Woodhead Publishing Series in Food Science, Technology and Nutrition: Number 250 Improving the safety and quality of nuts Edited by Linda J. Harris WP WOODHEAD PUBLISHING Oxford Cambridge Philadelphia New Delhi
Contents Contributor contact details xi Woodhead Publishing Series in Food Science, Technology and Nutrition Preface xv xxv Part I Production and processing practices and influence on nut contaminants 1 1 Agricultural practices to reduce microbial contamination of nuts 3 M. L. Wells, University ofgeorgia, USA 1.1 Introduction 3 1.2 Tree nut production systems 4 1.3 Good Agricultural Practices (GAPs) for nut production 9 1.4 Conclusion 18 1.5 References 19 2 Impact of nut postharvest handling, de-shelling, drying and storage on quality 22 A. A. Kader, formerly of the University of California, Davis, USA 2.1 Quality attributes of nuts 22 2.2 Impact of maturity at harvest and harvesting procedures on quality 25 2.3 Impact of postharvest handling operations on the quality of raw nuts 27 2.4 Impact of processing operations 29 2.5 Impact of marketing operations 32 2.6 References 33 Woodhead Publishing Limited, 2013
vi Contents 3 Non-thermal processing technologies to improve the safety of nuts 35 A. Prakash, Chapman University, USA 3.1 Introduction 35 3.2 Propylene oxide (PPO) 36 3.3 High pressure processing (HPP) 37 3.4 Irradiation and ultraviolet radiation 40 3.5 Ozone, cold plasma, high pressure carbon dioxide (HPCD) and sanitizer treatments 43 3.6 Conclusion 49 3.7 References 52 4 Pest control in postharvest nuts 56 J. Johnson, USDA-ARS, San Joaquin Valley Agricultural Sciences Center, USA 4.1 Introduction 56 4.2 Common postharvest pests of tree nuts 57 4.3 Orchard pest management strategies 68 4.4 Processing facility pest management strategies 71 4.5 Commodity treatments 74 4.6 Future trends 78 4.7 Sources of further information and advice 79 4.8 References 79 5 Mycotoxin contamination of nuts 88 D. Clavel and C. Brabet, CIRAD, France 5.1 Introduction 88 5.2 Aflatoxin regulations and analysis in nuts 89 5.3 From fungal spoilage to aflatoxin contamination in groundnuts 94 5.4 Prevention and control of pre-harvest aflatoxin contamination in groundnuts 99 5.5 Post-harvest strategies for preventing and reducing aflatoxin contamination in groundnuts 103 5.6 Aflatoxin risk management in groundnuts 107 5.7 Sources of further information and advice Ill 5.8 References Ill 6 Integrating Hazard Analysis Critical Control Point (HACCP) and Statistical Process Control (SPC) for safer nut processing 119 W. C. Hurst, University of Georgia, USA 6.1 Introduction 119 6.2 Compatibility of Hazard Analysis and Critical Control Point (HACCP) and Statistical Process Control (SPC) management systems 121
Contents vii 6.3 Origin of HACCP and planning an HACCP study 122 6.4 HACCP Principle 1: conducting a hazard analysis 126 6.5 HACCP Principle 2: using SPC to identify and stabilize variability at CCPs 128 6.6 HACCP Principle 3: conducting process capability analyses to verify critical limits (CLs) 130 6.7 HACCP Principle 4: establishing SPC procedures for monitoring CCPs 132 6.8 HACCP Principle 5: determining corrective action procedures 137 6.9 HACCP Principle 6: confirming HACCP implementation through verification and validation activities 137 6.10 HACCP Principle 7: establishing documentation and record keeping 140 6.11 Role of prerequisite programs in HACCP 141 6.12 Conclusion 143 6.13 References 143 7 Validation of processes for reducing the microbial load on nuts 148 C. Ivarsson, Napasol AG, Switzerland 7.1 Introduction 148 7.2 The science of validation 149 7.3 Technologies for microbial reduction in nuts 152 7.4 Principal elements of a validation program 155 7.5 Pasteurization performance of technologies used for processing nuts 158 7.6 Pasteurization technologies suitable for raw nuts 160 7.7 Validation in practice 162 7.8 Future trends for safe nuts 168 7.9 Sources of further information and advice 169 7.10 References 169 Part II Improving nut quality and safety 171 8 Impact of roasting on nut quality 173 R. Perren, RPN EXCELLENCE AG, Switzerland and F. E. Escher, ETH Zurich, Switzerland 8.1 Introduction 173 8.2 Nut roasting technology 175 8.3 Microstructure and quality of roasted nuts 181 8.4 Non-enzymatic browning reactions and quality of roasted nuts 190 8.5 Safety and nutritional aspects of nut roasting 191 8.6 Flavoring and seasoning technology for roasted tree nuts 192
viii Contents 8.7 Downstream processing, packaging and storage of roasted tree nuts 193 8.8 References 195 9 Oxidative rancidity in nuts 198 F. Shahidi and J. A. John, Memorial University of Newfoundland, Canada 9.1 Introduction 198 9.2 Mechanisms of oxidative rancidity in nuts 200 9.3 Factors affecting the rate of oxidation 202 9.4 Measuring oxidation in nuts 208 9.5 Effect of oxidation on sensory and nutritional quality and shelf life of nuts and nut oils 214 9.6 Protecting nuts and nut oils against oxidation 214 9.7 Future trends 221 9.8 References 222 10 Advances in automated nut sorting 230 N. Toyofuku, R. Haffand T. Pearson, USDA ARS WRRC, USA 10.1 Introduction 230 10.2 Advantages of automation 231 10.3 Computer vision-based sorting (CVBS) systems 232 10.4 Acoustics-based sorting (ABS) systems 235 10.5 Computer processing and algorithm development 237 10.6 Possible avenues of development in sorting nuts 238 10.7 Conclusion 240 10.8 References 240 11 Improving the quality and safety of walnuts 245 D. L. McNeil, University of Tasmania, Australia 11.1 Introduction 245 11.2 Food value 249 11.3 Safety 251 11.4 Quality 259 11.5 Walnut supply chains 263 11.6 Conclusion 267 11.7 References 267 12 Improving the quality and safety of macadamia nuts 274 M. M. Wall, US Department ofagriculture, Agricultural Research Service, USA 12.1 Introduction 274 12.2 Nut properties 276 12.3 Key safety issues 278 12.4 Genetics, breeding and variety selection 280 Woodhead Publishing Limited, 2013
Contents ix 12.5 Pre- and post-harvest factors affecting safety and quality 282 12.6 Processing effects on safety and quality 284 12.7 Quality assessment, nutritional aspects and food applications... 288 12.8 Conclusion 291 12.9 References 291 13 Improving the safety and quality of pecans 297 L. R. Beuchat and R. B. Pegg, University of Georgia, USA 13.1 Introduction 297 13.2 Historical perspective 298 13.3 Sources and routes of microbiological contamination 299 13.4 Safety and spoilage 305 13.5 Quality attributes and nutrients 312 13.6 Health benefits 320 13.7 Future trends 323 13.8 Sources of further information and advice 324 13.9 References 324 14 Improving the quality and safety of peanuts 330 S. Calhoun, American Peanut Council, USA 14.1 Introduction 330 14.2 Properties of peanuts 331 14.3 Key safety issues 331 14.4 The Peanut Genome Project 333 14.5 Breeding and varieties 334 14.6 Pre-harvest factors affecting safety and quality of peanuts 335 14.7 Post-harvest factors affecting safety and quality of peanuts 336 14.8 Processing effects on safety and quality of peanuts 337 14.9 Quality assessment 342 14.10 Nutritional aspects and food applications of peanuts 344 14.11 Future trends 345 14.12 Sources of further information and advice 346 14.13 References 346 15 Improving the safety of almonds and pistachios 350 L. J. Harris and L. Ferguson, University of California, Davis, USA 15.1 Introduction and historical perspective 350 15.2 Production, harvest and post-harvest practices 352 15.3 Microbiological safety 356 15.4 Sources and routes of contamination with enteric pathogens 361 15.5 Aflatoxin 362 15.6 Good Agricultural Practices (GAPs) to minimize pre-harvest contamination 364 15.7 Post-harvest options to reduce microbial loads 368
x Contents 15.8 Composition 370 15.9 Future trends 372 15.10 Sources of further information and advice 372 15.11 References 373 Appendix: Detecting tree nut and seed allergens in food 379 S. J. Koppelman, University of Nebraska-Lincoln, USA A 1.1 Introduction 379 Al.2 Prevalence of nut and seed allergies 380 A1.3 Thresholds 381 A1.4 Allergenic proteins in nuts and seeds 382 A1.5 Effect of food processing on allergenicity 3 83 A1.6 Detecting nut and seed residues in food: selecting a method 384 A 1.7 Conclusions 390 A 1.8 References 392 Index 397 Woodhead Publishing Limited, 2013