Cover
Title Page
Preface
1 Control of Biodeteriorationin Food
1. 1.1 OVERVIEW
2. 1.2 A SUMMARY OF THE DIFFERENT KINDS OF BIODETERIORATION
3. 1.3 KINDS OF LIVING ORGANISMS INVOLVED IN BIODETERIORATION
4. 1.4 FOOD BIODETERIORATION
5. 1.5 DESCRIPTION OF THE MECHANISMS OF FOOD BIODETERIORATION
6. 1.6 MICROORGANISMS INVOLVED IN BIODETERIORATION REACTIONS
7. REFERENCES
2 Principles of HACCP: The Importance of HACCP Systems in Food Manufacturing
1. 2.1 INTRODUCTION AND HISTORICAL PERSPECTIVE
2. 2.2 THE HACCP PRINCIPLES AND CODEX (CAC 1997)
3. 2.3 HACCP IMPLEMENTATION: IMPORTANT CONSIDERATIONS
4. 2.4 THE IMPORTANCE OF HACCP IN FOOD MANUFACTURING: THE PREVENTATIVE MINDSET
5. 2.5 THE LEGAL POSITION
6. 2.6 CLOSING THOUGHTS
7. APPENDICES
8. REFERENCES
3 Thermal Processing
1. 3.1 INTRODUCTION
2. 3.2 STERILISATION – LOW-ACID FOODS
3. 3.3 PASTEURISATION
4. 3.4 EQUIPMENT FOR THERMAL PROCESSING
5. 3.5 CONCLUSIONS
6. REFERENCES
4 Chilling
1. 4.1 INTRODUCTION
2. 4.2 CHILLING OPERATIONS
3. 4.3 CHILLED STORAGE
4. 4.4 RETAIL DISPLAY
5. 4.5 CONCLUSIONS
6. REFERENCES
5 Freezing
1. 5.1 INTRODUCTION
2. 5.2 THE PHYSICAL AND CHEMICAL ASPECTS OF FREEZING
3. 5.3 THE EFFECT OF FREEZING ON MICROORGANISMS
4. 5.4 FOOD FREEZING OPERATIONS
5. 5.5 MONITORING THE QUALITY AND SAFETY OF FROZEN FOODS
6. 5.6 NEW DEVELOPMENTS
7. 5.7 CONCLUSIONS
8. REFERENCES
6 Drying
1. 6.1 INTRODUCTION
2. 6.2 DRYING PROCESSES AND DRYING EQUIPMENT
3. 6.3 BACTERIA DEACTIVATION KINETICS DURING THE DRYING PROCESS
4. 6.4 CONCLUDING REMARKS
5. REFERENCES
7 Modified Atmosphere Packaging
1. 7.1 INTRODUCTION
2. 7.2 BACKGROUND INFORMATION
3. 7.3 MAP MATERIALS
4. 7.4 MAP MACHINERY
5. 7.5 SELECTED MAP FOOD APPLICATIONS
6. 7.6 MAP OF FRESH PRODUCE
7. 7.7 CONCLUSIONS
8. REFERENCES
8 Preservatives
1. 8.1 INTRODUCTION
2. 8.2 TYPES OF PRESERVATIVES
3. 8.3 CONCLUSIONS
4. REFERENCES
9 Hurdle Techniques
1. 9.1 INTRODUCTION
2. 9.2 HURDLE TECHNOLOGIES
3. 9.3 PREDICTIVE MODELLING
4. 9.4 CONCLUSIONS
5. REFERENCES
10 Novel Commercial Preservation Methods
1. 10.1 INTRODUCTION
2. 10.2 OHMIC HEATING
3. 10.3 HIGH PRESSURE PROCESSING (HPP)
4. 10.4 MICROWAVE AND RADIO-FREQUENCY HEATING
5. 10.5 PULSED ELECTRIC FIELD PROCESSING
6. 10.6 IRRADIATION
7. 10.7 CONCLUSIONS
8. REFERENCES
Index
End User License Agreement

List of Tables

Chapter 01
1. Table 1.1 Examples of the diversity of biodeterioration.
2. Table 1.2 Classification of microorganisms on the basis of their nutritional requirements.
3. Table 1.3 The composition of some common foods.
4. Table 1.4 The pH of selected foods.
Chapter 02
1. Table 2.1 Guidelines for the application of the HACCP system.
2. Table 2.2 The steps involved in HACCP [5].
3. Table 2.B.1 Product description – rice salad.
Chapter 03
1. Table 3.1 Heat resistance data for spoilage microorganisms relevant to low-acid foods.
2. Table 3.2 Process time at 121.1°C to achieve 12-log reductions in spores of C. botulinum and selected spoilage organisms of greater heat resistance.
3. Table 3.3 Heat resistance data for Bacilli and Clostridia.
4. Table 3.4 Heat resistance data for other bacteria.
5. Table 3.5 Heat resistance data for yeasts and moulds.
6. Table 3.6 Suggested P-values (T_ref 93.3°C, z 8.9°C) for fruit and vegetables.
7. Table 3.7 Minimum growth temperatures for some pathogenic bacteria.
Chapter 04
1. Table 4.1 Fruits and vegetables susceptible to chilling damage.
2. Table 4.2 Effect of air temperature and velocity on cooling time in 30-mm-thick two-compartment ready meals.
3. Table 4.3 Chilling time (hours) to maximum temperature of 10°C in beef side.
4. Table 4.4 Predicted cooling times (in hours) from 40 to 2°C at the centre of meat slabs in various cooling systems.
5. Table 4.5 Advantages and disadvantages of vacuum cooling in comparison with mechanical refrigeration.
6. Table 4.6 Advantages and disadvantages of total-loss refrigerants in comparison with mechanical refrigeration.
7. Table 4.7 The relationship between evaporative weight loss and the appearance of sliced beef topside after 6 hours display.
Chapter 05
1. Table 5.1 Variation of frozen water content of foods with temperature.
2. Table 5.2 Practical frozen storage lives (months) for various foods.
3. Table 5.3 Effect of frozen temperatures on water activity.
Chapter 06
1. Table 6.1 Relationship between latent heat and boiling point of water as a function of pressure.
2. Table 6.2 Optimal pH values for selected microorganisms.
Chapter 07
1. Table 7.1 Gas-mix guide for the MAP of retail food products
2. Table 7.2 Oxygen permeability and water vapour transmission rates of selected MAP materials
Chapter 08
1. Table 8.1 Examples of widely used preservatives in the EU.
Chapter 09
1. Table 9.1 Minimum growth conditions for food-borne microorganisms.
2. Table 9.2 Examples of intrinsic and extrinsic factors controlling the growth of microorganisms.
Chapter 10
1. Table 10.1 Industrially processed products in Emmepiemme equipment based on 2002 data (plant capacities from 1,000 to 6,000 kg/h).
2. Table 10.2 List of industrial plants installed globally by Emmepiemme (as of 2006).
3. Table 10.3 Examples of high-pressure products in the USA and Europe.
4. Table 10.4 Electromagnetic frequency allocations for industrial, scientific and medical purposes.
5. Table 10.5 Applications of microwave and radio-frequency radiation in food processing.

List of Illustrations

Chapter 01
1. Fig. 1.1 Some common biodeterioration problems. (a) Mouldy bread; (b) mould on antique book; (c) rotten floorboards; (d) soft rot on apples.
2. Fig. 1.2 Examples of foods derived from fermentation.
3. Fig. 1.3 Sample of typical cheeses.
4. Fig. 1.4 Metabolization of glucose (glycogen) via pyruvate.
5. Fig. 1.5 Examples of anaerobic fermentation.
6. Fig. 1.6 An example of aerobic fermentation.
7. Fig. 1.7 Production of cadaverine.
8. Fig. 1.8 Production of putrescine.
9. Fig. 1.9 pH growth ranges for selected microorganisms.
10. Fig. 1.10 Spoilage of yogurt owing to presence of lactic acid bacteria.
11. Fig. 1.11 Spoilage of strawberries owing to presence of mould.
Chapter 02
1. Fig. 2.1 Example of a CCP decision tree for process steps .
Chapter 03
1. Fig. 3.1 Maximum heat resistance data for C. botulinum, taken from Esty and Meyer [3]. Sixty billion spores in a phosphate buffer solution, pH 7.0.
2. Fig. 3.2 Maximum heat resistance data for C. botulinum, taken from Esty and Meyer [3]. Sixty billion spores in a phosphate buffer solution, pH 7.0. Data plotted with thermal death time on a logarithmic axis.
3. Fig. 3.3 Example of a first-order or logarithmic survivor curve, showing the calculation of decimal reduction time (D), the time required to decrease the concentration of organisms by a factor of 10.
Chapter 04
1. Fig. 4.1 Sugar loss from sweetcorn at different storage temperatures.
2. Fig. 4.2 Example of a chilling tunnel with longitudinal air circulation.
3. Fig. 4.3 Effect of air speed on the cooling time of pork pies.
4. Fig. 4.4 Example of a horizontal plate cooler.
5. Fig. 4.5 Cooling of liquid in 250-l vessel using a water cooling jacket or under vacuum.
6. Fig. 4.6 Heat exchangers used for cooling liquid foods. (a) Falling film, (b) double pipe, (c) multi-plate, (d) multi-tube.
7. Fig. 4.7 Three types of retail display cabinet for unwrapped products.
8. Fig. 4.8 Multi-deck display cabinets (open and enclosed) for wrapped products.
Chapter 05
1. Fig. 5.1 Typical time–temperature freezing curves.
2. Fig. 5.2 Principles of a blast freezing operation.
3. Fig. 5.3 Mechanical air-blast food freezing system.
4. Fig. 5.4 Cryogenic food freezing tunnel.
5. Fig. 5.5 Spiral freezer configuration.
Chapter 06
1. Fig. 6.1 Stability diagram for food materials.
2. Fig. 6.2 Schematic diagram of hot-air drying of a moist, porous material.
3. Fig. 6.3 Equilibrium relationship (isotherm) for surface water content and the relative humidity (RH) of the drying medium at constant temperature of the material being dried (e.g. the wet-bulb temperature). The dashed line indicates the probable actual RH at the surface as it gets dried and warmed up. X_s,c is a critical surface water content below which RH is lower than 100%. The region to the left of X_s,c represents the falling drying flux period and to the right of X_s,c is the constant drying flux period.
4. Fig. 6.4 Schematic diagram of the drying periods defined using the relationship between the drying flux and average water content (the surface water content X_s,c is lower than X_c under the same drying conditions).
5. Fig. 6.5 Qualitative equilibrium isotherms for various types of food material (crystalline sugar is an example of a ‘nearly non-hygroscopic’ material, while its amorphous form is an example of a ‘hygroscopic porous medium’).
6. Fig. 6.6 Equilibrium isotherms of a number of typical food materials.
7. Fig. 6.7 Possible cross sections of inter-particle or inter-cell channels or capillaries.
8. Fig. 6.8 Qualitative illustration of the temperature–time profiles and moisture content–time profile of a material being dried. (It is assumed that the initial water content is fairly high; for natural food materials, this assumption is generally true as their water contents are in the order of 80% by weight. For highly concentrated materials, such as high solid concentrate droplets in milk drying, the pseudo-wet-bulb period may be very short or does not exist.) T_A, temperature of the centre of the material being dried; T_B, temperature of the surface of the material being dried; X, moisture content.
9. Fig. 6.9 Phase diagram for water.
10. Fig. 6.10 Vapour pressure/temperature curve for water.
11. Fig. 6.11 Effect of air velocity on pressure drop through fluidised bed.
12. Fig. 6.12 Temperature required for initiating massive irreversible cross-linking of egg protein albumin at different water contents.
13. Fig. 6.13 Thermal stability or heat resistance of microorganisms as a function of water content (or water activity).
14. Fig. 6.14 Qualitative illustration of the moisture content–time profiles at the centre (X_A) and at the surface (X_B) of a food material during drying.
Chapter 07
1. Fig. 7.1 The interchangeable meat myoglobin forms and associated colours.
Chapter 10
1. Fig. 10.1 Schematic diagram of the operating principle of an ohmic heating device.
2. Fig. 10.2 Schematic diagram of the attachment of an ohmic heater to aseptic tanks.
3. Fig. 10.3 A typical ohmic heater,
4. Fig. 10.4 A horizontal batch high-pressure processing vessel from Avure pressure systems.
5. Fig. 10.5 A horizontal batch high-pressure processing vessel from NC Hyperbaric.
6. Fig. 10.6 Circuit for exponential decay pulse generation.
7. Fig. 10.7 Examples of pulse wave shapes in PEF.
8. Fig. 10.8 A cobalt-60 ‘pencil’.
9. Fig. 10.9 Penetration and absorbed dose – samples are typically dosed from two sides to minimise non-uniformity of dose across the product.
10. Fig. 10.10 Schematic diagram of a typical continuous gamma irradiation facility.

Pages

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Library of Congress Cataloging-in-Publication Data

Food biodeterioration and preservation.
Food preservation and biodeterioration / Gary S. Tucker. – Second edition.
      pages   cm
   Revised edition of Food biodeterioration and preservation. 2007.
   Includes bibliographical references and index.

   ISBN 978-1-118-90462-6 (cloth)
1. Food–Preservation.   2. Food spoilage.   3. Food–Microbiology.   I. Tucker, Gary.   II. Title.
   TP371.2.F58 2016
   664′.028–dc23

2015036796

A catalogue record for this book is available from the British Library.

Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic books.

Cover image: Dried tomatoes and glass of pickled dried tomatoes © Westends61

Preface

Biodeterioration is defined as the breakdown of food by agents of microbiological origin, either directly or indirectly from products of their metabolism. Preservation on the other hand is the process by which food materials are maintained in their original condition or as close to this as possible. This book discusses how the agents of food biodeterioration operate and how the commercial methods available to counteract these agents are applied to produce safe and wholesome foods.

Food preservation is aimed at extending the shelf life of foods. It originated with traditional methods such as curing, salting and sugaring, all of which are still important commercial methods. Major advances in preservation technology were the introduction of canning and freezing processes for extending the useable life of fruits and vegetables. These methods still form a substantial part of the food preservation business. In most cases, it is the growth of either spoilage or disease-causing microorganisms that limits the length of time that a food can be kept, and most preservation techniques are primarily based on reducing or preventing this growth. However, there are other factors that limit shelf life, such as the action of naturally occurring enzymes within the food or natural chemical reactions between the constituents of the food. Both microbiological and chemical pathways have to be taken into consideration when preserving food materials.

This second version of the book contains updated information on preservation methods but has also reorganised several chapters so that consistency between chapters is enhanced. Chapters 1 and 2 are largely unchanged because they provide background information that is still relevant and current. Chapter 1 describes the many types of microorganisms and enzymes responsible for biodeterioration of foods. This chapter sets the scene for the individual chapters dedicated to methods of preserving foods. Chapter 2 describes the HACCP system that is universally used for ensuring the safety of commercial food products. This sets out the context of how a food company should approach HACCP as the means of ensuring food is manufactured with the greatest probability of being free from biological, chemical or physical hazards. Subsequent chapters deal with individual methods of food preservation.

Chapter 3 on thermal processing has been rewritten to provide more focus on the thermal effects of sterilisation and pasteurisation and less on specific equipment. Chapter 4 on chilling has also been rewritten to provide a more general view on food chilling and to update it with recent industrial processes. Chapter 5 on freezing now has an update on the latest freezing techniques such as the Cells Alive System that originated in Japan. Chapter 6 on drying now contains descriptions of the different drying techniques used by the food industry. This chapter outlines mathematical approaches to define drying performance and efficiency. Chapter 7 is on modified atmosphere packaging and its effects on microorganisms.

There is a new chapter on preservatives that includes sections on chemical and natural preservatives (Chapter 8). Material has been taken out from other chapters so that preservatives have a dedicated chapter. This was thought to be important because preservatives can be used as stand-alone preservation techniques and do not always have to be used in combination. There is new material on natural methods that includes sourdough systems used in the bread sector.

Chapter 9 is on hurdle techniques. This reflects the increasingly common practice of using preservation methods in combination in order to reduce the severity of any individual method. For example, thermal processing is often used as part of a combination process designed to present ‘hurdles’ to microbial growth. One of the traditional preservation hurdles is acidity, used with fruits, jams and preserves, where the low pH in fruits prevents Clostridium botulinum spores from germinating, and so the thermal process only needs to be effective on less heat-resistant organisms. Advantages of hurdle technologies are in the milder treatments that can lead to the manufacture of better quality foods.

Chapter 10 on novel commercial preservation methods has been updated. Recent commercial developments in technologies such as ohmic, microwave, irradiation and high pressure are described. These technologies may have benefits in allowing foods to be minimally processed and in doing so retain more of their inherent attributes such as texture, colour and nutritional content. Many of these techniques are used as hurdles in which thermal effects are responsible for microorganism destruction.

Gary S. Tucker
Head of the Baking and Cereal Processing Department
Campden BRI
Chipping Campden
Gloucestershire