Food Preservation and Biodeterioration

GARY S. TUCKER is head of the Baking and Cereal Procession Department, Campden BRI Group, UK.

Preface xi

1 Control of Biodeterioration in Food 1

1.1 Overview 1

1.2 A summary of the different kinds of biodeterioration 2

1.2.1 Chemical biodeterioration 2

1.2.2 Physical biodeterioration 2

1.3 Kinds of living organisms involved in biodeterioration 5

1.3.1 Bacteria 5

1.3.2 Fungi 5

1.3.3 Algae, mosses and liverworts 5

1.3.4 Higher plants 5

1.3.5 Insects 5

1.3.6 Birds, mammals and reptiles 6

1.4 Food biodeterioration 6

1.4.1 The composition of food 7

1.5 Description of the mechanisms of food biodeterioration 10

1.5.1 Fermentation 10

1.5.2 Fermentation biochemistry 22

1.5.3 Putrefaction 23

1.5.4 Lypolysis 23

1.6 Microorganisms involved in biodeterioration reactions 24

1.6.1 Factors that affect microbial growth 24

1.6.2 Bacteria 27

1.6.3 Moulds 32

1.6.4 Yeasts 34

References 35

2 Principles of HACCP: The Importance of HACCP Systems in Food Manufacturing 36

2.1 Introduction and historical perspective 36

2.2 The haccp principles and Codex (cac 1997) 37

2.3 HACCP implementation: Important considerations 40

2.3.1 Prerequisite programmes 40

2.3.2 Application of the HACCP principles and the importance of training 41

2.4 The importance of haccp in food manufacturing: The preventative mindset 44

2.4.1 Food design 45

2.4.2 Food manufacturing 46

2.4.3 Globalization and trade 47

2.5 The legal position 47

2.6 Closing thoughts 49

Appendices 49

Appendix 2.A: Example of the make]up of an HACCP team 50

Appendix 2.B: Example of a product description 50

Appendix 2.C: Examples of process flow diagrams 51

Appendix 2.D: Hazard analysis tool as an example guide 53

Appendix 2.E: Examples of hazard analysis and CCP decision logic: Fresh vegetables, rice, vinaigrette, salad blending and assembly 54

Appendix 2.F: Example of the HACCP control chart (for rice salad) 58

References 59

3 Thermal Processing 60

3.1 Introduction 60

3.2 Sterilisation – low]acid foods 61

3.2.1 History of the canning industry 61

3.2.2 F0 3 sterilisation processes 63

3.2.3 Commercial sterilisation 66

3.2.4 Microorganism death kinetics 67

3.2.5 Log reductions 69

3.3 Pasteurisation 71

3.3.1 Control of the microorganism loading 75

3.3.2 Use of restrictive pH levels 75

3.3.3 Low temperatures 77

3.3.4 Dehydration or low water activity 79

3.3.5 Chemical preservation 80

3.4 Equipment for thermal processing 82

3.4.1 Heat exchangers 83

3.4.2 In]pack retorting 84

3.4.3 In]vessel systems 86

3.5 Conclusions 86

References 87

4 Chilling 89

4.1 Introduction 89

4.1.1 Effect of chilling on microorganism growth 90

4.1.2 Effect of chilling on enzymes and biochemical reactions 91

4.1.3 Effect of chilling on physical processes 92

4.1.4 Effect of chilling on physiological processes 93

4.2 Chilling operations 94

4.2.1 Moving air systems 95

4.2.2 Direct contact 100

4.2.3 Jacketed heat exchangers 101

4.2.4 Immersion/spray 104

4.2.5 Ice 105

4.2.6 Vacuum 106

4.2.7 Cryogenic 108

4.3 Chilled storage 111

4.3.1 Controlled atmosphere storage rooms 112

4.4 Retail display 112

4.4.1 Unwrapped products 113

4.4.2 Wrapped products 115

4.5 Conclusions 116

References 117

5 Freezing 119

5.1 Introduction 119

5.2 The physical and chemical aspects of freezing 121

5.3 The effect of freezing on microorganisms 127

5.4 Food freezing operations 130

5.5 Monitoring the quality and safety of frozen foods 134

5.6 New developments 135

5.7 Conclusions 137

References 138

6 Drying 139

6.1 Introduction 139

6.2 Drying processes and drying equipment 141

6.2.1 Vacuum drying 149

6.2.2 Freeze drying 151

6.2.3 Spray drying 153

6.2.4 Sun drying 154

6.2.5 Fluidised bed drying 155

6.2.6 Drum drying 157

6.2.7 Osmotic drying 157

6.3 Bacteria deactivation kinetics during the drying process 158

6.4 Concluding remarks 165

References 165

7 Modified Atmosphere Packaging 167

7.1 Introduction 167

7.2 Background information 167

7.2.1 MAP and related terminologies and technologies 168

7.2.2 Gases used for MAP 169

7.2.3 The benefits and disadvantages of MAP 172

7.2.4 Effects of MAP on microbial spoilage 172

7.3 MAP materials 174

7.3.1 Gas permeability 174

7.3.2 WVTR 176

7.3.3 Mechanical properties 176

7.3.4 Sealing reliability 176

7.3.5 Transparency 176

7.3.6 Type of package 176

7.3.7 Microwaveability 177

7.4 MAP machinery 177

7.4.1 Horizontal form–fill–seal 177

7.4.2 Vertical form–fill–seal 177

7.4.3 Thermoform–fill–seal 178

7.4.4 Preformed tray and lidding film 178

7.4.5 Vacuum chamber 178

7.4.6 Snorkel type 179

7.5 Selected MAP food applications 179

7.5.1 Raw red meat products 180

7.5.2 Raw fish and seafood products 180

7.5.3 Cooked, cured and processed meat products 181

7.5.4 Dairy products 182

7.5.5 Bakery products 183

7.5.6 Dried food products 183

7.6 MAP of fresh produce 184

7.6.1 Factors that affect the shelf life of fresh produce 184

7.6.2 Effects of MAP on fresh produce microbial growth and safety 186

7.7 Conclusions 190

References 190

8 Preservatives 193

8.1 Introduction 193

8.1.1 Labelling and legislation 194

8.2 Types of preservatives 195

8.2.1 Chemical preservatives 195

8.2.2 Natural preservatives 198

8.2.3 Modified atmosphere packaging 201

8.3 Conclusions 203

References 204

9 Hurdle Techniques 206

9.1 Introduction 206

9.2 Hurdle technologies 208

9.2.1 Heat treatment 208

9.2.2 Chilling 209

9.2.3 Acidification or low pH 210

9.2.4 Water activity 212

9.2.5 Modified atmosphere 213

9.2.6 Chemical preservatives 214

9.2.7 Natural antimicrobials 216

9.2.8 Microbial interactions 216

9.3 Predictive modelling 217

9.4 Conclusions 220

References 220

10 Novel Commercial Preservation Methods 223

10.1 Introduction 223

10.2 Ohmic heating 224

10.2.1 Background 224

10.2.2 Industrial applications 225

10.2.3 Equipment 227

10.2.4 Packaging considerations 229

10.2.5 Shelf life and product safety 229

10.3 High Pressure Processing (HPP) 229

10.3.1 Background 229

10.3.2 Industrial applications 230

10.3.3 Equipment 231

10.3.4 Packaging requirements 232

10.3.5 Shelf life and product safety 233

10.4 Microwave and radio]frequency heating 233

10.4.1 Background 233

10.4.2 Industrial applications 236

10.4.3 Packaging requirements 240

10.4.4 Shelf life and product safety 240

10.5 Pulsed electric field processing 241

10.5.1 Background 241

10.5.2 Industrial applications 241

10.5.3 Non]preservation applications 242

10.5.4 Equipment 242

10.5.5 Packaging considerations 244

10.5.6 Shelf life and product safety 244

10.6 Irradiation 247

10.6.1 Background 247

10.6.2 Industrial applications 247

10.6.3 Equipment 248

10.6.4 Shelf life and product safety 250

10.7 Conclusions 252

References 253

Index 257