Hurdle Technologies

Combination Treatments for Food Stability, Safety and Quality

FOOD ENGINEERING SERIES

Series Editor

Gustavo V. Barbosa-Canovas, Washington State University

Advisory Board

Jose Miguel Aguilera, Pontific a Universidad Catolica de Chile Petro Fito, Universidad Politecnica Richard W. Hartel, University of Wisconsin Jozef Kokini, Rutgers University Michael McCarthy, University of California at Davis Martin Okos, Purdue University Micha Peleg, University of Massachusetts Leo Pyle, University of Reading Shafiur Rahman, Hort Research M. Anandha Rao, Cornell University Y rjo Roos, University College Cork Walter L. Spiess, Bundesforschungsanstalt Jorge Welti-Chanes, Universidad de las Americas-Puebla

Food Engineering Series

Jose M. Aguilera and David W. Stanley, Microstructural Principles of Food Processing and Engineering, Second Edition (1999)

Stella M. Alzamora, Maria S. Tapia, and Aurelio Lopez-Malo, Minimally Processed Fruits and Vegetables: Fundamental Aspects and Applications (2000)

Gustavo Barbosa-Canovas and Humberto Vega-Mercado, Dehydration of Foods (1996)

Pedro Fito, Enrique Ortega-Rodriguez, and Gustavo Barbosa-Canovas, Food Engineering 2000 (1997)

PJ. Fryer, D.L. Pyle, and C.D. Rielly, Chemical Engineering for the Food Industry (1997)

Richard W. Hartel, Crystallization in Foods (2001) Marc E.G. Hendrickx and Dietrich Knorr, Ultra High Pressure Treatments of Food

(2000) S.D. Holdsworth, Thermal Processing of Packaged Foods (1997) Lothar Leistner and Grahame W. Gould, Hurdle Technologies: Combination

Treatments for Food Stability, Safety and Quality (2002) Michael J. Lewis and Neil J. Heppell, Continuous Thermal Processing of Foods:

Pasteurization and UHT Sterilization (2000) Rosana G. Moreira, M. Elena Castell-Perez, and Maria A. Barrufet, Deep-Fat

Frying: Fundamentals and Applications (1999) Rosana G. Moreira, Automatic Control for Food Processing Systems (2001) M. Anandha Rao, Rheology of Fluid and Semisolid Foods: Principles and

Applications (1999)

Hurdle Technologies Combination Treatments for Food Stability,

Safety and Quality

by

Lothar Leistner Formerly Director and Professor of the Federal Centre for Meat Research

Kulmbach, Germany

and

Grahame W. Gould Formerly Uni/ever Research

Bedford, United Kingdom

Springer Science+Business Media, LLC

ISBN 978-1-4613-5220-4 ISBN 978-1-4615-0743-7 (eBook) DOI 10.1007/978-1-4615-0743-7

©2002 Springer Science+Business Media New York Originally published by Kluwer / Plenum Publishers, New York in 2002

Softcover reprint ofthe hardcover Ist edition 2002

1098765432

A C.I.P. record for this book is available from the Library of Congress

AII rights reserved

No part of this book may be reproduced, stored in a retrieval system, ar transmitted in any form or by any means, electronic, mechanical, photocopying, microfilming, recording, or otherwise, without written permission from the Publisher,

with the exception of any material supplied specificaIly for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work

Foreword

The concept of using a hurdle approach, which employs a combination of treat­ments to increase the stability, safety, and quality of food, is a highly effec­tive means of preserving foods while retaining desired sensory characteristics. Two of the world's leading authorities on hurdle technology, Professor Lothar ("Felix") Leistner and Grahame Gould, have combined to co-author a benchmark treatise on the application of hurdle technology for food preservation. This vol­ume provides a comprehensive treatment of the subject, including an overview of the hurdle concept, a description from both an applied and a basic perspec­tive of the preservation treatments, and technologies that encompass the hurdle concept, a helpful approach on how to apply predictive microbiology to hurdle technology, instructions on how to design foods with minimal risk of microbial growth based on combinations of hurdles, and a comprehensive description of ap­plications of hurdle technologies for foods in both industrialized and developing countries.

Professor Leistner has a career of experiences in food microbiology and in developing practical food applications employing the hurdle concept. It was Professor Leistner who originally coined the name "hurdle technology." Since retiring from the German Meat Research Institute, he has continued to promote the concept, and to initiate research on its application in numerous industrialized and developing countries. He has summarized an enormous amount of material that he has generated from his own research and collected from around the world. He is internationally recognized for his practical contributions to the field of hurdle technology.

Professor Gould has retired from the research bench following a distinguished research career at Unilever, addressing basic principles of food preservation. He has been a pioneer in developing a basic understanding of the scientific ra­tionale underlying the success of many of the combination techniques used to preserve foods. Professor Gould describes how homeostasis, stress reactions, sta­tionary phase response, and metabolic exhaustion all influence food preservation by hurdle technology.

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VI HURDLE TECHNOLOGIES

I thank Professors Leistner and Gould for their efforts in developing this highly useful resource for practicing food microbiologists. It is a well-founded text that will have lasting value.

Michael P. Doyle Regents Professor of Food Microbiology

Director of Center for Food Safety University of Georgia

Preface

An enormous diversity of traditional and artisanal methods for the preservation of foods is employed around the world. The efficacy of the majority of them depend on the use of multiple means for the inactivation or inhibition of contaminant mi­croorganisms. Most of these methodologies were derived empirically. However, since the 1980s, a more systematic approach has been developed, following the acquisition of improved understanding of the basic principles underlying com­bined preservation methodologies, such as temperature, water activity, pH, redox potential, preservatives, and so on. This new understanding has led to the es­tablishment of the concept of hurdle technology. The term, hurdle technology, covers the intelligent use of multiple preservation procedures in combinations specifically relevant to particular types of foods. The concept is relevant to the control of pathogenic, as well as food spoilage microorganisms, and to almost all food commodities and products. Furthermore, hurdle technologies have been traditionally employed in all countries of the world, although with greatly differing emphasis dependent on the history and social characteristics of different cultures, and on their stages of development. For instance, in industrialized countries, the ready availability of energy, with resulting wide use of refrigeration, has tended to predominate and lead to a great variety of mild thermally processed, chill- and frozen-distributed foods. In contrast, in many developing countries, the empha­sis remains on simply produced, ambient-stable foods, that have minimal energy requirements for processing, storage, and distribution.

This book covers the whole range of hurdle technologies that are used world­wide, including those typical of industrialized countries and also those predomi­nantly used in countries that are less developed. This book is intended as a source of information for expert food developers and technologists in industry, as well as for experts in academia and newcomers to the field, such as students of food mi­crobiology, engineering, and technology. Therefore, the authors have used forms of language and expression that are meaningful to all.

Hurdle technology does not solely target microorganisms in foods, but also embraces aspects of sensorial and nutritional quality, and the economies of food production and distribution. Effective application of hurdle technology

VB

viii HURDLE TECHNOLOGIES

requires a truly interdisciplinary approach. This demands teamwork between microbiologists, technologists, nutritionalists, and engineers, and even experts in the marketing of foods. We hope that this book will help to fulfil the expecta­tions of all these different disciplines concerned with the preservation, safety, and quality of foods.

This book compiles the state of the art of today, but also emphasizes the sub­stantial potential for new developments. In providing a more profound basis of understanding we hope to encourage the broadening and deepening of hurdle technologies and their further application worldwide.

L. Leistner G.w. Gould

Acknowledgments

One of the authors worked for about 30 years with the Federal Centre for Meat Research (BAFF) at Kulmbach, Germany, and this was the cradle of understand­ing and application of hurdle technology. His co-workers at the Institute for Microbiology, Toxicology, and Histology of the BAFF, especially H. Hechelmann, W. Rodel, F-K. Lucke, and J. Dresel, carried out the crucial experiments, in co­operation with visiting scientists from Yugoslavia, China, Japan, Korea, and India. Furthermore, a European Union funded Concerted Action on "Food Preservation by Combined Processes," to which 13 scientists of 11 European countries con­tributed in a 3-year study, opened the application of hurdle technology to foods other than meats. About 2200 copies of the Final Report of this European study, edited by L. Leistner and L.G.M. Gorris, where distributed by request. Also, in 1994, Leistner published a "picture book," sponsored by the Adalbert Raps Foun­dation, on "Food Design by Hurdle Technology and HACCp," and 4500 copies of this booklet were distributed by request worldwide.

After his retirement in 1992, Lothar Leistner was invited to lecture and consult on the principles and applications of hurdle technology in countries throughout Europe, South and North America, and Asia, as well as in Australia and New Zealand. These visits and cooperations with about 50 different countries world­wide have greatly enhanced his knowledge of traditional and novel applications of hurdle technologies in food preservation. Leistner wants to thank all his col­leagues and the European Commisssion as well as the Adalbert Raps Foundation for their contributions, which helped to greatly broaden the scope of this volume and its practical value.

Grahame Gould, who joined forces in writing this book, contributed by under­pinning the principles of hurdle technology by scientific knowledge, and thus contributed greatly by deepening the understanding of this concept lifting it from empirical application to predictable performance. Both authors want to thank Aspen and Kluwer publishers for their help and encouragement. Finally, we gratefully acknowledge the invaluable contributions and patience of our dear wives, Joan Gould and KaiMin Leistner, in the creation of this book on hurdle technologies.

IX

Table of Contents

Chapter I-Introduction............................................................ 1 Current and Future Food Preservation Technologies ........................ 2

Low Temperature ................................................................. 5 Reduction in Water Activity ................................................... 6 Reduction in pH .................................................................. 8 Preservatives ...................................................................... 9 Vacuum-Packaging and Modified Atmosphere-Packaging .............. 10 Microstructure .................................................................... 11 Heat ................................................................................. 11 New and Emerging Physical Preservation Technologies................. 13

Conclusion ............................................................................ 15

Chapter 2-The Hurdle Concept ......... ....... ..................... ......... ... 17 Hurdle Effect ......................................................................... 18 Hurdle Technology .................................................................. 21 Total Quality .......................................................................... 22 Further Dimensions of Hurdle Technology ................................... 24

Medical Aspects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Barriers to Food .................................................................. 25 Hurdle Technology and Enzymes . .. .. ... .. .. .... . .. .. .. . .. .. .. . .. . .. . . . .. . . . 25 Hurdle Technology for Sustainable Food Processing ..................... 27 Quantitative Approach to Hurdle Technology.............................. 27

Chapter 3-Basic Aspects........................................................... 29 Homeostasis .......................................................................... 29

Acidification ...................................................................... 32 Organic Acid Preservatives .................................................... 34 Reduction in Water Activity.......... .......... .......... .................... 35 Temperature.................................. ......................... ... ......... 36 Heat ................................................................................. 36

Metabolic Exhaustion .............................................................. 37

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XlI HURDLE TECHNOLOGIES

Stress Reactions ..................................................................... 41 Multitarget Preservation ........................................................... 43

Chapter 4-Hurdles in Foods ........................................... ........... 47 Major Hurdles....... .......... ............................. .... ............ .......... 47 Additional Hurdles .................................................................. 48

Chapter 5-Predictive Microbiology............................................. 51 Background ........................................................................... 51 Status and Value of Predictive Modeling ....................................... 52 Relevance to Hurdle Technology................................................. 53

Chapter 6-Food Design and Risk Assessment............................... 59 Integrated Approach. ............. ........ ................ .... ...... ................ 59 User Guide for Food Design .... .............. ....... ... ..... ..... ................ 59 Risk Assessment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

Chapter 7-Applications in Industrialized Countries....................... 65 Raw Materials ........................................................................ 65 Fermented Foods .................................................................... 65

Fermented Sausages (Salami) ................................................. 66 Raw Hams ......................................................................... 68

Heated Foods ......................................................................... 69 F-SSP ............................................................................... 70 aw-SSP .............................................................................. 72 pH-SSP ............................................................................. 74 Combi-SSP ........................................................................ 76 Army Provisions .................................................................. 77

Chilled Foods. . .. .. .. .. . .. .. . ... . . .... .... .. .. .... . . .. . .. . ... . ... . . ... . . .. . . . . .. .. ... . 80 Raw Vegetables ................................................................... 80 Sous Vide Dishes ................................................................. 81 Invisible Technology. .. . .. .. . .. .. .. .. .. . ....... ... .. . . . . . . ... . . ... . .. . . . . .. .. . .. . 83

Healthful Foods ...................................................................... 83 Low-fat and/or Low-salt Foods ........... .......... ......... .... ........... ... 83 Functional Foods ................................................................. 84

Packaging of Foods ................................................................. 85 Packaging of Hurdle-Technology Foods .................................... 85 Less Packaging ................................................................... 85

Future Food Preservation .......................................................... 87 Irradiation.... . . .. ....... ... .. ... .. .. .. .. .. .. .. .. .. ... ... . ... . . .. . . .. . . . .. . . . .... . . . 87 Emerging Technologies ......................................................... 88

Chapter 8-Applications in Developing Countries........................... 91 Principles of Food Preservation in Developing Countries .................. 92

Intermediate-Moisture Foods...... .... ........................................ 93 High-Moisture Foods. ................... ....... ................................. 95

Recent Applications of Hurdle Technology in Developing Countries .... 96

Table of Contents Xlll

Latin America ........................................................................ 96 Fruit Products..................................................................... 98 Fish Products ...................................................................... 109 Meat Products ..................................................................... 111

India. .... ..... ........ ........................... ............... ...... .................. 113 Dairy Products .................................................................... 115 Cereal Products ................................................................... 118 Vegetables and Fruits ............................................................ 119 Meat and Poultry Products ..................................................... 122

China ................................................................................... 126 Meats in General................ ........ ... ............ ........ ........ ... ....... 127 Western Meats ............. ......... ...... ......... ......... ........... ........... 127 Fusion Meats ...................... ........ ........................ ........ ........ 128 Traditional Meats.......................... .... ................................... 129

Dried Meats .................................................................... 131 Raw Sausage ................................................................... 134 Raw Hams ...................................................................... 136

Rabbit Meats........................ ...... ............ .................... ........ 138 Game ................................................................................ 139

Africa .................................................................................. 140 South Africa ....................................................................... 140 Nigeria ....................... ......................... ... ........................... 141

Chapter 9-Legislatory Status..................................................... 145 Chilled Pasteurized Foods ......................................................... 146 Canned Meat Products ............................................................. 147 Built-in Safety Hurdles for Foods ....................... ....... ............... ... 149 Labeling ............................................................................... 150

Chapter 10-Conclusions and Perspectives .................................... 153 Potential for the Wider Use of Hurdles ......................................... 154 Multitarget Preservation ........................................................... 154 Metabolic Exhaustion ..... ........... ...... ...... ...... ...... ... ...... ............. 155 Modeling of Hurdle Preservation Systems..................................... 156 Hurdles and New and Emerging Preservation Technologies ............... 156 Cost, Convenience, and Sustainability .......................................... 157 Control ofNonrnicrobiological Quality Deteriorations ... ............... ... 158 Hurdles in Animals, Food, and Man............................................. 159 Linkage of Hurdle Technology with Other Concepts ........................ 159 Implementation ...................................................................... 160

References ............................................................................... 161 Index .... ........ ....... ....... .................. ............................. ........ ..... 185