YOGPR 6/1/99 4:43 PM Page i YOGHURT Science and Technology © 2000 Woodhead Publishing Limited YOGPR 6/1/99 4:43 PM Page ii Related titles on food science and technology from Woodhead Publishing: General Feta and related cheeses Eds R K Robinson and A Y Tamime (respectively Reading University and Scottish Agricul- tural College, U.K.) Contents include: traditional methods for the manufacture of Feta cheese; industrial manu- facture of Feta cheese; manufacture of Halloumi; manufacture of Egyptian, soft pickled cheeses; miscellaneous white-brined cheeses; cheeses made by direct acidification 272pp 234 ¥ 173mm hardback 1991 Chilled foods: a comprehensive guide Eds C Dennis and M Stringer (respectively Director-General and Director of Food Science Division, Campden and Chorleywood Food Research Association) “This book lives up to its title in reviewing a major section of the food industry.” Interna- tional Food Hygiene Contents include: trends in consumer tastes and preferences; market place product knowl- edge; legislation; refrigeration of chilled foods; temperature monitoring and measurement; processing; chilled food packaging; chilled foods microbiology; conventional and rapid ana- lytical microbiology; microorganisms and safety in refrigerated foods; non-microbial factors affecting quality and safety; shelf-life determination and challenge testing; quality and con- sumer acceptability; cleaning and disinfection; hygienic design; total quality management 400pp 234 ¥ 173mm hardback 1992 ISBN 1 85573 270 X Food safety and quality Instrumentation and sensors for the food industry Ed. Erika Kress-Rogers (ALSTOM; formerly Leatherhead Food RA) “In this book existing and forthcoming instrumentation systems are surveyed to provide a practical guide for those involved in designing, selecting and using such systems in the food industry. International experts have presented their knowledge in an applied framework to provide the most comprehensive workbook for practitioners ever written.” Food Science and Technology Abstracts Contents include: colour measurement; compositional and texture analysis; rheological mea- surement; analysis of water activity; ultrasound; infrared techniques; microwave measure- ment; laboratory instrumentation; chemical sensors, biosensors and immunosensors 740pp 234 ¥ 156mm hardback 1993 ISBN 1 85573 363 3 For more information contact Customer Services at Woodhead Publishing Ltd, Abington Hall, Abington, Cambridge CB1 6AH, England; tel: +44 (0)1223 891358 ext.30; fax: +44 (0)1223 893694; e-mail: [email protected] Please also visit our web site: www.woodhead-publishing.com © 2000 Woodhead Publishing Limited YOGPR 6/1/99 4:43 PM Page iii YOGHURT Science and Technology Second edition A. Y. Tamime Scottish Agricultural College Auchincruive, Food Standards & Product Technology Department, Ayr KA6 5HW, Scotland R. K. Robinson University of Reading, Department of Food Science & Technology, Reading RG6 2AP, England Cambridge England © 2000 Woodhead Publishing Limited YOGPR 6/1/99 4:43 PM Page iv Published by Woodhead Publishing Limited Abington Hall, Abington Cambridge CB1 6AH England Published in North and South America by CRC Press LLC 2000 Corporate Blvd, NW Boca Raton FL 33431 USA First published 1985, Pergamon Press Ltd Second edition 1999, Woodhead Publishing Ltd and CRC Press LLC © 1999, Woodhead Publishing Ltd The authors have asserted their moral rights. Conditions of sale This book contains information obtained from authentic and highly regarded sources. Reprinted material is quoted with permission, and sources are indicated. 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Woodhead Publishing ISBN 1 85573 399 4 CRC Press ISBN 0-8493-1785-1 CRC Press order number: WP1785 Cover design by The ColourStudio Typeset by Best-set Typesetter Ltd., Hong Kong Printed by TJ International, Cornwall, England. © 2000 Woodhead Publishing Limited YOGPR 6/1/99 4:43 PM Page v Contents Preface to second edition Preface to first edition 1 Historical background 1.1 Introduction 1.2 Evolution of the process 1.3 Diversity of fermented milks 1.4 Patterns of consumption 1.5 Methods of production and classification 1.6 References 2 Background to manufacturing practice 2.1 Introduction 2.2 Preliminary treatment of the milk base 2.2.1 Milk as a raw material 2.2.2 Separation of cellular matter and other contaminants present in milk 2.2.3 Milk reception and storage 2.3 Standardisation of fat content in milk 2.4 Standardisation of the solids-not-fat content in milk 2.4.1 Traditional process 2.4.2 Addition of milk powder 2.4.3 Addition of buttermilk powder 2.4.4 Addition of whey powder and/or whey protein concentrates 2.4.5 Addition of casein powder 2.4.6 Concentration by vacuum evaporation (VE) 2.4.7 Concentration by membrane filtration 2.4.8 Addition of non-milk proteins 2.5 Addition of stabilisers/emulsifiers © 2000 Woodhead Publishing Limited YOGPR 6/1/99 4:43 PM Page vi 2.5.1 General background 2.5.2 Miscellaneous properties and conditions 2.6 Addition of sweetening agents 2.6.1 General introduction 2.6.2 Types of carbohydrate sweetener 2.7 Addition of miscellaneous compounds 2.7.1 Penicillinase 2.7.2 Preservatives 2.7.3 Minerals, vitamins and/or fatty acids 2.8 Homogenisation 2.8.1 Effects on milk constituents 2.8.2 Aspects of processing 2.9 Heat treatment 2.9.1 Destruction of micro-organisms/pathogens 2.9.2 Production of stimulatory/inhibitory factors 2.9.3 Changes in the physicochemical properties of milk 2.9.4 Processing effects on the physical properties of the gel 2.10 Fermentation process 2.10.1 Introduction 2.10.2 Starter organisms 2.10.3 Gel formation 2.11 Cooling 2.11.1 One-phase cooling 2.11.2 Two-phase cooling 2.12 Addition of fruit/flavouring/colouring ingredients 2.12.1 Fruits 2.12.2 Flavouring agents 2.12.3 Colouring matter 2.13 Packaging 2.13.1 Introduction 2.13.2 Functions of packages 2.13.3 Types of packaging materials 2.13.4 Comparative studies on permeability of different yoghurt packages 2.13.5 Migration of monomers and other compounds 2.13.6 Tamper-evident packaging 2.13.7 Aluminium foil lids 2.13.8 Sterilisation of packaging materials 2.13.9 Outer or shipping container 2.14 Refrigerated cold storage, transport and distribution 2.14.1 The cold store 2.14.2 During transport 2.14.3 The retail shop and the consumer 2.15 Conclusion 2.16 References 3 Processing plants and equipment 3.1 Home or small-scale production © 2000 Woodhead Publishing Limited YOGPR 6/1/99 4:43 PM Page vii 3.1.1 Miscellaneous systems 3.1.2 Packaging system 3.2 Medium-scale production 3.2.1 Hand operated vat 3.2.2 Multipurpose vat 3.2.3 Mini dairy 3.2.4 Small-scale packaging machines 3.3 Large-scale production 3.3.1 Milk reception, handling and storage 3.3.2 Standardisation of fat content in milk 3.3.3 Fortification of milk solids 3.3.4 Homogenisation 3.3.5 Heat treatment 3.3.6 Fermentation/incubation of the milk 3.3.7 Cooling 3.3.8 Pumps 3.3.9 Miscellaneous fittings 3.3.10 Fruit handling and mixing units 3.3.11 Filling machines 3.3.12 Miscellaneous handling, chill cooling and refrigerated cold storage 3.4 Mechanisation of yoghurt production and plant design 3.5 Continuous yoghurt production 3.5.1 Background 3.5.2 The NIZO process 3.5.3 Recent developments 3.6 Automation/process control 3.6.1 Levels of automation 3.6.2 Area/department 1 3.6.3 Area/department 2 3.6.4 Area/department 3 3.6.5 Area/department 4 3.6.6 Area/department 5 3.6.7 Area/department 6 3.6.8 Management information system 3.6.9 System architecture 3.6.10 System security 3.7 Building design, maintenance and services 3.7.1 General background and introduction 3.7.2 Location of a dairy plant 3.7.3 Layout of a dairy plant 3.7.4 Design and construction of dairy buildings 3.8 Conclusion 3.9 References 4 Plant cleaning, hygiene and effluent treatment Cleaning aspects 4.1 Primary objectives 4.2 Principles of the cleaning process © 2000 Woodhead Publishing Limited YOGPR 6/1/99 4:43 PM Page viii 4.3 Factors involved in the selection and performance of a detergent 4.3.1 Type/range of detergents used in the yoghurt industry 4.3.2 Type of soiling matter 4.3.3 Water hardness and quality 4.3.4 Miscellaneous factors 4.4 Cleaning methods 4.4.1 Manual cleaning 4.4.2 Cleaning-in-place 4.4.3 Miscellaneous cleaning