Preface . . . .............................................................. xi List of contributors . . . . . ................................................ xiii Introduction: the chilled foods market 1 C. Dennis and M. Stringer, Campden and Chorleywood Food Research Association I.1 Definition . . . . ................................................ 1 I.2 Drivers in the chilled food sector . . . . ........................ 3 I.3 Overall market size . . . . ...................................... 6 I.4 Individual categories within the chilled food sector .......... 12 I.5 Conclusion . . . ................................................ 15 I.6 References . . . ................................................ 16 Part I Raw materials 1 Raw material selection: fruit and vegetables .................... 19 L. Bedford, Campden and Chorleywood Food Research Association 1.1 Introduction . . ................................................ 19 1.2 Criteria for selection . . . ...................................... 20 1.3 Specifications ................................................ 28 1.4 New trends in raw material production . . . . . ................. 30 1.5 New trends in plant breeding . ............................... 31 1.6 Conclusion . . . ................................................ 32 1.7 Sources of further information and advice . . ................. 33 1.8 References . . . ................................................ 33 Contents 2 Raw material selection: dairy ingredients ...................... 37 L. R. Early, Harper Adams University College 2.1 Introduction . . . . . . ........................................... 37 2.2 Milk composition . ........................................... 37 2.3 Functional approach . . . . . .................................... 38 2.4 Sensory properties ........................................... 39 2.5 Microbiological criteria for milk products . . . . ............... 41 2.6 Chilled dairy products and milk-based ingredients used in chilled foods . . . . . . ........................................... 41 2.7 Chilled desserts . . . ........................................... 52 2.8 Ready meals . . . . . . ........................................... 53 2.9 Maximising quality in processing . . . . . . ...................... 53 2.10 Food safety issues ........................................... 55 2.11 Future trends . . . . . ........................................... 57 2.12 References . . . . . . . . ........................................... 58 3 Raw material selection: meat and poultry ...................... 63 S. J. James, Food Refrigeration and Process Engineering Research Centre 3.1 Introduction . . . . . . ........................................... 63 3.2 The influence of the live animal ............................. 65 3.3 Pre- and post-slaughter handling ............................. 69 3.4 Conclusions . . . . . . . ........................................... 72 3.5 References . . . . . . . . ........................................... 73 Part II Technologies and processes 4 The refrigeration of chilled foods ............................... 79 R. D. Heap, Cambridge Refrigeration Technology 4.1 Introduction . . . . . . ........................................... 79 4.2 Principles of refrigeration .................................... 81 4.3 Safety and quality issues .................................... 81 4.4 Refrigerant fluids and the environment ...................... 82 4.5 Chilled foods and refrigeration . ............................. 83 4.6 Chilling . ..................................................... 84 4.7 Chilling equipment . . . . . . .................................... 85 4.8 Chilled storage . . . ........................................... 87 4.9 Refrigerated transport . . . . .................................... 90 4.10 Refrigerated display cabinets . . . ............................. 94 4.11 Regulations and legislation . . . . . ............................. 96 4.12 Sources of further information . . ............................. 97 4.13 References . . . . . . . . ........................................... 97 vi Contents 5 Temperature monitoring and measurement ..................... 99 M. Wolfe, Food Standards Agency, London 5.1 Introduction . . ................................................ 99 5.2 Importance of temperature monitoring . . . . . . ................. 101 5.3 Principles of temperature monitoring ........................ 102 5.4 Temperature monitoring in practice . . ........................ 105 5.5 Equipment for temperature monitoring . . . . . . ................. 116 5.6 Temperature and time–temperature indicators . . . . . . .......... 126 5.7 Temperature modelling and control . . ........................ 130 5.8 Further reading . . . . . . . . ...................................... 131 5.9 References . . . ................................................ 131 6 Chilled food packaging ........................................... 135 B. P. F. Day, Campden and Chorleywood Food Research Association 6.1 Introduction . . ................................................ 135 6.2 Requirements of chilled food packaging materials . .......... 135 6.3 Chilled food packaging materials . . . . ........................ 136 6.4 Packaging techniques for chilled food . . . . . . ................. 139 6.5 Future trends . ................................................ 147 6.6 Sources of further information ............................... 149 6.7 References . . . ................................................ 149 Part III Microbiological and non-microbiological hazards 7 Chilled foods microbiology ...................................... 153 S. J. Walker and G. Betts, Campden and Chorleywood Food Research Association 7.1 Introduction . . ................................................ 153 7.2 Why chill? . . . ................................................ 154 7.3 Classification of growth ...................................... 154 7.4 The impact of microbial growth . . . . . ........................ 156 7.5 Factors affecting the microflora of chilled foods . . . .......... 157 7.6 Spoilage microorganisms . . . . . ............................... 162 7.7 Pathogenic microorganisms . . . ............................... 167 7.8 Temperature control . . . ...................................... 173 7.9 Predictive microbiology ...................................... 174 7.10 Conclusions . . ................................................ 178 7.11 References . . . ................................................ 179 8 Conventional and rapid analytical microbiology ................ 187 R. P. Betts, Campden and Chorleywood Food Research Association 8.1 Introduction . . ................................................ 187 8.2 Sampling . . . . . ................................................ 188 8.3 Conventional microbiological techniques . . . ................. 188 8.4 Rapid and automated methods ............................... 191 Contents vii 8.5 Microbiological methods – the future . . ...................... 214 8.6 References and further reading . ............................. 214 9 Non-microbial factors affecting quality and safety ............. 225 H. M. Brown and M. H. Hall, Campden and Chorleywood Food Research Association 9.1 Introduction . . . . . . ........................................... 225 9.2 Characteristics of chemical reactions . . ...................... 226 9.3 Chemical reactions of significance in chilled foods . . . . . ..... 226 9.4 Characteristics of biochemical reactions . . . . . . ............... 231 9.5 Biochemical reactions of significance in chilled foods . ..... 233 9.6 Characteristics of physico-chemical reactions . ............... 238 9.7 Physico-chemical reactions of significance in chilled foods . 238 9.8 Non-microbiological safety issues of significance in chilled foods . . ..................................................... 243 9.9 Conclusions . . . . . . . ........................................... 248 9.10 References . . . . . . . . ........................................... 248 Part IV Safety and quality issues 10 Shelf-life determination and challenge testing . . . ............... 259 G. Betts and L. Everis, Campden and Chorleywood Food Research Association 10.1 Introduction . . . . . . ........................................... 259 10.2 Factors affecting shelf-life . . . . . . ............................. 260 10.3 Modelling shelf-life . . . . . . .................................... 268 10.4 Determination of product shelf-life . . . . ...................... 270 10.5 Maximising shelf-life . . . . .................................... 278 10.6 Challenge testing . ........................................... 279 10.7 Future trends . . . . . ........................................... 283 10.8 References . . . . . . . . ........................................... 283 11 Microbiological hazards and safe process design ............... 287 M. H. Brown, Unilever Research, Sharnbrook 11.1 Introduction . . . . . . ........................................... 287 11.2 Definitions . . . . . . . . ........................................... 290 11.3 Microbiological hazards . .................................... 304 11.4 Risk classes . . . . . . . ........................................... 307 11.5 Safe process design 1: equipment and processes . . . . . . . . ..... 308 11.6 Safe process design 2: manufacturing areas . . ............... 316 11.7 Safe process design 3: unit operations for decontaminated products ..................................................... 323 11.8 Control systems . . ........................................... 328 11.9 Conclusions . . . . . . . ........................................... 332 11.10 References . . . . . . . . ........................................... 333 viii Contents 12 Quality and consumer acceptability . . . . . ........................ 341 S. R. P. R. Durand, HP Foods Ltd 12.1 Introduction . . ................................................ 341 12.2 What defines sensory quality? ............................... 342 12.3 Sensory evaluation techniques ............................... 344 12.4 Determining consumer acceptability . ........................ 349 12.5 Future trends and conclusion . . ............................... 351 12.6 References . . . ................................................ 352 13 The hygienic design of chilled foods plant . . . . . ................. 355 J. Holah and R. H. Thorpe, Campden and Chorleywood Food Research Association 13.1 Introduction . . ................................................ 355 13.2 Segregation of work zones . . . . ............................... 357 13.3 High-risk barrier technology . . ............................... 363 13.4 Hygienic construction . . ...................................... 380 13.5 Equipment . . . ................................................ 389 13.6 Conclusion . . . ................................................ 394 13.7 References . . . ................................................ 394 14 Cleaning and disinfection . . ...................................... 397 J. Holah, Campden and Chorleywood Food Research Association 14.1 Introduction . . ................................................ 397 14.2 Sanitation principles . . . ...................................... 398 14.3 Sanitation chemicals . . . ...................................... 402 14.4 Sanitation methodology ...................................... 409 14.5 Sanitation procedures . . ...................................... 414 14.6 Evaluation of effectiveness . . . ............................... 416 14.7 Management responsibilities . . ............................... 421 14.8 References . . . ................................................ 423 15 Total quality management . ...................................... 429 D. J. Rose, Campden and Chorleywood Food Research Association 15.1 Introduction . . ................................................ 429 15.2 The scope of a quality system ............................... 433 15.3 Developing a quality system . . ............................... 435 15.4 Implementation . . . . . . . . ...................................... 442 15.5 Performance measuring and auditing . ........................ 446 15.6 Benefits . . . . . . ................................................ 448 15.7 Future trends . ................................................ 449 15.8 References and further reading ............................... 450 16 Legislation 451 K. Goodburn, Chilled Food Association 16.1 Introduction . . ................................................ 451 Contents ix 16.2 Food law is reactive . . . . . .................................... 451 16.3 Food laws and international trade . . . . . ...................... 452 16.4 Chilled foods are. . . . . . . . .................................... 453 16.5 Approaches to legislation .................................... 454 16.6 Codex . . ..................................................... 455 16.7 ATP . . . . ..................................................... 457 16.8 Canada . ..................................................... 458 16.9 European Union . . ........................................... 458 16.10 Australia/New Zealand . . .................................... 461 16.11 France . . ..................................................... 462 16.12 The Netherlands . . ........................................... 463 16.13 United Kingdom . . ........................................... 464 16.14 United States . . . . . ........................................... 465 16.15 Summary . . . . . . . . . ........................................... 468 16.16 References and further reading . ............................. 468 Index ................................................................... 474 x Contents