The microbiology of meat and poultry

Preface 1 The physiological attributes of Gram-negative bacteria associated with spoilage of meat and meat products M.L. GARCfA-LOPEZ, M. PRIETO and A. OTERO 1.1 1.2 1.3 1.4 1.5 Introduction Gram-negative spoilage bacteria in meat and meat products 1.2.1 Fresh meat 1.2.2 Vacuum stored meat 1.2.3 Modified atmosphere packed meat 1.2.4 Meat products 1.2.5 Offals 1.2.6 Irradiated products Taxonomy and physiology of Gram-negative bacteria associated with spoilage of meat and meat products 1.3.1 Gram-negative aerobic motile rods 1.3.2 Gram-negative nonmotile aerobic rods 1.3.3 Facultatively anaerobic Gram-negative rods Origin of Gram-negative bacteria in meat and meat products Methods of isolation and identification 1.5.1 1.5.2 1.5.3 1.5.4 1.5.5 1.5.6 1.5.7 Isolation and identification of species of Pseudomonas Isolation and identification of Shewanella, Alteromonas and Alcaligenes Isolation and identification of Flavobacterium Isolation and identification of Acinetobacter, Moraxella and Psychrobacter Isolation and identification of Enterobacteriaceae Isolation and identification of Aeromonas Isolation and identification of Vibrio References 2 The Gram-positive bacteria associated with meat and meat products W.H. HOLZAPFEL 2.1 Introduction 2.2 Taxonomy and physiology 2.2.1 The lactic acid bacteria 2.2.2 2.2.3 2.2.4 2.2.5 Other Gram-positive genera Depots and levels of contamination in the meat environment 2.3.1 Surface contamination The genera Brochothrix, Kurthia and Listeria The genera Micrococcus and Staphylococcus The endospore-forming genera Bacillus and Clostridium (nonpathogenic, nontoxinogenic) 2.3 ix xi 1 1 3 3 6 7 7 9 10 10 10 13 14 18 20 20 24 25 25 26 21 28 28 35 35 36 31 45 46 41 48 48 49 vi CONTENTS 2.3.2 Clostridia as contaminants 2.4.1 2.4.2 2.5.1 2.5.2 Processed meat products 2.6.1 Meat fermentations 2.6.2 2.7 Isolation and cultivation methods 2.7.1 Lactic acid bacteria 2.7.2 Brochothrix 2.7.3 Kurthia 2.7.4 Micrococcus spp. 2.7.5 Staphylococcus spp. 2.7.6 Enterococci 2.8 Identification and typing methods References 2.4 Growth and metabolism Factors influencing the growth, survival and persistance of Gram-positive bacteria in the meat environment Metabolic activities of importance in meat systems Meat (aerobic storage and vacuum or MA packed) 2.5 Spoilage 2.6 Beneficial associations Lactic acid bacteria as protective cultures 3 Yeasts and moulds associated with meat and meat products V.M. DILLON 3.1 Introduction 3.2 Yeast and mould contamination of meat animals 3.2.1 The field 3.2.2 The abattoir Mycoflora of meat and meat products 3.3.1 Chill storage 3.3.2 Processed meat products 3.3.3 Chemical additives 3.3.4 Physical factors 3.4 Chemistry of meat spoilage 3.5 Conclusions References 3.3 4 Microbiological contamination of meat during slaughter and butchering of cattle, sheep and pigs (2.0. GILL 4.1 Introduction 4.2 Process control 4.3 HACCP and QM systems 4.4 4.5 4.6 4.7 Sampling of carcasses 4.8 Carcass dressing processes 4.9 Product cooling processes 4.10 Carcass breaking processes 4.11 Storage and transport processes 4.12 Concluding remarks References Current recommendations on HACCP and QM implementation Indicator organisms and microbiological criteria The condition of stock presenting for slaughter 51 52 52 55 62 64 65 66 67 69 71 71 71 71 73 73 73 73 74 85 85 88 88 97 99 99 101 104 106 107 109 110 118 118 119 121 122 124 125 126 129 140 146 149 151 152 CONTENTS 5 The microbiology of the slaughter and processing of poultry N.M. BOLDER 5.1 Introduction 5.2 Poultry processing 5.3 Microbiology of poultry 5.4 Microbiology of poultry processing 5.4.1 Transport of live animals 5.4.2 Scalding 5.4.3 Plucking 5.4.4 Evisceration 5.4.5 Chilling 5.5 Packing 5.6 Further processing References 6 The microbiology of chill-stored meat L.H. STANBRIDGE and A.R. DAVIES 6.1 Introduction 6.2 6.3 Modified atmosphere packaging Bacterial spoilage of chilled fresh meats stored in air 6.3.1 Methods 6.3.2 6.3.3 The headspace in MAP 6.3.4 Safety concerns of MAP Spoilage of red meats stored in modified atmospheres 6.4.1 6.4.2 Potential future developments in MAP Gases used and their effects 6.4 Bacterial spoilage of modified atmosphere packaged meats Safety of meats stored in modified atmospheres 6.5 Appendix: The modified atmosphere packaging of fresh red meats References 7 Meat microbiology and spoilage in tropical countries D. NARASIMHA RAO, K.K.S. NAIR and P.Z. SAKHARE 7.1 7.2 7.3 7.4 7.5 7.6 7.7 7.8 Introduction Characteristics of meat Micro-organisms associated with meat 7.3.1 Pathogenic micro-organisms 7.3.2 Spoilage micro-organisms 7.3.3 Beneficial micro-organisms Sources of microbial contamination on meat Microbiology of market meat in India 7.5.1 Microbiology of sheep carcasses processed in the CFTRI modern abattoir Microbial growth and meat spoilage 7.7.1 7.7.2 7.7.3 Control of spoilage of meat: possible approaches 7.8.1 Lowering water activity 7.8.2 Reduction of surface pH 7.8.3 Treatment with organic acids Pathogenic micro-organisms isolated from meat Spoilage of fresh meat at warm temperatures Microbial spoilage in minced meat at ambient temperatures Meat spoilage at chill temperatures vii 158 158 160 160 161 161 163 166 167 168 169 170 171 174 174 175 177 177 178 181 181 183 183 194 198 199 212 220 220 221 222 222 222 222 222 224 227 232 235 237 240 243 247 247 247 247 viii CONTENTS 7.8.4 7.8.5 Sodium chloride treatment 7.8.6 Sorbate treatment 7.8.7 Enzyme inhibitors 7.8.8 Cooling 7.8.9 Lactic fermentation 7.8.10 Irradiation 7.8.11 Packaging Treatment with chlorine and hot water 7.9 Summary Acknowledgement References 8 The microbiology of stored poultry N.A. COX. S.M. RUSSELL and J.S. BAILEY 8.1 Introduction 8.2 8.3 8.4 8.5 8.6 Identification of spoilage flora 8.7 8.8 8.9 8.10 8.1 1 8.12 8.13 8.14 8.15 Bacterial ‘conditioning‘ 8.16 8.17 8.18 8.19 Enumeration of psychrotrophic bacteria 8.20 Enumeration of mesophilic bacteria 8.21 Determination of temperature abuse 8.22 References Factors affecting shelf-life of fresh poultry Multiplication of psychrotrophic spoilage bacteria Effect of cold storage on generation times of bacteria found on broiler carcasses Effect of elevated storage temperature on generation times The origin of psychrotrophic spoilage bacteria on broiler carcasses Identification of spoilage flora on broilers held at elevated temperatures Major causes of spoilage defects The development of off-odour and slime formation Metabolic adaptation of spoilage bacteria to refrigeration temperatures Effect of cold storage on lipase production Effect of cold storage on proteolytic activity Effect of cold storage on carbohydrate metabolism Survival of bacteria during storage Effects of freezing on shelf-life Effect of elevated storage temperature on bacterial multiplication growth temperature classification Use of different microbiological methods to determine temperature abuse 9 Chemical changes in stored meat G.-J.E. NYCHAS, E.H. DROSINOS and R.G. BOARD 9.1 Introduction 9.2 The status of substrates 9.3 9.1.1 The meat ecosystem Chemical changes in aerobic ecosystem 9.3.1 9.3.2 Chemical changes in meat ecosystems stored under vacuum or modified atmosphere packaging 9.4.1 9.4.2 9.5 Evaluation of spoilage