of milk daily. In addition, the formal milk industry in the North Eastern part of Brazil used to compete for the raw milk, and the small milk producers started to manufacture Rennet cheese, butter cheese, and butter, sweet and condensed milk (known in South America as Doce de Leite), and also to compete for the raw milk itself. As a consequence, many small cheese production units have been established, and create a modest income for the region. Incidentally, Rennet cheese has been made for about a century in the North Eastern States of Brazil, mainly as a way of preserving milk for sale at local fairs. Rennet cheese is considered the main product of the milk chain in Brazil, and the annual volume of cheese production is shown in Fig. 7.1. Consumption of Rennet cheese is an ancient tradition, and very small milk producers maintain this tradition and make the cheese at home. In fact, small cheese production factories have started to implement basic hygiene to manufacture this cheese variety. At present, the estimated cheese production in Pernambuco is ~10 400 tonnes, which is equivalent to 15% of local cheese consumption, and 7% of the total cheese production is Rennet cheese. Rennet cheese (sometimes known as Coalho cheese) is made by coagulating the milk using rennet or any other coagulating enzymes, with or without the presence of selected lactic acid bacteria. It is a semihard cheese that is usually matured, but is also consumed fresh within 10 days of manufacture. The product has a soft rind, and the body has an open texture with a slightly salty and sour taste. The shape of the product is cylindrical or rectangular, and the weight is 0.5–1.5 kg (BS, 2001). The moisture content of Rennet cheese ranges between medium and high, and the

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fat-in-dry matter (FDM) content varies from 37 to 60 g 100 g–1. The body characteristic of this semihard cheese is elastic and the texture is soft. Rennet cheese manufacture should follow speciﬁ cations laid down in Brazilian law in terms of its microbiological population and macroscopic and microscopic aspects (BS, 2001). When homemade cheese is manufactured, sour whey (i.e. from the previous day’s production) is added to raw whole milk, and coagulated with rennet or with an enzyme extracted from a rodent (Mocó); coagulation time is ~15 min at 37°C. Subsequently, the coagulum is cut with a knife, stirred by hand with a spoon, and drained of all the whey. Salt is added to the curd at the rate of 0.6 g 100 g–1, and the curd is then moulded in wooden moulds lined with a cheesecloth, and pressed by hand (Fig. 7.7). Rennet cheese is kept in the mould for 24 h and, when removed from the mould, is air dried. In the industrial method of Rennet cheese manufacture, milk is pasteurised and sour whey is added at the rate of 1–2 mL 100 mL–1. Commercial rennet is used to obtain coagulation in 40 min, and ~70% of the whey is withdrawn, heated (i.e. by addition of hot water or injection with steam) and poured over the curd to scald to 45°C (semi-cooked cheese) or 45–55°C (cooked cheese). The curd is then moulded and pressed (i.e. ﬁ rstly by hand and afterwards mechanically) overnight or for 2 days. The fresh cheese is stored at 10–12°C for almost 10 days, or it can be matured for up to one month at room temperature. Storage can be extended for up to one year, but in this case it becomes very dry. Rennet cheese is wrapped in paper or plastic bags, and sold at local fairs, beaches and also consumed during a barbecue (Fig. 7.4). The composition of Rennet cheese is shown in Table 7.2.

(a)

(b)

Fig. 7.7 Pressing the curd by hand (a) and moulding (b) of Rennet cheese. Reproduced in colour as Plate 2, after page 236

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7.3 Chilean dairy industry with particular emphasis on cheese production 7.3.1 Introduction The Ofﬁ ce of Studies and Agricultural Policies (ODEPA) of the Ministry of Agriculture of Chile publishes annual reports (i.e. the Milk Bulletin) regarding the dairy situation in the country, which includes milk production and utilisation of milk in the manufacture of different dairy products. Figure 7.8 shows the geographical location and the diverse areas of milk production in Chile. Cow’s milk is produced in: (a) the Central zone (e.g. Metropolitan region and its surrounding areas); (b) the South Central zone, i.e. region VIII, which is located 250 miles south from Santiago; and (c) the Southern zone, consisting of regions IX and X (which are around 400 and 500 miles south from Santiago), notably in Valdivia, Osorno and Chiloé districts – these districts are the largest area of milk production and includes a number of dairy factories. The pattern of annual milk production and the volume used in the manufacture of cheese between 1993 and 2003 is shown in Fig. 7.9. It is evident that a substantial volume of the milk is not processed in dairy factories, but on farms and/or at home for cheesemaking. During the same period, the growth of milk collection in Chile reached ~58% of total milk production (i.e. 4.7% annual growth rate), and cheese production accounted for 65% of milk received at dairy factories (equivalent to a 5.1% annual growth rate). In 2003, the utilisation of milk received at dairy factories in Chile for the manufacture of different dairy products is shown in Fig. 7.10 (ODEPA, 2004a). Cheese and milk powder are the most important dairy products manufactured locally at the present time. Milk utilised for cheesemaking in 2003 amounted to 568 million litres, to produce 7500 and 53 000 tonnes of fresh and matured brined cheeses, respectively; this is equivalent to 36% of the total milk processed in factories. Prior to the 1970s, Chile relied entirely on the importation of dairy products, but since then there has been a slow growth in locally manufactured dairy products – the annual growth rate has been ~0.34%. As a consequence, Chile was highly dependent on imports of dairy products, which averaged up to 67% of the national production. However, by 2000 this trade was evenly balanced, with 3057 tonnes of cheese exported, and 3115 tonnes imported. At present, there is a clear trend of increasing exports of dairy products, which is accelerated by new trading agreements. Increased exports of dairy products have great potential for enlarging the national milk industry; current availability of milk per capita is 135 L per annum. In the mid-1990s, average earnings from dairy exports were about U$17.0 million, whereas in 2001 and 2003 they were U$44.5 million and U$54.8 million, respectively. Exports have traditionally gone to Brazil, Bolivia, Peru, Argentina, Mexico and USA; in 2002, 98% of the cheese exports went to Mexico, while in 2003 other markets became important, such as Cuba (10.5%), Venezuela (1.85%), Bolivia (2.1%), and Peru (0.6%), in addition to Mexico (85%) (Anonymous, 2004b; Anrique et al., 1999, 2004; Dirven & Ortega, 2001; ODEPA, 2004b; Savello, 2003). The industrial production of dairy products is focused on 26 dairy factories that

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Tarapacá(I) P A Antofagasta (II) C I F Atacama (III) I 29˚ 20’ C Coquimbo (IV)

Valparaíso (V) Metropolitana Libertador General Bernardo O’Higgins (VI) O Maule (VII)

C Bío-Bío (VIII)

E Araucanía (IX) A Los Lagos (X) N

44˚ 04’

Aisén (XI)

Magallanes (XII)

ANTARCTIC

Fig. 7.8 Geographical location of dairy production units in Chile.

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2400 2200 2000 1800 1600 1400 1200 1000

Volume (millon L) (millon Volume 800 600 400 200 0 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 Year milk reception milk used for cheese milk production

Fig. 7.9 The total volume of milk production, reception (processing) and milk used in cheesemaking in Chilean dairy factories between 1993 and 2003. Data compiled from ODEPA (2004a).

Others Fluid milk 1% 20% Cheese 311 36% 568

139 526

Milk powder Yoghurt 34% 9%

Fig. 7.10 Milk utilisation for the manufacture of major dairy products in Chile in 2003. Data compiled from ODEPA (2004a). Note: the numbers in segments represent million L used to manufacture the product.

belong to 15 companies located between Santiago and the X region, four of which are cooperatives, and the rest are societies and private enterprises. Table 7.3 shows the pattern of milk production in Chile between 1993 and 2004, and the volume of milk used for the manufacture of dairy products in large factories, as well as the total volume of milk used in cheese production. Table 7.4 shows that 13 out of the 26 dairy factories produce matured cheese, and only 6 factories produce fresh cheeses.

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Table 7.3 Milk production, reception at factories and utilisation in cheesemaking between 1993 and 2002 in Chile

Milk Ripened cheese Fresh cheese Milk reception Cheese milk Cheese milk production production production Year (million L) (million L) (×million L) (% of milk received) (×1000 tonnes) (×1000 tonnes) 1993 1650 1121 392 35 36 6.6 1994 1750 1236 420 34 39 6.9 1995 1850 1358 438 32 41 5.9 1996 1924 1406 453 32 42 6.3 1997 2050 1497 472 32 44 7.1 1998 2080 1530 503 33 47 7.6 1999 2050 1470 483 33 45 7.0 2000 1990 1447 483 33 45 7.2 2001 2190 1637 540 33 50 7.2 2002 2170 1605 568 35 53 7.3 2003 2100 1563 568 36 53 7.5 Data compiled from ODEPA (1994 to 2004a).

Five dairy companies produce 82% of the total volume of matured cheese, the most relevant companies being Colún (34%), Soprole (23%) and Cumelen-Mulpulmo (13%) (Anonymous, 2004b; Esnaola, 2003). With increased local manufacture of different cheese varieties, Chilean consumers have the option to purchase a wide range of cheeses (Fig. 7.11). Cheese production over the last decade has increased every year, and it is possible to suggest certain factors that have contributed to this success (Dirven & Ortega, 2001; Savello, 2003): • opening of new niche markets for new varieties of cheeses; • local development and adoption of latest production technologies by means of patents, which has given the opportunity for diversiﬁ cation, standardisation and greater improvement in the quality of cheeses; • enhanced local research and development of new varieties of cheeses; • application of modern commercial and advertising techniques in marketing of cheeses; • stability of the national economy; • approved international agreements with countries that have large potential commercial markets for cheeses.

Cheese production in Chile has developed at three different levels: (a) industrial production, (b) on-farm production, and (c) home production (Brito, 1999; Dirven & Ortega, 2001). However, one aspect that has played a major role in the development of the cheese industry is centralisation of small factories into larger units of production, such as Soprole, Colún, Dos Alamos, Loncoleche, Lechera del Sur and others. The structure of most of the dairy factories is as enterprise conglomerates consisting of more than one production unit; several of them are multinational, whilst

11405124601_4_007.indd405124601_4_007.indd 223232 117/05/20067/05/2006 12:05:1212:05:12 11405124601_4_007.indd 233 4 0 5 1 2 4 6 0 1 _ 4 _ 0 0 7 . i n d d

2 3 3

Table 7.4 Milk reception (processing) and cheese production at the main Chilean dairy factories in 2003

Brined matured cheeses Fresh cheeses Dairy plants Milk reception (million L) Production (×1000 tonnes) Cheese milk (% of milk used) Production (×1000 tonnes) Cheese milk (% of milk used) Colún 280 18.0 34.3 0.3 4.0 Soprole 354 12.0 22.9 5.4 71.3

Cumelen-Mulpulmo 74 7.0 13.3 Brined CheesesandAnaloguesofLatinAmericanOrigin Chilolac 33 3.0 5.7 Loncoleche 210 3.0 5.7 Agrícola Cuinco Ltd 22 2.0 3.8 Cafra 33 2.0 3.8 Quillayes 35 2.0 3.8 1.3 17.2 Parmalat 102 1.0 1.9 Vitalac 12 0.9 1.7 0.4 5.3 Calan 19 0.9 1.7 0.07 0.9 Lacteos Puerto Varas 18 0.6 1.1 0.1 1.3 Campo Lindo 1 0.1 0.2 Total 1193 52.5a 100.0 7.57b 100.0 a Milk utilised in cheesemaking is equivalent to 525 million L. b Milk utilised in cheesemaking is equivalent to 38 million L. Note: no entry indicates that the cheese variety is not produced. Data compiled from ODEPA (2004a). 233 117/05/2006 12:05:12 7 / 0 5 / 2 0 0 6

1 2 : 0 5 : 1 2 234 Chapter 7

Fig. 7.11 Different cheeses marketed in Chile. Reproduced in colour as Plate 3, after page 236

others are cooperatives. In general, dairy factories manufacture several products and, within the same factory, different cheeses are produced (e.g. fresh, semihard, hard and mould ripened). Most of the dairy factories are medium in size and employ modern systems of cheese production (i.e. continuous or semicontinuous systems). In addition, these factories adopt improved quality control schemes to monitor cheese production and employ specialised dairy personnel (i.e. laboratory technicians and dairy technologists). As a consequence, the best quality cheeses are produced in these factories, which have the tendency to standardise the manufacturing stages, maintain process efﬁ ciency, ensure high performance and encourage permanent product development (Anonymous, 2004b; Anrique et al., 1999, 2003; Brito, 1999; Esnaola, 2003; ODEPA, 2004b; Savello, 2003). The production of cheeses at farm level depends particularly on the milk prices paid to dairy farmers. In the mid-1980s, as a result of a fall in prices to producers, a large number of cheesemaking units were established, but they had great difﬁ - culty in maintaining good product quality. However, Universidad Austral de Chile provided technical support, and product quality in most of these cheese production units was improved; the successful cheesemakers became part of the industrial sector, but others have yet to improve their production systems (Anonymous, 2000a; Brito, 1991; Brito et al., 1991; Dirven & Ortega, 2001; Esnaola, 2003; Schöbitz et al., 2001). One hundred on-farm cheese factories were registered, and produced principally 12 000 tonnes of farm-type Chanco cheese, which is also known as ‘creamy’ cheese (Fig. 7.12). The capacity of individual on-farm cheese production units varies

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Fig. 7.12 Farm-made Chilean Chanco cheese.

from 500 to 12 000 L d–1, but some units are capable of handling 25 000 L d–1 or more. In general, the on-farm cheesemaking units may be classiﬁ ed into three categories, based on their daily handling capacities: (a) large (12% of the total), able to handle 8 000 L d–1 or more; (b) medium-size (24% of the total), which can process 2 000–8 000 L d–1; and (c) small (60% of the total), which can process less than 2 000 L d–1. Only the largest factories on-farm use technical practices in cheesemaking and employ trained dairy personnel. Although this situation has been improving gradually in recent years, there is still a wide variation in the quality of the cheese, including the sensory properties of the products, which is the result of inefﬁ ciently controlling the cheesemaking process (Brito et al., 1991; Molina et al., 1996; Schöbitz et al., 2001). Typically, the on-farm cheese factory is structured so that the head of the family manages the production unit, and hired staff perform the activities of milk analysis and cheese production; the products are mainly sold in small nearby shops, whilst some factories have their own retail shop, especially in highly populated zones of the country. In general, these production units utilise their milk for cheese production but, in some instances, they buy milk from their neighbours. By contrast, homemade cheesemaking is characterised by being very small and seasonal and, consequently, it takes place in the season of high milk production (late spring and early summer). These products are made by small milk producers of the zone near Santiago, in the South of the country (mainly in the VIII to X regions), and in the area around the island of Chiloé, which is in region X. These products are manufactured in houses, sheds or warehouses, which are not devoted exclusively

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to dairying, and they are sold in the same establishment, in fairs, at nearby markets or to tourists and holiday centres. The cheese producers and their family handle the animals, milk the cows and process the milk and, thus, manage production as well as the retailing; these are truly family businesses (Anonymous, 2000a; Brito, 1999).

7.3.2 Cheese varieties produced in Chile Historically, production of different cheese varieties has never existed in Chile and, until 25 years ago, only semihard cheeses were produced. Some of these cheese varieties are known as Chanco and Gouda-type (Gauda) and, at present, they still represent an important volume of production (Esnaola, 2003). In the 1980s, special cheese varieties were imported from different European countries (e.g. Denmark and France), and the prices were very high; at present, large volumes of such cheese varieties are locally produced (Fig. 7.13). For example, Quesillo, Chacra and Queso Fresco cheeses are traditional fresh (rennet) varieties, but some fresh cheeses are acidiﬁ ed using starter cultures except Quesillo variety (spread cheeses, cheese rolls with added plant seeds or spices) are produced in Chile as well. At an industrial level, the Chilean Gauda cheese predominates; it has little similarity to the Dutch Gouda, and occupies ﬁ rst place in terms of volume of production, followed by Chanco. The annual production of these two types of cheese totals 47 000 tonnes, which is 85–90% of the national industrial cheese production (Dirven & Ortega, 2001; Esnaola 2003). The remaining cheese production in this group comprises cheese varieties for grating, such as Reggianito (Reggiano-type), Red Ball (Edam-type), Gruyère-type, Cheddar-type, and other varieties including mould-ripened cheeses (e.g. Camembert, Brie and blue vein), Piamont, Tilsit, Dutch and Mozzarella. The increase in production of the latter type of cheese is due to the rise in demand by the fast-food chains and the international chains that sell ready-made foods, and

Fig. 7.13 Special Chilean cheese varieties produced locally and imported.

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include the use of Mozzarella cheese in the preparation of sandwiches, pizzas and empanadas (Esnaola, 2003; Savello, 2003). Traditional Chanco cheese is mainly produced on-farm, and the annual volume of production has increased to 13 500 tonnes in recent years (Esnaola, 2003). However, cheese made from goat’s milk is only produced in the Northern zone of the country (i.e. IV region), which is located 250 miles north of Santiago. The national cheese specifi cations are fairly recent (INN, 1999a, 1999b) and, unlike the specifi cations of other dairy products, the Chilean cheese industry was until 1999 governed by international specifi cations, such as the Codex Alimentarius of the Food and Agriculture Organization (FAO) of the United Nations, International Dairy Federation (IDF), and MERCOSUR. Furthermore, in Chile, there are some general regulations, for example, the Sanitary Regulation of Foods (Anonymous, 2000b) and, recently, the Environmental Law that regulates the treatment of industrial wastes (Palma, 1997).

7.3.3 Main brined cheeses produced in Chile The most common industrially made brined cheeses in Chile are Chanco and Gauda (Dutch-type); all the other varieties, such as Mozzarella and Grana, will not be reviewed here.

Chanco According to IDF (1981), the Chilean Chanco cheese has a semi-soft consistency and creamy body, and the texture contains an abundance of small and irregular eyeholes. The weight of the cheese ranges between 8 and 10 kg; it is produced from cow’s milk, and is normally matured for 12 to 30 days (Fig. 7.14). This type of cheese is also known by different names, such as Mantecoso, Los Alerces, Llifén, Ranco, Los Alpes, El Rincón, Campo Bueno, Quilque and Los Fundos. The district of Chanco, after which the cheese is named, is a small coastal location in the region of Maule, about 240 km south of Santiago. In the 18th century, the Spanish colonialists commented on the Chilean daily meals as follows: ‘the lunches include a fi rst course where olives, butter, radishes and tuna are served and also cheese; Chanco is regarded as the best variety’ (Pereira, 1977). Dalgalarrando (1932) and Avendaño (1936) defi ned and characterised Chanco cheese based on its sensory attributes, chemical composition and form; they also indicated that the cheese should be made from raw cow’s milk. Later, Rosemberg (1940), Peñafi el & García (1947) and Ramirez (1949) reported their fi rst experiences of the quality of Chanco cheese made from pasteurised milk and, thus, introduced the use of pure starter cultures, such as Lac. lactis subsp. lactis to acidify the milk, and liquid commercial rennet instead of ‘manzanilla’ (natural calf rennet maintained in whey with salt) which was used for cheesemaking. These aspects introduced a fundamental technological advance into the manufacture of cheese, and became common practices during the birth of the Chilean dairy industry in the 1950s. Gradually, advances in the technical knowledge of the cheese process were imple-

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Fig. 7.14 Industrially made Chilean Chanco cheese. Reproduced in colour as Plate 4, after page 236

mented, including improvements in the quality of the product and microbiological hygiene during manufacture. At present, Chanco cheese is made at industrial level using selected cow’s milk that is standardised and pasteurised. The product has retained its creamy characteristic, primarily due to the technical studies by Royo & Adamik (1974), which were conducted at the Universidad Austral de Chile. Chanco cheese is slightly yellow in colour, has a ﬁ ne thin layer, but a hard dry skin; it should not show any fungal growth or scratches on the surface, and is rectangular in shape with irregular edges. Table 7.5 shows the characteristics of the product based on the National Speciﬁ cation

Table 7.5 Physical and chemical speciﬁ cations (g 100 g–1) of Chilean Chanco cheese

Farmhouse Chanco cheese Factory-made Constituent Short-maturation Matured Chanco cheese Moisture 46–50 44–48 44–48 Dry matter 50–54 52–56 52–56 Fata 28 28 25 Fat-in-dry matter (FDM)a 52 50 45 Moisture-in-fat-free cheese (MFFC) 65–69 58–66 61–67 pH 5.2–5.4 5.2–5.4 5.2–5.4 Nitrate (mg kg–1)b –5050 Phosphatase test –ve –ve –ve aValues quoted are for minimum level. bValues quoted are for maximum level. Data compiled from INN (1999a)

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Norma Chilena No. 2090 (INN, 1999a). Chanco cheese is also produced in on-farm factories from pasteurised milk. The primary objective during the manufacture of Chanco cheese is controlled acid production in the milk. For example, the pH of the milk is reduced from 6.6–6.8 to 5.8–6.0 in 5–6 h. Such an acidifi cation profi le will ensure that the milk constituents are properly concentrated in cheesemaking; for example, if the moisture of the milk is 88 g 100 g–1, the anticipated moisture content of the cheese after 28 days of maturation is 44–48 g 100 g–1 (INN, 1999a). Industrial cheese production in the larger factories uses standardised and pasteurised milk, commercial coagulant and starter cultures. The cheesemaking process is normally carried out in round-ended closed vats (15 000–25 000 L capacity), is fully automated and under the supervision of a technical cheesemaker. Alternatively, smaller and open rectangular vats (4 000–5 000 L capacity) are used, and should be constructed with a double jacket connected to cold water and steam inlets. In this case, several workers under the supervision of a technician or a senior cheesemaker will carry out the process of cheesemaking. Rennet is used to coagulate the milk at 30–32°C, and the coagulation time ranges between 35 and 50 min (Fig. 7.15). Coagulants, such as genetically modifi ed rennet (Chymax and Chymogen), are widely used at present, but fungal and 50/50 (chymosin–pig pepsin) were commonly used in the past to coagulate the milk. However, blends of mesophilic starter cultures consisting of Lac. lactis subsp. lactis, Lac. lactis subsp. cremoris, Lac. lactis subsp. lactis bv. diacetylactis and Leuconostoc spp. are used during the manufacture of Chanco cheese. Afterwards, the coagulum is cut into cubes with blades spaced at 10 mm and agitated; this is followed by a partial withdrawal of the whey (30% of the initial milk used) and its replacement with hot water (i.e. half the volume of the removed whey) at 65–70°C. The addition of hot water tends to increase the temperature of the curd/diluted whey mixture from ~32°C to ~38°C in about 20 min. The primary function of diluting the whey is to reduce the amount of lactose and, therefore, control the rate of acid development because the product should have a low- to medium-level of acidity. At the right degree of curd fi rmness, the rest of the whey is drained off, and brine solution is added to the curd granules. The granules are kneaded in the salty solution for 10 min, and followed by moulding and pressing (4.9 MPa for 1 h, 9.8 MPa for 1 h or 17.2 MPa for 30 min). This variety of cheese is normally salted by two combined methods: fi rstly, a small amount of fresh brine is added to the curd in the cheese vat (the brine is prepared as follows: 300 g salt is dissolved in 1 L of water, heated to 90–100°C using direct injection of steam and cooled to 40°C; this volume of brine is used per 100 L of cheese milk); and secondly, the pressed cheese is partially brined (i.e. 20°Beaumé or 22 g NaCl 100 mL–1) for 6–8 h. Since the maturation period of the cheese is rather short, this method of salting can ensure rapid salt diffusion into the product and, at the same time, ensure a homogeneous salty taste in the matured cheese. Brining of the cheese allows the formation of a fi ne skin, which serves as a protective layer around the product during the maturation period, both in retailing and at home. Furthermore, the maturation of the cheese takes place in humidity- and temperature-controlled rooms with suf-

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Milk selection & standardisation

Pasteurisation (72ºC at 15 s)

Milk setting (32ºC) CaCl2 Starter culture (0.5 mL 100 mL–1) Milk ripening

Rennet Renneting (30ºC for 30min)

Cutting

1st agitation (20 min)

Whey off (30%)

Curd cooking (36.5–37.5ºC)

2nd agitation (20–30 min) NaCl Curd salting & moulding (36.5–37.5ºC)

Pressing

Salting (6 h)

Maturation (14ºC at 85% RH for 28 d)

Fig. 7.15 Generalised scheme illustrating the manufacturing stages of Chilean Chanco cheese. After Brito (1985).

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ﬁ cient ventilation to allow enough air interchange to cope with the release of volatile components as a result of biochemical degradation of the main milk components (e.g. protein and partial fat hydrolysis), the transformation of lactic acid to lactates, and citrate degradation (Brito, 1985; Royo & Adamik, 1974).

Gauda Not much is known about the history of Chilean Gauda, but it is safe to assume that it is a modifi ed version of the well-known Dutch Gouda. The production of this cheese variant was promoted by European specialists, who apparently initiated industrial cheese production in the mid-1950s. At present, the characteristics of Gauda are different from Dutch Gouda in terms of its chemical composition as well as sensory properties, which were derived mainly from modifying the cheesemaking process of Dutch Gouda. The National Institute of Normalization (INN) is an organisation responsible for the study and preparation of the technical standards of food products at a national level, and it has defi ned Gauda cheese as follows: ‘Chilean product corresponding to a matured cheese made from cow’s milk that has been pasteurised, coagulated by using enzymes and partial acidifi cation of the milk due to the microbial activity of the starter cultures, and matured in a thermo retractile package for a minimum duration of 15 d under controlled conditions’; the physical, chemical, microbiological and sensory properties of the cheese are specifi ed by the National Chilean Standard – NCh No. 2478 (INN, 1999b). In addition, based on the fat content in the product, the cheese is classifi ed as Gauda cheese (full-fat) or Gauda semi-skimmed cheese. The compulsory raw materials include pasteurised cow’s milk (full-fat or semi- skimmed), lactic starter culture, rennet or other appropriate coagulating enzymes, and sodium chloride; in addition, calcium chloride, sorbic acid, colorants, nitrates, salts and other antifungal compound(s) for external application on the surface of the cheese are optional additives. In terms of sensory characteristics, the cheese should be without rind, and have a fi rm body, a close texture with some eyeholes, an elastic consistency, suitable for slicing, a pale-yellow colour and rectangular shape, and weigh between 2 and 15 kg (Fig. 7.16). The product is retailed as full blocks for restaurants and caterers, or sold sliced and/or portioned (500 g or 1000 g), and vacuum packed or with a modifi ed atmosphere packaging (MAP). Table 7.6 shows the physical and chemical specifi cations of Gauda cheese. Like all cheeses, Gauda must fulfi l these specifi cations for labelling of the nutritional constituents. In addition, the cheese should not contain any macroscopic or microscopic impurities or foreign substances of any nature, and must also meet the sanitary requirements corresponding to medium moisture cheeses, which were established by the Sanitary Regulation of Chilean Foods (Anonymous, 2000b; see also Recordón et al., 1982; Royo & Adamik, 1974). The main difference between Chanco and Gauda cheeses is that the latter product is more suitable for slicing and has a fi rmer consistency, whilst Chanco cheese can be easily spread, especially the creamy variant. For this reason, Gauda cheese contains less fat, more moisture and a lower pH than Chanco cheese. Although the manufactur-

11405124601_4_007.indd405124601_4_007.indd 224141 117/05/20067/05/2006 12:05:1912:05:19 242 Chapter 7

Fig. 7.16 Typical Gauda cheeses produced in Chile. Reproduced in colour as Plate 5, after page 236.

Table 7.6 Physical and chemical speciﬁ cations (g 100 g–1) of Chilean Gauda cheese

Constituent Full-fat Reduced-fat Moisture 46–48 48–50 Dry matter 52–54 50–52 Fat-in-dry matter (FDM) 45.0–59.9 25.0–44.9 Sodium or potassium nitrate (mg kg–1)50 50 pH 5.1–5.3 5.1–5.3 Phosphatase test –ve –ve Data compiled from INN (1999b)

ing stages of Gauda and Chanco cheeses are very similar (Fig. 7.17), there are some essential differences that can affect the overall characteristics of these products, as shown in Table 7.7.

Other cheese varieties Chile is also home to traditional fresh cheeses, which are produced from cow’s and goat’s milk. Although they are not brined cheeses, they are brieﬂ y reviewed here for general interest. Both Quesillo and fresh cheeses are made industrially, mainly from UF cow’s milk. Goat’s cheese is produced in small-scale factories; the goat farms are located in

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Milk selection & standardisation

Pasteurisation (72ºC for 15s)

Milk setting (32ºC) CaCl2 Starter culture (1.0 mL 100 mL–1) Milk ripening

Rennet Renneting (32ºC for 30min)

Cutting

1st agitation (20 min)

Whey off (25%)

Cooking (38ºC)

2nd agitation (20-30 min)

Prepress (20 min)

Pressing

Salting (24 h)

Maturation (15ºC at 85% HR for 30 d)

Fig. 7.17 The manufacturing stages of Chilean Gauda cheese. After Recordón et al. (1982).

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Table 7.7 Summary of differences of the manufacturing stages of Gauda and Chanco cheeses that inﬂ uence the overall characteristics of the products

Processing stages Gauda Chanco Fat content in the milk (g 100 g–1) 2.5 3.0–3.2 Amount of starter culture used 1.0 0.5 (mL 100 mL–1) Agitation time after cutting the Shorter (5–8 min) Longer (10–15 min) coagulum Scalding temperature (°C) 38–39 37–38 pH level before salting 5.0 5.2–5.3 Salting One stage brining (see text) Two-stage brining (see text) Prepressing In-vat in the whey None Pressing in the mould Higher pressure for longer duration, Lower pressure for shorter e.g. 9.8 MPa for 30 min, 14.7 MPa for duration, e.g. 4.9 MPa for 30 min or 19.6 MPa for 30 min 1 h, 9.8 MPa for 1 h or 17.2 MPa for 30 min Bulk packaging In vacuum and heat shrink laminate that Not packaged is permeable to gases Rind condition No rind is formed Rind is formed

regions IV (Ovalle, Combarbalá), V (Hijuelas, Quillota, Chincolco) and the area surrounding the Metropolitan Region (Colina, Melipilla); the production season is very short. There are two categories of goat’s cheese: Cordillera cheese, which is a semihard variety produced during the summer season, and the fresh white cheese variety (Brito & Jofré, 1987; Haverbeck et al., 1981; Pinto et al., 1992; Quiroz, 1983).

7.4 Conclusions

The evolution of the South American dairy industry, in particular cheese production, is mainly based on a traditional model compared with the more competitive one using modern technology in Europe, Oceania and North America. Over the past few decades it is evident that milk and cheese production have increased, coupled with an increase in cheese consumption. However, at present some countries in South America have adopted modern cheesemaking technology in order to export the product. The development of the cheese industry in South America, especially in Brazil and Chile, is primarily based on demands from the research institutions, ﬁ nancial agencies supporting research and development, and the government in order to stimulate the following aspects for the future: (a) higher milk and cheese production including increased consumption of dairy products; (b) improvements to produce good-quality milk and cheese; (c) decreasing the costs of milk and cheese production; (d) preservation of traditional products and traditional manufacturing methods; and (e) development of new products and technology.

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Acknowledgement

Marice Oliveira wishes to thank the CNPq and Mr Dirceu Torres from Associação Brasileira das Indústrias de Queijos, São Paulo, and Carmen Brito wishes to thank some of her students for typing the manuscript, and to her family for the pictures and permanent encouragement of her job (Chile).

References

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Brito, C. & Jofré, H. (1987) Introducción de tecnología intermedia en la fabricación tradicional de queso de cabra. Alimentos, 12, 20–23. Brito, C., Jofré, H., Oettinger, G., Haverbeck, J., Molina, L.H., Carrillo B. & Horzella, M. (1991) Diagnóstico de la Producción Actual de Queso Chanco de Campo y Desarrollo de Tecnologías Intermedias para su Producción. In: Diagnóstico Intermedias para su Producción, Informe Final. Ministerio de Agricultura de Chile, Ediciones Universidad Austral de Chile, Valdivia. BS (1996a) Portaria no. 146 de 7/03/1996 – Regulamento Técnico de Identidade e Qualidade de Queijos. Ministério de Estado da Agricultura e Abastecimento e da Reforma Agrária, Brasília, DF. BS (1996b) Portaria no. 352 de 4/09/1996 – Regulamento Técnico de Identidade e Qualidade do Queijo Minas Frescal. Ministério de Estado da Agricultura e Abastecimento e da Reforma Agrária, Brasília, DF. BS (1998) Legislação Comentada de Produtos Lácteos e de Alimentos para fi ns Especiais: Diet, Light e Enriquecidos, Padrões de Identidade e Qualidade, pp. 28–35 and 71–74. Milkbizz, São Paulo. BS (2001) Instrução Normativa 30 de 16/07/2001 – Regulamento Técnico de Identidade e Qualidade de Queijo de Coalho. Ministério de Estado da Agricultura e Abastecimento e da Reforma Agrária, Brasília, DF. Caro, J. & Ortega, E. (2002) Situación del Mercado de Lácteos de los Países Andinos. Proyecto Regional para los países Andinos sobre Políticas y Comercio, Instituto Interamericano de Cooperación para la Agricultura, Lima. Cunha, C.R., Spadoti, L.M. & Zacarchenco, P.B. (2002a) Effect of ultrafi ltration retentates concentration factor on the yield of low fat ‘minas frescal’ cheese. Ciência e Tecnologia de Alimentos, 22, 76–81. Cunha, C.R., Spadoti, L.M., Zacarchenco, P.B. & Viotto, W.H. (2002b) Effect of retentate concentration factor in the composition and proteolysis of low fat ‘minas frescal’ cheese made by ultrafi ltration. Ciência e Tecnologia de Alimentos, 22, 82–87. Dalgalarrando, A.J. (1932) Estudio para estandarizar el queso Chanco. Tesis Ingeniero Agronomo, Facultad de Agronomía, Universidad de Chile, Santiago. Dirven, M. & Ortega, L. (2001) El complejo productivo lácteo en Chile. In: Apertura Económica y (des) Encadenamientos Productivos – Refl ecciones Sobre el Complejo Lácteo en América Latina, pp. 143–208. Comisión Económica para América Latina y el Caribe (CEPAL), United Nations Publication, Santiago. EMBRAPA (2004) Gado de Leite. Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA), Brasília, DF (http://www.cnpgl.embrapa.br). Esnaola, V. (2003) Situación del mercado del queso en Chile. Mercados Agropecuarios, 133, 1–6. FAO (2004) Price of Milk. Food and Agriculture Organization of the United Nations, Rome (http://www.laticinino.net). Furtado, M.M. & Lourenço Neto, J.P.M. (1994) Tecnologia de Queijos, pp. 90–93. Manual Técnico para Produção Industrial de Queijos, Valinhos. Gonzalez, V. (1999) Evolução de acidos graxos livres durante a maturação de queijo Prato e sua infl u- ência na textura. Dissertação de Mestrado, Faculdade de Ciências Farmacêuticas/USP, São Paulo. Gonzalez, V., Gioielli, L.A. & Oliveira, M.N. (1998) Tamanho da amostra e da lubrifi cação na deter- minação da textura instrumental de queijo tipo Minas Frescal. Revista de Farmácia e Bioquímica da Universidade de São Paulo, 34, 109–113. Haverbeck, J., Cartes, M., Horzella, M. & Henriquez, O. (1981) Estudio preliminar del comportamiento de cultivos lácticos mixtos mesófi los en leche de cabra. Alimentos, 6, 5–11. IDF (1981) Catalogue of Cheeses, Document No. 141, 40 pp. International Dairy Federation, Brussels. INN (1999a) Productos Lácteos – Queso Chanco – Requisitos, NCh 2090. Instituto Nacional de Normalización, Santiago.

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INN (1999b) Productos Lácteos – Queso Gauda – Requisitos, NCh 2478. Instituto Nacional de Normalización, Santiago. Lourenço Neto, J.P. M. (1996a) A salga de queijos em salmoura – Parte 1. Leite & Derivados, 6, 37–52. Lourenço Neto, J.P.M. (1996b) A salga de queijos em salmoura – parte fi nal. Leite & Derivados, 6, 16–22. Maubois, J.L. & Mocquot, G. (1975) Application of membrane ultrafi ltration to preparation of various types of cheese. Journal of Dairy Science, 58, 1001–1007. Maubois, J.L., Mocquot, G. & Vassal, L. (1969) Procedé de Traitement du Lait et des Sous-Produits Laitiers. French Patent 2 052 121. Mehaia, M.A. (2002) Manufacture of fresh soft white cheese (Domiati-type) from ultrafi ltered goats´ milk. Food Chemistry, 79, 445–452. MERCOSUR (1996) Regulamento Técnico Mercosul de Identidade e Qualidade do Queijo Prato, Resolução num. 831/96. Mercado do Cone Sul, Brasília, DF. Molina, L.H., Barría, M. & Brito, C. (1996) Características de calidad y sensorial del Queso Chanco de campo del mercado de Chile. Alimentos, 21, 23–25. Narimatsu, A., Dornellas, J.R.F. & Spadoti, L.M. (2003) Proteolysis and melting evaluation on Prato cheese obtained by ultrafi ltration. Ciência e Tecnologia de Alimentos, 23, 177–182. ODEPA (1994) Boletín de la Leche 1993. Ministerio de Agricultura de Chile, Ofi cina de Estudios y Políticas Agrarias, Santiago. ODEPA (1995) Boletín de la Leche 1994. Ministerio de Agricultura de Chile, Ofi cina de Estudios y Políticas Agrarias, Santiago. ODEPA (1996) Boletín de la Leche 1995. Ministerio de Agricultura de Chile, Ofi cina de Estudios y Políticas Agrarias, Santiago. ODEPA (1997) Boletín de la Leche 1996. Ministerio de Agricultura de Chile, Ofi cina de Estudios y Políticas Agrarias, Santiago. ODEPA (1998) Boletín de la Leche 1997. Ministerio de Agricultura de Chile, Ofi cina de Estudios y Políticas Agrarias, Santiago. ODEPA (1999) Boletín de la Leche 1998. Ministerio de Agricultura de Chile, Ofi cina de Estudios y Políticas Agrarias, Santiago. ODEPA (2000) Boletín de la Leche 1999. Ministerio de Agricultura de Chile, Ofi cina de Estudios y Políticas Agrarias, Santiago. ODEPA (2001) Boletín de la Leche 2000. Ministerio de Agricultura de Chile, Ofi cina de Estudios y Políticas Agrarias, Santiago. ODEPA (2002) Boletín de la Leche 2001. Ministerio de Agricultura de Chile, Ofi cina de Estudios y Políticas Agrarias, Santiago. ODEPA (2003) Boletín de la Leche 2002. Ministerio de Agricultura de Chile, Ofi cina de Estudios y Políticas Agrarias, Santiago. ODEPA (2004a) Boletín de la Leche 2003. Ministerio de Agricultura de Chile, Ofi cina de Estudios y Políticas Agrarias, Santiago. ODEPA (2004b) Boletín de Comercio Exterior Silvoagropecuario 2003. Ministerio de Agricultura, Ofi cina de Estudios y Políticas Agrarias, Santiago. Oliveira, J.S. (1987) Queijos: Fundamentos Tecnológicos, pp. 68–70 and 115–120. Unicamp, Campinas. Oliveira, M.N., Lacerra, A.A., Gioielli, L.A. & Baruffaldi, R. (1997) Effetto della temperatura e del tempo di coagulazione del latte sulla consistenza del formaggio ‘Minas Frescal’. In: Ricerche e Innovazioni Nell’Industria Alimentare (ed. S. Porretta), vol. 2, pp. 575–584. Chiriotti, Pinerolo. Palma, M. (1997) Normativa Ambiental – Disposiciones Generales de la Ley No. 19.300 Bases Generales del Medio Ambiente, pp. 13–24. Ediciones Jurídicas, Santiago. Peñafi el, R. & García, R. (1947) Análisis físico y químico de los Quesos Chanco y Holandéz. Tesis Ingeniero Agronómo, Universidad de Chile, Santiago.

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Pereira, S.E. (1977) Apuntes para la Historia de la Cocina Chilena. Editorial Universitaria, Santiago. Pinto, M., Brito, C., Fraser, B., Molina, L.H. & Gómez, C.E. (1992) Composición química de leche de cabra mestiza Saanen. Terra Arida, 11, 138–144. Quiroz, R. (1983) Prefactibilidad económica y comercial de una planta procesadora de Queso de Cabra en la comuna de Lampa. Tesis Ingeniero Agrónomo, Facultad de Agronomía, Universidad de Chile, Santiago. Ramirez, S.C. (1949). La Leche y las Industrias de la Leche. Editorial Zig-Zag, Santiago. Recordón, J., Mortensen, P. & Brito, C. (1982) Guía de práctico de Queso Gouda – curso laboratorio de tecnología de la leche. Magíster en Ciencias y Tecnología de la Leche, Universidad Austral de Chile, Valdivia. Rosemberg, M. (1940) Nuevos estudios tendientes a estandarizar el Queso Chanco. Tesis Ingeniero Agrónomo, Facultad de Agronomía, Universidad de Chile, Santiago. Royo, R. & Adamik, K. (1974) Importantes Principios Tecnológicos de Quesos y Algunos de sus Defectos. Ediciones Universidad Austral de Chile, Valdivia. Savello, P.A. (2003) Descripción General y Desafíos de la Industria Láctea de Chile. Informe Final Consultoría Técnica, Instituto Interamericano de cooperación para la Agricultura (IICA) and Ministerio de Agricultura de Chile, Santiago. Schöbitz, R., Marín, M., Horzella, M. & Carrasco, E. (2001) Presencia de Listeria monocytogenes en leche cruda y quesos frescos artesanales. Agro Sur, 29, 114–119. Spadoti, L.M., Dornellas, J.R.F. & Petenate, A.J. (2003) Evaluation of the yield of Prato cheese obtained by modiﬁ cations of the traditional manufacturing process. Ciência e Tecnologia de Alimentos, 23, 492–499. Ventura, R.F., Furtado, M.M., Wolfschoon-Pombo, A.F., Lourenço, J.P. de M. & Lima, A. (1984) Queijo prato: comparação de fabricação usando leite pasteurizado por sistema de placas e ejetor de vapor. Revista do Instituto de Laticínios Cândido Tostes, 39, 59–70.

11405124601_4_007.indd405124601_4_007.indd 224848 117/05/20067/05/2006 12:05:2412:05:24 Brined Cheeses Edited by Dr Adnan Tamime Copyright © 2006 by Blackwell Publishing Ltd 8 Indigenous Brined Cheese of the Philippines

V.L. Barraquio

8.1 Introduction

The manufacture of soft white cheese from raw carabao’s milk (domesticated Philippine swamp buffalo – a subspecies of Bubalus bubalis L.) is one of the oldest cottage industries in the Philippines. This cheese was reported in the Philippines even before the 20th century (Dulay, 1991). The industry is centred in a number of towns in the provinces of Laguna, Cavite and Bulacan in Luzon island and Cebu, Leyte and Samar in the Visayas islands (Barraquio et al., 2001). The cheese is popularly known as ‘kesong puti’ (local dialect for ‘white cheese’) or Santa Cruz cheese in Laguna province, and ‘kasilyo’ (local dialect for the Spanish ‘quesillo’, meaning ‘small cheese’) in Cavite province. It is an unmatured type of cheese, whitish to creamy in colour, and generally produced from raw carabao’s milk. However, due to the shortage of raw carabao’s milk, the use of cow’s milk alone or in combination with carabao’s milk has become common practice and very popular in recent years (Barraquio et al., 1997). Abomasal extract (rennet), dilute acetic acid or vinegar may be used as the milk coagulant during the manufacture of ‘kesong puti’ (Kisworo & Barraquio, 2003). The production stages were learned from ancestors, and handed down over succeeding generations. Since the method is very crude, no temperature and quantity measurements were done, and all the manufacturing steps and amounts of ingredients were established through experience. Due to differences in manufacturing conditions, cheeses from the different localities vary in texture, fl avour and keeping quality (Bayot et al., 1999). The cheese is marketed locally, packed either in banana leaves or in plastic laminates (Fig. 8.1). The colour of the cheese is infl uenced by the type of milk used in cheesemaking, and it varies from very light yellow or creamy to white. The texture of the cheese is generally smooth and soft depending on the type of coagulant used, method of salting, and the extent of draining of the whey from the curd. Cheeses made with vinegar as the coagulant have a fi rmer body and coarser texture than those made with rennet. Cheeses salted in brine have a fi rm body, while similar products made with salt added to the milk before the coagulation stage tend to be softer. In addition, the fl avour varies from mild to strong, the cheese tastes salty, and consumers’ preference is for products made from carabao’s milk due to the stronger fl avour of the cheese. Also, by using carabao’s milk, the yield of the cheese is higher than when using other types of milk or milk mixtures. Banana leaves are traditionally and widely used as packaging material. The preparation of the banana leaves is as follows: fi rstly, the leaves are wilted by soaking briefl y in hot water, and secondly, the

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Fig. 8.1 White soft cheese – ‘kesong puti’.

cheese wrapped in the leaves are placed in tiers of twos or threes, wrapped in betel nut palm peduncle, and tied-up for ease of peddling (Fig. 8.1). The primary objective of the hot-water treatment of the banana leaves is to make them pliable rather than sanitising them. Recently, the co-operative dairy plants federation of South Luzon and the Dairy Training and Research Institute (DTRI) in the Philippines have recommended the use of plastic laminates for packaging. Nevertheless, the use of banana leaves as packaging material highlights the indigenous nature of the cheese, whilst the choice of plastic laminates over banana leaves is mainly for convenience, sanitation and to differentiate between cheese producers. Both packaging materials allow further whey drainage during distribution, retailing, and until the cheese is consumed. Very recently, cheesemakers in the town of Lumban in Laguna province have started to use microwaveable transparent plastic containers. These cheeses are considered a delicacy in localities where they are produced, and the mass of milk made into soft white cheese in 2003 was estimated at 231, 626 kg (Anonymous, 2003a; personal communication with cheese factories).

8.2 Physicochemical and microbiological quality of the milks used for cheesemaking

Although ‘kesong puti’ is generally made from raw carabao’s milk, the use of cow’s milk or a mixture of carabao’s and cow’s milk has become popular lately for

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cheesemaking due to a shortage in supply of carabao’s milk. In 2002, the populations of milking cattle and carabaos were 1 718 and 2 788 head, respectively. The total milk production during the same period was 7.1 million litres; however, the percentage of production was as follows: cattle 64%, native carabaos, buffaloes and crossbreeds 34.7%, and goats 1.3% (Anonymous, 2003b). It is well established that the quality of the cheese depends greatly on the type and quality of milk used along with other factors, such as differences in manufacturing procedures, sanitary conditions during the production of the cheese, and added ingredients. Data available between 1931 and 2004 showed that raw cow’s milk has a speciﬁ c gravity ranging from 1.025 to 1.030, and the ranges of compositional quality (g 100 g–1) are as follows: fat 3.42–5.55; protein 2.90–5.77; total solids 11.62–15.50; and titratable acidity 0.13–0.20 (Table 8.1). The coliforms and total bacterial counts (TBC) averaged 1 × 104 and 2.4 × 107 colony-forming units (cfu) mL–1, respectively (O.C. Emata & V.L. Barraquio, unpublished data). In addition, raw carabao’s and buffalo’s milk has speciﬁ c gravities ranging from 1.032 to 1.035, and the ranges of compositional quality (g 100 g–1) are as follows: fat 6.40–12.0; protein 2.53–6.30; total solids 16.81–26.2; and titratable acidity 0.12–0.13. Coliform count and TBC were 1.5 × 104 and 1.8 × 109 cfu mL–1, respectively (Table 8.2). The microbial load in milk is rather high, and the poor quality can be traced to bad milking practices and conditions, lack of education and training in hygiene and sanitation, poor-quality water supply, and lack of chilling facilities. The Philippines follow the US standards of 2 × 105 cfu mL–1 for TBC for raw milk, and 3 × 104 cfu mL–1 (or g–1) for TBC for pasteurised milk and other milk products including cheese. The coliform count limit for pasteurised milk and milk products including cheese is 10 cfu mL–1 or g–1. There is no coliform count limit for raw milk.

Table 8.1 Physicochemical and microbiological quality of raw cow’s milk in the Philippines

Constituent Santos & Reantaso (1940) Villegas Castillo Palad Davide O.C. Emata & (g 100 g–1) and Ascalon & Cruz et al. et al. et al. V.L. Barraquio, count (cfu mL–1) (1931) Nellore Native (1958) (1963) (1964) (1986) unpublished Cow Cow data Protein 4.5 3.07 3.29 5.77 3.81 3.2 2.90 2.96 Solids-not-fat 10.0 9.74 10.66 10.07 9.21 8.2 8.20 7.96 Fat 5.5 3.75 4.33 4.56 5.14 3.5 3.42 4.10 Moisture 84.5 86.50 85.01 85.37 ND 88.3 88.38 87.94 Total solids 15.5 13.49 14.99 14.63 ND 11.7 11.62 12.06 Lactose 5.0 4.65 4.53 5.91 ND 4.3 ND ND Ash 0.8–1.0 0.87 1.10 0.96 ND 0.7 0.66 ND Speciﬁ c gravity NDa 1.025 1.029 1.030 ND ND ND 1.029 pH ND ND ND ND ND ND 6.58 6.66 Titratable acidity ND ND ND ND ND ND 0.13 0.2 Coliforms count ND ND ND ND ND ND ND 1 × 104 Total bacterial ND ND ND ND ND ND ND 2.4 × 107 count a ND, not determined.

11405124601_4_008.indd405124601_4_008.indd 225151 116/05/20066/05/2006 16:01:0216:01:02 11405124601_4_008.indd 252 4 0 5 1 2 4 6 0 1 _ 4 _ 0 252 0 8 . i n Chapter 8 d d

2 5 2

Table 8.2 Physicochemical and microbiological quality of raw carabao’s and buffalo’s milk in the Philippines

Gomez (1926) Constituent Palad Villegas Tena & O.C. Emata & (g 100 g–1) and Philippine Indian Rajbhandary et al. Parducho et et al. Davide et Aranas Calub V.L. Barraquio, count (cfu mL–1) carabao buffalo (1962) (1964) al. (1967/68) (1968/69) al. (1969) (1978) (1964) unpublished data Protein 5.98 5.74 4.78 6.3 5.1 5.34 5.29 5.09 ND 2.53 Solids-not-fat 12.17 11.70 9.75 14.2 11.5 10.72 11.48 11.43 11.08 9.33 Fat 10.17 7.31 8.59 12.0 6.4 9.39 9.93 10.46 11.50 7.48 Moisture ND ND ND ND ND ND ND ND ND 83.19 Total solids 22.34 19.01 18.34 26.2 17.94 20.11 21.41 21.89 22.58 16.81 Lactose 4.93 4.89 4.10 7.1 5.5 4.67 5.29 3.24 ND ND Ash 0.87 0.81 0.87 0.8 0.9 0.99 0.90 0.82 ND ND Speciﬁ c gravity 1.035 1.032 NDa ND ND 1.032 1.034 ND ND 1.034 pH ND ND ND ND ND ND ND ND ND 7.10 Titratable acidity ND ND ND ND ND 0.12 0.13 ND ND 0.13 Coliforms count ND ND ND ND ND ND ND ND ND 1.5 × 104 Total bacterial ND ND ND ND ND ND ND ND ND 1.8 × 109 count a ND, not determined. 116/05/2006 16:01:02 6 / 0 5 / 2 0 0 6

1 6 : 0 1 : 0 2 Indigenous Brined Cheese of the Philipines 253

8.3 Manufacturing methods

As mentioned earlier, the manufacturing methods vary depending on the locality, and Figs 8.2 to 8.6 provide detailed information on how the different cheeses are made. The Santa Cruz and Lumbang method (Fig. 8.2) uses rennet extract prepared by cutting a piece of abomasum, ~10 cm2, from a whole dried piece, then placing it in

Strain the milk

↓

Add rennet extract gradually with stirring of the milk (the amount is determined by experience), and the milk should coagulate in 15-30 min

↓

Cut the curd with a knife or flat stick

↓

Drain the whey in a bamboo sieve (Note:- part of the whey is saved to extract the rennet from the abomasum for next day’s cheese production)

↓

Transfer the curd to a container

↓

Crumble and mix the curd with salt by hand, and mix for 10-15 min

↓

Transfer the salted curd to moulds made of wood or banana leaves (usual size is 10 x 10 x 2 cm)

↓

Wrap each mould with wilted banana leaves (i.e. in tiers of two’s or three’s), and finally with banana sheaths or with a peduncle of betel nut palm

Fig. 8.2 The Santa Cruz and Lumbang methods of cheesemaking. After Limuaco (1925) and Rajbhandary (1970).

11405124601_4_008.indd405124601_4_008.indd 225353 116/05/20066/05/2006 16:01:0216:01:02 254 Chapter 8

Strain the milk

↓

Heat the milk (i.e. almost boiling)

↓

Transfer the milk to pails containing vinegar while stirring, more vinegar is added if the whey is cloudy

↓

Press curd between hands to squeeze out whey

↓

Transfer curd to a bamboo tube with perforated base

↓

Press curd with piston to further remove the remaining whey

↓

Transfer round cheese cakes to brine

Fig. 8.3 The Meycawayan cheesemaking method. After Limuaco (1925).

a container with a small amount of milk. If chymosin or pepsin is present, coagulation of the milk will take place in a few hours. The whey is ﬁ ltered and used as the rennet extract. The same piece of the abomasum is used for 5–7 days until coagulation is lost. The common practice is to save a portion of the cheese whey, and use for repeated extraction of the rennet (Limuaco, 1925). Limuaco (1925) also reported the San Pedro Tunasan method for cheesemaking, which was the same as the Santa Cruz and Lumbang methods, but differed in the methods used for the extraction of rennet. The ﬁ rst extraction method was the same as described in Fig. 8.2, whilst the other extraction method relied on soaking a dried piece of abomasum (e.g. 8 × 2 cm) in warm water for up to 18 h until the rennet is used in cheesemaking. Part of the rennet extract was used, and thereafter until the extract could no longer coagulate the milk. It is of interest to note that San Pedro Tunasan is another town in Laguna province in Luzon. In the Cebu method (Fig. 8.4), the abomasum from the carabaos was used instead. A piece of dried abomasum is cut and placed for at least 12 h in a cup containing vinegar before the rennet extract is used (Limuaco, 1925).

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Strain fresh carabao’s milk

↓

Add the rennet extract1 (e.g. the amount used is dependant on the strength)

↓

Slice the curd, then press through a bamboo sieve

↓

Add salt then stir with a stick

↓

Transfer the curd to wooden mould lined with sinamay2 cloth

↓

Press for 24 h

Fig. 8.4 Flow chart showing the Cebu cheesemaking method. 1Abomasum from carabaos is used instead of from cattle; a piece of dried abomasum is cut and placed in a cup containing vinegar for at least 12 h before the rennet extract is used. 2Made from abaca ﬁ bre. After Limuaco (1925).

In the Dairy Training and Research Institute (DTRI) method, which is a modiﬁ - cation of Santa Cruz method, a calibrated amount of rennet, based on its strength, is used so that the milk starts to coagulate within 15–20 min of adding the rennet. With the exception of the DTRI method, none of the processing systems employ exact measurements of temperature, strength or amount of rennet extract, brine or amount of salt, and amount of vinegar in relation to the volume of milk intended for cheesemaking. Based on personal experience and communication with cheesemakers in Cavite and Cebu provinces, the technology is handed down through generations within the family. Hence, every step and amounts of ingredients have been established by experience. No pasteurisation of the milk is involved except in the DTRI and Meycawayan methods (Figs 8.3 & 8.5). However, the Cavite method (Fig. 8.6) is similar to the Meycawayan method employing vinegar as a coagulant and the pressed cheeses are immersed in brine.

8.4 Modifications to the manufacturing methods

Since the 1940s, the Santa Cruz, Cebu and Meycawayan methods for cheesemaking have been developed and/or improved. For example, Reantaso (1940) reported

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Weigh the milk and add salt (3.5 g 100 g-1)

↓

Filter the milk through a cloth

↓

Pasteurise at 72°C for at least 15 s

↓

Cool to 40°C, and add rennet while stirring the milk1 (e.g. 5-7 ml rennet kg-1)

↓

Leave undisturbed for 20 min

↓

Slice the curd or scoop in thin slices into cheese moulds lined with a cloth

↓

Drain the curd for 3-4 h at room temperature or 4-6 h in the cold store

↓

Cut into blocks of desired size, then wrap

Fig. 8.5 DTRI method – a modiﬁ cation of the Santa Cruz process. 1Correct amount of rennet is used if milk starts to coagulate within 15–20 min after adding the rennet. After Dulay (1988).

that all the utensils should be sterilised when using the Santa Cruz method, and the replacement of the locally prepared rennet by imported rennet from Denmark. Cheesecloths were used to drain the whey instead of bamboo sieves, and the amount of added salt was based on the weight of the curd instead of tasting the salted curd (Limuaco, 1925). After salting, the curd was allowed to drain in wooden moulds for 2–3 h before wrapping. The Cebu method was also improved, in a similar manner to the Santa Cruz method, including the use of imported rennet extract. The curd was wrapped in cheesecloth prior to pressing to prevent curd losses. Little pressure was applied at the start, and the cheese was wrapped after 24–36 h of pressing. However, for the Meycawayan method, the milk was heated to 60°C in a specially designed double-jacketed utensil and a thermometer was used to monitor the temperature; warm vinegar was added slowly to the heated milk under continuous stirring (Reantaso, 1940). Furthermore,

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Heat the milk (i.e. lukewarm)

↓

Coagulate the milk by using vinegar, and stirring by hand while adding the vinegar

↓

Form curd into ball by hand

↓

Press into the moulder until firm

↓

Soak in brine solution

↓

Wrap in banana leaves

Fig. 8.6 The Cavite method for making cheese. After Barraquio et al. (1997).

rather than squeezing the curd between the hands, cheesecloth was used to drain the whey and salt was added (i.e. instead of brining) while stirring the curd with a wooden paddle. Arpon (1971) recommended the following to improve the quality of Santa Cruz cheese: • pasteurisation of the cheese milk; • addition of starter culture grown in the whey at a rate of 0.5 mL 100 mL–1 and 2 g salt 100 mL–1; • crumbling the curd by hand and draining the whey for at least 3 h; and • wrapping the cheese in aluminium foil, which had been sanitised in 0.03 mL sorbic acid 100 mL–1 solution.

Furthermore, Dulay (1991) also recommended the sanitation of the utensils and the processing area, pasteurisation of the milk, and standardisation of the manufacturing procedures in order to improve indigenous technologies. In recent years, improvements in the methods of white soft cheesemaking, with consequent extension of the shelf-life of the product, have included the pasteurisation of the cheese milk and preripening the milk using single or mixed strain lactic starter cultures (Barraquio & Maguyon, 1993; Davide et al., 1994; Dulay, 1973; Dulay et al., 1984, 1986; Gomez, 1977; Pedraga & Dulay, 1982; Pilobello & Gomez, 1981; Walde & Dulay, 1988). Heat treatment of the cheese milk was reported to

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increase the yield because of moisture retention by the curd, and was also shown to improve the shelf-life of the cheese. Some examples of lactic starter cultures (i.e. single or mixed stains) during the manufacture of cheese include: Lactococcus lactis subsp. lactis, Lactococcus lactis subsp. cremoris, Lactococcus lactis subsp. lactis bv. diacetylactis, Lactobacillus helveticus, cheese mixed culture, HBR (a strain of Lac. lactis subsp. lactis bv. diacetylactis that has been isolated from Santa Cruz cheese – Miranda et al., 1982; Rajbhandary, 1970), and a yoghurt starter. If the starter cultures were used before pasteurisation of the cheese milk, the organisms were added at a rate of 10–15 mL 100 mL–1; a few minutes were allowed for ripening the milk. If the starter cultures were added after heating the cheese milk, an inoculation rate of 0.5–2.0 mL 100 mL–1 was recommended. All of these studies concluded that the addition of starter cultures reduced the cheesemaking period due to enhanced or quicker curd formation, increased the yield of the cheese, and improved the general acceptability of the product. In addition, the use of sorbic acid (0.03–0.06 mL 100 mL–1) extended the shelf-life of the soft cheese by 1–2 days at room temperature, and 10–19 days in refrigerated storage. As early as the mid-1920s, Limuaco (1925) reported that the Cebu method of white soft cheesemaking involved the use of crude rennet extract from carabao abomasum. Davide et al. (1982) compared the suitability of crude abomasal extract from adult carabao and commercial imported rennet tablets during the manufacture of matured soft cheese from cow’s milk; they concluded that the sensory scores of matured soft cheese made with crude abomasal extract from adult carabao did not differ signifi cantly from those of fresh cheese made with imported rennet. Apuan and Dulay (1984) used 10 mL 100 mL–1 glacial acetic acid as a coagulant; it was added to the hot milk, and was followed by washing the curd twice with chilled water. The use of table vinegar as a coagulant produces a soft cheese of inferior texture compared with cheese made with crude rennet extract (Estefa & Dulay, 1983). Later modifi cations to the basic manufacturing procedure of soft cheesemaking included the fortifi cation of cow’s or carabao’s milk with skimmed milk powder (SMP) with a view to: (a) increase the volume of milk for cheesemaking; (b) improve the quality of the product; and (c) increase the yield of the cheese (Garsuta & Dulay, 1983; Josef & Dulay, 1974; Laranang & Dulay, 1983; Ranas-Oliveros & Dulay, 1982). An alternative approach to increase the volume of milk was to blend coconut milk, water and SMP (Davide et al., 1983). More recently, strategic studies were carried out on the potential of white cheese as a food carrier for probiotic microorganisms (Barraquio et al., 2001; Bayot et al., 1999; Villajin, 2003). However, adoption of these modifi cations and technological changes by local cheesemakers to improve the quality of the product has been poor. To date, only the organised cheese factories (e.g. members of the co-operative federation) have adopted the DTRI method (Fig. 8.5) for the manufacture of cheese. The home-based cheesemakers still use their ancestral techniques.

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Table 8.3 The effect of type of coagulant, method of manufacture and type of milk used on the cheese yield

Cheese yield (%) Method of manufacture Type of milk Limuaco (1925)a Reantaso (1940) Using local rennet extract Santa Cruz and Lumbang 33.4 San Pedro Tunasan 42.1 Cebu Philippine carabao 25.8 Using commercial rennet Santa Cruz and Lumbang 34.2 Santa Cruz Nellore cow 15.61 Native cow 18.55 Indian buffalo 25.41 Philippine carabao 32.46 Cebu Nellore cow 9.91 Native cow 11.60 Indian buffalo 15.82 Philippine carabao 18.85 Using vinegar Meycawayan 57.2 Meycawayan Nellore cow 17.72 Native cow 19.40 Indian buffalo 21.88 Philippine carabao 31.19 aMilk used from native cattle, Nellore, Nellore × native cattle, native carabao and Indian buffalo.

8.5 Yield, composition and microbiological quality of the cheese

The yield of the cheese is dependent on the type of milk and the manufacturing method used (Table 8.3). Higher cheese yields were obtained from milks containing higher solids content, such as from the native cow, Indian buffalo and Philippine carabao. More recent data gathered through personal contact with the industry (Barraquio, unpublished data) showed that mean cheese yield from cow’s milk was 16.7%, compared with 36.1% from native carabao, buffalo and crosses of native carabao and buffalo. The yield of cheese was calculated by dividing the weight of cheese by the weight of milk used and multiplying by 100. Yield was inﬂ uenced not only by the type of milk and coagulant used, but also by the method of manufacture employed, such as the salting method used and extent of draining of the

Table 8.4 Compositional quality (g 100 g–1) of different soft cheeses made in the Philippines

Cheese Moisture Protein Fat Salt Ash pH Cavite 60.48 17.88 17.6 2.16 2.96 5.80 Santa Cruz 66.01 18.70 23.7 2.11 3.06 6.01 Gatas Pinoya 61.45 18.27 23.15 1.34 3.04 5.45 DTRI-CA, UPLBb 65.60 16.96 15.70 1.61 2.55 NDc Hacienda Macalauana 59.93 ND 20.50 1.99 ND 6.59 a Unpublished data.# b University of the Philippines Los Baños. c ND, not determined.

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Table 8.5 Microbiological quality (cfu g–1) of different soft cheeses made in the Philippines

Type of cheese Total bacterial count Coliforms Yeasts and moulds Laguna (Los Baños & Bay) 5.8 × 105 4.1 × 105 5.9 × 104 Santa Cruz 1.0 × 107 5.5 × 105 9.3 × 105 Cavite 4.1 × 108 7.6 × 105 1.0 × 106 KKMIa 1.9 × 104 NDb ND Hacienda Macalauan 3.4 × 105 2.5 × 104 ND aUnpublished data. bNot determined. Data compiled from Barraquio et al. (1995, 1996, 1997).

whey. The chemical composition of the cheese was also found to be dependent on the manufacturing method and type of milk used (Table 8.4). As mentioned elsewhere, pasteurisation of milk is not the common practice during the manufacture of cheese in the Philippines except when using the DTRI and Meycawayan methods. Although the high moisture content of the cheese contributes to the softness of the product, the shelf-life of the cheese is rather short. Improvement of the manufacturing technology is required to produce good-quality cheese. Analytical studies on the microbiological quality of the cheese are summarised in Table 8.5. The high microbial counts in the cheeses were attributed to contaminated utensils, water, hands, clothing of dairy personnel, and the air in the processing area (Barraquio et al. 1996). The microbiological quality of the raw milk also contributed to the high microbial counts in the cheese as only visual observations were used to check the quality of the incoming raw milk (Dulay, 1991). Furthermore, most cheesemaking methods rely on using bare hands to break the coagulum, and the microbial content of the product reﬂ ects the hygiene practices used during the processing and handling of both the milk and cheese. So far, no outbreaks of human pathogens have been recorded arising from the consumption of these cheeses. In a more recent study (Kisworo & Barraquio, 2003), high counts of lactic acid bacteria (LAB) were found in the cheese and in raw milk (i.e. cow’s and buffalo’s; Table 8.6). The highest LAB counts were obtained from white soft cheeses made

Table 8.6 Mean lactic acid bacteria (LAB) counts (cfu mL–1) in soft cheeses, and raw cow’s and carabao’s milk

Cheese/milk samples LAB counts Rosario cheesea 9.7 × 1014 General Trias cheesea 2.7 × 1011 Tanza cheesea 1.3 × 109 Santa Cruz cheese 4.9 × 107 Gatas Pinoy cheese 8.5 × 104 Raw cow’s milk 5.2 × 104 Raw carabao’s milk 7.5 × 102 aRosario, General Trias and Tanza are towns in Cavite province where the soft cheeses are manufactured. After Kisworo & Barraquio (2003).

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from unpasteurised carabao’s milk, namely Rosario, General Trias, Tanza and Santa Cruz cheeses. The LAB isolates belonged to the following species: Lactobacillus helveticus, Lac. lactis subsp. lactis, Lactobacillus rhamnosus, Leuconostoc mesenteroides subsp. dextranicum, Lactobacillus plantarum, Lactobacillus acidophilus, Lactobacillus brevis and Lactobacillus curvatus.

8.6 Conclusion

The method of manufacturing ‘kesong puti’, or soft white cheese is very old and has to date remained artesanal in nature in certain provinces of Luzon and Visayas islands in the Philippines. The technique is passed on through generations within the family. No measuring of temperature or quantities of ingredients is done, and all the manufacturing stages of cheesemaking, including the amounts of ingredients, have been established through years of experience. The characteristics of the cheese depend on the manufacturing procedures of the locality where it is made and the type and quality of the milk used. Though highly popular locally, the volume of production is limited by the supply of carabao’s milk, which is generally preferred by the cheesemakers and consumers over cow’s milk. More recently, due to shortage of carabao’s milk, cow’s milk alone or a combination of cow’s and carabao’s milk is used to make the cheese. In spite of numerous scientifi c studies with recommendations to improve the manufacturing processes of many cheeses made in the Philippines, the adoption of new techniques has been poor. Despite the fact that most cheesemakers do not pasteurise the milk, no disease outbreaks from the consumption of the cheese have ever been reported. The fl avour of the cheese varies from mild to strong, and the taste is salty; the colour varies from very light yellow or creamy to white depending on the type of milk used. The texture is infl uenced by the type of coagulant used, which is either rennet or dilute vinegar. Packaging material for the cheese is either banana leaves or plastic laminates, depending on the place of manufacture and cheesemaker. The use of banana leaves typifi es the uniqueness and indigenous nature of this cheese. However, improvement(s) in the manufacturing technology are required to improve the quality.

References

Anonymous (2003a) Annual Report. Dairy Training and Research Institute (DTRI), University of the Philippines Los Baños, College, Laguna. Anonymous (2003b) Dairy Enterprises Inventory and Proﬁ ling Project (Final Report). A joint project of the National Dairy Authority (NDA), Philippine Carabao Center (PCC), Dairy Training and Research Institute (DTRI), and Bureau of Agricultural Statistics (BAS), Quezon City, Philippines.

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Apuan, E. & Dulay, T.A. (1984) Studies on the Manufacture of Rennet-free Soft-type Unripened Cheeses (ed. M.B. Quilloy), p. 69, Abstract Bibliography of Completed DTRI Researches (1983–1995). University of the Philippines, Los Baños, Laguna. Arpon, Jr. A.T. (1971) Possibility of improving Santa Cruz soft cheese II – coagulant extraction, Santa Cruz starter and further improved soft cheese. MS thesis, University of the Philippines Los Baños, Laguna. Barraquio, V.L. & Maguyon, C.M. (1993) Effects of Sta. Cruz cheese starter bacterium (HBR), Lactococcus lactis subsp. lactis, and L. lactis subsp. lactis biovar. diacetylactis on the quality of soft cheese. Asia Life Sciences, 2, 9–14. Barraquio, V.L., Pacañot, P.A., Triños, M.C.dP. & Almazan, E.N. (1995) Occurrence of food-borne pathogens in Laguna ‘kesong puti’ and ‘pastillas de leche’. Philippine Journal of Veterinary and Animal Science, 21, 1–8. Barraquio, V.L., Saavedra, M.N. & Almazan, E.N. (1996) Detection of Escherichia, Salmonella, Shigella, Yersinia and Staphylococcus in ‘kesong puti’ from Sta. Cruz, Laguna. Philippine Journal of Veterinary and Animal Science, 22, 25–37. Barraquio, V.L., Villanueva D.C. & Almazan, E.N. (1997) Detection of Escherichia, Salmonella, Shigella, Staphylococcus, and Yersinia in ‘kesong puti’ from Cavite province. Philippine Agriculturist, 80, 126–133. Barraquio, V.L., Militante, S.T., Gonzaga, J.O. & Emata, O.C. (2001) Fermented milk drink as starter adjunct in the manufacture of probiotic white soft cheese. The Philippine Agricultural Scientist, 84, 382–387. Bayot, A.N., Barraquio, V.L. & Mabesa, R.C. (1999) The viability of Lactobacillus acidophilus Moro in soft white cheese (‘kesong puti’). The Philippine Agricultural Scientist, 82, 151–157. Calub, A.D. (1964) A survey of the production, distribution, and utilization of milk in the barrio. BSc thesis, University of the Philippines Los Baños, Laguna. Castillo, L.S., Trimberger, G.W., Henderson, C.R., Herrington, B.L. and Turk, K.L. (1963) Variations in protein, solids-non-fat and fat of milk. Philippine Agriculturist, 46, 618–633. Davide, C.L., Clamohoy, L.L. & Garcia, G.V. (1969) Carabao milk II. Analysis of some physical and chemical properties. Philippine Journal of Animal Science, 6, 31–37. Davide, C.L., Frogozo, A.T. & Almazan, E.N. (1982) Suitability of adult carabao abomasal extract as milk coagulant in making ripened soft cheese. Philippine Agriculturist, 65, 59–72. Davide, C.L., Peralta, C.N., Sarmago, I.G. & Yap, M.T. (1983) Utilization of Skimmed Milk Powder for Filled Soft Cheese Manufacture (ed. M.B. Quilloy), p. 50. Abstract bibliography of Completed DTRI Researches (1983–1995), University of the Philippines Los Baños, Laguna. Davide, C.L., Peralta, C.N., Sarmago, I.G. & Sarmago, L.E. (1986) Suitability of goat’s milk in Cheddar and Edam cheese production. Philippine Agriculturist, 69, 131–141. Davide, C.L., Sarmago, I.G. & Peralta, C.P. (1994) Characteristics and consumers’ acceptability of a new soft cheese with yoghurt starter bacteria. Philippine Agriculturist, 77, 295–305. Dulay, T.A. (1988) Laboratory Manual in Dairy Technology. Technoguide Series No. 30, pp. 73–78. National Bookstore Inc., Manila. Dulay, T.A. (1991) Technology Improvement of Indigenous Dairy Products in the Philippines. A report submitted to FAO, DTRI-CA, University of the Philippines Los Baños (unpublished). Dulay, T.A. (1973) The effect of some lactic cultures on the quality of DTRI prepared white soft cheese. MS thesis, University of the Philippines Los Baños, Laguna. Dulay, T.A., Gonzaga, J.O. & Borromeo, A.M. (1984) The inﬂ uence of cheese cultures on the quality of soft cheese. Philippine Journal of Veterinary and Animal Science, 10, 31. Dulay, T.A., Gonzaga, J.O., Bote, A.C. & Rivera, C. (1986) The quality of pararennet prepared directly from fresh abomasum. Philippine Agriculturist, 69, 1–8. Estefa, R.R. & Dulay, T.A. (1983) The Quality and Shelf-life of Soft Cheese Prepared from Cow’s Milk Coagulated by Table Vinegar (ed. M.B.Quilloy), p. 74. Abstract Bibliography of Completed DTRI Researches (1983–1995), University of the Philippines Los Baños, Laguna.

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Garsuta, M.S.G. & Dulay, T.A. (1983) Studies on cheese manufacture from partly reconstituted skimmilk powder II. The quality and shelf-life of soft cheese prepared from carabao’s milk with 30 and 40% reconstituted non-fat dry milk. BSc thesis, University of the Philippines Los Baños, Laguna. Gomez, J.S. (1926) Comparative analyses of the milk of carabao and Indian buffalo. Philippine Agriculturist, 15, 77–84. Gomez, I.V. (1977) An improved method of soft cheese manufacture (Sta. Cruz type) from pooled carabao’s milk. Philippine Journal of Veterinary and Animal Science, 3, 1–13. Josef, L.G. & Dulay, T.A. (1974) A study on the yield and quality of soft cheese from cow’s milk fortifi ed with skimmilk powder. BS thesis, University of the Philippines Los Baños, Laguna. Kisworo, D. & Barraquio, V.L. (2003) Characteristics of lactic acid bacteria from raw milk and white soft cheese. The Philippine Agricultural Scientist, 86, 56–64. Laranag, C.L.A. & Dulay, T.A. (1983) Studies on cheese manufacture using fresh cow’s milk fortifi ed with non-fat dried milk (ed. M.B. Quilloy, p. 77, Abstract Bibliography of Completed DTRI Researches (1983–1995). University of the Philippines Los Baños, Laguna. Limuaco, M.E. (1925) A study of soft cheese making. Philippine Agriculturist, 14, 143–154. Miranda, L.D.C., Barraquio, V.L., Calisay, O.G. & Martin, O.C. (1982) Identifi cation of Sta. Cruz soft cheese starter organism. Kalikasan, Philippine Journal of Biology, 11, 273–283. Palad, J.G., Abdon, I.C., Lontoc, A.V., Dimaunahan, L.B., Eusebio, E.C., & Santiago, N. (1964) Nutritive value of some foodstuffs processed in the Philippines. Philippine Journal of Science, 93, 355–384. Parducho, R.R., Clamohoy, L.L. & Garcia, G.V. (1967–1968) Carabao milk: variations in the yield and composition of carabao milk as affected by stage of lactation, age and season. Philippine Journal of Animal Science, 4–5, 89–98. Pedraga, I.F. & Dulay, T.A. (1982) The effects of ripening cheesemilk on the quality of soft cheese. BSc thesis, University of the Philippines Los Baños, Laguna. Pilobello, A.L.H. & Gomez, I.V. (1981) A preliminary study on the pre-ripening of carabao’s milk using single-strain starters. BSc thesis, University of the Philippines Los Baños, Laguna. Rajbhandary, H.B. (1962) Factors affecting the composition of Sta. Cruz soft cheese. MSc thesis, University of the Philippines Los Baños, Laguna. Rajbhandary, H.B. (1970) Possibilities of improving Sta. Cruz soft cheese. PhD thesis, University of the Philippines Los Baños, Laguna. Ranas-Oliveros, M.C. & Dulay, T.A. (1982) Studies on cheese manufactured from partly reconstituted skimmilk powder I. The quality of soft cheese prepared from cow’s milk with two levels of reconstituted skimmilk powder. Philippine Journal of Veterinary and Animal Science, 8, 77–82. Reantaso, S.R. (1940) Manufacture of soft cheese. Philippine Agriculturist, 29, 492–506. Santos, F.O. & Ascalon, S.J. (1931) Amount of nutrients in the Philippine food materials. Philippine Agriculturist, 20, 405. Tena, E.V. & Aranas, T.J. (1978) A comparison of computed calorifi c value of carabao’s milk with the value obtained from adiabatic bomb calorimetry determination. BSc thesis, University of the Philippines Los Baños, Laguna. Villajin, J.L.S. (2003) Development of probiotic white soft cheese. BSc thesis, University of the Philippines Los Baños, Laguna. Villegas, V. & Cruz, E.C. (1958) Dairy qualities of Philippine cows. Philippine Agriculturist, 41, 495–498. Villegas, L.N., Davide, C.L., Clamohoy, L.L. & Janolino, V.G. (1968–1969) Carabao milk: VI. Its physical and chemical properties as related to stage of lactation. Philippine Agriculturist, 52, 518–523. Walde, G.I. & Dulay, T.A. (1988) The Infl uence of Pre-Acidifi ed Milk on the Sensory Quality and Shelf- life of Soft Cheese (ed. M.B. Quilloy), p. 71, Abstract Bibliography of Completed DTRI Researches (1983–1995). University of the Philippines Los Baños, Laguna.

T. Bintsis

9.1 Introduction

Salt (i.e. sodium chloride – NaCl) has a unique place in human evolution. Since prehistoric times, the preservation of foods has been based on three classic methods, all of which are incorporated in cheesemaking, namely fermentation, dehydration and salting/brining. It is not known whether salt was fi rst added to food for fl avour or for preservation, but its history as an additive goes back to about 3000 BC (Dickinson, 1980). The Bible calls it ‘the essence of life’. Salt was very useful as a preservative, and was used as a form of currency in exchange for goods and labour. In localities where salt was obtained by the evaporation of sea water, it would be reasonable to consider the salty water (i.e. brine) for salting rather than waiting for the evaporation process. Thus, Mediterranean countries developed brining to preserve cheese, and in some islands, even today they use sea water for cleaning the surface of their cheeses of moulds or slime formation. On the other hand, dry-salting appears to have evolved in Britain, probably in the English county of Cheshire, where rock salt is abundant. Interestingly, British regional cheeses, such as Cheddar and Cheshire, are dry-salted, as are blue-veined cheeses such as Stilton, Wensleydale and Dorset. The salt content of cheeses ranges from 0.5–0.7 g 100 g–1 for Emmental to 5–6 g 100 g–1 for Domiati, Feta and similar white-brined cheeses (Table 9.1). One of the characteristics of white-brined cheeses is their high salt content, and this probably accords with the fact that they are traditionally manufactured in countries with hot climates. It is accepted that sodium is a vital constituent of the body, since it is the principal cation in the extracellular fl uid, plays a key role in maintaining

Table 9.1 Differences in the salt and moisture contents (g 100 g–1) of some cheese varieties

Cheese variety Salt Moisture References Cottage 0.25–1.0 70–80 Robinson & Wilbey (1998) Gouda 1.5–2.2 38–42 Robinson & Wilbey (1998) Cheddar 1.75–1.95 35–39 Robinson & Wilbey (1998) Domiati 5.0–6.0 51–55 Abd El-Salam & Alichanidis (2004) Feta 3.5–5.0 52–58 Abd El-Salam & Alichanidis (2004) Teleme 3.0–4.7 50–55 Alichanidis et al. (1981) Fresh Halloumi 2.7–3.0 47–49 Papademas & Robinson (1998) Mature Halloumi 3.8–5.7 32–35 Papademas & Robinson (1998) Parmigiano Regiano 2.0–2.5 32–34 Robinson & Wilbey (1998)

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Salting – Brining

Salt uptake Moisture content Cheese composition

Brining – Starter growth Water activity Maturation

Enzyme activities Safety

Development Development of desirable of acidity secondary microflora Development Development of undesirable of flavour/texture microfloras

Fig. 9.1 Principal functions of salting/brining in white-brined cheeses.

the water balance of the body, and regulates water movement into and out of cells, and tissue osmolarity (Anonymous, 2003). The high level of salt strongly affects the microfl ora, enzymology and maturation of white-brined cheeses; also, another special feature of this category of cheeses is that their maturation takes place in the brine. Brining serves two major functions in white-brined cheeses, namely uptake of salt (i.e. salting of the cheese, which in turn has multiple functions), and regulating the maturation; the latter aspect takes place with the cheese blocks submerged in their brines (Fig. 9.1). The quality of the brine is a crucial factor in determining the quality and consumer safety of the corresponding cheese. Although the main constituent of the brine is salt, the overall composition of the brine is much more complex, and the chemical balance plays an important role in determining the quality of the fi nal cheese. Additionally, the microbiological quality is crucial, since the brines constitute a specifi c environment with a well-adapted microfl ora. This chapter reviews the latest developments concerning the chemical composition, microbiological quality, handling and processing of brines.

9.2 Role of brining

Salt is added to all cheese varieties at some point of manufacture. The salting in the maturation of cheese performs a variety of functions (Fox, 1987; Fox & McSweeney, 1998; Guinee & Fox, 1993):

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• it affects the growth and survival of bacteria; • it affects the activity of enzymes (indigenous milk enzymes, rennet, enzymes from starter and secondary microfl oras); • it promotes syneresis of the curd resulting in whey expulsion and, thus, in a reduction in the moisture content of cheese; • it causes physical changes in the proteins that affect the texture of the cheese and protein solubilities; • it has a positive effect on fl avour and taste, either directly to give the characteristic fl avour or indirectly by masking off-fl avours and/or inhibiting those undesirable bacteria that cause off-fl avours; • it contributes to the dietary intake of sodium (Na+). Thus, salt concentration in cheese may infl uence many of the chemical, biochemical and microbiological processes that occur during the maturation of cheeses and result in the preservation as well as the development of the typical sensory and compositional characteristics of each cheese variety (Fig. 9.1). Interestingly, the impact of salt in the cheese depends on the concentration in the moisture of the product, namely, its concentration in solution, or salt-in-moisture (SM); this is a strong determinant of many of the microbiological and biochemical changes that occur during cheese maturation. SM is defi ned as follows:

SM = 100 × S/(S + M),

where S = % NaCl content (g 100 g–1), and M = % moisture content (g 100 g–1). Thus, SM is higher than the salt content; if, for example, a cheese block contains 50 g moisture 100 g–1 and 5 g salt 100 g–1, then the SM will be 9 g 100 g–1.

9.2.1 Methods of salting/brining Apart from Domiati, which is manufactured with salted milk (10–15 g NaCl 100 mL–1 added in the milk), all cheeses are salted after rennet coagulation and curd formation. Thus, three principal methods of salting are used in cheesemaking: • mixing dry salt – direct addition and mixing of salt to broken or milled curd; • surface dry salting – rubbing of salt on the surface of the pre-cheese blocks; • brine salting or brining – the cheese is immersed in brine solution (10–27 g NaCl 100 g–1).

Recently, novel methods have been evaluated at an experimental level; these are brine injection under pressure (Guinee, 2004), and vacuum impregnation brining (Pavia et al., 1999), but these approaches are not, at present, applied for brining white cheese varieties. There is a great variability in the way that white-brined cheeses are salted/brined, and sometimes a combination of these methods is used, as shown in Table 9.2. Opinions differ about which is the best method of salting (brining or dry-salting)

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2 6 7

Table 9.2 Examples of salting/brining conditions for different white-brined cheeses

Salting/brining Brining/maturation Cheese variety Salt (g 100 mL–1) Time Temperature (°C) Salt (g 100 mL–1) Time Temperature (°C) Storage (°C) References Feta Dry salting 1–5 d 18–20 7 7–15 d 18–20 2–4 Anonymous (2004) Telemes 14–18 12–24 h 14–20 5–12 7–15 d 14–20 2–8 Veinoglou et al. (1980) Domiati 5–15a 10–15b Ambient Abd El-Salam (1987) Halloumi Dry salting 2–4 h 12–13 <6 Papademas & Robinson (1998) Kalathaki Limnou Dry salting 1–4 h 6–8 3 weeks 14–18 <6 Anonymous (2004) Batzos Dry salting 5 d 10–12 3 months <6 <6 Anonymous (2004) White brined 10–12 15–30 d 15 10–12 months 4–5 Lloyd & Ramshow (1979) White brined 23 24 h 18–20 Soak in water, Mondal et al. (1989) dry and vacuum pack Bjalo Salamureno 22–24 12–24 h 14–16 10–12 12–15 d 14–15 3–4 Karakus & Alperden (1995) Beyar Peynir 14–16 6–8 h 12–26 12–15 d 14 4–10 Hayaloglou et al. (2002) Bulgarian White 12–24 12 h 12 8–12b 6–8 6–8 Abd El-Salam (1987) Brinza 12–24 24–48 h 6–8 10–14b 6–8 6–8 Abd El-Salam (1987) Urfa Dry salting 18–20 h 2 15 4 Ozer et al. (2002) ult fteBie Quality oftheBrine Chanakh 16–22 12–15 d 12–15 16 8–10 Hayaloglou et al. (2002) aSalt is added to the milk before cheesemaking (see Chapter 5). bSalted whey. Note: empty spaces mean data not reported. 267 116/05/2006 16:56:45 6 / 0 5 / 2 0 0 6

1 6 : 5 6 : 4 5 268 Chapter 9

for this category of cheeses; brining does require a large space where it is kept in tanks. Brining tends to give faster rates of salt absorption, produce a more even distribution of salt in the cheese, and give cheeses with higher retention of moisture (i.e. higher yields) (Bines & Holmes, 1994). However, the hygienic condition of the brine is the main concern of the cheesemaker (see Section 9.4). Higher total counts are developed in dry-salted cheeses than in those salted in brine (Hayaloglu et al., 2002), but these lower counts may be benefi cial for certain cheese varieties. The role of dry-salting is very important in the development of the secondary microfl ora (e.g. slime formation in traditional manufacture), which is a major parameter in the development of the desired cheese fl avour. The reduction of the time of dry-salting or even replacement by brining have possible implications for the mild fl avour of the industrial Feta and Feta-type cheeses. In fact, early brining interrupts the biochemical activities during the maturation, and the lactic acid produced by the starter accumulates resulting in high-acid cheese.

9.2.2 Mechanism of brining When a cheese block is immersed in a concentrated or saturated solution of sodium chloride, the difference in osmotic pressure between the brine and the cheese water causes diffusion of salt into the cheese block. Consequently, water diffuses out of the cheese matrix so as to restore the osmotic pressure equilibrium (Guinee & Fox, 1986). The quantity of water lost is about twice the quantity of salt gained (varies from 1.5 to 2.5 times), as the size of the Na+Cl– ion pair is about twice that of H+OH– (Guinee, 2004). Thus, salted cheeses are, in general, smaller and lighter than unsalted ones. However, this is not the case for white-brined cheeses, which are matured in brines and may take up some moisture from the brine during the maturation period (Alichanidis et al., 1981; Pappas et al., 1996). Moisture uptake from the brine may occur during initial storage in the cold room, and this is probably due to the swelling of the caseins at low temperatures, the cleavage of peptide bonds, and the generation of new ionic groups that require water for their hydration (Creamer & Olson, 1982; Pappas et al., 1996; Samal et al., 1993). Salting Feta cheese for 2 days with dry salt gave lower moisture and higher salt contents than salting for 1 day (Pappas et al., 1996). Similarly, cheeses salted in more concentrated brines had lower moisture and higher salt contents (Prasad & Alvarez, 1999). Generally, as the salt content increases, the moisture decreases, and this phenomenon is independent of the method of salting. However, an increase in the salt concentration of brine resulted in decreased moisture content in Gaziantep cheese and, consequently, an increase in hardness (Kaya, 2002). Weakening in the structure was observed in the cheese stored in weak brine as a result of water absorbed from the brine. The penetration of salt into cheese, and outward migration of moisture – together with soluble components – into the brine can be satisfactorily described as an impeded mutual diffusion process. The molecules of salt diffusing in the cheese moisture have to travel from the exterior surface to the centre of the block within the water phase of the cheese, through the network formed by paracasein micelles

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and bypass obstructing protein strands and fat globules, which they cannot penetrate. Thus, the higher the moisture content, the more porous the structure of the cheese. White-brined cheeses are high-moisture products, and their salting period is relatively short (Table 9.2). Geurts et al. (1974) used Fick’s law of diffusion to predict the uptake of salt

by Gouda-type cheese placed in brine. The molecules of NaCl and H2O move in response to their respective concentration gradients. Their diffusion rates are much lower than those in pure solution, due to a variety of impeding factors. The diffusion coefﬁ cient for NaCl in pure water at 12.5°C was found to be 1.0 cm2 d–1, and for NaCl in the cheese moisture it varied from 0.1 to 0.3 cm2 d–1 depending on cheese composition and brining conditions (Geurts et al., 1974). A simpliﬁ ed relationship, which nevertheless gives a good approximation of the salt uptake by a cheese placed in brine, has been reported by Choisy et al. (2000):

SM = 2 × SB × A/V (D × t/π)1/2

where the SM is expressed in g salt 100 g–1 of water in the cheese, the SB is the concentration of the brine (g salt 100 g–1 of water), A is the surface area of the cheese (cm2) and V its volume (cm3), t is the duration of salting (in days), π = 3.14, and D is the diffusion coefﬁ cient of salt (cm2 d–1), which is characteristic of the cheese type, structure and composition, and brining conditions. The application of the above relationship requires that the temperature is constant, the brine is stirred to avoid the formation of a dilute layer around the cheese, and that the volume of brine is sufﬁ ciently large in relation to the volume of cheese, so that variation of the SB due to salt absorption is negligible. In addition Tukan and Humeid (1991) derived two regression equations for the prediction of salt in white-brined cheeses:

SC = 1.04 + 0.46 × SB

and

SC = 0.79 + 1.02 × (SB × M/100)

where SC is the salt content in the cheese, SB is the salt concentration in the brine, and M is the moisture level of the cheese.

9.2.3 Factors affecting the rate and quantity of salt absorbed Brine concentration and duration of salting Higher NaCl levels in the brine give higher rates of absorption to the cheese in the range of 5–25%. Prasad & Alvarez (1999) found that increasing the salt concentration in the brine from 8 to 18 g salt 100 g–1 resulted in higher levels of salt in the cheese at 60 days; the increased salt in the brine for salting the Feta cheese resulted in faster salt diffusion and accelerated salt uptake, with concomitant reduced ﬁ nal

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moisture. However, Melilli et al. (2003) demonstrated that using 18 g salt 100 g–1 in the brine instead of saturated brine (i.e. 26 g 100 g–1) for the ﬁ rst 8 days of a 24-day brining increased the rate of salt uptake, compared with 24 days in saturated brine. The cheese in 18 g salt 100 g–1 in the brine at 18°C achieved in 12 days the same salt content as the cheese in saturated brine for 24 days at 18°C. The increased rate of salt uptake with 18 g 100 g–1 brine compared with saturated brine was related to the impact of lower brine concentration on the moisture content and porosity of the cheese near the surface of the block. Brine with higher salt content causes a rapid loss of moisture from near the surface of the cheese block. This moisture loss causes shrinkage of the cheese structure and decreases porosity, which impedes moisture movement out and salt movement into the block.

Composition of the curd and the brine The moisture content of the curd is the key factor for salt absorption, and the rate of absorption increases as the moisture content of the curd increases. Additionally, the pH and calcium content of the brine may inﬂ uence salt uptake from the cheese. Geurts et al. (1972) reported that a brine pH similar to the cheese pH and a calcium concentration of about 0.5–0.6 g 100 g–1 was necessary to avoid soft rind defects and abnormal uptake of salt in Gouda cheese. The higher salt uptake by the cheese at lower pH coincides with a lower water loss during brining, which may be attributed to a higher lactate level in the low pH cheese (Guinee, 2004). In practice, during the manufacture of Feta and related cheeses, the pH of the brine is adjusted to 4.6–5.0 and, depending on the stage of manufacture at which the brining occurs, this has a preservative effect as well.

Temperature of the brine The temperature of the brine varies from 4°C to 20°C, and increasing the temperature increases both the diffusion rate and the quantity of salt absorbed (Turhan & Kaletunç, 1992). The diffusion coeffi cient of salt in Turkish white cheese was 0.18 cm2 d–1 at 4°C and 0.27 cm2 d–1 at 12.5°C for brine concentrations of 15 and 20 g 100 g–1, respectively; however, the corresponding values for the diffusion coeffi cient at 20°C were 0.34 cm2 d–1 and 0.29 cm2 d–1, respectively. The viscosity of the water phase is also temperature dependent, with lower brining temperatures favouring higher viscosity and lower salt penetration (Payne & Morisson, 1999). A lower temperature may be preferable to reduce the growth of gas-forming bacteria (see Section 9.4.3), but it could also stimulate their growth by reducing the rate of salt penetration in the cheese. It is possible that the combination of lower salt concentration in the brine and lower brine temperature could achieve the same salt concentration in the centre of the cheese in a certain time, and provide an additional benefi t in slowing the growth of undesirable gas-producing bacteria in the cheese. However, the survival/growth of potentially pathogenic bacteria in weak brine is possible, and it is very important that any changes in technological parameters must be carefully examined from all aspects of the cheesemaking process.

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Size and shape of the cheese block The size and the shape of a block are of primary importance, with smaller cheeses and cheeses with ﬂ at surfaces taking up salt faster than larger cheeses and cheeses with cylindrical shapes (Guinee & Fox, 1986; Hayaloglu et al., 2002). It is important, therefore, to determine the appropriate amount of curd for the speciﬁ c cheese block. Usually, white-brined cheese blocks are 11.5 × 11.5 × 8 cm and weigh ∼1 kg, but for larger blocks the amount of salt needs to be determined.

Brine volume/cheese weight The rate of salt uptake by the cheese is also infl uenced by the ratio of the volume of brine to the cheese. Zorilla and Rubiolo (1994) demonstrated with a mathematical model that the uptake of salt was slower when there was too much cheese in the brine. They concluded that the brine volume should be fi ve times the volume of the cheese or greater to ensure that the uptake of salt from the brine is not infl uenced by the amount of cheese in the brine.

9.3 Chemical composition of brines

The chemical composition of the brine may play an important role in the chemical composition of the cheese, as white-brined cheeses mature in their corresponding brines. When cheese is immersed into fresh brine, the brine is progressively enriched with various soluble substances, derived mainly from the cheese (i.e. soluble proteins and peptides, inorganic salts, lactose, lactates and even cheese particles), but also from the water used for preparing the brine and the salt if not adequately purifi ed. In parallel to this, a slow dilution of the brine can be noted due to the absorption of salt by the cheese (Choisy et al., 1987). During the fi rst stages of the maturation, there is an exchange of water-soluble compounds between the cheese and the corresponding brine; thereafter, equilibrium is obtained. Commonly, the brine contains: • salt; • milk protein (whey proteins, cheese fi nes); • milk fat; • lactose; • lactate; • salt. Data for the chemical composition of commercial and experimental brines of Feta- type cheeses throughout the maturation period are shown in Table 9.3. A great variation in brine composition exists between different dairies. However, an increase in the concentration of nitrogenous compounds can be noticed during maturation, which is more obvious in the experimental brines (Table 9.3). This is probably caused by

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Table 9.3 Chemical composition of commercial Feta and experimental Feta-type cheese brines

Commercial Experimental Constituent Fresh Matureda Fresh Matured pH 4.25 4.35 4.40 4.45 Salt (g 100 mL–1) 6.65 6.7 5.37 5.21 Protein (g 100 mL–1) 1.9 2 1.61 2.13 Lactose (g 100 mL–1) 1.25 0.2 1.1 0.6 Lactate (mg 100 mL–1) 2.45 2.8 2.6 2.8 VFFAb (mg 100 mL–1) 98 52 171.6 115.1 a60 days old. bVFFA = volatile free fatty acids. After Bintsis et al. (2000c) and Bintsis (2001).

the diffusion of water-soluble proteolysis products, namely peptides and free amino acids, from the cheese to the brine. The peptide proﬁ le of Feta brine was found to be dominated by hydrophilic peptides and whey proteins and to be very similar to that of the water-soluble fraction of the cheese, but without the hydrophobic peptides (Michaelidou-Koniordou, 1997). It is interesting to note that the concentration of volatile free fatty acids (VFFA) declined over the maturation period in both brines (Table 9.3). This pattern suggests that biochemical changes of various types are occurring in the brine throughout the maturation period, and it is most likely that different substrates and/or proportions of substrates are being fermented, forming variable end-products. The exchange of the substrates and/or end-products of the fermentation(s) with the cheese together with moisture exchange makes the brining a very crucial step in the manufacturing process. The mineral composition of the brine also changes during the maturation. Abd El-Salam (1987) estimated that 1 kg of Feta-type cheese discharges 2.5–2.76 g Ca, 1–1.2 g P, 1.04–1.24 g K and 0.12 g Mg after 4 months storage in 15 g NaCl 100 mL–1 brine. Increasing the concentration of NaCl in the brine and the storage temperature increases the release of minerals into the brine.

9.4 Low-sodium cheeses

During recent decades, the topic of sodium in the human diet has become a major health issue. The primary concern is the association of sodium with hypertension, or high blood pressure, a major contributor to the development of cardiovascular diseases (Reddy & Marth, 1991), osteoporosis and the incidence of kidney stones (Goulding et al., 1993). Although it is difﬁ cult to assess the exact amount of sodium required, healthy adults can maintain a sodium balance with intakes of 10–20 mmol (230–460 mg) d–1, while the average daily intake in the UK is between 85 and 145 mmol (3.0–5.1 g) d–1 – derived mainly from sodium chloride – around ten times the amount needed to maintain balance (1 mmol = 23 mg sodium, 1 g salt contains

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17.1 mmol sodium) (IFST, 1999). There is considerable pressure by consumer groups and the medical profession in Western countries to reduce salt consumption. However, in hot climates, the amount of sodium required is higher, as it is essential for maintaining the osmotic pressure of the body fl uids, and highly salted cheeses have been traditionally consumed in such areas. The globalisation of the market has forced cheesemakers to consider ways of reducing the sodium content of these types of cheese as they are traded in countries that consider the reduction of sodium consumption is important. Alongside this is the fact that, nowadays, the universal possession of domestic refrigeration and the development of chilled distribution is a reality, and the need for high salt levels for preservation purposes has been reduced. When the salt concentration in a cheese is reduced, water activity, the degree of proteolysis, acidity, and possibly bitterness increase, but fi rmness and saltiness decrease (Reddy & Marth, 1995). The lower salt concentration tends to produce a cheese with lower pH values, presumably due to the action of the starter cultures; the lower salt content results in more moisture and, therefore, presumably more residual lactose, the fermentation of which could contribute to the lower pH values. A number of unwanted fermentations may occur, and El-Neshawy et al. (1988) reported the manufacture of low-salt-content Domiati cheese of acceptable quality from milk containing 2 g NaCl 100 mL–1; however, the cheese was treated with 20 µg 100 g–1 Delvocid to retard the spoilage of the cheese. It is technologically diffi cult to reduce the sodium level without adversely affecting the quality of the cheese. The most common approach is to replace a portion of the NaCl with KCl, since the complete replacement tends to cause bitter or other taste defects (i.e. metallic taste). Reddy and Marth (1995) reported that the use of KCl to replace some of the NaCl had no signifi cant effect on the counts and the types of lactic acid bacteria (LAB) developed during the maturation of Cheddar cheese. Larson et al. (1993) found no difference between sodium chloride and potassium chloride on the behaviour of either Listeria monocytogenes or Salmonella heidelberg in cheese whey; they concluded that sodium and potassium appear to function interchangeably in simulated cheese safety systems. Katsiari et al. (1997) reported that reduction of the sodium content of Feta cheese by up to 50% is feasible with partial replacement of NaCl by KCl, without any adverse effects on the quality. The cheese salted with the 3:1 NaCl:KCl mixture received a higher fl avour score than the cheese salted with a 1:1 NaCl:KCl mixture, and in the cheese with 1:1 NaCl:KCl mixture, a slightly bitter-metallic aftertaste, typical of KCl, was detected by two panellists. A similar trend has been observed by Reddy & Marth (1994) in Cheddar cheese, Aly (1995) in ultrafi ltrated (UF) Feta-type, and Ramadan (1995) in Domiati cheese, and in each case the sensory panel described a bitter-metallic aftertaste, typical of KCl. Despite this minor fl avour defect, the cheese was acceptable, while the 3:1 did not exhibit a bitter-metallic taste, probably due to the masking effect of NaCl.

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9.5 Microbiology of brines 9.5.1 Effect of salt on microbes As mentioned elsewhere, salting by brining – or any other method of salting – of cheese is an important step in controlling undesirable bacteria, and this preservative effect derives from its inﬂ uence on the water activity of the cheese. All microorganisms require water for growth, and one of the most effective ways to control their growth is to reduce the available water. The availability of the water in foods

is determined by the water activity (Aw), which is deﬁ ned as the ratio between the vapour pressure of the water present in a system (p) and that of pure water (po) at the same temperature:

Aw = p/po

Aw ranges from 0 to 1, and during the ﬁ rst stages of cheese manufacture, the Aw is ~0.99, which supports the growth and activity of the starter culture. Throughout the

maturation period, the Aw levels are much lower, ranging between 0.91 and 0.98 (Table 9.4). However, the concentration of salt required to inhibit bacteria depends on the nature of the food, its pH and its moisture content. The relationship between

salt concentration in the water phase of the cheese and Aw is almost linear (Guinee & Fox, 2004; Sutherland, 2002):

× Aw = 1 – 0.00565 [SM],

Where the [SM] is the percentage concentration of salt (g 100 g–1) in the moisture of the cheese. The salt concentrations in cheeses range from 0.25 to 6 g 100 g–1 (see Table 9.1),

and their Aw values vary from 0.99 to 0.91 (see Table 9.4). Many microorganisms can grow under such conditions (Table 9.5), and LAB generally have higher Aw

Table 9.4 Reported and calculated water activities (Aw) of some cheese varieties

Aw Cheese variety 1.00 Cheese curd, whey cheese 0.99 Cottage, Quarg 0.98 Munster, processed cheese 0.97 Brie, Camembert, Emmental, Bjalo Salamurenoa, Telemea, Halloumia (fresh) 0.96 Edam, Havarti, Beyaz Peynira, Brinzaa, Fetaa 0.95 Gorgonzola, Gouda, Manchego, Domiatia 0.94 Idiazabal, Mozzarella, Romano, Stilton, Chanakha, mature Halloumia (matured) 0.93 Danablu 0.92 Parmesan 0.91 Provolone aCalculated values (refer to text). After Marcos (1993) and Guinee & Fox. (1993).

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Table 9.5 Minimal water activities (Aw) for growth of certain microorganisms

Aw Microorganisms 0.98 Streptococcus thermophilus 0.97 Pseudomonas fragi 0.96 Flavobacterium spp., Lactobacillus helveticus, Yersinia enterocolitica 0.95 Bacillus cereus, Clostridium botulinum type A, Escherichia coli, Salmonella spp. 0.94 Lactobacillus plantarum, Enterobacter aerogenes, Vibrio parahaemolyticus 0.93 Lactococcus spp., Lactobacillus spp. 0.92 Rhodotorula spp., Listeria monocytogenes 0.90 Saccharomyces cerevisiae, Micrococcus spp. 0.88 Candida spp. 0.83 Debaryomyces hansenii 0.80 Saccharomyces bailli, Penicillium citrinum 0.78 Aspergillus ﬂ avus 0.77 Aspergillus niger 0.75 Halobacterium halobium 0.62 Saccharomyces rouxii After ICMSF (1988) and Barbosa-Canavas & Vega-Mercado (1996).

minima than other cheese bacteria (Beresford et al., 2001). The Aw of a salt solution is dependent on the concentration of the salt, as shown in Table 9.6. Brines with salt concentrations of 5–7 g 100 g–1, which are used for the maturation of Feta cheese (Table 9.2), may support the growth of a wide range of microorganisms, including certain pathogens. For brines with salt concentrations of 10–14 g 100 g–1, used for salting a variety of white-brined cheeses, lactobacilli and yeasts can grow, together with some spoilage bacteria, whereas only certain yeasts can grow in brine with a concentration exceeding 20 g salt 100 g–1. However, other factors are also involved and, while the combination of low pH and low-temperature storage limits the range of microorganisms that can grow, the survival of certain microbes is of great concern.

Table 9.6 Water activities (Aw) of common salt solutions

–1 Aw NaCl concentration (g 100 mL ) 0.99 1.75 0.98 3.57 0.96 7.01 0.95 8.82 0.94 10.34 0.92 13.50 0.90 16.54 0.88 19.40 0.86 22.21 0.85 23.55 0.84 24.19 0.82 27.29 0.80 30.10 After Tschager (1988) and Lück & Jager (1995).

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9.5.2 The microflora of the brines The brines used for salting and storing the cheese during maturation constitute a very specifi c environment for microbial survival and/or growth. This is due to their high salt concentration (great variability, but may reach up to 30 g NaCl 100 g–1) and low pH value, together with the low temperatures that usually apply. Some microorganisms are capable of surviving the harsh environment of cheese brines, and the salting and storage in brine are crucial steps in the manufacture of white- brined cheeses that may affect the growth and activity of the starter culture, as well as the development of the secondary microfl ora. These latter microorganisms can be either desirable lactobacilli and yeasts or undesirable spoilage types (i.e. yeasts, lactobacilli, micrococci, staphylococci) or even pathogenic bacteria (L. monocytogenes, Escherichia coli and Staphylococcus aureus). Brines may be contaminated from the immersed cheese, the water or salt, or the equipment and cheese plant environment. In addition, re-use of old brine is a common practice in traditional cheesemaking, as it is believed to act as a fl avour enhancer. The use of old brine is common in traditional Feta manufacture, and the same has been reported for other cheeses (Geurts et al., 1972). Although the old brine will help the new one to obtain a certain ‘in-house’ microfl ora, which will make a contribution to maturation and fl avour development in the cheese, this is a possible source of contamination for undesirable bacteria. Continuous monitoring of the microbiological quality of the old brine added to the new one is absolutely essential. After immersing the cheese in the corresponding brine, there is a continuous exchange of microfl ora between the cheese and the brine, in parallel with the exchange of moisture and other solutes (see Section 9.3). Thus, the development of the secondary microfl ora is regulated, among other factors, by the brining step. The LAB used as starters have varying salt tolerances for growth. Among the lactococci species, Lactococccus lactis subsp. cremoris is generally more salt sensitive than Lactococcus lactis subsp. lactis; although there are strain-dependent variations (Sutherland, 2002). During the manufacture of Teleme cheese, lactococci were present only in 5-day-old cheese due to the inhibitory effect of the low pH and high salt-in-moisture values of these cheeses (Tzanetakis & Litopoulou-Tzanetaki, 1992). Similarly, yoghurt starter cultures die out early in the maturation of Feta cheese (Vafopoulou-Mastrojiannaki et al., 1990). Therefore, it could be argued that the proper salt concentration of the brine and the timing of the brining step are crucial for the growth and/or survival of the starter cultures and, thus, the development of the acidity in the cheese. Inhibition of starter organisms would result in the development of an undesirable microfl ora and a loss of control of maturation. Despite the unfavourable environment of the brine, high counts were reported for commercial brines (Bintsis et al., 2000c); total counts and total LAB were in the range of 106 to 108 colony-forming units (cfu) mL–1 in mature brines (Yanai et al., 1977; Yaygin, 1971). As far as the yeast counts are concerned, ‘old’ brines had viable counts of yeasts of up to 106 cfu mL–1 (Mansour & Alais, 1973). Great variations were observed between the studies, and these could be attributed to the

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Table 9.7 Predominant bacteria and yeasts in cheese brines

Microorganism Microbial species Lactic acid bacteria (LAB) Lactobacillus paracasei subsp. paracasei Lactobacillus plantarum Enterococcus spp. Yeasts Debaryomyces hansenii Saccharomyces cerevisiae Candida versatilis Kluyveromyces marxianus var. marxianus Torulospora delbrueckii Yarrowia lipolytica Candida famata Pichia membranaefaciens After Bintsis et al. (2000c) and Bintsis & Papademas (2002).

different procedures used to manufacture white-brined cheeses, as well as to the different hygiene levels. The predominant species isolated from cheese brines are presented in Table 9.7. The proteolytic and esterase enzyme activities of the lactobacilli and yeast isolates from Feta cheese brines were studied by Bintsis et al. (2003). It was found that cell-free extracts of Lactobacillus paracasei subsp. paracasei showed peptidase and esterase activities, while strains of Debaryomyces hansenii and Saccharomyces cerevisiae were more proteolytic and especially caseinolytic; the yeast strains preferentially degraded short-chain fatty acids. The release of free amino acids may contribute to fl avour development either directly (Seth & Robinson, 1988) or by serving as substrates for other fl avour-generating compounds (Fox & Wallace, 1997). The release of fatty acids, on the other hand, is vital for the development of the characteristic, slightly rancid, fl avour of Feta cheese (Georgalla et al., 1999; Vafopoulou et al., 1989).

9.5.3 Defects caused by spoilage microorganisms Although the secondary microfl ora may make a benefi cial contribution to the development of cheese fl avour, some defect-causing microorganisms have been found in brines. The presence of slime (i.e. ropiness of the brine) in the brine of white-brined cheeses is a common defect (Abd El-Salam & Alichanidis, 2004). This defect is usually not associated with any undesirable organoleptic characteristics in the cheese, but it affects the appearance of the brine at the retail point, and thus the reaction of the consumer. Slime formation can be caused by strains of Lactobacillus plantarum and/or Lb. casei subsp. casei (Yankov & Denkov, 1972), Lactobacillus plantarum var. viscosum (Chomakov, 1967) and Lactobacillus pseudoplantarum and Alcaligenes spp. (Samaras et al., 2003); the defect can be prevented by ensuring that the pH of the brine is <4.5, and the salt content higher than 8 g 100 g–1. Yoghurt cultures containing strains capable of producing exopolysaccharides may be responsible for ropiness as well (Samaras et al., 2003), thus the selection of the proper starter culture

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is an absolute must. Brines with less than 12 g NaCl 100 g–1 at a pH of 4.5 and above allowed the formation of slime on the cheese or the cheese became very soft (Luck et al., 1982). The salt concentration of brines with pH values of less than 4.5 can be reduced to 8 g 100 g–1 without the danger of slime formation. However, as the authors noticed, the bacteriological quality of the samples tested was quite poor due to a lack of hygiene during the manufacture of the cheese. The most common defect of brined cheeses is, however, ‘early blowing’, which is characterised by large gas holes and a spongy texture of the cheese; early gas formation generally occurs 1–2 days after manufacture. This defect is due to coliforms and/or yeasts growing in excessive numbers (Bintsis & Papademas, 2002). Coliform bacteria include a certain number of genera (Citrobacter, Enterobacter, Escherichia, Klebsiella) belonging to the Enterobacteriaceae. They are Gram-negative, facultative anaerobes, nutritionally undemanding and very widespread in nature; they ferment

lactose with the production of acid (CO2 and H2), and are quite tolerant of salt concentrations of 10 g NaCl 100 g–1 in the cheese brines (Yanai et al., 1977). The most frequent species in early swelling is Enterobacter aerogenes. The gas

produced by coliforms is mainly H2, which is produced by formic hydrogenase activity from formate, a product of lactose metabolism. It is more common in soft and

semisoft cheeses than in hard cheese because of the high Aw values of the former. The presence of coliforms in cheese, particularly Aerobacter aerogenes, has been reported to be responsible for blown tins of Domiati cheese (Bintsis & Papademas, 2002); a salt content of 9 g 100 mL–1 in the milk can prevent this defect. Klebsiella aerogenes was found to be responsible for early blowing and poor cheese quality in white-brined cheese (Abo El-Naga, 1971). Heterofermentative lactobacilli are also able to generate this type of defect from lactose, and species most often involved are Lactobacillus brevis (able to grow at 15°C but not at 45°C) and Lactobacillus fermentum (able to grow at 45°C but not at 15°C). In addition, Leuconostoc mesenteroides subsp. dextranum may be involved (Bergere & Lenoir, 2000). In practice, these early swellings occur only if the number of the microorganisms responsible is relatively large (>106 cfu mL–1), and most of the time are related to low salt and/or insuffi cient acidifi cation. Yeasts may be responsible for gas formation; in the case of white-brined cheeses, swelling of the cans can be caused by yeasts that ferment lactose (i.e. Kluyveromyces spp.) to ethanol, acetaldehyde and carbon dioxide. Discoloration of the surface of the cheese has been attributed to pigment-producing yeasts. It is important that the yeast microfl ora be dominated by non-fermenting, non-pigment-producing strains, and Bintsis et al. (2002) suggested the use of a non-fermenting strain of D. hansenii as a brine adjunct culture. Late swelling or ‘late blowing’ is another defect in cheeses; this is attributed to anaerobic and spore-forming bacteria that ferment lactates, namely species of clostridia (e.g. Clostridium butyricum and Clostridium tyrobutyricum). These

bacteria ferment lactate to butyrate producing copious amounts of H2; this group are sensitive to acid and salt, and they may cause problems only in some cheese varieties (i.e. Swiss- and Dutch-type cheeses); their presence in Feta and related cheeses has not been reported. However, according to Bergere and Lenoir (2000),

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Cl. tyrobutyricum is acid-resistant (grows well in a 4.5–7.5 pH zone), and relatively salt-tolerant (tolerates as much as 5.5–6.0 g NaCl 100 g–1 at its optimal pH). It can ferment lactates producing butyric acid, which can give an unpleasant aroma at high concentration, and carbon dioxide together with hydrogen. Other bacteria can also ferment lactates, residual lactose or even possibly amino acids, and thus generate these gases. Late blowing caused by Bacillus subtilis, Bacillus fastidiosus, Bacillus pumilus, Bacillus fi rmus, Clostridium paratrifi cum and Clostridium tertium were reported in white cheese (Abdel-Fatah et al., 1998). Silage is a potent source of clostridia, and for this reason it is forbidden in some countries to feed it to animals whose milk is intended for cheesemaking. The development of moulds causing visible defects has been reported for various cheeses, but since white-brined cheeses are stored in the metal containers fi lled with brine, the development of moulds is rare provided that the cheese blocks are completely immersed in the brine. Growth of Penicillium commune can result in discoloration of the cheese surfaces, and the production of off-fl avours (Bintsis & Papademas, 2002). The above defects are rare in modern dairies, provided that effi cient pasteurisation and good manufacturing and hygiene practices are applied. Furthermore, the activity of the starter cultures is crucial for the control of coliforms by decreasing the pH and the amount of lactose in the curd.

9.5.4 Use of preservatives Many preservatives have been suggested for addition to brines in order to inhibit the growth of undesirable bacteria, yeasts and moulds. Sorbic acid, potassium sorbate, benzoic acid, sodium benzoate, and calcium and sodium propionate are considered safe from the viewpoint of consumer safety. Other preservatives that have been used in the manufacture of Domiati are hydrogen peroxide (i.e. 30% solution) at 0.2 mL 100 mL–1 with the excess being removed by catalase, formalin and/or formaldehyde, and potassium nitrate (Abou-Donia, 1991). According to Lloyd and Ramshaw (1979), the addition of various inhibitory preparations, such as 1–3 g L–1 benzoate or sorbate, 1–3 IU penicillin, 1 g 100 mL–1 natamycin or nipagin (ethyl hydroxybenzoate), to the brine was not very effective against undesirable lactobacilli. Alternatively, nisin could be added to the brine during the production of Feta- type cheeses (Tamime & Kirkegaard, 1991). The use of these preservatives in Feta and similar white-brined cheeses is regulated by statutory instruments in different countries, and in some instances they are prohibited. The use of sorbic acid as a preservative is permitted in some countries (i.e. Greece and Italy); sorbate-resistant moulds (i.e. Paecilomyces variotti) and yeasts (i.e. D. hansenii) are able to grow in the presence of 3 mg of sorbic acid g–1, and are also able to transform sorbic acid to trans-1,3-pentadiene, which gives an unclean odour to the cheese.

An effective way of controlling early gas is to add KNO3 or NaNO3 at low levels (i.e. 0.2 g 100 g–1) to the milk, where statutory instruments allow. Nitrate does not prevent the growth of coliforms, but acts as an alternative electron acceptor,

allowing complete oxidation of lactose to CO2 and H2O rather than fermentation

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to formate, thus effectively reducing the production of H2 from formate (Beresford et al., 2001).

9.5.5 Survival of pathogens in brines Although storage in brine is thought to decrease populations of undesirable contaminants, there is great concern that the brine employed for the storage of white-brined cheeses can also serve as a potential reservoir of certain salt-tolerant pathogens. The most important pathogenic bacteria that are salt-tolerant and may contaminate cheese brines are: L. monocytogenes, S. aureus, enterohaemorrhagic E. coli, Yersinia enterocolitica and Salmonella spp. The survival and/or growth of these pathogens in the cheese brines could be serious.

Listeria monocytogenes L. monocytogenes is a Gram-positive, facultatively anaerobic, non-spore-forming rod; because of the ability of this bacterium to grow at low temperatures (Table 9.8), it is classiﬁ ed as psychrotrophic (Petran & Zottola, 1989). It is catalase-positive and oxidase-negative, and expresses a β-haemolysin, which produces zones of clearing on blood agar (Farber & Peterkin, 1991). This organism is not a fastidious bacterium, and has been found to survive in faeces, milk (of normal and mastitic cows), soil, water, silage and on plants (Pearson & Marth, 1990). In addition, it has been isolated from cattle, sheep, goats and poultry (Farber & Peterkin, 1991). There is increasing interest in the incidence of Listeria spp. in cheese brines, and Papageorgiou and Marth (1989a) examined the fate of L. monocytogenes during the manufacture and maturation of Feta cheese, as well as its survival in the corresponding brines. They concluded that the manufacture of Feta cheese may support the growth of L. monocytogenes and, when added to pasteurised milk (∼5 × 3 –1 –1 10 cfu mL ) it was able to grow by, on average, 1.5 log10 cfu g during the ﬁ rst 2 –1 days of maturation at 22°C. The pathogen decreased by 1.3–3.0 log10 cfu g during 90 days of storage at 4°C when the pH was low (pH 4.3); however, the pathogen survived longer (90 d) in the brine than in the actual cheese (60 d). In white-brined cheese, the numbers of L. monocytogenes increased from 1.2 × 105 cfu g–1 at day 0 to 1.0 × 107 cfu g–1 after 40 days of storage in 10 g 100 g–1 brine at 4°C (Katic, 1995). Larson et al. (1999) reported that L. monocytogenes survived for 118 days in fresh Feta cheese brines (6.5 g NaCl 100 g–1 and pH 6.8) at 4°C and 12°C. The same bacterium survived for 34 days at 4°C and 13 days at 12°C, but only for a week in highly acidic Feta cheese brine (5.6 g NaCl 100 g–1 and pH 4.4). Moreover, it has been shown that L. monocytogenes can grow in a 6 g NaCl 100 g–1 solution but, in brines, the survival of the pathogen is dependent on the strain, substrate, pH, temperature and concentration of NaCl. Since certain white-brined cheeses (i.e. Halloumi and Domiati) are frequently stored in salted whey containing various concentrations of NaCl, Papageorgiou and Marth (1989b) studied the fate of L. monocytogenes in salted whey. They found that the pathogen was able to grow in 6 g 100 g–1 salted whey (pH 5.65), but was inhibited by

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2 8 1

Table 9.8 Growth conditions and illness characteristics of selected pathogenic bacteria

Growth factors Causative agent Symptoms Time before onset of symptoms Minimum Optimum Maximum Listeria monocytogenes Meningitis, septicaemia, headache, 4 days to several weeks 0°C 28–30°C 50ºC – infection nausea, vomiting, shock, coma, pH 4.0 pH 7.0–7.5 pH 9

interrupted pregnancy, stillbirth Aw 0.95 Staphylococcus aureus – toxin Nausea, vomiting, abdominal 3–6 h 7ºC 37ºC 48ºC cramps pH 4.5 pH 7.0–7.5 pH 9.3

Aw 0.86 Escherichia coli O157:H7 Haemorrhagic colitis, haemolytic –2ºC30–42ºC 45.5ºC – infection uraemic syndrome, abdominal pH 4.4 pH 7.0 pH 9.0

pain, vomiting, anaemia Aw 0.95 Yersinia enterocolitica – infection Abdominal pain, fever, diarrhoea, 1–3 days 3ºC 37ºC 40ºC and/or toxin vomiting, skin rashes pH 4.2 pH 7 pH 9

Salmonella spp. – infection Nausea, vomiting, diarrhoea, fever, 6–24 h 5ºC 37ºC 47ºC abdominal pain, may be preceded pH 4.0 pH 7 pH 9

by chills and headache Quality oftheBrine Note: preventive measures for all the above illnesses are: avoid contamination, ensure proper sanitation and personnel hygiene. Data compiled from different sources (refer to text). 281 116/05/2006 16:56:49 6 / 0 5 / 2 0 0 6

1 6 : 5 6 : 4 9 282 Chapter 9

12 g 100 g–1 salt concentration in the whey (pH 5.50); great variation in salt tolerance between the strains was observed.

Staphylococcus aureus S. aureus is a Gram-positive coccus forming spherical to ovoid cells about 1 µm in diameter (Adams & Moss, 1995). Cell division occurs in more than one plane, so that the cells form irregular clumps resembling bunches of grapes. The organism is a catalase-positive, oxidase-negative, facultatively anaerobic bacterium. The pH range for growth of S. aureus is 4.5–9.3 with an optimum of 7.0–7.5 (Table 9.8). It grows readily in media containing 5–7 g NaCl 100 g–1, and some strains are capable of growth in up to 20 g NaCl 100 g–1 (Adams & Moss, 1995). Nevertheless, it was reported by Minor and Marth (1972) that the combination of 7.5 g NaCl 100 g–1 and a pH lower than 5 caused inactivation of S. aureus at 37°C. The addition of high salt levels to raw milk (10 g 100 g–1) during the manufacture of Domiati cheese allows the survival of S. aureus due to the slow decrease in pH. Ahmed et al. (1983) found that the addition of 5 and 10 g salt 100 mL–1 to raw milk induced an inhibition of growth of microorganisms other than S. aureus, and minimised the decrease in pH value. This inhibition of the competitive microﬂ ora, including the LAB, coupled with the favourable pH of the cheese medium, provided an opportunity for S. aureus to grow rapidly. In the manufacture of Turkish Feta-type cheese, the numbers of S. aureus increased during the ﬁ rst day of manufacture, but the salting of the cheese together with the decline in pH resulted in a decrease of the population (Erkmen, 1995). However, S. aureus can survive in brines because it is salt-tolerant, although Abdalla et al. (1993) showed that LAB starter culture inhibited S. aureus in 4 g 100 g–1 brine solutions by lowering the pH. Interestingly, excessive salting of the cheese may induce an inhibition of growth of microorganisms other than S. aureus. Thus, if inhibition of the starter culture occurs and the pH is not developed as normal, then S. aureus will have the opportunity to grow in the cheese. High numbers of S. aureus may result in the production of enterotoxin, which is not affected by the storage conditions of the cheese.

Enterohaemorrhagic Escherichia coli E. coli is the type species of the genus Escherichia, a member of the family Enterobacteriaceae. It is a catalase-positive, oxidase-negative, fermentative, short, Gram-negative, non-spore-forming rod. Enterohaemorrhagic E. coli (EHEC) is sometimes also known as verotoxin-producing E. coli (VTEC), and constitutes the most important group of virulent E. coli. The other three strains (based on their mechanisms of virulence) are: enterotoxigenic E. coli (ETEC), enteroinvasive E. coli (EIEC), and enteropathogenic E. coli (EPEC). However, E. coli O157:H7 is the serotype of EHEC that is most frequently isolated from humans (Adams & Moss, 1995). In addition, has it been reported by Foster (1990) that dairy cattle are a natural reservoir of E. coli O157:H7.

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These organisms grow over a wide range of pH, from 4.4 to 9.0 (Table 9.8), and they can tolerate the highly acidic conditions found in cheese brines. Enterohaemorrhagic E. coli O157:H7 has a high acid tolerance, resistance to fermentation by-products, survival during storage at 4°C, and high salt tolerance and, thus, its survival in cheese brines might be a problem. Ramsaran et al. (1998) investigated the survival of E. coli O157:H7 in soft cheeses, and reported that it can survive the manufacturing stages of Feta cheese and the numbers at the end of the storage period were greater than the initial inoculum. Interestingly, at the end of the storage (75 d), E. coli O157:H7 was found to be present in the brine, and Ingham et al. (2000) reported that the same strain survived for several weeks in model and commercial brines, the composition of the latter (i.e. pH and NaCl concentration) having an effect on the survival rates. Similarly, Hudson et al. (1997) reported a tenfold increase during the ﬁ rst stages of Feta cheese manufacture. Although the maturation of Cheddar cheese

resulted in a 2 log10 unit reduction after 60 days, viable cells of E. coli O157:H7 were detected in 25 g of cheese (with a salt-in-moisture content of 2.8–3.8 g 100 g–1) after 158 days (Reitsma & Henning, 1996).

Yersinia enterocolitica Y. enterocolitica is an asporogenous, short, Gram-negative, facultatively anaerobic rod belonging to the family Enterobacteriaceae. It is catalase-positive and oxidase- negative, and has the ability to grow well at refrigeration temperatures. This organism is widely distributed in the food environment, and has been recovered from a range of foods including milk and milk products (Swaminathan et al., 1982). Due to the fact that Y. enterocolitica is unlikely to survive pasteurisation (Hanna et al., 1977), the organism can only be a problem with post-pasteurisation contamination. Kendall and Gilbert (1980) have reported that the minimum pH for growth of Y. enterocolitica, using buffered media, is 4.2–4.4 at 22°C, while other researchers (Brocklehurst & Lund, 1990) recorded growth at pH 4.18 (20°C) adjusted with HCl. Furthermore, Y. enterocolitica has been found to survive, but not to grow, at pH 3.6 in microbiological media (Kendall & Gilbert, 1980). At a temperature of 3°C, Y. enterocolitica grows in the presence of 5 g sodium chloride 100 g–1, but not 7 g 100 g–1 (Stern, 1981). Y. enterocolitica can multiply and subsequently survive for 30 days in Feta cheese when the pH remains high (i.e. above 4.5), which is not normal for Feta cheese (Karaioannoglou et al., 1985). Similarly, Erkmen (1996) demonstrated that Y. enterocolitica becomes inactive and is ultimately destroyed in Feta cheese when the acidity of the cheese develops normally. In addition, Y. enterocolitica can grow and subsequently survive during the manufacture of Colby-like cheese (Moustafa et al., 1983).

Salmonella species Salmonellae are Gram-negative, non-spore-forming rods (typically 0.5 × 1–3 μm), members of the Enterobacteriaceae, which are facultatively anaerobic, catalase-posi-

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tive, oxidase negative, and are generally motile with peritrichous ﬂ agella. Growth has been recorded from 5ºC up to 47ºC, with an optimum at 37ºC (Table 9.8). They

are heat sensitive, the minimum Aw for growth is around 0.93, and minimum pH for growth varies with the acidulant from 5.4 with acetic acid to 4.05 with hydrochloric and citric acids (Adams & Moss, 1995). The survival of Salmonella typhimurium in model cheese brine (23 g salt 100 g–1, pH 5.7) was investigated by Ingham et al. (2000); they concluded that the population of S. typhimurium decreased slowly over 28 days of storage, with a decrease –1 of 1.3 and 1.7 log10 cfu mL at 8°C and 15˚C, respectively. Similarly, Erkmen and Bozoglu (1995) concluded that the salt concentration alone did not decrease the numbers of S. typhimurium in the early stages of maturation of Feta-type cheese; however, pH values of 5.7 or lower were effective on S. typhimurium.

9.5.6 Stressed cells When microorganisms are subjected to environmental stresses, such as sublethal exposures to high salinity, heat or freezing, many of the individual cells undergo metabolic stress, and the stressed cells are more resistant to certain sublethal processes. Stress mechanisms that are induced in harsh, but full-nutrient, environments like cheese brines can provide protection against a variety of other inhibitory treatments, a phenomenon called ‘stress hardening’ or ‘cross-protection’. For example, acid-adapted cells of L. monocytogenes were found to be more resistant to bacteriocins than normal cells (Van Schaik et al., 1999) or showed enhanced survival in milk fermented by LAB (Gahan et al., 1996). Similarly, cells of E. coli incubated at a mildly acid pH (pH 5.0) showed an increase in UV resistance compared with cells grown at pH 7.0 (Goodson & Rowbury, 1989). The internal osmotic pressure in bacterial cells is higher than that of the surrounding medium and this results in a pressure, called the turgor pressure, being exerted outwards on the cell wall (Abee & Wouters, 1999; Csonka, 1989). The result of a lowering of the external water activity (hyperosmotic shock) is a rapid efﬂ ux of water and loss of turgor. The response of many bacteria to a hyperosmotic shock is the cytoplasmic accumulation of a certain class of solutes, termed ‘compatible solutes’ or ‘osmolytes’ (Abee & Wouters, 1999; Csonka, 1989; Smith et al., 1998). Such compatible solutes include: K+, amino acids (glutamate, proline), quaternary amines (glycine betain, carnitine), peptides, sugars (trehalose, sucrose, mannitol) and tetrahydropyrimidines (ectoine) (Abee & Wouters, 1999; Poolman & Glaasker, 1998). Compatible solutes need the aid of transport systems to cross the cell membranes (Csonka, 1989). Apparently, microorganisms can accumulate a wide spectrum of compatible solutes, most of which are present in signiﬁ cant amounts in foods, particularly in proteinaceous foods such as dairy products. Stressed cells are characterised by their inability to form colonies on selective media that uninjured cells can tolerate. Thus, whether an organism has suffered metabolic stress could be determined by plating aliquots of the sample both on a selective and a nonselective medium and, after proper incubation, the difference will show the number of stressed cells.

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9.6 Control measures

Based on these reports, it can be concluded that brine solutions with <10 g salt 100 g–1 could be considered as potential reservoirs of pathogenic bacteria, and that the development of acidity is the crucial factor determining their fate. The use of good management practices, focusing on proper cleaning and sanitation, seems to be the way to prevent the contamination of brines with pathogens. Large brine tanks should be equipped with cleaning-in-place (CIP) apparatus, and cleaned and sanitised every time that they are emptied. They should be rinsed with water to remove gross soiling (i.e. minerals, protein and degradation products, lipids, carbohydrates and microorganisms), washed with detergent solutions and disinfected. Acid solutions should be incorporated when tank materials permit their use. For small dairies, small brine tanks are used, and these are manually cleaned and sanitised; they should have stainless steel surfaces that are cleaned easily. A cleaning and sanitising programme needs to be selected; this should be completed with expert advice because it is very specifi c to the application. A cleaning programme for brine tanks has been suggested by Ecolab (personal communication); the cleaning cycle is as follows. • Alkaline treatment with a sodium-based detergent, such as P3-mip LFT at a concentration of 3.0 mL 100 mL–1 (or similar product) at 60–70°C for 15 min. • Empty the tank and rinse with cold water at 10°C; there is a high demand for potable quality water. • Acid cleaning with P3-horolith CIP 2 mL 100 mL–1 for 15 min at 50–60°C. • Empty the tank and rinse with cold water at 10°C. • Sanitation with P3-oxonia active 0.5 mL 100 mL–1 at 10°C for 10 min. • Rinse with potable water. The effi ciency of the cleaning is checked by the bacteriological quality of the last rinse (negative cfu 100 mL–1). Due to the fact that disinfectants affect microorganisms differently and at different concentrations, tests should be performed to determine the appropriate disinfectant for each specifi c plant and cheese environment (as well as the concentrations), and verify their effi ciency with microbiological analyses. In addition, for economic reasons, the water of the fi nal rinses of the equipment could be utilised for the preparation of the next cleaning solution and, hence, reduce the water consumption and waste discharges. Failure of the cleaning and sanitation programme to remove the residual soil from the surfaces of the brine tank(s) and/or the microorganisms on it may cause the formation of biofi lms, a major problem in the dairy industry. Biofi lm is a convenient term to designate microorganisms adhering to and growing on wet surfaces, and acquiring, within a matter of hours, resistance to adverse environmental conditions (Carpentier et al., 1998). Adhered cells in a biofi lm are more resistant than free-living cells to adverse conditions, such as antibiotics, disinfectants, starvation, inconsistent nutrient supply and extreme cold or heating (Mostert & Jooste, 2002).

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The existence within a biofi lm of stressed cells that survive these stressful conditions is also possible. Areas in which biofi lms most often develop are those that are the most diffi cult to rinse, clean and sanitise, and also the more diffi cult to sample. Dead ends, joints, grooves, surface roughness, by-pass valves, overfl ow siphons in fi lters and corrosion patches are ‘hard-to-reach’ areas. The walls, fl oors and ceilings of ripening, brining and maturation areas should be washed with fungicidal solutions (Marriot, 1999).

9.7 Quality control of brines

It is commonly accepted among cheesemakers that optimal composition and other characteristics of the brine are very important to achieve the desired cheese quality. Thus, the consistency, maturation, ﬂ avour and microbiological quality of the cheese are all inﬂ uenced by the quality of the brine, and the latter needs to be frequently monitored and standardised. In the brine bath, the cheese is part of an open system – there is an exchange of soluble components between the cheese and the brine. Consequently, quality control of the brine is a prerequisite for the production of high-quality cheese.

9.7.1 Physical and chemical control The quantity of the brine is the fi rst point that the cheesemaker needs to check; the cheese blocks must always be submerged in the brine, since proper brining occurs only inside the brine. Circulation of the brine in large tanks is necessary, since the concentration of salt tends to stratify, as salt is absorbed into the cheese from the top of the tank. Furthermore, the salt content in the cheese is of great importance, and must be kept within a very narrow range. This can only be achieved if the salt concentration of the brine is kept constantly within a limited range, which is typical for the specifi c cheese. Thus, precise control of the salt concentration is needed, in order to standardise the salt content of the cheese. Brine tanks equipped with automated dosing devices are available. Any variation from the optimum salt concentration may cause defective acidifi cation of the curd. Low salt, for example, can cause overacidifi cation caused by excessive growth of the starter organisms, which induces excess drainage; the cheese obtained is dry and hard, with the formation of a rind on the surface. On the other hand, insuffi cient acidifi cation, which is most frequently caused by excessive salting, will result in draining defects. In this case, the acidifi cation process may be very long, resulting in an excessively moist cheese; microbial and enzyme activities are likely to be excessive, and a marked proteolysis may cause soft cheeses and possible off-fl avours (i.e. bitterness), or softening due to absorption of moisture from the brine. Growth of undesirable microorganisms is an additional risk (see Section 9.5.3).

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A simple and rapid method for checking the salt content of the brine on a daily basis, is by using the Baumé hydrometer. However, the use of this instrument may lead to considerable errors. The hydrometer is adjusted in a 2-point adjustment operation with distilled water and a 10 g sodium chloride 100 g–1 solution; the distilled water indicates the zero point and the salt solution the 10-point on the scale. There is a uniform calibration between the above adjustment points. However, the ratio between specifi c gravity and the percentage of sodium chloride is not linear (Table 9.9). In fact, at high salt concentrations, the degrees Baumé are considerably lower than the content of sodium chloride in terms of percent. At 15° Baumé the difference is 0.5, while at 22° Baumé it is approximately 2.0 (Table 9.9). In addition, the brine may contain other dissolved substances, which increase the specifi c gravity. Thus, in highly polluted brine, the degrees Baumé are substantially higher than the content of sodium chloride in terms of percent. It is recommended, therefore, to check the brine at reasonable intervals by means of a method that directly measures the content of sodium chloride. Offi cial methods for the determination of sodium chloride are either potentiometric (AOAC, 2000; IDF, 1988) or titrimetric (IDF, 1972); alternatively, fl ame photometry can be used (Kirk & Sawyer, 1991). High-purity salt is required for the preparation of the brine, that is, salt that conforms to the specifi cations of FAO (2001) (see Table 9.10), and the water used needs to meet the European Union standards for chemical parameters for drinking water (EU, 1998) (see Table 9.11). Furthermore, the acidity of the brine should be checked, and the pH value of the brine must match the pH value of the cheese;

Table 9.9 Relationship between salt concentration and degrees of Baumé (°Bé) of aqueous sodium chloride solutions at 20°C

Salt concentration (g NaCl 100 g–1 ) Degrees Baumé (°Bé) 12 11.5 13 12.4 14 13.3 15 14.2 16 15.1 17 16.0 18 16.9 19 17.8 20 18.7 21 19.6 22 20.4 23 21.3 24 22.2 25 23.1 26 23.9 After Zerﬁ ridis (2001).

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Table 9.10 Speciﬁ cations of salt for use in cheesemaking

Component Max concentration (mg kg–1) Arsenic (As) 0.5 Copper (Cu) 2.0 Lead (Pb) 2.0 Cadmium (Cd) 0.5 Mercury (Hg) 0.1 After FAO (2001).

Table 9.11 Chemical composition standards for drinking water

Component Maximum concentration (μg L–1)

Nitrate (NO3) 50 000

Nitrite (NO2) 500 Pesticides 0.1 Arsenic (As) 10 Cadmium (Cd) 5 Chromium (Cr) 50 Copper (Cu) 2000 Lead (Pb) 10 Mercury (Hg) 1 Nickel (Ni) 20 After EU (1998).

the cheese must be submerged in the brine only at the correct pH value, which is specifi ed for each variety. If the cheese is introduced into the brine at a higher than optimum pH, then an extremely high-salt cheese will be obtained, since the cheese will contain much of the whey (high moisture) and, thus, higher rates of salt absorption will occur (see Section 9.2.3). Variations from the optimum pH can also cause cheese defects; too low a pH will result in the exchange of calcium ions with hydrogen ions, resulting in a hard, defective cheese body. Too high a pH, on the other hand, will result in a ‘greasy’ and ‘slippery’ cheese. Provided that the composition of the brine is within the normal range, then the brine has a specifi c buffering capacity, and a certain pH range corresponds to a certain range of acidity. However, in a heavily contaminated brine at normal acidity, the pH value is too high, whilst in a very recently made brine it will be too low. The calcium content is equally important. The determination of calcium is nowadays a routine titration method (Kirk & Sawyer, 1991). In order to achieve a fi rmer rind, the calcium must be within a range that is typical for the specifi c cheese involved. Too low a calcium content results in a soft and weak rind, while too high a concentration leads to a fi rm and dry cheese. The temperature of the brine is another important factor. At low temperatures the salt is absorbed too slowly (see Section 9.2.3) and less whey (i.e. syneresis) is

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expelled, resulting in faulty cheeses and bitter defects. At high temperatures, on the other hand, undesirable microorganisms can grow.

9.7.2 Microbiological control The water used for the preparation of the brine must be of the highest microbiological quality, meeting the requirements for drinking water (Table 9.12), or preferably exceeding these standards. Some dairies are using pasteurised water to ensure the production of pathogen-free brine, since the options for heating the brine are limited due to the corrosion caused by the salt. Monitoring the microbiological quality of the brine is an absolute need in any quality-management system, but the development of speciﬁ cations for the microbiological quality of the brine is not feasible due to the different brining conditions that are used. As a general guideline, some suggested microbiological tests are shown in Table 9.13. The hygiene of the brine tanks should also be monitored, and different methods and/or techniques for the assessment of dairy equipment hygiene have been devised (Mostert & Jooste, 2002). Enumerations of total counts of bacteria, coliforms, yeasts and moulds are the most common microbiological tests carried out to assess the contamination level of the surfaces. The frequency of applying these tests is critical, and the results are valuable only when values for a typical ‘high standard of hygiene’ for a given plant along with acceptable tolerances have been established (Tamime & Robinson, 1999). The swab method is commonly used as it is applicable to any surface (ﬂ at or curved, horizontal, vertical or sloped) (Mostert & Jooste, 2002). A sterile swab,

Table 9.12 Microbiological standards for drinking water

Microorganism Count (cfu) Escherichia coli -ve 100 mL–1 Enterococcus spp. -ve 100 mL–1 After EU (1998).

Table 9.13 Suggested microbiological tests for cheese brines

Test Method References Yeasts Colony count at 25°C for 5 d IDF (1990) Coliforms Most probable number (MPN) at 30°C IDF (1998) Escherichia coli Colony count at 44°C using membranes IDF (1999) Listeria monocytogenes Selective enrichment, isolation, presumptive identifi cation, IDF (1995b) confi rmation Salmonella spp. Pre-enrichment, selective enumeration, identifi cation, IDF (1995a) confi rmation

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moistened in an appropriate solution, is rubbed over a designated area of the surface to be examined, usually with the aid of a sterile template. The swab is then transferred to its holder with a known volume (e.g. 10 mL) of a physiologically neutral solution, vigorously agitated, and microbiological tests are carried out for the selected group of microorganisms, usually coliforms. The swab and rinse methods may be supplemented by a bioluminescence test for total adenosine-5-triphosphate (ATP), which is a rapid and convenient test (Mostert & Jooste, 2002).

9.8 Purification methods for cheese brines

In principle, the brine can be reused many times if salt is added to replace that absorbed by the cheese. This practice would have the benefi t of maintaining the chemical and microbiological ‘balance’, which gives the desired cheese quality. However, cheese brines are considered as potential reservoirs of pathogenic bacteria, and thus the reuse of old brine is feasible only under strict microbiological control. The need to control the microfl ora of the cheese brines, together with the economic and environmental aspects of discharging the old brines, raises the need for a purifi cation method for brines, so that the brine can be reused safely and for longer periods. The optimal purifi cation method should fulfi l the following requirements (Ottosen, 2004): • removes microorganisms, such as moulds, yeasts, pathogenic bacteria and other contaminants; • does not change the chemical composition of the brine; • does not denature the whey proteins in the brine; • reduces salt and water losses to a minimum; • removes physical impurities (cheese fi nes); • is simple, cheap and reliable; • does not introduce any foreign material into the brine or the cheese. The most common purifi cation methods that are used in the dairy industry are discussed below.

9.8.1 Chemical treatment Chemical treatment has been suggested using different antimicrobial compounds and preservatives, such as hydrogen peroxide (Abdalla et al., 1993; Hinterberger, 1964), sodium hypochlorite (Larson et al., 1999), potassium sorbate (Abdalla et al., 1993), sodium benzoate, antibiotics or ozone (Jedrychowski et al., 1990). Despite the efﬁ ciency of the above preservatives against a variety of microorganisms, the presence of residual traces of chemical is the main disadvantage of most chemical treatments.

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It has been reported that the addition of sorbic acid to the brine (10 g NaCl 100 g–1) of Feta cheese causes an off-ﬂ avour characterised as ‘plastic paint or kerosene’ (Horwood et al., 1981). Generally speaking, the use of chemicals and additives should be abandoned wherever technically possible, since there is a consumer trend towards avoiding foodstuffs containing chemical preservatives.

9.8.2 Heat treatment Heat treatment of cheese brines (20–50 min at 80–100°C) has been traditionally employed as a decontamination process. Although such treatment is effective against both spoilage and pathogenic microbes, it has certain disadvantages. The process will affect the chemical composition of the brine, as 20–40 g 100 g–1 of the whey protein is denatured and calcium phosphate is precipitated, with a concomitant decrease in the pH. The low calcium content will inﬂ uence the quality of the cheese (Section 9.2.3), and the composition of the brine needs to be adjusted. The high temperature may cause corrosion of the stainless steel ﬁ ttings, such as the plate heat exchanger (PHE) and pipes, due to the high salt concentration and low pH of the brines. However, a titanium PHE has been used, but the plates are very expensive, and the heating cost is quite high. Novel types of pasteurisation, such as electrical pasteurisation (low voltage, low current) have been studied (Anonymous, 1999), but no industrial application has been reported. In addition, the chemical composition of the brine may be changed due to the denaturation of proteins and peptides, and calcium phosphate precipitation occurs at high temperatures. Also, some microorganisms that are desirable in the brine may be killed. This change in the balance of both chemical and microbiological quality of the brines is of crucial importance for white-brined cheeses.

9.8.3 Treatment with UVC light Short-wave ultraviolet (UVC ~254 nm) irradiation has been proposed for the disinfection of the brine used to salt Mozzarella cheese (Anonymous, 1994). The application of UVC is a very simple and effective disinfection process against bacteria, and has no effect on the chemical composition of the brine. However, the limited penetration of the UVC into the brine is the main problem to be overcome (Bintsis et al., 2000b). Recently, Hanovia Ltd (Slough, UK) has developed a UVC disinfection system suitable for brine treatment (Fig. 9.2). Equipped with a 2.5 kW arc tube, the Hanovia UV system can disinfect up to 10 m3 h–1 of low-transmission brine. According to the company’s newsletter, it is a non-chemical brine disinfection system that would not alter the quality of the cheese. In addition, it is a ‘simple to use’ system, and requires little maintenance. In terms of capital and running costs, UV offers the most effective method of disinfection. Compared with the more conventional heat treatment, the operating costs of UV are far lower than those of pasteurisation.

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Fig. 9.2 Ultraviolet C radiation (UVC) brine disinfection system. By permission of Hanovia Ltd, Slough, UK (www.hanovia.com).

9.8.4 Treatment with UVA light plus furocoumarins While UVC has the disadvantage of limited penetration in liquids, long-wave UV (UVA ~320–400 nm) can penetrate further in liquids. However, the latter has little impact on microbial cells, unless the lethality can be enhanced by the coincidental absorption into the cells of an exogenous photosensitiser (Mitchell, 1978). One group of compounds that meets this requirement are the tricyclic furocoumarins, which are formed by the fusion of a furan ring with a coumarin molecule (Cimino et al. 1985); fi ve plant families, namely the Umbelliferae (e.g. celery, parsley and parsnip), Rutaceae (e.g. bergamot fruit and lime), Moraceae (e.g. fi g), Leguminosae and the Orchidaceae have been identifi ed as natural sources. Dried plant materials, expressed juice or even pure compounds like psoralen, could be considered for direct addition to the brine prior to irradiation with UVA. At present, the system with UVA/psoralen treatment does not have potential as a novel decontamination process for brines, because the high cost of the pure psoralen, together with its toxicity at high concentrations, may prevent it from being applied (Bintsis et al., 2000b). The use of novel, chemically synthesised furocoumarins, which are more active and do not exhibit toxicity, may need some consideration (Santana et al., 2000).

9.8.5 Kieselguhr filtration Kieselguhr fi ltration has been widely used for brine treatment in some countries, such as Spain; however, this technology is more commonly used in the fi ltration of wine and beer (Otero-Rodriguez et al., 1998). Kieselguhr is a diatomaceous earth, a form of silica composed of the siliceous shells of unicellular aquatic plants of microscopic size. It needs manual handling, and breathing the dust from kieselguhr is thought to be harmful and suspected to be carcinogenic (Ottosen & Konigsfeldt, 1999). Otero-Rodriguez et al. (1998) studied the effect of fi ltration using fi lter aids,

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such as diatomaceous earth, and achieved retentions of 94.0, 93.8 and 90.4% for total viable counts, staphylococci, and yeasts and moulds, respectively. Disposal of used kieselguhr ﬁ lters is restricted for environmental purposes, and there is some risk that kieselguhr ﬁ nes are transmitted to the cheese (Holmstrom, 1996).

9.8.6 Microfiltration Microfi ltration is another technology that has been suggested for the treatment of cheese brines (Merin et al., 1983; Otero-Rodriguez et al., 1998; Ottosen, 2004; Ottosen & Konigsfeldt, 1999). Ceramic-based membranes with pore sizes ranging from 0.1 to 20 μm have been used in the dairy industry since the early 1980s (Saboya & Maubois, 2000) and they satisfy all the requirements, namely, strong mechanical resistance and wide tolerance to pH. Microfi ltration is a very interesting technique for the cleaning/sanitation of cheese brines, as it removes microorganisms and physical contaminants from the brine, while avoiding changes in chemical composition and mineral balance (e.g. the denaturation of the protein and sedimentation of calcium phosphate due to heat treatment) or contamination with chemical residues. Merin et al. (1983) studied the effect of a multilayer and serial construction microfi ltration system, which affords pre-fi ltration via a glass-fi bre medium in the top layer, and fi nal fi ltration via two membranes with a nominal pore size of 0.8 μm; constant permeate fl ux was 67 L m–2 h–1. While the yeasts and moulds were completely rejected by the membrane, the bacterial count was reduced by 2–3 orders of magnitude (from 1.2 × 106 cfu mL–1 to 3.5 × 103–1.2 × 104 cfu mL–1). The same authors also studied the effect of different pore sizes, and concluded that bacteria can be reduced to <10 cfu mL–1 by 0.2 and 0.65 μm membranes. Microfi ltration systems have been applied in several cases with good results, but have the disadvantage of high investment costs, especially for small dairies. Since cheese brines may contain some cheese fi nes, usually of a size of 1–20 μm, it is necessary to remove the fi nes by means of a pre-fi ltration step. A microfi ltration plant which is equipped with spiral-wound membranes type DSS FSM – 0.45PP (pore size 0.45 μm), is shown in Fig. 9.3 (DSS Silkeborg AS, Silkeborg, Denmark; www.dss-silkeborg.com). It is interesting to note that a temperature of 20°C is recommended for microfi ltration of the brine instead of the 40–50°C that is used for milk. Heating the brine to that temperature would cause precipitation of calcium phosphate complexes on the membrane and cause fouling, as the solubility of these complexes decreases with increasing temperature. In addition, a temperature of 20°C will minimise the need for cooling, and cause minimal change to the mineral balance of the brine during the fi ltration process (Pedersen, 1992). Any method used for the purifi cation of cheese brines has both advantages and disadvantages. However, since any treatment would affect the microbiological ‘balance’ of the brine, the addition of brine adjunct cultures has been suggested by Bintsis et al. (2002), and cultures of yeasts and LAB associated with fl avour production are available from commercial suppliers of dairy starter cultures.

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Fig. 9.3 BrineClear300 microﬁ ltration system. After Ottosen (2004). Reproduced by permission of International Dairy Federation, Boulevard A. Reyers 80, 1030 Brussels, Belgium (www.ﬁ l-idf.org).

9.9 Conclusion

One of the characteristic features that distinguishes white-brined cheeses from other cheese varieties is that they are matured in brines for long periods, and the quality of the brine has a defi nite role in regulating the microbiological and biochemical changes throughout the maturation period. The specifi c environment of the brine is dominated by desirable and/or spoilage lactobacilli and yeasts, while some pathogenic bacteria may survive. The reuse of old brine for the brining of fresh cheese can be benefi cial for cheesemakers since it can help the fresh cheese to achieve the chemical and microbiological ‘balance’, which creates the desired quality in the cheese. However, safety aspects may call for a purifi cation method to be applied during the preparation of the new and/or reused brine.

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Fox, P.F. & McSweeney, P.L.H. (eds) (1998) Chemistry and biochemistry of cheese and fermented milks. In: Dairy Chemistry and Biochemistry. pp. 379–436, Blackie Academic & Professional, London. Fox, P.F. & Wallace, J.M. (1997) Formation of fl avour compounds in cheese. Advances in Applied Microbiology, 45, 17–85. Gahan, C.G.M., O’Driscoll, B. & Hill, C. (1996) Acid adaptation of Listeria monocytogenes can enhance survival in acidic foods and during milk fermentation. Applied and Environmental Microbiology, 62, 3128–3132. Georgalla, A.K, Kandarakis, I.G., Kaminarides, S.E. & Anifantakis, E.M. (1999) Volatile free fatty acid content of Feta and white-brined cheeses. Australian Journal of Dairy Technology, 54, 5–8. Geurts, T.J., Walstra, P. & Mulder, H. (1972) Brine composition and the prevention of the defect ‘soft rind’ in cheese. Netherlands Milk and Dairy Journal, 26, 168–179. Geurts, T.J., Walstra, P. & Mulder, H. (1974) Transport of salt and water during salting of cheese. I. Analysis of the process involved. Netherlands Milk and Dairy Journal, 28, 102–129. Goodson, M. & Rowbury, R.J. (1989) Resistance of acid-habituated Escherichia coli to organic acids and its medical and applied signifi cance. Letters in Applied Microbiology, 8, 211–214. Goulding, A., Gold, E. & Campbell, A.J. (1993) Salty foods increase calcium requirements and are a potential risk factor for osteoporosis. IDF Newsletter, 138, 16–19. Guinee, T.P. (2004) Salting and the role of salt in cheese. International Journal of Dairy Technology, 57, 99–109. Guinee, T.P. & Fox, P.F. (1986) Transport of sodium chloride and water in Romano cheese slices during brining. Food Chemistry, 19, 49–64. Guinee, T.P. & Fox, P.F. (1993) Salt in cheese: physical, chemical and biological aspects. In: Cheese: Chemistry, Physics and Microbiology, 2nd edn (ed. P.F. Fox) vol. 1, pp. 257–302. Chapman & Hall, London. Guinee, T.P. & Fox, P.F. (2004) Salt in cheese: physical, chemical and biological aspects. In: Cheese: Chemistry, Physics and Microbiology, 3rd edn (eds P.F. Fox, P.L.H. McSweeney, T.M. Cogan and T.P. Guinee), vol. 1, pp. 207–259. Elsevier Academic Press, London. Hanna, M.O., Stewart, J.C., Carpenter, Z.L. & Vanderzant, C. (1977) Heat resistance of Yersinia enterocolitica in skim milk. Journal of Food Science, 42, 1134–1136. Hayaloglu, A.A., Guven, M. & Fox, P.F. (2002) Microbiological, biochemical and technological properties of Turkish White cheese ‘Beyaz Peynir’. International Dairy Journal, 12, 635–648. Hinterberger, S. (1964) Brine and its sterilization. Ostterich Milchwissenschaft, 19, 401–404 [abstract in Dairy Science Abstracts (1965), 27, 403]. Horwood, J.F., Lloyd, G.T., Ramshaw, E.H. & Stark, W. (1981) An off-fl avour associated with the use of sorbic acid during Feta cheese maturation. Australian Journal of Dairy Technology, 36, 38–39. Holmstrom, P. (1996) Purifi cation of cheese brine. Scandinavian Dairy Information, 10(1), 36–37. Hudson, L.M., Chen, J., Hill, A.R. & Griffi ths, M.W. (1997) Bioluminescence: a rapid indicator of Escherichia coli O157:H7 in selected yoghurt and cheese varieties. Journal of Food Protection, 60, 891–897. ICMSF (1988) Micro-organisms in Foods 4: Application of the Hazard Analysis Critical Control Point (HACCP) System to Ensure Microbiological Safety and Quality. International Commission on Microbiological Specifi cations for Foods (ICMSF) of the International Union of Microbiological Societies. Blackwell Science Ltd., London. IDF (1972) Determination of the Salt Content of Cheese, IDF Standard 17A. International Dairy Federation, Brussels. IDF (1988) Determination of Chloride Content – Potentiometric Titration Method, IDF Standard 88A. International Dairy Federation, Brussels. IDF (1990) Milk & milk products – Enumeration of Yeasts & Moulds – Colony Count Technique at 25°C, IDF Standard 94B. International Dairy Federation, Brussels.

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IDF (1995a) Milk & Milk Products – Detection of Salmonella spp., IDF Standard 93B. International Dairy Federation, Brussels. IDF (1995b) Milk & Milk Products – Detection of Listeria monocytogenes, IDF Standard 143A. International Dairy Federation, Brussels. IDF (1998) Milk & Milk Products – Enumeration of Coliforms at 30°C, IDF Standard 73B. International Dairy Federation, Brussels. IDF (1999) Milk & Milk Products – Enumeration of Presumptive Escherichia coli Content by Colony Count Technique at 44°C Using Membranes, IDF Standard 170. International Dairy Federation, Brussels. IFST (1999) Salt – Institute of Food Science and Technology (IFST) position statement. Food Science and Technology Today, 13, 221–225. Ingham, S.C., Su, Y-C. & Spangenberg, D.S. (2000) Survival of Salmonella typhimurium and Escherichia coli O157:H7 in cheese brines. International Journal of Food Microbiology, 61, 73–79. Jedrychowski, L., Reps, A., Jarmul, I. & Babuchowski, A. (1990) Use of natamycin for a protection of semi-hard cheeses against moulding. Brief Communications of XXIII International Dairy Congress, vol. 1, pp. 134. Mutual Press, Ottawa. Karaioannoglou, P., Koidis, P., Papageorgiou, D. & Mantis, A. (1985) Survival of Yersinia enterocolitica during the manufacture and storage of Feta cheese. Milchwissenshaft, 40, 204–206. Karakus, M. & Alperden, I. (1995) Effect of starter composed of various species of lactic acid bacteria on quality and ripening of Turkish white pickled cheese. Lebensmittel Wissenschaft und Technologie, 28, 404–409. Katic, V. (1995) The survival of Listeria monocytogenes in white brined cheese. Acta Veterinaria- Beograd, 45(1), 31–36. Katsiari, M.C., Voutsinas, L.P., Alichanidis, E. & Roussis, I.G. (1997) Reduction of sodium content in Feta cheese by partial substitution of NaCl by KCl. International Dairy Journal, 7, 465–472. Kaya, S. (2002) Effect of salt on hardness and whiteness of Gaziantep cheese during short-term brining. Journal of Food Engineering, 52, 155–159. Kendall, M. & Gilbert, R.J. (1980) Survival and growth of Yersinia enterocolitica in broth media and in food. In: Microbial Growth and Survival in Extremes of Environment (eds G.W. Gould & J.E.L. Corry), The Society for Applied Bacteriology Technical Series No. 15, pp. 215–226. Academic Press, London. Kirk, R.S. & Sawyer, R. (1991) Pearson’s Composition and Analysis of Food, 9th edn, pp. 47–52. Longman Scientiﬁ c and Technical, London. Larson, A.E., Johnson, E.A. & Nelson, J.H. (1993) Behavior of Listeria monocytogenes and Salmonella heidelberg in rennet whey containing added sodium and/or potassium chloride. Journal of Food Protection, 56, 385–389. Larson, A.E., Johnson, E.A. & Nelson, J.H. (1999) Survival of Listeria monocytogenes in commercial cheese brines. Journal of Dairy Science, 82, 1860–1868. Lloyd, G.T. & Ramshaw, E.H. (1979) The manufacture of Bulgarian-style Feta cheese – A review. Australian Journal of Dairy Technology, 34, 180–183. Luck, E. & Jager, M. (1995) Common salt. In: Antimicrobial Food Additives – Characteristics, Uses, Effects, 2nd edn, pp. 80–83. Springer, Berlin. Lück, H., Dunkeld, M. & Van DerMerwe, N.L. (1982) White pickled cheeses – manufacture and quality recommendations. South African Journal of Dairy Technology, 14, 31–35. Mansour, A. & Alais, C. (1973) Etude du salage et de l’afﬁ nage du fromage en saumure. Lait, 53, 137–145. Marcos, A. (1993) Water activity in cheese in relation to composition, stability and safety. In: Cheese: Chemistry, Physics and Microbiology, 2nd edn (ed. P.F. Fox), vol. 1, pp. 439–469. Chapman & Hall, London. Marriot, N.G. (1999) Principles of Food Sanitation, 4th edn. Aspen Publishers, Gaithersburg.

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Melilli, C., Barbano, D.M., Licitra, G., Tumino, G., Farina, G. & Carpino, S. (2003) Infl uence of presalting and brine concentration on salt uptake by Ragusano cheese. Journal of Dairy Science, 86, 1083–1100. Merin, U., Gordin, S. & Tanny, G.B. (1983) Microfi ltration of cheese brine. Journal of Dairy Research, 50, 503–509. Michaelidou-Koniordou, A.M. (1997) Protein hydrolysis during ripening of Feta cheese. PhD thesis, Aristotle University of Thessaloniki, Thessaloniki. Minor, T.E. & Marth, E.H. (1972) Loss of viability by Staphylococcus aureus in acidifi ed media: II Inactivation by acids in combination with sodium chloride, freezing and heat. Journal of Milk and Food Technology, 53, 548–555. Mitchell, R. (1978) Water Pollution Microbiology, Vol. 2. John Wiley & Sons, New York. Mondal, S., Gouph, R.H., Ryan, J.J. & Adkinson, R.W. (1989) Manufacture and evaluation of a Feta cheese. Cultured Dairy Products Journal, 24(4), 16–20. Mostert, J.F. & Jooste, P.J. (2002) Quality control in the dairy industry. In: Dairy Microbiology Handbook, 3rd edn (ed. R.K. Robinson), pp. 655–736. John Wiley & Sons, New York. Moustafa, K.M., Ahmed, A.H.A. & Marth, E.H. (1983) Behaviour of virulent Yersinia enterocolitica during manufacture and storage of Colby-like cheese. Journal of Food Protection, 46, 318–320. Otero-Rodriguez, A., Fernandez, A., Mendez, J. & Sanchez, S. (1998) Brining of cheese-brine recycling systems. Alimentacion Equipos y Technologia, 16, 71–75. Ottosen, N. (2004) Extension of Brine-processing Cycle Times by Membrane Technology. Document No. 389, pp. 121–127. International Dairy Federation, Brussels. Ottosen, N. & Konigsfeldt, P. (1999) Microfi ltration of cheese brine. Scandinavian Dairy Information, 13(1), 18–20. Ozer, B., Atasoy, F. & Akin, S. (2002) Some properties of Urfa cheese (a traditional white-brined Turkish cheese) produced from bovine and ovine milks. International Journal of Dairy Technology, 55, 94–99. Papademas, P. & Robinson, R.K. (1998) Halloumi cheese: the product and its characteristics. International Journal of Dairy Technology, 51, 98–103. Papageorgiou, D.K. & Marth, E.H. (1989a) Fate of Listeria monocytogenes during the manufacture, ripening and storage of Feta cheese. Journal of Food Protection, 52, 82–87. Papageorgiou, D.K. & Marth, E.H. (1989b) Behavior of Listeria monocytogenes at 4 and 22°C in whey and skim milk containing 6 or 12% sodium chloride. Journal of Food Protection, 52, 625–630. Pappas, C.P., Kondyli, E., Voutsinas, L.P. & Mallatou, H. (1996) Effects of salting method and storage time on composition and quality of Feta cheese. Journal of the Society of Dairy Technology, 49, 113–118. Pavia, M., Guamis, B., Trujillo, A.J., Capellas, M. & Ferragut, V. (1999) Changes in microstructural, textural and colour characteristics during ripening of Manchego-type cheese salted by brine vacuum impregnation. International Dairy Journal, 9, 91–98. Payne, M.R. & Morisson, K.R. (1999) A multi-component approach to salt and water diffusion in cheese. International Dairy Journal, 9, 887–894. Pearson, L.J. & Marth, E.H. (1990) Listeria monocytogenes – threat to a safe food supply: A review. Journal of Dairy Science, 73, 912–928. Pedersen, P.J. (1992) Microfi ltration for the reduction of bacteria in milk and brine. In: New Applications of Membrane Processes, IDF Special Issue 9201, pp. 33–50. International Dairy Federation, Brussels. Petran, R.L. & Zottola, E.A. (1989) A study of factors affecting growth and recovery of Listeria monocytogenes Scott A. Journal of Food Science, 54, 458–460. Prasad, N. & Alvarez, V.B. (1999) Effect of salt and chymosin on the physicochemical properties of Feta cheese during ripening. Journal of Dairy Science, 82, 1061–1067. Poolman, B. & Glaasker, E. (1998) Regulation of compatible solute accumulation in bacteria. Molecular Microbiology, 29, 397–407.

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Ramadan, F.A.M. (1995) Partial replacement of sodium by potassium in the manufacture of Domiati cheese. Egyptian Journal of Dairy Science, 23, 259–270. Ramsaran, H., Chen, J., Brunke, B., Hill, A. & Griffi ths, M.W. (1998) Survival of bioluminescent Listeria monocytogenes and Escherichia coli O157:H7 in soft cheese. Journal of Dairy Science, 81, 2053–2064. Reddy, K.A. & Marth, E.H. (1991) Reducing the sodium content of foods: A review. Journal of Food Protection, 54, 138–150. Reddy, K.A. & Marth, E.H. (1994) Sensory evaluation of Cheddar cheese made with sodium chloride or mixtures of sodium and potassium chloride. Journal of Sensory Studies, 9, 187–204. Reddy, K.A. & Marth, E.H. (1995) Microfl ora of Cheddar cheese made with sodium chloride, potassium chloride, or mixtures of sodium and potassium chloride. Journal of Food Protection, 58, 54–61. Reitsma, C.J. & Henning, D.R. (1996) Survival of Escherichia coli O157:H7 during the manufacture and curing of Cheddar cheese. Journal of Food Protection, 59, 460–464. Robinson, R.K. & Wilbey, R.A. (1998) Cheesemaking operation. In: Cheesemaking Practice – R. Scott, 3rd edn, pp. 165–192. Aspen Publishers, Maryland. Saboya, L.V. & Maubois, J-L. (2000) Current developments of microfi ltration technology in the dairy industry. Lait, 80, 541–553. Samal, P.K., Pearce, K.N., Bennett, R.J. & Dunlop, F.P. (1993) Infl uence of residual rennet and proteolysis on the exudation of whey from Feta cheese during storage. International Dairy Journal, 3, 729–745. Samaras, F.I., Kehagias, C., Arkoudelos, J.S. & Bocaris, M.I. (2003) Investigation on ropiness by isolates of the genera Lactobacillus, Alcaligenes and Feta cheese starter cultures. Food Microbiology, 20, 503–509. Santana, L., Uriarte, E., DallaVia, L. & Gia, O. (2000) A new benzoangelicin with strong photobio- logical activity. Bioorganic and Medicinal Chemistry Letters, 10, 135–137. Seth, R.J. & Robinson, R.K. (1988) Factors contributing to the fl avour characteristics of mould-ripened cheese. In: Developments in Food Microbiology (ed. R.K. Robinson), vol. 4, pp. 23–47. Elsevier Applied Science, London. Smith, G.M., Smith, L.T., Gerhardt, P.N.M. & Ko, R. (1998) Solute transport enzymes related to stress tolerance in Listeria monocytogenes: A review. Journal of Food Biochemistry, 22, 269–285. Stern, N.J. (1981) Isolation of potentially virulent Yersinia enterocolitica from variety meats. Journal of Food Science, 46, 41–42. Sutherland, B.J. (2002) Salting of cheese. In: Encyclopedia of Dairy Science (eds H. Roginski, J.W. Fuguay & P.F. Fox), pp. 293–300. Academic Press, London. Swaminathan, B., Harmon, M.C. & Mehlamn, I.J. (1982) Yersinia enterocolitica: A review. Journal of Applied Bacteriology, 52, 151–183. Tamime, A.Y. & Kirkegaard, J. (1991) Manufacture of Feta cheese – Industrial. In: Feta and Related Cheeses (eds R.K. Robinson & A.Y. Tamime), pp. 70–143. Ellis Horwood, Chichester. Tamime, A.Y. & Robinson, R.K. (1999) Yoghurt Science and Technology, 2nd edn. Woodhead Publishing, Cambridge. Tschager, E. (1988) Quality control of brine in practical operations. North European Food and Dairy Journal, 7, 249–255. Tukan, S.K. & Humeid, M.A. (1991) Salt and moisture relationships in brined cheese. Australian Journal of Dairy Technology, 11, 85–87. Turhan, M. & Kaletunç, G. (1992) Modeling of salt diffusion in white cheese during long-term ripening. Journal of Food Science, 57, 1082–1085. Tzanetakis, N. & Litopoulou-Tzanetaki, E. (1992) Changes in numbers and kinds of lactic acid bacteria in Feta and Teleme, two Greek cheeses from ewe’s milk. Journal of Dairy Science, 75, 1389–1393. Vafopoulou, A., Alichanidis, E. & Zerfi ridis, G. (1989) Accelerated ripening of Feta cheese, with heat- shocked cultures of microbial proteinases. Journal of Dairy Research, 56, 285–296.

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Vafopoulou-Mastrojiannaki, A., Litopoulou-Tzanetaki, E. & Tzanetakis, N. (1990) Effect of Pediococcus pentosaceus on ripening changes of Feta cheese. Microbiologie-Aliments-Nutrition, 8, 53–62. Van Schaik, W., Gahan, C.G.M. & Hill, C. (1999) Acid-adapted Listeria monocytogenes displays enhanced tolerance against the antibiotics nisin and lacticin 3147. Journal of Food Protection, 62, 536–539. Veinoglou, B.C., Boyazoglou, E.S. & Kotouza, E.D. (1980) The effects of starters on the production of Teleme cheese. Dairy Industries International, 45(8), 11–16 & 63. Yanai, Y., Rosen, B., Pinsky, A. & Sklan, D. (1977) The microbiology of pickled cheese during manufacture and maturation. Journal of Dairy Research, 44, 149–153. Yankov, Y. & Denkov, T. (1972) Microbiological study of the cause of slime formation in the brine of white pickled cheese. Izvestiya, 6, 103–111 [abstract – 3367; Dairy Science Abstracts (1974) 36, 397]. Yaygin, H. (1971) [The properties of White cheese brines.] Dairy Science Abstracts, 35, 848. Zerﬁ ridis, G.K. (2001) Technology of Milk Products – Cheese Technology, 2nd edn. Aristotle University of Thessaloniki, Thessaloniki. Zorrilla, S.E. & Rubiolo, A.C. (1994) Modeling NaCl and KCl movement in Fynbo cheese during salting. Journal of Food Science, 59, 976–980.

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A.Y. Tamime and R.K. Robinson

10.1 Background

The earliest type of cheese appears to have been produced in Iraq around 6 000 BC, but the idea spread rapidly into Egypt where soft curd cheeses made from caprine milk became part of the normal diet. Although mildly acidic from the fermentation of lactose to lactic acid by the indigenous microfl ora of the milk, those soft cheeses would have deteriorated rapidly at the temperatures prevalent in the Middle East. However, the addition of salt would have offered a number of advantages, including: • a restriction of unwanted microbial growth; • an expulsion of whey and fi rming of the curd; • a masking of any off-fl avours that may have developed during production; and • an improvement in the desired fl avour. It was not surprising, therefore, that the addition of salt to the curd and/or the storage of the curd in brine became the standard practice throughout the Middle East and those countries that border the Mediterranean. Numerous local variants arose over time, and some types became identifi ed with specifi c geographical areas, for example Feta in Greece, Halloumi in Cyprus and Domiati in Egypt (see Chapters 2, 4 and 5). In some cases, the derivation of a local cheese involved a modifi cation of the basic process in order to give a cheese with distinctive characteristics, or to make it amenable to storage. The boiling of Halloumi cheese in salted whey, for example, gives a cheese that is unique in texture and fl avour. The fact that many of these cheeses still dominate the markets in their regions of origin emphasises their historic links, and such links have given local inhabitants hundreds of years to consider how best to exploit and enjoy the special properties of the cheeses in question. In some cases, the product(s) of these developments have acquired international status through emigration, so that today, restaurants around the world might make a cheese-based dish or foodstuff that was originally found only in one or two villages. Obviously, cheese will always remain a staple food in its own right, but some of the ways in which traditional cheeses have been utilised to enhance the diets of ordinary people deserve a special mention. It is universally accepted that cheese is mainly consumed in sandwiches, or with biscuits, fruits, nuts and wine complementing the other courses of the main meal

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at home or in restaurants. However, consumers in different parts of the world dic- tate how cheese is consumed, based on tradition and food habits, and this chapter provides a brief overview of how brined cheeses are utilised in different regions of the world. Although the content of this chapter may not be highly scientiﬁ c, the unique forms of brined cheese consumption may give scientists and technologists an insight into how to develop closely related cheese varieties, which are unknown to local consumers and, at the same time, may assist the marketing of the well-known imported brined cheese varieties in local markets.

10.2 Salad dishes

Brined cheeses are distinctively salty in nature, and a very popular way to consume some of these varieties, for example Feta, in many Mediterranean countries is to utilise the cheese as an ingredient during the preparation of fresh salads. One such example is known as Greek salad. A dressing is prepared in a large bowl using a clove of garlic (i.e. crushed), lemon juice and olive oil (without the addition of salt as Feta cheese is rather salty). Lettuce and tomatoes are cut into small pieces, along with cheese and cucumber, and mixed with the dressing. This salad can be eaten as an aperitif or as a salad side-dish complementing the main course of the meal. A closely similar dish, which is very popular in Cyprus, is known as Nicosia or tuna salad. It is prepared in a similar manner to the Greek salad containing Feta cheese, but boiled vegetables (e.g. peas, green beans and carrots), potatoes and egg are diced and added to the lettuce, tomatoes and cucumber mixture. Finally, processed tuna ﬁ sh (i.e. from a metal tin) is added to the other ingredients and mixed together. Although this dish is eaten as an aperitif, on a hot day it may be consumed with pitta bread as a main course of a meal. Other salad dishes which are made with Feta cheese and are popular in Greece are known as aubergine salad (melitzanosalata me feta) and village salad (salata horiatiki) (Tolis, 1999).

10.3 Snacks and savoury dishes 10.3.1 Cheese snacks Halloumi recipes Halloumi cheese is considered to be one of the most versatile types of cheese in the world. It can be served fresh together with fruit, especially watermelon, grilled due to its unique property of not melting, fried in omelettes, used to accompany traditional Cypriot foods, such as sausages, bakery goods or traditional cheese pies, or grated on top of pasta and other dishes. Well-matured Halloumi cheese can be served with alcoholic drinks, such as rich red wines and locally made white strong spirits (e.g. Zivania). The distinctive properties of some brined cheese varieties are reﬂ ected in their usage, so that while Feta, for example, is mainly consumed with fresh salads,

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Halloumi is often grilled or fried in butter and eaten warm. The cheese portion is removed from the brine, rinsed with good quality tapwater and cut into thick slices to be eaten fresh or cooked. Halloumi cheese is used in many food recipes, and some of the most popular ones are described here. • Halloumi cheese in pitta bread – the fresh product is grilled and placed between the two layers of warm pitta bread; slices of tomato are usually added and it is eaten as a hot sandwich (Fig. 10.1); alternatively, it is prepared as a sandwich with jam. • Ravioli with Halloumi cheese – ravioli, the traditional pasta of Cyprus, is stuffed with Halloumi cheese; once boiled, fresh Halloumi is grated on top together with crushed mint. • Fried Halloumi cheese with lime and caper vinaigrette – the fresh product is cut in thin slices, covered with ﬂ our and fried in a hot pan in little olive oil, until golden; this is followed by the addition of caper vinaigrette, and it is served with warm pitta bread (Fig. 10.2).

The melting properties of Halloumi cheese during cooking are totally distinct from the properties of Mozzarella cheese, for example. The exploitation of the unique properties of certain cheeses continues today, so that a pizza topped with Mozzarella

Fig. 10.1 Halloumi cheese shallow-fried in olive oil and served in pitta bread with tomato and fresh mint. Reproduced in colour as Plate 6, after page 236

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Fig. 10.2 Halloumi cheese. From left to right: fried in olive oil, grilled and both served with capers; fresh cheese served with blackcurrant jam; grated cheese with dried crushed mint leaves. Reproduced in colour as Plate 7, after page 236

gives the consumer a sensory reaction that is totally different from biting into a pizza made with Halloumi.

Akkawi recipes Akkawi, Nabulsi, braided or Halloumi cheeses are widely consumed as a snack in the form of a sandwich using a French baguette. The high salt content in these cheeses may limit consumer acceptability; however, in certain instances, jam may be added to the sliced cheese during the preparation of the sandwich (Fig. 10.2). Alternatively, the cheese baguette may be heated between two hot metal plates or grilled to melt the cheese; before serving, sliced tomatoes and/or diced cucumber are added on top of the melted cheese in order to garnish the sandwich and reduce the salty taste. In Lebanon and most Arab countries, a very popular snack is known as Mankoushi or Mankousheh with Zaatar, regarded as a herb-type pizza (Saleh, 1996). The dried ingredients used to prepare Zaatar are: thyme, sumac (http://www.theepicentre. com/Spices/sumac/html), sesame seed and salt. The other ingredients required to make the Mankoushi are: pitta or Arabic bread dough (i.e. made from unbleached ﬂ our, yeast, salt and water), olive oil and onions. A small ball of the prepared

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(a) (b) (c)

Fig. 10.3 Lebanese Mankoushi cheese preparation (a), after baking (b) and the stretching of the cheese (c). Reproduced in colour as Plate 8, after page 236

dough is fl attened fi rst by hand and then with a rolling pin into a circle ~ 20–25 cm in diameter. Then the onion is chopped into fi ne pieces, mixed with Zaatar and marinated with olive oil to form a thick but runny mixture; this mixture is spread thinly over the dough, which is baked in an oven for few minutes until the top is slightly golden in colour. Chopped fresh mint can be added to the Zaatar and olive oil mixture if desired. A variant of this snack is known as Mankoushi with cheese. Desalted Akkawi, Nabulsi or any closely related brined cheese is chopped into fi ne pieces and sprinkled evenly over the Mankoushi dough (Fig. 10.3a), followed by baking in an oven (Choueiri, 1998). As a consequence, the cheese melts during the baking stage (Fig. 10.3b), which results in the stretching of the cheese (Fig. 10.3c). Incidentally, the Mankoushi is normally consumed hot. In some instances, half of the Mankoushi dough is covered with a thyme/oil mixture, whilst the remaining section is topped with desalted Akkawi cheese. When this type of Mankoushi is consumed hot, the taste of the melted cheese complements the taste of the thyme in the product.

Creamy Chanco (Gauda) recipes A Chilean cheese snack known as Empanada is made with creamy Chanco cheese (Fig. 10.4). The dough is prepared from wheat ﬂ our (500 g), salt (5–10 g) and water and, when ready, it is rolled into a thin sheet 4–6 mm thick; the amount of cheese used is ~500 g. The ﬂ attened dough is cut into circles (i.e. 10 cm in diameter), and the diced Chanco cheese is placed onto one half of the circle. The circumference of the dough is moistened with water, folded in a semicircle and pressed to seal the edges. The snack is fried and served hot with wine for adults or with a sweet beverage for children.

Rennet cheese In Brazil, Rennet cheese is mainly roasted over a barbecue, and it is a popular snack on the beach or around the swimming pool (Fig. 10.5).

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Fig. 10.4 A Chilean snack (Empanada) made with creamy Chanco cheese. Reproduced in colour as Plate 9, after page 236

Fig. 10.5 Barbecued Rennet cheese. Reproduced in colour as Plate 10, after page 236

10.3.2 Savoury dishes A wide range of savoury dishes are made in different countries using brined cheese as one of the ingredients during cooking, and some examples follow.

Lebanese cuisine (see www.lebaneseproducts.com/recipe/main.htm) Fatayer with spinach is a famous and nutritious Lebanese dish (Saleh, 1996), which is made with dough that has been kneaded with olive oil. The dough is ﬂ attened with a rolling pin into a large circle, and cut into small circles (4–5 cm in diameter) using a pastry cutter. In the meantime, the spinach leaves are washed with cold water, drained, sprinkled with a little salt mixed with chopped onions, and ﬂ avoured with concentrated sour pomegranate juice or lemon juice, pepper and pine nuts (optional). Hand-mix all the ingredients together until the volume of the spinach is reduced. Afterwards, a small amount of the spinach mixture is placed in the centre of each

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Fig. 10.6 Lebanese cheese rolls made with desalted Akkawi cheese and deep fried in oil. Reproduced in colour as Plate 11, after page 236

small dough circle, and the dough is formed into a triangle by bringing-up three sides to the centre and pinching the edges fi rmly to seal in the fi lling. The triangles are placed on an oiled tray and baked for ~20 min. To enhance the fl avour of Fatayer, fi nely chopped brined cheese (e.g. Nabulsi, Akkawi or Feta) is added to the spinach mixture (without the addition of pomegranate or lemon juice) before forming the pastry dough triangle. The cooked pastry may be consumed hot or cold. A similar dish is prepared by replacing the spinach fi lling with cooked mince plus onions and pine nuts before shaping the pastry and baking; the dish is known as Sambousek with lamb (Saleh, 1996). Alternatively, another Lebanese snack (i.e. cheese rolls) is made from desalted Akkawi cheese mixed with fi nely chopped parsley and grated onions. The dough, which is known locally as Rqaq, is cut into triangles, topped with the cheese mixture, and the dough is wrapped into ‘fi ngers’ or rolls; the open ends are dampened with milk or egg batter, pressed to close, and the rolls are deep fried in oil (Fig. 10.6) (Choueiri, 1998).

Moroccan cuisine Shrimps with tomato and Feta cheese is a Moroccan dish prepared by frying chopped onions in olive oil at low temperature in a pan and, when sautéed, adding sliced pepper and cooking for 2–3 min. Deseeded ripe tomatoes that have been cut into large pieces are added, and garnished with salt, sugar, oregano and pepper. After simmering and stirring for 15 min until the sauce thickens, cleaned shrimps with parsley are added, and the sauce is placed in a tray, sprinkled with diced Feta or a closely related cheese, and baked for 30 min. The dish is served hot with boiled rice (optional) and a salad. Meat soup with Feta cheese is another tasty Moroccan dish. Meat broth is placed in a casserole along with carrots, onions and celery, and simmered for 15 min. Washed rice or star-shaped pasta is added and simmered for another 20 min. When

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ready, small pieces of Feta cheese are added and, after sprinkling with pepper, the dish is served hot.

Miscellaneous Greek dishes made with Feta cheese Greek cuisine is rich and famous, with many recipes for the preparation of a wide range of dishes, and the reader should refer to relevant websites to obtain more information on how the dishes are prepared in detail, for example: http://www. gourmed.gr/greek-recipes/show.asp?gid=1&nodeid=17&arid=5078, and http:// www. dodonicheese.com/Home/Recipes/SaladsAppetizers/Saganaki.xml.aspx? Some examples of these dishes, which are made with Feta cheese, are given here. • Shrimps with onions, garlic, tomatoes, bay leaf, salt, pepper and sugar (garides me feta). The onions are fried in oil in a saucepan and all the ingredients added except the cheese (simmer for 20 min). After cleaning, the shrimps are added to the pan and boiled for 5 min. All the ingredients are then put into a clay pot, covered with thick slices of Feta cheese, and the dish is baked for 6–8 min, then served hot. • Pie dishes made with spaghetti and layers of pastry (makaronopitta), cheese pie (tiropitta) and rice pie (rizopitta). • Eggs with tomatoes, green pepper and Feta cheese (avga kayiana). Slices of tomato are fried in oil for a few minutes in a pan. Eggs beaten with milk are added to the frying pan along with grated cheese and cooked for few minutes with continuous stirring. After garnishing with pepper and oregano, the dish is served hot on sliced bread. • Balls made with zucchini (kolokythokeftedes), or potato (patatokeftedes) and cheese. • Little cheese pies made from ‘ﬁ lo’ pastry ﬁ lled with grated cheese, chopped parsley, eggs and grated cheese (tiropittakia). The pies are brushed with melted butter and baked for 15 min (Tolis, 1999). • Feta and lamb pie (Barron, 2002).

Turkish cuisine Many Turkish dishes are made using traditional cheeses; excluding food garnished with cheese and pasties, some examples are as follows. Bacu is made from White brined cheese slices, which have been softened by the addition of boiling water. The softened cheese slices are covered with fl our (sometimes after fi rst being dipped in beaten egg) and fried in a frying pan. Bacu is served garnished with chopped tomatoes, green pepper and parsley. Mihlama is a traditional dish in which a dried white cheese made from sheep’s or goat’s milk is melted in a frying pan, and cornfl our and eggs are added to the melted cheese. The mixture is stirred vigorously and served as a hot dish.

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Brazilian cuisine Brazilian cheeses, such as Minas Frescal and Minas Padrão, are widely used for the preparation of baked cheese rolls with salami (Rocambole Salgado; www.vigor. com.br), and a cheese and potato soup (Sopa de Batata com Queijo; www.prolane. com.br), respectively. For the former dish, the ﬂ attened dough is covered with diced cheese, slices of salami, pieces of tomatoes and chopped onions. The dough with its ingredients is rolled, placed on a greased tray and baked for 40 minutes. The cheese roll is sliced and served hot (optional cold). The soup dish is prepared using chicken stock and one chicken breast, potatoes, tomatoes, chillies, chopped onion, garlic and chopped parsley. Mashed potatoes are added to the chicken broth after cooking the breast and the rest of the ingredients, and the whole is simmered gently. The parsley and grated Minas Padrão cheese are added to the soup when it is ready to be served (www.prolane.com.br). Baked cheese ball, known as Bolo Salgado de Milho (i.e. salty maize cake; www. vigor.com.br), is made from corn, fried onions, eggs and Minas Frescal cheese. The ingredients are baked in a greased pan for 50 minutes, and the cheese balls are mainly consumed hot

Philippine cuisine Most of the uncooked cheese varieties made in the Philippines are used as a fi lling for ‘pan de sal’, a local bread usually eaten by Filipinos at breakfast. The cheese is also used as an ingredient in fresh vegetable salads made up of Romaine or Iceberg lettuce, tomatoes, cucumber and spring onions. Diced cheese in cubes is also served during cocktail parties. One culinary use of the cheese is as a topping together with salted egg in ‘bib- ingkang galapong’, a native rice cake prepared from a mixture of fermented rice fl our, sugar and water, and cooked in shallow clay dish lined with banana leaves; hot charcoal is placed on the top and the bottom of the dish. The cheese is also used in cordon bleu entrées or sliced, fried and then eaten with rice. Old cheese (i.e. 2–3 weeks) is washed, sliced, fried and then eaten as a fi lling in sandwiches or as rice-food dishes.

10.4 Desserts 10.4.1 Knafeh, Kunafeh or K’nefe bi-jibn (pastry with cheese) This dish is a good example of how a local cheese with special properties was used to make a dessert that is now popular throughout the Middle East (see Fig. 10.7). It originated in Jordan, and owed much of its early popularity to the special properties of Nabulsi cheese (Haddadin et al., 1995). The Lebanese variant is made from the following main ingredients: desalted Akkawi or a closely related brined cheese, semidried vermicelli or semolina, anhydrous milk fat (AMF)/ghee or melted butter (Fig. 10.8a), and it is served with

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Fig. 10.7 General view of a sweet dish called Knafeh. Reproduced in colour as Plate 12, after page 236.

(a) (b)

Fig. 10.8 Preparation and serving of Knafeh. (a) Main ingredients (see text); (b) ﬁ lling and compressing the vermicelli or semolina/AMF mixture in a greased baking tray; (c) spreading the desalted cheese; and (d) stretching the cheese after the baking stage. Reproduced in colour as Plate 13, after page 236

a syrup known as ‘atter’. The vermicelli is mixed with tempered AMF, warmed in a pan over an open fi re and turned for a few minutes. After cooling, it is ground through a coarse sieve. A shallow baking tray is then smeared with AMF, and the vermicelli/AMF mixture is fl attened into a thin layer (~0.5 cm) using a nonstick paper or plastic sheet (Fig. 10.8b). This ensures a compact layer of the cereal mixture without any air holes. The tray is heated gently over an open fi re until the mixture

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is golden brown in colour (Fig. 10.7); afterwards, the topside can be browned in an oven (optional) (J. Ghazal & K. Ghazal, personal communication). In the meantime, the desalted slices of Akkawi cheese are crumbled and warmed in a pan. After allowing the cheese to cool slightly, it is squeezed by hand to remove the excess moisture and distributed evenly over the cooked vermicelli, i.e. ~1 cm in depth (Fig. 10.8c). An empty shallow baking tray is smeared with AMF, and placed upside down over the fi rst tray containing the cooked vermicelli and layer of cheese; the empty tray should be slightly larger in diameter. The trays are turned over so that the cooked vermicelli is on the top side, whilst the cheese now forms the bottom layer; the top tray is tapped gently to release the cooked vermicelli without breaking. Place the tray over an open fi re and, while heating slowly, gently press the entire surface to ensure that the cheese layer is free from any air pockets, otherwise the heated air will burst through the cooked surface of the vermicelli. Afterwards, spread a thin layer of syrup over the surface to consolidate the cereal layer, and keep heating gently over an open fi re until the Knafeh is ready (i.e. the cheese stretches; see Fig. 10.8d). An alternative method of Knafeh preparation consists of spreading the cereal/AMF mixture in a greased shallow baking tray, topping with desalted Akkawi cheese and baking in the oven. When the dish is ready, the entire contents are inverted onto another tray as described above. The atter or syrup is prepared by boiling sugar (285 g) with water (200 mL) and lemon juice; the mixture is allowed to simmer for 8–10 min until it thickens, and then it is garnished with rose water. It is placed in a jug and stored at ambient temperature (Choueiri, 1998; Saleh 1996). As a sweet dish, Knafeh is mainly served warm with ‘caake’, i.e. pitta bread made with sesame seeds. The bread is split open, smeared with atter (Fig. 10.9a) and fi lled with a portion of Knafeh (Fig. 10.9b). Alternatively, it can be eaten in sweet shops, and the Knafeh is served on a plate (Fig. 10.9c).

10.4.2 ‘Sweet’ cheese This is another Lebanese sweet dish made with cheese, which is known locally as Halawet al-jibn (‘sweet cheese’ in Arabic). It originated from Tripoli in the north, and it is made from desalted Akkawi or Mujaddal/braided cheese and a syrup similar to atter. According to Saleh (1996), the homemade sweet dish consists of melting the cheese (500 g) in a nonstick pan and, when melted, adding the syrup (110 mL), semolina (225 g), rose water (120 mL) and stirring vigorously until the cheese/dough mixture pulls away nicely from the side of the pan. In the meantime, some syrup is spread over a clean work surface (45 × 45 cm in area) and, while the cheese/dough is still hot, it is placed over the syrup and ﬂ attened into a rectangular shape (3–4 mm thick) using a rolling pin moistened with more syrup, and allowed to cool. The cool cheese/dough mixture is cut into small rectangles (3.75 × 5 cm), rolled into ‘bite-size’ pieces and served with ‘kashta’ (prepared by heating milk in shallow trays and skimming the denatured proteins containing the fat that rises to the surface). Sometimes, the rolled pieces are covered with cracked pistachio nuts.

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(a) (b)

Fig. 10.9 Serving Knafeh as a sweet dish. (a) Smearing the ‘caake’ with atter; (b) placing a Knafeh portion in the ‘caake’; and (c) serving Knafeh on a plate in a sweet shop. Reproduced in colour as Plate (c) 14, after page 236

However, the industrial preparation of Halawet al-jibn consists of melting the desalted Akkawi or Mujaddal/braided cheese (Fig. 10.10a ) at ~60°C or until the cheese mass acquires a dough-like consistency (Fig. 10.10b); the end point is assessed when the mass can be stretched with a spatula without breaking. Fine semolina is added, and mixed thoroughly with the cheese mass (Fig. 10.10c). The mix is placed on a stainless steel board, and subjected to cycles of stretching and folding (i.e. usually 4 or 5 times) (Fig. 10.10d). The cheese/semolina mixture is ﬂ attened into a layer (~0.5 cm thick) by stretching manually (Fig. 10.10e), coated with syrup and rested for 5–10 min (Fig. 10.10f). Finally, it is cut into rectangular pieces (5–6 cm × 50 cm), topped with Kashta and rolled into a cylinder. It is then cut into ‘bite-size’ pieces, coated with syrup and garnished with crushed pistachio nuts and served (Fig. 10.11) (Najjar, 2004).

10.4.3 Hosmerim Hosmerim is a Turkish dessert that is made mainly from unsalted or desalted White cheese. The cheese is melted in a frying pan and ﬂ our is added slowly to the melted cheese. The mixture is stirred for ~20–30 min, and then poured into another pan, i.e. ~1 cm thick, and fried for 6–7 min. Sugar is then added to the hot mixture of cheese and ﬂ our. The Hosmerim is allowed to cool and is served cold as a dessert.

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(a) (b)

(e) (c)

(d) (f)

Fig. 10.10 Preparation of Halawet al-jibn. (a) Desalted brined cheeses; (b) melting the cheese; (c) mixing with semolina to form a dough-like consistency; (d) folding/stretching the cheese mixture; (e) manually stretching the cheese dough; and (f) coating the stretched cheese dough with syrup. Reproduced in colour as Plate 15, after page 236

Fig. 10.11 Halawet al-jibn as a sweet dish. Reproduced in colour as Plate 16, after page 236.

10.4.4 Brazilian sweet cheese dishes Some examples of sweet dishes made with cheeses such as Minas Frescal and Minas Padrão in Brazil include creamed cheese pudding (Pudim de Queijo Cremoso), cheese cake (Queijadinha Cake) and cheese ball (Bolo de Milho). The cheese pudding is made from wheat ﬂ our (360 g), milk (750 mL), cheese (500 g plus 50 g Parmesan), eggs (15 yolks), sugar (800 g plus 120 g granulated brown sugar for caramelisation) and melted butter (5 tablespoons). The pie tin containing all the

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ingredients is placed in a large roasting pan ﬁ lled with water, and cooked in the oven similar to crème caramel.

10.5 Conclusion

This chapter has sought to highlight some traditional uses of white brined cheeses that are specifi c to those countries where the preservation of cheese in brine has been practised for many years. Equally important is the fact that routine culinary uses, such as the crumbling of Gibna Baida over bean dishes in Sudan, have been ignored, and yet the coverage still emphasises just how versatile cheeses like Feta or Akkawi can be. Thus, whether the cheese is served sliced or crumbled, hot or cold, these white brined cheeses can bring a texture and fl avour to a dish that is totally distinctive. The wide range of dishes is also an indication of widespread consumer acceptability of a product that, aside from its fl avour impact, provides an excellent source of protein. Obviously some authorities may criticise brined cheeses for their high salt content but, as a component of a balanced meal, the overall intake of NaCl is probably lower than might be associated with many factory-processed foods. In addition, some of the earlier chapters have indicated just how important the production of brined cheeses is to many rural economies, so that even more widespread usage in a variety of local dishes is a trend that deserves to be encouraged.

Acknowledgement

The authors thank all the authors of this publication for providing information regarding the utilisation of cheeses in their own country; also, one of us (AYT) thanks Jamal Ghazal and Kamal Ghazal for all the illustrations regarding the manufacture of Knafeh.

References

Barron, R. (2002) Meze – Small Bites, Big Flavors from the Greek Table. Chronicle Books, San Francisco. Choueiri, R. (1998) [Chef Ramzi Fi Alam Al Sabah.] Academia International, Beirut. Haddadin, M.S.Y., Shahin, R.M.A. & Robinson, R.K. (1995) Nabulsi: a Jordanian cheese. Dairy Industries International, 60(7), 33–35. Najjar, M. (2004) Development of a Hazard Analysis Critical Control Points (HACCP) plan for Halawet El Jibn (a Lebanese cheese derived pastry). MSc thesis, Faculty of Agricultural and Food Sciences, American University of Beirut (AUB), Beirut. Saleh, N. (1996) Fragrance of the Earth – Lebanese Home Cooking, pp. 71–75 & 205–210. Saqi Books, London. Tolis, T. (1999) Greek Cooking – Traditional Recipes. Ekdotiki Athinon, Athens.

Note: page numbers in bold indicate tables or salting/brining data 267 illustrations bleaching agents 97–8 ‘blowing’, caused by coliforms 278 abomasa, rennet production 47–8, 140, 157–8, bovine milk 198 breeds and composition 120–1 acidifi cation see pH caseins 18 Acinetobacter spp. 204 milk salts 9 Aeromonas spp. 204 whey proteins 16 blowing 278 world production 4 Domiati cheese 149 Braided cheese 167, 171 Akkawi cheese 188–9 Brazil 212–28 composition 189, 194 Meia Cura 223 recipes 305–6, 308, 310–12 milk utilization for cheese 214 albumins 16–17 Minas varieties 215–23 Alcaligenes spp., slime formation 277 names and volumes of cheese 215 Algeria Prato 223–7 milk consumption 142 productivity of dairy cattle 212–14 milk production 141 recipes 310, 314–15 alkaline phosphatase 26–7 Rennet cheese 227–8 alpha-lactalbumin (alpha-la) 16 Brevibacterium linens 148 amines 70, 204 brine tanks, cleaning programme 285–6 amino acids, White (Turkish) cheeses 203 brine/brining 264–301 Anthotiros whey cheese 60 brine volume/cheese weight 271 chemical composition of brines 271–2 Bacillus cereus, Domiati cheese 149 concentration, and Baumé hydrometry 287 Bacillus spp., ‘late blowing’ 278–9 concentration and duration of salting 269–70 Bacteriologically Acidifi ed Feta-type (BAF) system dry-salting vs brining 266–8 87–92, 90 methods 266–9 plant specifi cation 104–5 microbiology of brines 274–9, 289–90 bactofugation 84–5 purifi cation methods 290–4 Bacu 309 chemical 290–1 Balkan cheeses 68–9 heat 291 banana leaves, packing 249–50 kieselguhr fi ltration 292–3 Batzos cheese 62–3 optimal 290 salting/brining data 267 ultrafi ltration 293–4 Baumé hydrometry, and salt concentration 287 UVA light + furocoumarins 291–2 Belir Sir U Kriskama 69 UVC light 291 1-3-benzoate 279 quality control 286–90 benzoyl peroxide, Feta-type cheese 97–8 role of brining 265–6 beta-lactoglobulin (beta-lg) 15–16 temperature of brine 270, 288–9 Beynaz Peynir 69 water activities 275 salting/brining data 267 brined cheeses, world production 1–3, 2 biofi lms 285–6 Brinza, salting/brining data 267 Bjalo Salamureno Sirene 68–9 Bryophyllum spp. 159 compared with Feta 68 buffalo, carabao (Philippine swamp buffalo) 249

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buffalo milk Chanco cheese 237–41 caseins 18 recipes 306 milk salts 9 schema 240 whey proteins 16 Cheddar cheese, salt content 264 world production 4 chemical, purifi cation of brine 290–1 Bulgarian white, salting/brining data 267 Chile 229–44 Chanco 237–41 calcium cheese varieties 236–7 measurement 288 Gauda 241, 243 and rennet-induced coagulation 31–2 main dairy plants 233 calcium chloride 216 milk utilization for cheese 231, 232 Feta-type cheese 95–7 recipes 306 and pH 31 chymosin, recombinant 140 calcium phosphate, colloidal (CCP) 9–10, 19 cleaning programme, brine tanks 285–6 calcium phosphate nanoclusters 20, 21, 22 Clostridium spp. calotropain 159 Domiati cheese 149 Calotropis procera 159, 160 ‘late blowing’ 278–9 camel’s milk Mish cheese 154 addition of calcium salts 174 coagulation brined cheese 172–5, 176–9 acid-induced 23 composition 173 in Feta-type cheese 91 vs cow’s milk 173 in Halloumi cheese 122 Campylobacter spp., Domiati cheese 149 heat-induced 23 Candida boidinii 131 plant coagulants 158–9, 198–9 Candida parapsilosis 131 rennet-induced 29–33 Candida versatilis 131 Coalho (Rennet) cheese, Brazil 227–8 caprine milk cold storage, and casein dissociation 32 caseins 18 coliforms Cyprus, breeds and composition 118–21 defi ned 278 Greece, breeds and composition 47 drinking water, standards 289 milk salts 9 ‘early blowing’ 278 whey proteins 16 colloidal calcium phosphate (CCP) 9–10, 19 world production 4 colostrum, immunoglobulins 17 caproic, caprylic and capric acids 47 compatible solutes 284 carabao (Philippine swamp buffalo) 249 control measures 285–6 cardoon 158–9 cooking see food preparations casein micelles 19–24 Coryneforuis spp., Domiati cheese 149 acid-induced coagulation 23 Cottage cheese, salt content 264 addition of ethanol 24 cow’s milk see bovine milk binding of caseins and calcium phosphate culinary use see food preparations nanoclusters 22 Cynara cardunculus (cardoon) 158–9 cross-section 20 Cyprus dual binding model of structure 21 cheese production 117 heat-induced coagulation 23 milk production 120 microstructure 19–22 see also Halloumi cheese stability and dissociation 22–4 caseins 17–24, 18 Debaryomyces hansenii 131 alpha-casein 18 decolorising agents, Feta-type cheeses 97 beta-casein 18 Delvocid 273 casein micelles 19–24 desserts 310–15 caseinates, recombined Feta-type cheeses 102 diatomaceous earth (kieselguhr) fi ltration 292–3 kappa-casein 19–20 diffusion in rennet-induced coagulation 30 Fick’s law 269 catalase 28 salt/moisture content 268–9 ceramic-based membranes, microfi ltration 293–4 disinfection 285–6 Chanakh, salting/brining data 267 UVC light 291

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Domiati cheese 140, 142–87 milk consumption 142 cheese yield 144–5 milk production 141 coagulants 143 compositional changes during storage 145–7 fat see lipids microbiological quality 148–9 Fatayer recipe 307 Mish cheese 152–4 fatty acids preservatives 279 oxidation 14–15 salt content 264 various mammals 11 salting/brining data 267 volatile free (VFFA) 272 starter cultures 144 Feta cheese 43–61 Tallaga cheese 151–2 see also Feta-type cheeses technological aspects 142–3 defects 60 texture and microstructure 147–8 Greek cheeses 61–3 ultrafi ltration 149–51 EU standards 44 traditional vs UF 150 manufacturing stages 45–53 Double Crème cheese 189 cutting 49 composition 189, 194 fl ow chart 46 dried milk powder mechanisation 53, 54 Halloumi cheeses 102–3 moulding 49–50 lactose in 8 packing and maturation 51–2 recombined Feta-type cheeses 99–103 salting 50–3 skim milk membrane (SMM) 12–13 microorganisms 55, 56 skimmed milk powder specifi cations 101 adjunct cultures 59 drinking water, specifi cation/standards 288, 289 milk for cheese production 45–9 dyes 87 chemical composition 47 renneting 48–9 Egypt 139–54 treatment of cheese milk 47–8 annual milk and cheese production 77 production methods 44–5 Feta cheese 140 properties 53–9 milk consumption 142 composition and pH 55 milk production 141 evolution of microbial groups 56 see also North Africa FAAs 58 Empanada, recipes 306 FFAs 56–7 emulsions 11–12 mean gross composition and pH values 55 Enterobacter aerogenes microorganisms 55, 56 blowing 278 proteolysis and nitrogenous fractions 57, 58, 59 drinking water, standards 289 recipes 308–9 Turkish cheese 204 salt/moisture content 264, 268 Enterococcus durans, Feta cheese 55 salting/brining data 267 Enterococcus faecium seasonality 44, 45 Domiati cheese 148 whey 60–1 Feta cheese 55 Feta-type cheeses Halloumi cheese 130 additives and treatments 95–9 Enterococcus spp. 164–6 decolorising agents 97 Nabulsi cheese 193 future 107–9 Escherichia coli HACCP implementation 103–7 coagulant 92 industrial manufacture 77–116 drinking water, standards 289 lipase 98–9 enterohaemorrhagic 282–3 Middle East production 78 Feta cheese 92 plant specifi cation 103 Turkish cheese 204 preservatives 99 see also pathogens process 79–94 Escherichia coli O157:H7, growth conditions and bactofugation 84–5 illness characteristics 281 clarifi cation 83 Ethiopia composition and microorganisms 81–2 cheese varieties 167 fl ow diagram, ultrafi ltration 80

11405124601_6_index.indd405124601_6_index.indd 331919 113/04/20063/04/2006 11:54:5611:54:56 320 Index

handling and storage 82 ultrafi ltration 126 microfi ltration 85–6 hazard appraisal/analysis critical control points standardisation 86–7 (HACCP), implementation 103–7 production methods (BAF, GDL and cast) 87–94 heat treatment 33 recombined cheeses 99–103 brine 291 safety, HACCP system 103–7 pasteurisation 47, 291 starter cultures 89, 95, 96 thermisation 48 world production 1–2, 77 high pressure treatment 33 see also Feta cheese homogenisation 13–14 food preparations 302–15 Hosmerim 313–14 desserts 310–15 hydrometry, and salt concentration 287 salads, savouries, snacks 303–10 hydroperoxides 14–15, 279 furocoumarins, purifi cation of brine 291–2 hygiene brine tanks 289–90 gamma-glutamyl transferase 28–9 control measures 285–6 Gauda, Chile 241, 243 recipes 306 immunoglobulins (Ig) 16, 17 Gaziantep cheese, salt/moisture content 268diffusion Iran, annual milk and cheese production 77 Gibna Bayda cheese 139, 102, 168–9 Gibneh 139 Jben 139 glucono delta-lactone (GDL) process 92–4 recombined powder 102 goat see caprine milk Jben Malah 167, 170 Gouda cheese, salt content 264 Jibneh Gibna 139 Greek Feta cheeses 61–3 Batzos 62–3 Kalathaki Limnou cheese 63 EU standards 44 salting/brining data 267 Kalathaki Limnou 63 Kashkaval cheese 167, 171–2 recipes 309 KCl, replacement of NaCl 273 Sfela 61–2 Kefalotyri whey cheese 60 see also Feta cheese kieselguhr fi ltration 292–3 Klebsiella spp., ‘early blowing’ 278 Halawet al-jibn 312, 314 Kluyveromyces lactis coagulant 91, 199 Halloumi cheese 117–38 Knafeh 310–12 composition 189, 189, 194 microorganisms 129, 130–1 LAB (lactic acid bacilli) 7–8 dried milk powder 102–3 Domiati cheese 148 exports 119 Feta cheese 48 future prospects 118 Feta-type cheese 95, 96 FVFA 133 mature brines 276 historical aspects 117 Nabulsi cheese 193 industrial process 123–6 ‘O’ culture 216–18 Mentha (mint) 121–2 White (Turkish) cheeses 200–2 milk 118–21 see also Enterococcus; Lactobacillus; Lactococcus; nutritional value 135 Leuconostoc quality and safety 134–5 lactalbumin (alpha-la) 16 recipes 303–5 L-lactate dehydrogenase 27–8 rheology 132–4 Lactobacillus alimentarius 148 salt content 264 Lactobacillus brevis 131, 148 salting 121 ‘early blowing’ 278 salting/brining data 267 Lactobacillus casei subsp. casei 148 sensory profi ling 132–4 slime formation 277 traditional methods 122–3 Lactobacillus cypricasei 131 types Lactobacillus delbrueckii subsp. bulgaricus fresh 127–8 Feta cheese 48 low-fat 128–9 Feta-type cheese 95, 96 mature 128 Lactobacillus fermentum, ‘early blowing’ 278

11405124601_6_index.indd405124601_6_index.indd 332020 113/04/20063/04/2006 11:54:5611:54:56 Index 321

Lactobacillus paracasei subsp. paracasei 131 Maillard reactions 153 Lactobacillus pentosus 131 mammals, chemical composition of milk 3–4 Lactobacillus plantarum 131, 148 Mankoushi with Zaatar recipes 305–6 slime formation 277 Manouri whey cheese 60 Lactobacillus rhamnosus 193 mastic, Pistacia lentiscus 191 Lactococcus lactis subsp. cremoris 48 Mauritania in fast-acid production 89 cheese varieties 167, 174 salt sensitivity 276 milk consumption 142 Lactococcus lactis subsp. lactis 89, 48 milk production 141 lactoglobulins 15–16 Meia Cura 223 lactoperoxidase 27 Mentha (mint), Halloumi cheese 121–2 lactose 5–8 Michaelis—Menten kinetics 30 biosynthesis 5–6 microbiology chemical structure 5 brines 274–9 in dairy products 8 pathogens 280–4 fermentation 7–8 spoilage 275, 277–9 physical properties 6–7 suggested tests 289 crystallisation 6–7 Domiati cheese 148–9 mutarotation 6–7 drinking water, specifi cation/standards 289 solubility 6 Feta cheese 55, 56 reactions 7–8 Feta-type cheeses 81–2 changes on heating 7 Halloumi cheese 129, 130–1 enzymatic hydrolysis 7–8 Philippines cheeses 258–60 various mammals 3 stressed cells 284 Latin America 211–48 traditional brined cheeses of North Africa 163–6 annual milk and cheese production 211 microfi ltration 293–4 Brazil 212–28 Feta-type cheeses 85–6 Chile 229–44 Middle East 188–94 Lebanese cuisine 307–8, 310–12 Mihaliç Peynir 71 Leuconostoc mesenteroides subsp. cremoris Mihlama 309 ‘early blowing’ 278 milk 1–42 Feta-type cheese 95, 96 chemical composition 3–4 North African cheeses 164 constituents 4–29 Libya indigenous milk enzymes 24–9 milk consumption 142 lactose 5–8 milk production 141 lipids 10–15 light, and lipid oxidation 14–15 North African production/consumption 141–2 lipase 98–9 pH 10, 31 lipids 10–15 powdered see dried milk powder composition 11 proteins 15–24 creaming 12–13 rennet-induced coagulation 29–33 fat globules 11–12 salts 8–10 volume frequency distribution 13 world production 1–3, 4 fatty acid profi le 11 see also bovine; camel; caprine; ovine homogenisation 13–14 milk enzymes 24–9 milk fat emulsion stability 12–13 alkaline phosphatase 26–7 oxidation 14–15 catalase 28 various mammals 3 gamma-glutamyl transferase 28–9 lipoprotein lipase 26 L-lactate-dehydrogenase 27–8 Listeria monocytogenes 280–2 lactoperoxidase 27 Domiati cheese 149 lipoprotein lipase 26 growth conditions and illness characteristics 281 other indigenous milk enzymes 27–9 see also pathogens plasmin 24–5 low-sodium cheeses 272–3 superoxide dismutase 28 xanthine oxidase 28 mahaleb 191 milk fat globule membrane (MFGM) 12

11405124601_6_index.indd405124601_6_index.indd 332121 113/04/20063/04/2006 11:54:5711:54:57 322 Index

milk proteins 15–24 Greece 47 alpha-lactalbumin (alpha-la) 16 caseins 18 beta-lactoglobulin (beta-lg) 15–16 milk salts 9 caseins 17–24 whey proteins 16 immunoglobulins (Ig) 17 world production 4 proteose peptones (PP) 17 serum albumin (SA) 16–17 palmetto 160 various mammals 3 papain 159 whey proteins 15–17 Parmigiano cheese, salt content 264 milk salts 8–10 pathogens 280–4 partitioning, colloidal/soluble phases 9–10 control measures 285–6 salt balance 9–10 salt tolerance 149 milk thistle 158–9 stressed cells 284 Minas cheese 215–23 survival in brine 275, 280–4 Minas Frescal 217, 218–21 Urfa-type Turkish cheeses 204 Minas Padrao 221–2 White cheeses 204 recipes 310, 314–15 penicillin, as preservative 279 minerals, various mammals 3 pH mint, Halloumi cheese 121–2 acidiﬁ cation, quality control of brine 286–7 Mish cheese 152–4, 155 brine and cheese 270, 287–8 Mizethres whey cheese 60 milk 10, 31 Morocco Philippines 249–63 Jben 167 manufacturing methods 253–8 recombined powder 102 Cavite 257 milk consumption 142 Cebu 255 milk production 141 DTRI 256 recipes 308–9 Meycawayan 254 see also Jben Santa Cruz and Lumbang 253 Mucor miehi coagulant 91 milk quality 250–2 Mudaffara cheese 167, 171 recipes 310 Mujaddal/Braided cheese 189–90 yield and microbiology 258–60 phosphoproteins 17 Nabulsi cheese 188, 189, 190–4 Piccantase A 203 composition 189, 194 Pichia membranaefaciens 131 recipes 305, 308, 310–11 Pistacia lentiscus 191 natamycin, as preservative 279 plant coagulants 158–9, 198–9 nipagin, as preservative 279 plasmin 24–5 North Africa 139–87 plate heat exchanger 291 milk production 141 potassium chloride, replacement of NaCl 273 production/consumption of dairy products 141–2 potassium nitrate, as preservative 99, 279–80 recipes 308–9 potassium sorbate 99, 279, 290 traditional brined cheeses 154–75 Prato cheese 223–7 camel’s milk 172–5 schema 225 coagulation 156–9 UF process 227 manufacturing steps 155 preservatives 99, 279–80 microbiology 163–6 Propionibacterium jensenii 148 salting and preservation 160–1 proteose peptones (PP) 16, 17 semihard brined cheeses 171–2, 162 Prunus mahaleb 191 soft-type brined cheeses 166–70, 162 Pseudomonas spp. 204 see also Egypt; Morocco; Tunisia psychrotrophic bacteria 204

off ﬂ avours 14–15 quality control of brine osmolytes 284 microbiological 289–90 ovine milk physical and chemical 286–9 breeds and composition Cyprus 118–21 recipes see food preparations

11405124601_6_index.indd405124601_6_index.indd 332222 113/04/20063/04/2006 11:54:5711:54:57 Index 323

Rennet cheese, Brazil 227–8, 306 Staphylococcus aureus 282 rennet production, abomasa 47–8, 140, 157–8, 198 growth conditions and illness characteristics 281 rennet-induced coagulation 29–33 salt tolerance 149 calcium concentration 31–2 starter cultures cold storage 32 Feta-type cheeses 89, 95, 96 heat treatment 33 Halloumi cheese 122 high pressure treatment 33 Stokes’ law 12 milk pH 10, 31 Streptococcus thermophilus primary and secondary stages 29–30 Feta cheese 48 ultrafi ltration (UF) 32 Feta-type cheese 95, 96 Rhizopus/Rhizomucor miehi coagulant 91, 198 stressed cells 284 Rqaq 308 Sudan Gibna Bayda 102, 167–9 Saccharomyces cerevisiae, Feta cheese 92 milk consumption 142 Sahara Touareg, camel’s milk cheese 172–5 milk production 141 salads, savouries, snacks 303–10 Mudaffara 167 salmonellae 283–4 superoxide dismutase 28 growth conditions and illness characteristics 281 salt tolerance 149 Tallaga cheese 151–2 Urfa-type Turkish cheeses 204 Telemes cheese 63–8 see also pathogens characteristics 67–8 salt-in-moisture (SM) compared with Feta 64–7 brining 269 composition 67 defi ned 266, 274 fl ow chart 64 salt/salting salt content 264, 276 advantages of salting 302 salting 65–6 concentration, and Baumé hydrometry 287 salting/brining data 267 dry-salting vs brining 266–8 Tetra Tebel Casofi ll Feta cheese 50–1 Bacteriologically Acidifi ed Feta-type (BAF) 87–92, Halloumi cheese 121 104–5 solutions, water activities 275 cast Feta-type 94 specifi cation for cheesemaking 287, 288 glucono delta-lactone (GDL) process 92–4 various cheeses 264 texture profi les see also brining Domiati cheese 147–8 sanitisaation, cleaning programme 285–6 Turkish White cheese 205 Scamorsa 166–8 thermisation 48 Seronoa repens (palmetto) 160 titanium oxide 98 serum albumin 16–17 Touareg, camel’s milk cheese 172–5 serum (whey) proteins 15–16 Tunisia Sfela cheese 61–2 cheese varieties 167 sheep see ovine milk milk consumption 142 Silybum marianum (milk thistle) 158–9 milk production 141 Sirene cheese 68–9 Turkish cuisine 309, 313 skim milk membrane (SMM) 12–13 Turkish White and Urfa-type cheeses 69–71, 194–207 skimmed milk powder see dried milk powder texture and microstructure 205–6 sodium benzoate 290 Feta-type cheeses 99 ultrafi ltration sodium chloride Halloumi cheese 126 direct measurement 287 purifi cation of brine 293–4 human diet 272–3 and rennet-induced coagulation 32 see also brine; salt/salting Urfa-type cheeses 69–71, 194–207 sodium dodecylsulphate, protein dissociation 23 salting/brining data 267 sodium hypochlorite 290 Urucum, yellow pigment 224 sodium nitrate, as preservative 99 UVA light + furocoumarins, purifi cation of brine sorbate, preservative 99, 279 291–2 South America see Latin America UVC light 291

11405124601_6_index.indd405124601_6_index.indd 332323 113/04/20063/04/2006 11:54:5811:54:58 324 Index

Wagashi cheese 159, 167, 169–70 yeasts water activity, deﬁ ned 274–5 in brine 277 whey proteins 15–17 Candida spp. 131 various mammals 16 Domiati cheese 148 White and Urfa-type Turkish cheeses 194–207 Saccharomyces cerevisiae, Feta cheese 92 salting/brining data 267 yellow pigment, Urucum 224 whiteners 98 Yersinia enterocolitica 283 world production 1, 3 growth conditions and illness characteristics bovine, caprine, ovine milk 4 281 types of brined cheeses 2 yoghurt, lactose in 8

xanthine oxidase 28 Zaatar recipes 305–6

11405124601_6_index.indd405124601_6_index.indd 332424 113/04/20063/04/2006 11:54:5811:54:58 Plate 1 Illustration of cheeses produced in Brazil. (1) Traditional Minas Frescal, (2) ultraﬁ ltered Minas Frescal, (3) Minas Meia Cura, (4) Minas Padrão, (5) Rennet.

(a)

(b)

Plate 2 Pressing the curd by hand (a) and moulding (b) of Rennet cheese.

11405124601_8_plates.indd405124601_8_plates.indd 1 117/05/20067/05/2006 12:31:2412:31:24 Plate 3 Different cheeses marketed in Chile.

Plate 4 Industrially made Chilean Chanco cheese.

11405124601_8_plates.indd405124601_8_plates.indd 2 117/05/20067/05/2006 12:31:4412:31:44 Plate 5 Typical Gauda cheeses produced in Chile.

Plate 6 Halloumi cheese shallow-fried in olive oil and served in pitta bread with tomato and fresh mint.

11405124601_8_plates.indd405124601_8_plates.indd 3 117/05/20067/05/2006 12:31:4812:31:48 Plate 7 Halloumi cheese. From left to right: fried in olive oil, grilled and both served with capers; fresh cheese served with blackcurrant jam; grated cheese with dried crushed mint leaves.

(a) (b) (c)

Plate 8 Lebanese Mankoushi cheese preparation (a), after baking (b) and the stretching of the cheese (c).

11405124601_8_plates.indd405124601_8_plates.indd 4 117/05/20067/05/2006 12:31:5312:31:53 Plate 9 A Chilean snack (Empanada) made with creamy Chanco cheese.

Plate 10 Barbecued Rennet cheese.

Plate 11 Lebanese cheese rolls made with desalted Akkawi cheese and deep fried in oil.

11405124601_8_plates.indd405124601_8_plates.indd 5 117/05/20067/05/2006 12:32:0312:32:03 Plate 12 General view of a sweet dish called Knafeh.

(a) (b)

Plate 13 Preparation and serving of Knafeh. (a) Main ingredients; (b) ﬁ lling and compressing the vermicelli or semolina/AMF mixture in a greased baking tray; (c) spreading the desalted cheese; and (d) stretching the cheese after the baking stage

11405124601_8_plates.indd405124601_8_plates.indd 6 117/05/20067/05/2006 12:32:1212:32:12 (a) (b)

Plate 14 Serving Knafeh as a sweet dish. (a) Smearing the ‘caake’ with atter; (b) placing a Knafeh portion in the ‘caake’; and (c) serving Knafeh on a (c) plate in a sweet shop.

11405124601_8_plates.indd405124601_8_plates.indd 7 117/05/20067/05/2006 12:32:2112:32:21 (a) (b)

(e) (c)

(d) (f)

Plate 15 Preparation of Halawet al-jibn. (a) Desalted brined cheeses; (b) melting the cheese; (c) mixing with semolina to form a dough-like consistency; (d) folding/stretching the cheese mixture; (e) manually stretching the cheese dough; and (f) coating the stretched cheese dough with syrup.

Plate 16 Halawet al-jibn as a sweet dish

11405124601_8_plates.indd405124601_8_plates.indd 8 117/05/20067/05/2006 12:32:2512:32:25