MODIFIED ATMOSPHERE PACKAGING of FOOD ELLIS HO,RWOOD SERIES in FOOD SCIENCE and TECHNOLOGY Editor-In-Chief: I

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MODIFIED ATMOSPHERE PACKAGING OF FOOD ELLIS HO,RWOOD SERIES IN FOOD SCIENCE AND TECHNOLOGY Editor-in-Chief: I. D. MORTON, Professor and formerly Head of Department of Food and Nutritional Science, King's College, London. Series Editors: D. H. WATSON, Ministry of Agriculture, Fisheries and Food; and M. J. LEWIS, Department of Food Science and Technology, University of Reading parat Dictionary of Food and Nutrition and Biochemistry J. Adrian, G. Legrand & R. Frange Food Biochemistry CAlais & G. Linden Fats for the Future R. C Cambie Traditional Fermented Foods M.Z. Ali & R.K. Robinson Food Microhiology, Volumes I & 2 CM. Bourgeois, J.F. Mescle & J. Zucca Food Handbook CM.E. Catsberg & G.J.M. Kempen-van Dommclen Determination of Veterinary Residues in Food N.T. Crosby & CM. Clark Food Container Corrosion D.R. Davis & A.Y. Johnston Microwave Processing and Engineering R.Y. Decareau & R.A. Peterson Modern Food Processing P. Fellows Principles and Applications orGas Chromatography in Food Analysis M.H. Gordon Technology of Meat and Meat Products J. P. Girard Dairy Technology A. Grandison, M.J. Lewis, R.A. Wilbey & R.K. Robinson Separation Processes: Principles and Applications A. Grandison & M.J. Lewis Microbiology of Chilled and Frozen Foods W.F. Harrigan Fnndamentals of Food Chemistry W. Heimann Nitrates and Nitrites in Food and Water M.J. Hill Nitrosamines M.J. Hill Sensory Evalnation of Food G. Jcllinck Hygienic Design and Operation of Food Plant R. Jowitt Modern Food Processing J. Lamb Food TeChnology Data M.J. Lewis Tecbnology of Biscuits, Crackers and Cookies, 2nd Edition D.J. R. Manley Ingredients for Bakers S. Matz Second European Conference on Food Science and Technology I. D. Morton Principles of Design and Operation of Catering Equipment A. Milson & D. Kirk Cereals in a European Context I.D. Morton Animal By-Product Processing H.W. Ockerman & P.E. Hansen Modified Atmosphere Packaging of Food B. Ooraikul & M. E. Stiles The Role of Fats in Human Nutrition F.B. Padley, J. Podmore, B.W. Nicols, R. Burt & J.P. Burn Food, Volumes I & 2 P. Patel Flavour of Distilled Beverages J. R. Piggott Distilled Beverage Flavour J.R. Piggott & A.Y. Tamine Fats and Related Cheeses R.K. Robinson Advanced Sugar Chemistry R.S. Shallenberger Handbook of Edible Gums K.R. Stauffer Egg and Ponltry-Meat Processing W.J. Stadelman, Y.M. Olson & G.A. Shemwell Vitamins and Minerals M. Tolonon Frying of Food G. Yarela Applied Human Nutrition: For Food Scientists and Home Economists A.F. Walker Natural Toxicants in Food D.H. Watson MODIFIED ATMOSPHERE PACKAGING OF FOOD

Editors

B. OORAIKUL Dip.Agr.. B.Food Tech .. M.Tcch .. Ph.D.

M. E. STILES BSc. M.Sc .. Ph.D. both of Department of Food Science Faculty of Agriculture and Forestry University of Alabama, Edmonton, Canada

ELLIS HORWOOD NEW YORK LONDON TORONTO SYDNEY TOKYO SINGAPORE First published in 1991 by ELLIS HORWOOD LIMITED Market Cross House, Cooper Street, Chichester, West Sussex, P019 lEB, England A division of Simon & Schuster International Group A Paramount Communicalions Company

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British Lihrary Cataloguing in Puhlication Data Modified atmosphere packaging of food I. Food. Packaging I. Ooraikul, B. II. Stiles, M. E. 664.092 ISBN 0-7476-0064-3

Lihrary of Congrcss Cataloging-in-Puhlication Data Modified atmosphere packaging of food / editors, B. Ooraikul, M. E. Stiles p. cm. - (Ellis Horwood series in food science and technology) Includes hihlographical references and index. ISBN 0-7476-0064-3 I. Food - Packaging. 2. Protective atmospheres. I. Ooraikul, B. II. Stiles, M, E. III. Series. TP374.M63 1990 664' .092-dc20 90-5063 CIP CONTRIBUTORS

MURRA Y G. FlERHELLER, M.Sc., Food Scientist, Food Processing Development Centre, Alberta Agriculture, P.O. Box 3476, Leduc, AB, Canada T9E 6M2 BUNCHA OORAIKUL, Ph.D., Professor, Department of Food Science, University of Alberta, Edmonton, AB, Canada T6G 2P5 WILLIAM D. POWRIE, Ph.D., Professor, Department of Food Science, University of British Columbia, Vancouver, B.C., Canada V6T lW5 BRENT 1. SEKURA, Ph.D., Associate Professor, Department of Food Science, University of British Columbia, Vancouver, B.C., Canada V6T 1W5 MICHAEL E. STILES. Ph.D., Professor, Department of Food Science, University of Alberta, Edmonton, AB, Canada T6G 2P5 T ABLE OF CONTENTS

Preface xiii

Chapter 1 INTRODUCTION: REVIEW OF THE DEVELOPMENT OF MODlFlED ATMOSPHERE PACKAGING B. Ooraikul and M. E. Stiles 1 1.1 Historical perspective 1 1.2 Perishability of food 4 1.2.1 Microbial problems 4 1.2.2 Physicochemical problems 7 1.2.2.1 Fruits and vegetables 7 1.2.2.2 Meat 8 1.2.2.3 Fish and marine products 9 1.2.2.4 Other foods 10 1.3 Conclusions 11 References 13

Chapter 2 SClENTlFIC PRINCIPLES OF CONTROLLEDjMODlFlED ATMOSPHERE PACKAGING ME~il~ 18 2.1 Introduction 18 2.2 Effect of food type 20 2.2.1 Fruit and vegetable produce 20 2.2.2 Meats and fish 20 2.2.3 Baked goods 22 2.2.4 Dairy foods 22 2.3 Gas atmosphere 22 2.4 Hypobaric storage 24 2.5 Conclusions 24 References 25

Chapter 3 TECHNOLOGICAL CONSIDERATIONS IN MODlFlED ATMOSPHERE PACKAGING B. Ooraikul 26 3.1 Packaging materials 26 3.1.1 The nature of the product 26 3.1.2 Disposition of metabolic products 27 3.1.3 Permeability of the packaging material 27 3.1.3.1 Metal containers 28 3.1.3.2 Glass containers 28 3.1.3.3 Rigid/semirigid plastic and paper containers 28 3.1.3.4 Flexible films 29 3.2 Packaging technology 34 3.2.1 Atmosphere modification 34 VJll Table of contents

3.2.1.1 Gas flushing 34 3.2.1.2 Atmosphere modifier 35 3.2.1.3 Headspace gas analysis 37 3.2.2 Packaging equipment 37 3.2.2.1 Chamber packaging system 38 3.2.2.2 Form-fill-seal packaging system 39 3.3 Storage temperature 40 3.4 Shelf-life dating of MAP food 42 3.4.1 Shelf-life determination 42 3.4.2 Regulations governing shelf life dating 44 References 46

Chapter 4 MODIFIED ATMOSPHERE PACKAGING OF BAKERY PRODUcrS B. Ooraikul 49 4.1 Introduction 49 4.2 Comparative economy of MAP vs freezing 56 4.2.1 Process energy requirements 56 4.2.2 Advantages and disadvantages 61 4.3 Application of MAP to other bakery products 62 4.3.1 Dough and batter products 63 4.3.1.1 Crumpets 63 4.3.1.2 Waffles 63 4.3.1.3 Cake doughnuts 67 4.3.1.4 Yeast doughnuts 68 4.3.1.5 Crusty rolls 70 4.3.2 Cake or pastry-type products 71 4.3.2.1 Chocolate Danish 71 4.3.2.2 Carrot muffins 72 4.3.3 Layer cakes 74 4.3.3.1 Strawberry layer cake 74 4.3.3.2 Cherry cream cheese cake 76 4.3.4 Pies or products with fillings 80 4.3.4.1 Butter tarts 80 4.3.4.2 Apple turnovers 81 4.3.4.3 Mini blueberry pie 82 4.3.4.4 Raw apple pie 84 4.3.4.5 Baked apple pie 87 4.3.5 Summary of problems requiring further study 89 4.3.5.1 Mould problem 92 4.3.5.2 Yeast problem 92 4.3.5.3 Health aspect 92 4.4 Studies of mould problems 93 4.4.1 Types of products susceptible to mould problems 93 4.4.2 Use of preservatives with or without MAP 94 4.4.3 Removal of headspace oxygen 95 4.4.3.1 Minimum headspace oxygen concentration for mould growth 96 4.4.3.2 Use of oxygen absorbant to remove headspace oxygen 96 4.4.3.3 Application of oxygen absorbant to crusty rolls 98 4.5 Studies of yeast problems 99 4.5.1 Types of products susceptible to yeast problems 99 Table of contents ix

4.5.2 Use of preservatives with or without MAP 99 4.5.2.1 Delvocid 100 4.5.2.2 Parabens 101 4.5.3 Control of yeast growth with ethanol vapour 102 4.5.3.1 Effect of ethanol concentration on yeast growth 103 4.5.3.2 Effect of aw on yeast growth and subsequent ethanol and C02 production 104 4.5.3.3 Effect of aw and headspace ethanol on yeast growth 105 4.5.3.4 Combined effects of Ethicap and MAP or ethyl paraben in controlling yeast growth 107 4.5.4 Application of Ethicap to bakery products 109 4.5.4.1 Yeast doughnut 109 4.5.4.2 Vanilla layer cake 109 4.5.4.3 Apple turnover 110 4.5.4.4 Cherry topping 111 4.5.4.5 Cherry cream cheese cake 112 4.6 Conclusions and recommendations 112 4.6.1 Minor problems and possible solutions 113 4.6.2 Major problems and possible solutions 113 4.6.3 Matching products with control measures 114 References 115

Chapter 5 MODIFIED ATMOSPHERE PACKAGING OF MEAT, POULTRY AND THEIR PRODUCTS M.E. Stiles 118 5.1 Introduction 118 5.2 Factors influencing storage life of meat 120 5.2.1 Initial microbial load 121 5.2.2 Storage temperature 121 5.2.3 Gas atmosphere 122 5.2.3.1 Carbon dioxide 123 5.2.3.2 Nitrogen 124 5.2.3.3 Oxygen 125 5.2.4 Gas permeability of packaging materials 125 5.3 Applicability of MAP to different meat types 125 5.3.1 Raw chilled meats 126 5.3.2 Cooked and cured (processed) meats 127 5.4 Meat microbiology 128 5.5 Packaging systems for meat 135 5.6 Research needs 136 References 139

Chapter 6 MODIFIED ATMOSPHERE PACKAGING OF FISH AND FISH PRODUCTS B.J. Skura 148 6.1 Problems 148 6.2 Past and present developments 148 6.2.1 Trout 149 6.2.2 Salmon 150 6.2.3 Cod 150 x Table of contents

6.2.4 Snapper 151 6.2.5 Other whitefish 152 6.2.6 Herring and sardines 154 6.2.7 Mackerel 155 6.2.8 Scallops 155 6.2.9 Prawns 155 6.2,10 Crab 156 6.3 Synopsis of benefits of MAP 157 6.4 Risks associated with MAP of fish products 157 6.5 Future developments 162 References 163

Chapter 7 MOD1FIED ATMOSPHERE PACKAGING OF FRUITS AND VEGETABLES William D. Powrie and Brent J. Skura 169 7.1 Introduction 169 7.1.1 Food trends 169 7.1.2 Terminology for fruits and vegetables 170 7.1.3 Market perspective of fresh fruits and vegetables 172 7.2 Quality considerations 172 7.2.1 Developmental stages of horticultural commodities 172 7.2.2 Quality maintenance of fresh fruits and vegetables 173 7.2.3 Postharvest losses of fresh fruits and vegetables 174 7.3 An integrated approach to MAP technology of fruits and vegetables 174 7.4 Chemical composition and structure of fruits and vegetables 176 7.4.1 Chemical composition 176 7.4.2 Parenchyma cell 177 7.4.3 Plant tissues 180 7.5 Respiration in fruits and vegetables 181 7.5.1 Overview 181 7.5.2 Glycolysis 182 7.5.3 Pentose phosphate pathway 183 7.5.4 Anaerobic respiration 185 7.5.5 Krebs cycle 186 7.5.6 Oxidative phosphorylation 187 7.5.7 Heat of respiration 190 7.5.8 Respiration rate 190 7.6 Ripening of fruits 194 7.6.1 Ethylene synthesis and action 195 7.6.2 Softening of fruit tissue 197 7.7 Strategy for prolonging the shelf life of fresh fruits and vegetables 198 7.8 Dimensions of modified atmosphere packaging 199 7.9 Complementary factors to modified atmosphere packaging 203 7.9.1 Cultivar and maturity selection 203 7.9.2 Harvest and postharvest handling 204 7.9.3 Minimal pretreatment processing 205 7.9.3.1 Washing 205 7.9.3.2 Tissue shearing 206 7.9.3.3 Cooling and temperature conditioning 206 7.9.3.4 Spoilogen control 207 7.9.3.5 Food additive diffusion and infusion 209 Table of contents Xl

7.10 Packaging systems 211 7.11 Dynamics of gases within fruits and vegetables under MAP 215 7.11.1 Diffusion of 02 into cell 216 7.11.2 Solubility characteristics of 02, C02 and N2 217 7.12 Responses of fruits and vegetables to low 02 and high C02 levels in modified atmospheres 218 7.12.2 Metabolic responses 221 7.12.2.1 Respiration 221 7.12.2.2 Ethylene synthesis and sensitivity 224 7.12.3 Ultrastructural changes 224 7.12.4 Quality changes 224 7.12.4.1 Flavour 225 7.12.4.2 Colour 225 7.12.4.3 Texture 225 7.13 The future of MAP 226 References 228

Chapter 8 MODlFlED ATMOSPHERE PACKAGING OF MISCELLANEOUS PRODUCTS M.G. Fierheller 246 8.1 Convenience foods 246 8.1.1 Modified atmosphere packaging of minimally processed foods 247 8.1.2 Hot fill and pasteurized products 250 8.1.3 Health concerns 251 8.2 Dairy products 253 8.3 Intermediate moisture foods 254 8.4 Dehydrated foods 255 8.5 Conclusion 256 References 258

Chapter 9 FURTHER RESEARCH IN MODlFlED ATMOSPHERE PACKAGING B. Ooraikul 261 9.1 Shelf life extension and safety 262 9.1.1 Promotion of growth of certain microorganisms on product 263 9.1.2 Use of preservatives in combination with MAP 264 9.2 Packaging materials 266 9.2.1 Ongoing development of barrier films 266 9.2.2 Use of edible films 267 9.3 Headspace atmospheres 269 9.3.1 Gas combinations and modifications 269 9.3.2 Modelling of MAP regimes for produce 270 9.4 Effects of MAP on organoleptic quality of products 272 9.5 Quality assurance for MAP operations 275 References 278

INDEX 283 PREFACE

At the 50th Anniversary Meeting of the Institute of Food Technologists the ten most significant innovations in food science developed during the past 50 years were named (Food Technology, September 1989). Among the "Top 10" innovations, controlled atmosphere packaging (CAP) for fruits and vegetables was listed 5th in order of importance. Of course, CAP is a forerunner of MAP (modified atmosphere packaging) in which a variety of food products are packaged under selective mixtures of atmospheric gases, but without the on-going maintenance (control) of the gas mixture. Development of packaging systems and films that are selectively permeable to specific gases has been the key element in the commercialization of controlled and modified atmosphere packaging of foods.

It may not be far from the truth to say that since then there has been an explosion of activities around MAP/CAP, especially in research and development into various aspects of this technology. The application of MAP to some bakery products, fresh fruits and salads and fresh meats and meat products has reached a significant level both in Europe and North America. The increasing consumer demand for fresh or near-fresh products and convenient, microwavable foods has added impetus to the growth of MAP/CAP technology. It is, therefore, timely that a comprehensive book that provides scientific background and practical applications of the technology should be written.

In writing this book a group of scientists and technologists who have had firsthand experience in various areas of MAP technology was assembled to contribute chapters in their areas of expertise. The book is a collection of up-to-date reviews of scientific and technological developments as well as some research data which have not yet been published. It is hoped that the text will stimulate the interests of both researchers and users of the technology. The dynamism of this field of technological development is such that it is impossible to keep current with all of the developments taking place. This book is an attempt to provide a reference base, but it will likely require updating with subsequent editions on a regular basis for the foreseeable future.

B. Ooraikul M.E. Stiles September 23, 1991