Microbiology of fruits and vegetables /

Table Of Contents:
SECTION I Contamination and State of Micro flora on Fruits and Vegetables

1 Microbial Contamination of Fresh Fruits and Vegetables 3(30)

Jim Gorny

1.1 Introduction 4(1)

1 2 Produce Contamination 5(2)

1.3 Microorganisms of Concern 7(1)

1.4 Incidence and Association of Human Pathogens with Produce 8(5)

1.4.1 FDA Imported Produce Survey 8(1)

1.4.2 FDA Domestic Produce Survey 9(1)

1.4.3 USDA Microbiological Data Program (MDP) 10(2)

1.4.4 Produce-Associated Foodborne Illness Traceback Investigation Results 12(1)

1.5 Potential Sources of Produce Contamination by Human Pathogens 13(8)

1.5.1 Food Safety. Risk Factors Associated with Production of Fresh Produce 13(1)

1.5.1.1 Land Use 14(1)

1.5.1.2 Soil Amendments 14(1)

1.5.1.3 Wild and Domestic Animal Control 14(1)

1.5.1.4 Irrigation Water 15(1)

1.5.1.5 Harvest Operations 15(1)

1.5.2 Food Safety Risk Factors Associated with Postharvest Handling of Produce 16(1)

1.5.2.1 Employee Hygiene 16(1)

1.5.2.2 Equipment 16(1)

1.5.2.3 Wash and Hydrocooling Water 17(1)

1.5.2.4 Cold Storage Facilities 17(1)

1.5.2.5 Packaging Materials 18(1)

1.5.2.6 Modified Atmosphere Packaging of Fresh Produce 18(1)

1.5.2.7 Refrigerated Transport, Distribution, and Cold Storage 19(1)

1.5.3 Food Safety Risk Factors Associated with Foodservice, Restaurant, and Retail Food Stores Handling of Produce 20(1)

1.5.4 Consumer Handling of Produce from Purchase to Plate 21(1)

1.6 Effective Management Strategies: Contamination Prevention and Intervention 21(4)

1.6.1 Good Agricultural Practices (GAPs) 22(1)

1.6.2 Current Good Manufacturing Practices (cGMPs) 23(1)

1.6.3 Hazard Analysis Critical Control Point (HACCP) 24(1)

1.7 Research Needs 25(2)

1.7.1 Microbial Ecology of Human Pathogens in the Agricultural Production Environment 26(1)

1.7.2 Agricultural Water 26(1)

1.7.3 Soil Amendments 26(1)

1.7.4 Proximity Risk of Potential Contaminant Sources 27(1)

1.7.5 Intervention Strategies to Reduce the Risk of Human Pathogen Contamination of Fresh Produce 27(1)

1.8 Summary 27(1)

References 28(5)

2 Attachment of Microorganisms to Fresh Produce 33(42)

Robert E. Mandrell, Lisa Gorski, and Maria T. Brandl

2.1 Introduction 34(1)

2.2 Basic Anatomy and Biochemistry of Roots and Leaves 35(2)

2.2.1 Rhizoplane 35(1)

2.2.2 Phylloplane 36(1)

2.3 Microbial Flora of Plants 37(1)

2.4 Attachment by Plant Nitrogen Fixing, Epiphytic, and Pathogenic Bacteria to Plants 38(10)

2.4.1 Rhizobium spp. (Rhsp) 38(1)

2.4.1.1 Two-Step Model of Attachment 40(1)

2.4.1.2 Attachment Factors 40(1)

2.4.2 Agrobacterium tumefaciens (Agt) 41(1)

2.4.2.1 Agt and Rhicadhesin 43(1)

2.4.2.2 Pili 43(1)

2.4.2.3 Cellulose 43(1)

2.4.3 Ralstonia (Pseudomonas) solanacearum (Rs) 43(1)

2.4.3.1 EPS and LPS 43(1)

2.4.3.2 Type III Secretion System (T3SS) 44(1)

2.4.3.3 Type II Secretion System (T2SS) 45(1)

2.4.3.4 Rs Lectins, Fimbriae, FHA 45(1)

2.4.4 Erwinia spp. 45(1)

2.4.5 Pseudomonas spp. 46(1)

2.4.6 Xanthomonas campestris (Xc) 47(1)

2.4.7 Azospirillum spp. 48(1)

2.4.8 Klebsiella spp. 48(1)

2.5 Fungi and Viruses and Plants 48(1)

2.6 Potential Attachment Factors of Enteric Bacterial Pathogens for Plants 48(4)

2.7 Attachment of Human Enteric Pathogens to Plants and other Interactions 52(8)

2.7.1 Lettuce and E. coli O157:H7 52(2)

2.7.2 Tomatoes and Apples and Salmonella emerita (Se) 54(1)

2.7.3 Sprouts and E. coli 0157 (EcO157) and Se 54(2)

2.7.4 Cilantro and Se Thompson (SeT) 56(1)

2.7.5 Produce Samples and L. monoutogenes (Lin) 56(2)

2.7.6 Cantaloupe and Se, EcO157, and Lm 58(1)

2.7.7 Arabidopsis thaliana and EcO157 and Se 58(1)

2.7.8 Plant鈥擬icrobe Bioelms 59(1)

2.8 Conclusions 60(1)

Acknowledgments 61(1)

References 61(14)

3 Internalization and Infiltration 75(20)

Jerry A. Bartz

3.1 Overview of Internalized Microorganisms 75(2)

3.2 Location of Internalized Organisms in Plants 77(1)

3.3 Structures that Enable Internalization 78(2)

3.4 Process of Internalization 80(1)

3.5 Internal Structures of the Plant Involved in Internalization 80(2)

3.6 Types of Internalization 82(5)

3.6.1 Aerosols 82(1)

3.6.2 Water Channels and Water Congestion 82(1)

3.6.3 Internalization in Wounds 83(1)

3.6.4 Infiltration of the Plant Surface by Aqueous Cell Suspensions 84(1)

3.6.5 Events in Plant Development 85(2)

3.7 Implications and Control 87(3)

References 90(5)

4 Microbial Stress Adaptation and Safety of Produce 95(22)

Luis A. Rodriguez-Romo and Ahmed E. Yousef

4.1 Microbial Stress Adaptation Phenomenon 95(3)

4.1.1 Stress 95(1)

4.1.2 Stress Response 96(1)

4.1.3 Stress Adaptation and the General Stress Response 96(1)

4.1.4 Regulation of the General Stress Response 97(1)

4.2 Produce Microbiota as Influenced by Stress History 98(8)

4.2.1 Preharvest Stress 98(1)

4.2.1.1 Temperature Fluctuation 99(1)

4.2.1.2 Ultraviolet Radiation 100(1)

4.2.1.3 Osmotic Stress 101(1)

4.2.2 Postharvest Stress 102(1)

4.2.2.1 Cold Stress 102(1)

4.2.2.2 Acid Stress 104(1)

4.2.2.3 Oxidative Stress 105(1)

4.2.2.4 Minimal Processing 106(1)

4.3 Microbial Stress Adaptation on Produce 106(1)

4.4 Assessing Stress Adaptation and Associated Risks 107(1)

4.5 Summary 108(1)

References 108(9)
SECTION II Microbial Spoilage of Fruits and Vegetables

5 Bacterial Soft Rot 117(18)

Ching-Hsing Liao

5.1 Introduction 117(1)

5.2 Diversity of Soft-Rot Bacteria 118(2)

5.2.1 Pectolytic Erwinia spp. 119(1)

5.2.2 Pectolytic Fluorescent (PF) Pseudomonads 119(1)

5.3 Factors Affecting the Survival of Soft-Rot Bacteria in Nature 120(2)

5.3.1 Plant Vegetation 120(1)

5.3.2 Temperature and Atmospheric Conditions 121(1)

5.3.3 Latent Infection and Internalization 121(1)

5.4 Enzymatic and Molecular Mechanism of Tissue Maceration by Soft-Rot Bacteria 122(3)

5.4.1 Biochemical Characterization of Pectate Lyase (PL) 122(1)

5.4.1.1 Analysis of PL Isozymes 122(1)

5.4.1.2 Production of Other Pectic Enzymes 122(1)

5.4.2 PL as the Principal Tissue-Macerating Factor 123(1)

5.4.2.1 Transposon Mutagenesis 123(1)

5.4.2.2 Cloning and Analysis of PL Genes 123(1)

5.4.3 Control of PL Production and Pseudomonas Rot 123(1)

5.4.3.1 Two-Component Regulatory Gene System 123(1)

5.4.3.2 Role of Calcium Ions 124(1)

5.4.3.3 Use of Ion-Chelating Agents for Control of Pseudomonas Rot 125(1)

5.5 Interactions Between Soft-Rot and Human Pathogens on Fresh Produce 125(2)

5.5.1 Synergistic Interactions 126(1)

5.5.2 Antagonistic Interactions 126(1)

5.6 Selected Farm Practices for Control of Both Soft-Rot and Human Pathogens 127(1)

References 128(7)

6 Microbial Spoilage of Fresh Mushrooms 135(24)

Naveen Chikthimmah and Robert B. Beelman

6.1 Fresh Mushrooms 135(3)

6.1.1 Introduction 135(1)

6.1.2 Commercial Growing Practices 136(1)

6.1.3 General Composition 137(1)

6.2 Microbiology of Fresh Mushrooms 138(1)

6.3 Spoilage of Fresh Mushrooms 139(13)

6.3.1 Sources of Microorganisms Causing Spoilage 142(1)

6.3.2 Cultural (Growing) Practices Favoring Spoilage 142(1)

6.3.3 Cultural Practices to Suppress Spoilage of Fresh Mushrooms 142(4)

6.3.4 Postharvest Conditions Favoring Spoilage of Fresh Mushrooms 146(1)

6.3.5 Postharvest Practices to Suppress Spoilage of Fresh Mushrooms 147(1)

6.3.5.1 Packaging 148(1)

6.3.5.2 Washing Treatments 149(1)

6.3.5.3 Irradiation 150(1)

6.3.5.4 Pulsed Ultraviolet Light Treatment 151(1)

6.4 Conclusions 152(1)

References 153(6)

7 Spoilage of Juices and Beverages by Alicyclobacillus spp. 159(28)

Mickey E. Paris

7.1 Introduction 160(1)

7.2 Taxonomic History 160(4)

7.3 Physiological and Phenotypic Characteristics 164(1)

7.3.1 Distinguishing Features 164(1)

7.3.2 Thermoacidophilic Growth 164(1)

7.3.3 Alicyclic Fatty Acids in Membrane 165(1)

7.4 Thermal Resistance Characteristics 165(7)

7.4.1 D- and z-values 165(1)

7.4.2 Factors Affecting Thermal Resistance 166(5)

7.4.3 Other Control Measures 171(1)

7.5 Industrial Importance 172(2)

7.5.1 Emergence as Spoilage Organisms 172(1)

7.5.2 Types of Spoilage 172(1)

7.5.3 Sanitation 173(1)

7.6 Detection and Identification 174(5)

7.6.1 Controversy 174(1)

7.6.2 Media 175(2)

7.6.3 Heat Shock Conditions 177(1)

7.6.4 Enumeration 177(1)

7.6.5 Detection by Enrichment 178(1)

7.6.6 Identification and Confirmation 178(1)

7.7 Significance of Detection/Isolation from Foods 179(1)

7.8 Future Direction 179(1)

Acknowledgment 180(1)

References 180(7)
SECTION III Food Safety Issues

8 Interventions to Ensure the Microbial Safety of Sprouts 187(24)

William F. Fett

8.1 Introduction 187(1)

8.2 Foodborne Illness Associated with Sprouts 188(3)

8.3 Interventions: Seeds 191(7)

8.3.1 Chemical and Physical 191(6)

8.3.2 Biological 197(1)

8.4 Interventions: Sprouts 198(2)

8.5 Reducing the Risk of Future Outbreaks 200(1)

8.6 Research Needs 201(1)

Acknowledgments 202(1)

References 202(9)

9 Microbiological Safety of Fresh Citrus and Apple Juices 211(20)

Susanne E. Keller and Arthur J. Miller

9.1 Introduction 211(1)

9.2 Juice Production 212(1)

9.3 Physicochemical Properties and Endogenous Juice Microflora 213(3)

9.3.1 Citrus Juice 213(1)

9.3.2 Apple Cider 214(2)

9.4 Pathogens Associated with Fresh Juice and Their Environmental Sources 216(3)

9.4.1 Enterohemorrhagic Escherichia coli 216(1)

9.4.2 Salmonella Species 217(1)

9.4.3 Cryptosporidium parvum 218(1)

9.4.4 Listeria monocytogenes 218(1)

9.5 Juice HACCP Rule 219(1)

9.6 Importance of SSOPs to HACCP 219(2)

9.7 Application of the 5-Log Standard 221(1)

9.8 Intervention Treatments 222(1)

9.9 Other Juice HACCP Considerations 223(1)

9.10 Labeling 224(1)

9.11 Conclusion 224(1)

References 224(7)

10 Microbiological Safety Issues of Fresh Melons 231(1)

Dike O. Ukuku and Gerald M. Sapers

10.1 Introduction 231(1)

10.2 Microflora of Melons 232(2)

10.2.1 Spoilage Organisms 233(1)

10.2.2 Human Bacterial Pathogens 233(1)

10.3 Factors Contributing to Melon Contamination 234(3)

10.3.1 Preharvest and Harvest Conditions 234(1)

10.3.2 Postharvest Conditions 235(1)

10.3.3 Mode of Microbial Attachment to Melons 236(1)

10.4 Efficacy of Conventional Washing 237(2)

10.4.1 Washing in the Packinghouse 237(1)

10.4.2 Laboratory-Scale Washing Studies 237(2)

10.5 Novel Disinfection Treatments 239(3)

10.5.1 Hydrogen Peroxide 239(1)

10.5.2 Hot Water 240(1)

10.5.3 Steam 241(1)

10.5.4 Other 242(1)

10.6 Issues with Fresh-Cut Melons 242(2)

10.6.1 Transfer of Bacteria from Rind to Flesh 243(1)

10.6.2 Outgrowth on Flesh 243(1)

10.6.3 Suppression of Outgrowth 244(1)

10.7 Methodology for Microbiological Evaluation of Melons 244(2)

10.8 Research Needs 246(1)

References 247(6)

11 Fresh-Cut Vegetables 253(1)

Pascal Delaquis

11.1 Introduction 253(1)

11.2 Fresh-Cut Carrots 254(1)

11.3 Fresh-Cut Cabbage 255(1)

11.4 Fresh-Cut Lettuce 256(1)

11.5 Occurrence and Behavior of Human Pathogens in Fresh-Cut Vegetables 257(2)

11.6 Interactions Between Microorganisms and Plant Tissues 259(3)

References 262(5)

12 Outbreaks Associated with Cyclospora and Cryptosporidium 267(1)

Ynes R. Ortega and Charles R. Sterling

12.1 Introduction 267(1)

12.2 Overview of the Parasites 267(2)

12.3 Sources of Contamination 269(1)

12.4 Description of the Foodborne Outbreaks for Both Parasites 270(1)

12.5 Detection and Enumeration Methodologies 271(2)

12.6 Interventions for Decontamination 273(1)

12.7 Conclusions 274(1)

References 275(6)

13 Patulin 281(1)

Lauren Jackson and Mary Ann Dombrink-Kurtzman

13.1 Introduction 282(1)

13.2 Methods of Analysis 283(3)

13.2.1 Introduction 283(1)

13.2.2 Thin-Layer Chromatography (TLC) 283(1)

13.2.3 Gas Chromatography (GC) 284(1)

13.2.4 Liquid Chromatography (LC) 284(1)

13.2.5 Micellar Electrokinetic Capillary Chromatography(MECC) 285(1)

13.2.6 Other Methods 285(1)

13.3 Toxicological Effects of Patulin 286(2)

13.3.1 Introduction 286(1)

13.3.2 Acute Toxicity Studies 286(1)

13.3.3 Immunotoxicity Studies 286(1)

13.3.4 Reproductive Toxicity and Teratogenicity Studies 287(1)

13.3.5 Genotoxicity Studies 287(1)

13.3.6 Carcinogenicity Studies 287(1)

13.3.7 Mechanism(s) of Toxicity 288(1)

13.4 Regulatory Aspects 288(1)

13.5 Fungal Species Producing Patulin in Foods 288(1)

13.6 Natural Occurrence of P. expansum and Patulin in Fruits and Vegetables 289(1)

13.7 Factors Affecting Patulin Production 290(3)

13.7.1 Introduction 290(1)

13.7.2 Physical, Chemical, and Microbial Properties of Apples 291(1)

13.7.3 Environmental Factors 292(1)

13.8 Approaches for Controlling Patulin Levels 293(7)

13.8.1 Introduction 293(1)

13.8.2 Preharvest 294(1)

13.8.3 Harvest 295(1)

13.8.4 Postharvest 295(1)

13.8.4.1 Introduction 295(1)

13.8.4.2 Washing Treatments 296(1)

13.8.4.3 Culling, Sorting, and Trimming 297(1)

13.8.4.4 Chemical, Heat, and Biological Control, and Irradiation Treatments 297(1)

13.8.4.5 Storage 299(1)

13.8.4.6 Controls for Processed Apple Products 300(1)

13.9 Conclusions 300(1)

References 301(12)

14 Safety of Minimally Processed, Acidified, and Fermented Vegetable Products 313(1)

F. Breidt, Jr.

14.1 Introduction 314(1)

14.2 Vegetable Microflora 314(4)

14.2.1 Washing Procedures 316(1)

14.2.2 Biocontrol in Minimally Processed Vegetable Products 316(2)

14.3 Fermented Vegetables 318(1)

14.3.1 Fermentation Chemistry 319(1)

14.4 Acidified Vegetables 319(3)

14.4.1 Definitions and Regulations for Acid and Acidified Foods 320(1)

14.4.2 Pathogenic Bacteria 321(1)

14.5 Organic Acids and Destruction of Pathogens 322(5)

14.5.1 Specific Effects of Acids 323(2)

14.5.2 Genetic Regulation of Acid Resistance 325(2)

14.6 Conclusions 327(1)

Acknowledgments 327(1)

References 327(12)
SECTION IV Interventions to Reduce Spoilage and Risk of Foodborne Illness

15 HACCP: A Process Control Approach for Fruit and Vegetable Safety 339(204)

William C. Hurst

15.1 Introduction 339(1)

15.2 What Is HACCP? 340(2)

15.3 Applying the HACCP Concept 342(1)

15.4 Prerequisites for HACCP 343(1)

15.5 Planning and Conducting an HACCP Study 344(1)

15.6 Conducting a Hazard Analysis/Risk Assessment Study (HACCP Principle 1) 345(2)

15.7 Using SPC to Ensure HACCP Control 347(1)

15.8 Identifying and Stabilizing Variability at CCPs (HACCP Principle 2) 348(3)

15.9 Conducting Process Capability Analyses to Verify Critical Limits (HACCP Principle 3) 351(3)

15.10 Establishing SPC Monitoring Procedures (HACCP Principle 4) 354(2)

15.11 Determining Corrective Action Procedures (HACCP Principle 5) 356(1)

15.12 Confirming HACCP Implementation Through Verification Activities (HACCP Principle 6) 357(2)

15.13 Establishing Documentation and Record Keeping (HACCP Principle 7) 359(2)

15.14 Summary 361(1)

References 362(3)

16 Effect of Quality Sorting and Culling on the Microbiological Quality of Fresh Produce 365(1)

Susanne E. Keller

16.1 Introduction 365(1)

16.2 Grade Standards 366(1)

16.3 Effectiveness of Good Agricultural Practices (GAPs) 366(1)

16.4 Effectiveness of Sorting and Sorting Methods 367(3)

16.5 Impact on Food Safety 370(1)

References 371(4)

17 Washing and Sanitizing Treatments for Fruits and Vegetables 375(1)

Gerald M. Sapers

17.1 Introduction 376(1)

17.2 Conventional Washing Technology 376(11)

17.2.1 Washing Agents 376(1)

17.2.1.1 Chlorine 376(1)

17.2.1.2 Alternatives to Chlorine 378(5)

17.2.2 Washing Equipment 383(1)

17.2.2.1 Types of Washers 383(1)

17.2.2.2 Efficacy of Washers 385(2)

17.2.3 Factors Limiting the Efficacy of Washing 387(1)

17.3 Novel Washing Technology 387(4)

17.3.1 Hydrogen Peroxide 387(1)

17.3.2 Trisodium Phosphate and Other Alkaline Washing Agents 388(1)

17.3.3 Organic Acids 389(1)

17.3.4 Other Experimental Antimicrobial Washing Agents 390(1)

17.3.5 Synergistic Treatment Combinations 390(1)

17.4 Foodservice and Home Applications 391(3)

17.4.1 FDA Recommendations 391(1)

17.4.2 Other Options 392(1)

17.4.3 Commercial Equipment and Wash Formulations for Home or Foodservice Use 393(1)

17.5 Conclusions 394(1)

Acknowledgments 394(1)

References 394(7)

18 Gas/Vapor-Phase Sanitation (Decontamination) Treatments 401(1)

Richard H. Linton, Yingchang Han, Travis L. Selby, and Philip E. Nelson

18.1 Introduction 402(1)

18.2 Chlorine Dioxide Gas 402(12)

18.2.1 Physical, Chemical, and Safety Properties of C10, Gas 402(2)

18.2.2 Antimicrobial Properties of Aqueous and Gaseous C102 404(1)

18.2.3 C102 Gas Generation 404(3)

18.2.4 General Gas/Vapor Treatment Systems 407(2)

18.2.5 Mechanisms for Microbial Inactivation 409(1)

18.2.6 Factors Influencing ClO2 Gas Treatment 409(3)

18.2.7 Efficacy in Reducing Microorganisms on Different Produce Surfaces 412(2)

18.2.8 Effects of ClO2 Gas Treatment on Quality of Produce 414(1)

18.3 Ozone Gas 414(8)

18.3.1 Properties of Ozone 414(1)

18.3.2 Potential Applications of Ozone in the Food Industry 415(1)

18.3.3 Generation of Ozone 415(1)

18.3.4 Treatment Systems 416(1)

18.3.5 Mechanisms of Inactivation of Microbes 417(1)

18.3.6 Factors Influencing Sanitation Treatment by Ozone Gas 417(1)

18.3.7 Efficacy in Reducing Foodborne Microorganisms on Produce Surfaces 418(3)

18.3.8 Effects of Ozone Gas Treatments on Quality of Fruits and Vegetables 421(1)

18.4 Allyl Isothiocyanate Gas 422(1)

18.4.1 Properties 422(1)

18.4.2 Mechanisms and Factors Influencing Sanitation Treatment 422(1)

18.4.3 Efficacy in Reducing Foodborne Pathogens on Produce Surfaces 422(1)

18.4.4 Effects of AITC Vapor Treatment on Quality of Fruits and Vegetables 422(1)

18.5 Other Gases/Vapors 423(3)

18.5.1 Hydrogen Peroxide Vapor 423(1)

18.5.2 Acetic Acid Vapor 424(1)

18.5.3 Other Natural Plant Volatiles 425(1)

18.6 Present and Future Applications of Gaseous/Vapor-Phase Antimicrobials for Decontamination of Fresh Produce 426(1)

18.7 Regulatory Considerations 427(1)

References 428(9)

19 Modified Atmosphere Packaging 437(1)

B.G. Werner and J.H. Hotchkiss

19.1 Introduction 437(2)

19.1.1 Definitions 438(1)

19.2 Antimicrobial Activity of MAP Gases 439(2)

19.2.1 CO2 439(1)

19.2.2 Superatmospheric O2 440(1)

19.3 Packaging and Films for MAP Produce Systems 441(4)

19.3.1 Film Permeability and CO2/O2 Permselectivity 441(1)

19.3.2 Active Packaging: Antimicrobial Films 442(1)

19.3.2.1 Synthetic Polymer Films 442(1)

19.3.2.2 Edible and Biodegradable Films 443(2)

19.4 An Integrated Approach: Multiple Barriers and MAP 445(3)

19.4.1 Background 445(1)

19.4.2 Biopreservation and Protective Cultures 445(2)

19.4.3 O2/CO2 Absorbers and Generators 447(1)

19.4.4 Pretreatments and Miscellaneous Strategies 447(1)

19.5 Microbiology of Map Fruits and Vegetables 448(7)

19.5.1 Minimally Processed Fruits and Vegetables 448(2)

19.5.2 Spoilage Organisms and Commodity Shelf Life 450(1)

19.5.3 Pathogenic Organisms and Shelf Life 451(1)

19.5.3.1 Food Safety Risk of MAP Produce 451(1)

19.5.3.2 Psychrotrophic Pathogens 452(1)

19.5.3.3 Other Pathogens of Concern 453(1)

19.5.4 Microbial Ecology of MAP Systeins 454(1)

19.6 Mathematical Predictive Modeling 455(1)

19.7 Future Directions 456(1)

References 456(5)

20 Hot Water Treatments for Control of Fungal Decay on Fresh Produce 461(1)

Elazar Fallik

20.1 Introduction 461(2)

20.2 Technologies 463(1)

20.3 Heat Treatments 464(6)

20.3.1 In Vitro Studies 464(1)

20.3.2 In Vivo Studies 465(4)

20.3.3 Heat Damage 469(1)

20.4 Mode of Action 470(2)

20.5 Conclusions 472(1)

Acknowledgments 472(1)

References 472(7)

21 Surface Pasteurization with Hot Water and Steam 479(1)

Bassam A. Annous and Michael F. Kozempel

21.1 Introduction 479(1)

21.2 Surface Pasteurization with Hot Water 480(3)

21.3 Surface Pasteurization with Steam 483(10)

21.3.1 Thermosafe Process 485(1)

21.3.1.1 Process Operation 485(1)

21.3.1.2 Process Effectiveness 485(1)

21.3.1.3 Product Quality 486(1)

21.3.2 University of Bristol Process 486(1)

21.3.2.1 Process Operation 486(1)

21.3.2.2 Process Effectiveness 486(1)

21.3.2.3 Product Quality 487(1)

21.3.3 Ventilex Continuous Steam Sterilizing System 487(1)

21.3.3.1 Process Operation 487(1)

21.3.3.2 Process Effectiveness 487(1)

21.3.3.3 Product Quality 488(1)

21.3.4 Vacuum鈥擲team鈥擵acuum (VSV) Process 488(1)

21.3.4.1 Process Operation 491(1)

21.3.4.2 Process Effectiveness 491(1)

21.3.4.3 Product Quality 493(1)

21.4 Conclusions 493(1)

References 494(3)

22 Novel Nonthermal Treatments 497(1)

Dongsheng Guan and Dallas G. Hoover

22.1 Introduction 498(1)

22.1.1 Nonthermal Processing Methods 498(1)

22.1.2 Advantages and Disadvantages of Application 498(1)

22.2 High Hydrostatic Pressure Processing (HPP) 499(6)

22.2.1 Introduction 499(1)

22.2.1.1 Definition and Historical Perspective 499(1)

22.2.1.2 Equipment 500(1)

22.2.1.3 Critical Processing Factors 500(1)

22.2.2 Inactivation of Problematic Microorganisms 501(1)

22.2.2.1 Spores and Vegetative Bacteria 501(1)

22.2.2.2 Viruses 504(1)

22.2.2.3 Parasites 505(1)

22.2.3 Summary 505(1)

22.3 Irradiation 505(4)

22.3.1 Introduction 505(1)

22.3.2 Application to Fruits, Vegetables, and Juices 506(1)

22.3.2.1 Spores and Vegetative Bacteria 506(1)

22.3.2.2 Parasites 508(1)

22.3.2.3 Viruses 508(1)

22.3.3 Summary 509(1)

22.4 Pulsed Electric Fields in Juice Processing 509(3)

22.4.1 Introduction 509(2)

22.4.2 Application to Juices 511(1)

22.4.3 Summary 512(1)

22.5 Ultrasonic Waves for Preservation of Fruit and Vegetable Products 512(2)

22.5.1 Introduction and Description of Process 512(1)

22.5.2 Microbial Inactivation 513(1)

22.5.3 Summary 514(1)

22.6 Electrolyzed Water 514(2)

22.6.1 Introduction 514(1)

22.6.2 Application as a Novel Disinfectant for Fruits and Vegetables 515(1)

22.6.3 Summary 516(1)

22.7 Final Remarks and Future Perspectives 516(1)

Acknowledgment 517(1)

References 517(6)

23 Biological Control of Microbial Spoilage of Fresh Produce 523(1)

Julien Mercier and Pamela G. Marrone

23.1 Introduction 523(1)

23.2 Approaches to Biocontrol in Postharvest Situations 524(4)

23.2.1 Use of Naturally Occurring Antagonists for Colonization of Infection Sites 524(1)

23.2.1.1 Postharvest Applications 524(1)

23.2.1.2 Preharvest Applications 525(1)

23.2.1.3 Possible Mechanisms for Biocontrol 526(1)

23.2.2 Use of Mutant Pathogen Strains 527(1)

23.2.3 Biological Fumigation 528(1)

23.3 Advantages and Limitations of Postharvest Biocontrol 528(2)

23.3.1 Advantages of Postharvest Biocontrol 528(1)

23.3.2 Disadvantages of Biocontrol Agents 529(1)

23.4 Enhancing Biocontrol Activity 530(3)

23.4.1 In Combination with Other Treatments 530(1)

23.4.2 Improvement in Formulation 531(1)

23.4.3 Screening and Selection of the Microorganism 532(1)

23.4.4 Collaborative Research Among Industry, University Researchers, Government, and Growers/Packers 532(1)

23.5 Regulatory Process for Biocontrol Agents 533(1)

23.5.1 U.S. Environmental Protection Agency (EPA) 533(1)

23.5.2 California and International Regulations 534(1)

23.6 Concluding Remarks 534(1)

References 535(8)
SECTION V Microbiological Evaluation of Fruits and Vegetables

24 Sampling, Detection, and Enumeration of Pathogenic and Spoilage Microorganisms 543(78)

Larry R. Beuchat

24.1 Introduction 543(2)

24.2 Pathogen or Spoilage Microorganism Under Study 545(6)

24.2.1 Media for Routine Microbiological Analyses 546(2)

24.2.2 Selection of Test Strains for Sanitizes Efficacy and Challenge Studies 548(3)

24.3 Types of Produce and Methods for Preparing Samples 551(5)

24.4 Procedures for Inoculation 556(1)

24.5 Efficiency of Retrieval 557(1)

24.6 Efficacy of Decontamination Treatment 558(1)

24.7 Procedures for Detection and Enumeration 558(1)

24.8 Number of Samples Analyzed and Reporting the Results 559(2)

References 561(4)

25 Rapid Detection of Microbial Contaminants 565(1)

Daniel Y.C. Fung

25.1 Introduction 565(1)

25.2 Sample Preparation and Treatments 566(1)

25.3 Total Viable Cell Count Methodologies 567(5)

25.4 Advances in Miniaturization and Diagnostic Kits 572(3)

25.5 Immunological Testing 575(4)

25.6 Instrumentation and Biomass Measurements 579(4)

25.7 Genetic Testing 583(5)

25.8 Biosensors 588(2)

25.9 U.S., World Market, and Testing Trends (1999-2008) 590(2)

25.10 Predictions of the Future 592(1)

Acknowledgment 593(1)

References 593(2)

26 Methods in Microscopy for the Visualization of Bacteria and Their Behavior on Plants 595(1)

Maria T. Brandl and J.-M. Monier

26.1 Introduction 596(1)

26.2 Visualization of Bacteria on Plants: Available Tools 596(4)

26.2.1 Labeling of Bacteria with Fluorescent Proteins 596(2)

26.2.2 Labeling of Bacteria with Dyes and Fluorescent Conjugates 598(2)

26.3 Applications 600(12)

26.3.1 Spatial Distribution 600(2)

26.3.2 Cell鈥擟ell Interactions 602(2)

26.3.3 Measurement of Biological Parameters 604(1)

26.3.3.1 Kogure Assay for Cell Viability 605(1)

26.3.3.2 Indicators of Membrane Integrity 606(1)

26.3.3.3 GFP Fluorescence and Cell Viability 607(1)

26.3.3.4 Other Fluorescent Indicators of Bacterial Physiology 607(1)

26.3.4 Bacterial Gene Expression In Situ on Plants 608(1)

26.3.4.1 GFP as a Reporter of Gene Expression 608(1)

26.3.4.2 Practical Note on the Use of GFP for Gene Expression Measurements 610(1)

26.3.4.3 FISH for the Detection of Bacterial mRNA 611(1)

26.3.4.4 Immunolabeling of Gene Products 611(1)

26.4 Other Types of Microscopy 612(2)

26.4.1 Multiphoton Excitation Fluorescence Microscopy 612(1)

26.4.2 Fluorescence Stereomicroscopy 613(1)

26.4.3 Immunoelectron Microscopy 613(1)

26.5 Concluding Remarks 614(1)

References 615(6)
Index 621