Gracey's Meat Hygiene

About the Editors David S. Collins, MVB, DVPH(MH), MRCVS Formally City Veterinarian for Belfast, he has served as a Member of Northern Ireland Food Standards Advisory Committee as well as on the Meat Hygiene Advisory Committee of the UK Food Standards Agency. His work has involved forensic investigation for the Ministry of Defence and insurance companies; advising veterinary pharmaceutical companies regarding adverse reactions, product registration and clinical trials; and advising the government on animal experimentation including clinical trials for veterinary pharmaceuticals. He is a former Chief Examiner for the Royal College of Veterinary Surgeons in Veterinary Public Health, UK, and was Consultant Editor for Northern Ireland Veterinary Today. Robert J. Huey, TD, MVB, DVPH(MH), MRCVS Robert is Chief Veterinary Offi cer in the Department of Agriculture and Rural Development Northern Ireland (DARDNI) veterinary service. He is currently Vice President of the Federation of Veterinarians of Europe and a past President of the Union of European Veterinary Hygienists. He is also a former President of the Veterinary Public Health Association and was Chief Examiner in Veterinary Public Health for the Royal College of Veterinary Surgeons, 1998–2010.

Contributors xi

Preface xiii

Acknowledgements xv

1 The food animals 1

Dietary factors 2

World livestock production 3

UK meat plants and throughputs 4

Cattle 4

Breeds 4

Systems of beef production 6

Growth promoters 7

Definitions 7

Sheep 7

Definitions 9

Pigs 10

Pig breeds 10

Pig breeds in the United Kingdom 11

Pig production 11

Pig meat production 13

Glossary of terms 13

Additional facts 13

Goats 13

Poultry 14

Definitions 14

Rabbits 15

Deer 16

Handling of deer 17

References 17

Further reading 17

Form animal welfare council 17

2 Anatomy 19

Descriptive terms 19

Osteology and arthrology 19

Bones 19

Digestive system 21

Tongue 21

Stomach 22

Mucous membranes 22

Intestines 23

Liver 24

Pancreas (gut sweetbread) 25

Respiratory system 26

Lungs 26

Pluck 26

Circulatory system (heart, arteries, capillaries and veins) 26

Heart 26

Portal circulation 27

Spleen (melt) 27

Lymphatic system 28

Haemal lymph nodes 28

Lymph nodes of the ox 29

Nodes of the head and neck 30

Nodes of the chest and forequarter 30

Nodes of the abdomen and hindquarter 31

Lymph nodes of the pig 33

Head and neck 33

Other nodes 33

Urogenital system 34

Urinary organs 34

Genital organs 34

Kidney 34

Reproductive system 34

Uterus 34

Udder 36

Endocrine system 36

Thymus 36

Adrenal (suprarenal) bodies 36

Testicles (testes) 37

Collection and yield of glands 37

Skin 37

Horns 37

Muscular system 37

Connective tissue 38

Fat 38

Determination of age by dentition 38

Teeth 38

Determination of sex 39

Cattle 39

Sheep 40

Pigs 41

Horse and ox differentiation 41

Debasement of food

(adulteration and substitution) 41

Food tampering 43

References 43

Further reading 43

3 Meat establishment construction and equipment 45

Site 45

Environmental statement 45

Submission of plans 46

Area size 46

Facilities 47

Equipment design 50

Pest control 51

Small abattoir units 51

Lairage 52

Cattle lairage 52

Sheep lairage 52

Pig lairage 52

Deer lairage 53

Clipping or cleaning of livestock 53

Manure disposal 53

Slaughterhall 53

Stunning area 53

Bleeding area 54

Cattle carcase dressing 54

On-the-rail dressing 55

Sheep slaughterhall 56

Pig slaughterhall 57

Singeing and scraping 58

Refrigeration accommodation 58

Detained meat room 59

Condemned meat room 60

Hide and skin store 60

Gut and tripe room 60

Red offal room 60

The edible fat room 61

Cutting rooms 61

Equipment wash 61

Fresh meat dispatch area 61

Vehicle washing 62

General amenities for personnel 62

Veterinary office 62

Treatment of effluent 62

Pollution parameters 63

Treatment 63

Preliminary treatment: Screening, solids and grit removal 63

Secondary treatment 64

Further reading 65

4 Preservation of meat 67

Physical changes in stored meat 67

Chemical changes in stored meat 68

Water activity or water availability (aw ) 68

Meat curing 68

Salt 68

Ingredients used in curing 69

Production of bacon and ham 69

Cutting 70

Application of the pickle 70

Production of cooked hams 71

Traditional dry-cured bacon 71

Alternative dry cure 71

Smoking 71

Common defects in cured meat 71

Micro-organisms on cured product 72

Refrigeration 72

Mechanical refrigeration 72

Chilling of meat 73

Freezing of meat 75

Freeze-drying or lyophilisation 76

Storage of fresh meat 76

Vacuum packing 76

Modified atmosphere packing 76

Refrigerated meat transport and storage 76

Changes in frozen meat 77

‘Weeping’ or ‘drip’ 77

Durability of frozen meat 78

Effect of freezing on pathogenic micro-organisms and parasites 78

Heat: Thermal processing 78

Traditional canning methodology 79

Treatment of food to be canned 79

Canning operations 80

Canning of meats 82

Foods packed in glass 82

Spoilage in canned foods 82

Types of spoilage 83

The public health aspect of canned foods 85

Other methods of meat preservation 86

Antioxidants 86

Preservatives 86

Irradiation 86

Infrared radiation 86

Ultraviolet radiation 86

Ionising radiation 86

High pressure 87

References 87

Further reading 88

5 Plant sanitation 89

Reasons for cleaning and disinfecting plant 89

‘Scotoma effect’ or ‘factory-blindness’ 90

The chemistry of cleaning 90

The soil 91

The substrate: Materials of construction 91

Energies of cleaning 92

Chemical and physical reactions of cleaning 92

Detergents: Design and choice 95

Principles of disinfection 95

Biocidal active components 95

Disinfectants: Design and choice 97

Hygiene equipment and application methods 97

Manual cleaning 98

Foam cleaning 98

Foam and disinfectant application equipment 98

Gels 99

Spray 100

Fogging 100

Knife and cutting tool disinfection during processing 100

Machine washing 102

Cleaning-in-place (CIP) 102

Rinse systems 104

Contamination and re-contamination 105

Air 105

Water 106

People 106

Surfaces 106

Cleaning procedures 106

The cleaning sequence 106

Monitoring of hygiene 108

Training 110

Safety 110

Effluent and external odour control 110

Conclusion 111

Note 111

References 112

6 From farm to slaughter 113

Production of clean, healthy livestock 113

Clean livestock 115

Healthy livestock 117

Safe use of animal medicines 117

Safe disposal of animal waste 117

Animal welfare on the farm 119

Assessment of an animal’s welfare 119

Transportation of livestock 122

Loading and unloading 122

The journey to slaughter 123

EU transport legislation 123

Protection during transport 123

Means of transport 123

Space allowances 123

Duties of transporters 123

Feed, water and rest periods 123

Treatment of sick animals 124

Travel documentation 124

Loss of weight during transport 124

Transport mortality 125

Lairage construction 126

Animal husbandry in the lairage 127

Moving animals within the lairage 127

Social stress 128

Watering 128

Fasting 128

Resting of animals prior to slaughter 129

Pre-slaughter handling and meat quality 129

Stress and the animal 129

Stress and meat quality 130

Pre-slaughter feeding of sugars 131

Traumatic injury 131

Time of bruising 131

Rough handling 132

Presence of horns 132

Temperament 132

Stunning box design 132

Mixing of animals 133

Breed 133

Incentives and education 133

References 133

Further reading 134

7 Humane slaughter 135

Pre-slaughter handling/restraint 136

Cattle movement and restraint 136

Pig movement and restraint 137

The slaughtering process 137

Assessment of unconsciousness at

slaughter 137

Methods of stunning 138

Percussive stunning 138

Head sites for percussive stunning 140

Water jet stunning 142

Carbon dioxide and other gas mixtures 142

Electrical stunning 144

Effect of stunning on meat quality 146

Slaughter of minor species 146

Slaughter of deer 146

Slaughter of ostriches 147

Slaughter of rabbits 147

Other methods of slaughter 147

Slaughter of poultry 148

Electrical stunning of poultry 148

Assessment of unconsciousness in

electrical water bath stunned poultry 149

Stunning/killing poultry with controlled atmospheres 149

Percussive stunning of poultry 150

Other methods of slaughter 150

Effects of stunning on poultry meat quality 150

Pithing 150

Bleeding 151

Cattle 151

Sheep 151

Pigs 152

Efficiency of bleeding 153

Slaughter without pre-stunning 153

Shechita – Jewish religious slaughter 153

Muslim methods of slaughter 156

Slaughter of poultry without stunning 157

References 157

Further reading 158

8 Meat hygiene practice 159

Meat and animal by-products 159

Hygienic production 159

Sources of contamination 159

Outer integument – hide, hair, fleece or skin 159

Gastrointestinal tract 160

Stunning and sticking 160

Physical contact with structures 160

Operatives 160

Equipment and utensils 161

The slaughter hall environment 161

Vermin and pests 161

Chemical contamination 162

Methods of reducing contamination 162

Dealing with the dirty animal 162

Clipping cattle on line 163

Protecting the meat from the worker 163

Good hygiene practice 165

Layout and flow lines 167

Dressing techniques – Removal of hide/fleece/hair 167

Preventing contamination from the gastrointestinal tract 170

Post-slaughter decontamination 172

Water 172

Trimming 173

Chemical treatments 173

Bacteriophages 174

Ultraviolet and pulsed high-intensity light 174

Outputs of the slaughterhouse 174

Treatment of edible co-products 175

Fats 175

Edible fat rendering 176

Stomach and intestines 176

Bones 177

Hides and skins 177

Animal by-products 178

Category 1 178

Category 2 179

Category 3 (can be used for pet food) 180

Materials for technical uses 181

Hygiene requirements for animal by-product processing establishments 183

Rendering processes 183

References 184

9 Meat inspection protocols 185

The case for change 185

The holistic approach 187

Integrated Food Safety Assurance 187

Farm to fork 187

Food chain information 187

Ante-mortem inspection 188

Ante-mortem inspection procedure in the slaughter establishment 189

Practical ante-mortem procedure 190

Emergency slaughter animals 191

Emergency slaughter: The decision on farm 191

Emergency slaughter: The decision

at the slaughter establishment 192

Post-mortem inspection 192

Facilities for post-mortem inspection 192

Carcase identification and traceability 193

Traditional post-mortem inspection 194

Traditional post-mortem inspection of cattle 194

Traditional post-mortem inspection of calves 196

Traditional post-mortem inspection of sheep and goats 196

Traditional post-mortem inspection of pigs 196

Traditional post-mortem inspection of equines 197

Traditional post-mortem inspection of poultry 197

Decisions at post-mortem examination 198

Common post-mortem findings 203

Abscesses 203

Omphalophlebitis 204

Arthritis 204

Oedema 204

Pneumonia and pleurisy 205

Endocarditis 206

Pericarditis 207

Pyelonephritis 207

Bruising 208

Pigmentation 208

Haematogenous pigments 209

Bile pigments 209

Porphyrin 210

Lipofuscin (‘wear-and-tear pigment’, pigment of brown atrophy, lipochrome, haemofuscin) 211

Xanthosis (xanthomatosis, osteohaematochromatosis, brown atrophy) 211

Tumours 211

Classes of tumours 212

Causes of tumours 212

Effect on host 212

Nomenclature of neoplasms 212

Judgement of neoplasia 213

Poor condition/emaciation 213

Contamination 215

Parasitic conditions 215

Ascaris suum 215

Echinococcus granulosus: Hydatidosis and hydatid cyst 215

Taenia hydatigena (known as Cysticercus tenuicollis in larval stage) 216

Taenia ovis (previously known as Cysticercus ovis) 216

Fasciola hepatica: Liver fluke 216

Paramphistomiasis 216

Sarcocystis 216

Courses of action 217

Utilisation of post-mortem data 218

Control of hygienic production 218

Hazard analysis and critical control points (HACCP) 219

Implementation of an HACCP system 219

Worldwide food safety standards 221

References 222

Further reading 222

10 Poultry production, slaughter and inspection 223

Production of poultry 223

Poultry feedingstuffs 225

Poultry flock health 226

Catching and crating 226

Reception and unloading 227

Pre-slaughter inspection 228

Shackling 228

Stunning and slaughter 229

Scalding and defeathering 230

Defeathering 231

Evisceration 232

Chilling 235

Ante-mortem health inspection 237

Post-mortem inspection in the plant 240

Decision of the official veterinarian at the post-mortem inspection 241

General contamination 242

Guidelines on trimming poultry 242

Coliform infections 243

Salmonellosis 243

Campylobacteriosis 244

Chlamydiosis (psittacosis/ornithosis) 245

Miscellaneous conditions 245

Dead on arrival 245

Bruising and fractures 245

Breast blisters and hock burn 246

Ascites 246

Slaughter liver or cholangiohepatitis 246

Fatty liver haemorrhagic syndrome (FLHS) 246

Vices 246

Contamination 247

Decomposition 247

Barking 247

Diseases of the female reproductive system 247

Oregon disease 247

Over-scald 247

Fevered carcases 247

Septicaemia 247

Insufficient bleeding 247

Emaciation 247

Viscera absent 247

References 248

Further reading 248

11 Exotic meat production 249

Rabbits 249

Slaughter 249

Inspection 250

Post-mortem judgements in rabbit meat inspection 250

Zoonoses 251

Guidelines on contamination, missing viscera and trimming 252

Farmed deer 252

Handling and slaughter 252

Park deer 254

Wild deer 254

Killing 254

Ostriches 255

Restraint 256

Stunning 256

Dressing 256

Changes after slaughter 257

Commercial squab production 257

Further reading 257

12 Food poisoning and meat microbiology 259

Part 1: Food poisoning 259

Types of food poisoning 259

Surveillance of food poisoning 259

Laboratory reports of enteric infections 260

Outbreak surveillance 261

General considerations 261

Food-borne pathogens 261

Part 2: Meat microbiology 267

Bacteriological examination of carcases 267

Part 3: Meat decomposition and spoilage 271

Assessment of decomposition 277

Further reading 278

13 Controls on veterinary drug residues in the European Union 279

Legal framework 279

Licensed veterinary medicines 279

Hormones and ß-Agonists 280

Prohibited compounds 280

Unauthorised and unlicensed compounds 281

Regulatory limits: MRLs, MRPLs and RPAs 281

The National Residue Control Plan in EU member states 282

Compound groups 282

Sampling levels for each species 282

Relationship between species and substance to be analysed 283

Testing procedures and performance characteristics 284

Testing procedures 284

CCα and CCβ 285

Sampling of imported food 285

Legal basis for sampling of imports from third countries 285

Frequency of sampling of imports from third countries 285

Interpretation of non-compliant results 285

The Rapid Alert System for Food and Feed (RASFF) 285

Legal basis and description of the RASFF 285

RASFF notification types 286

Notification basis 286

Action taken 286

Distribution status 286

Actions taken following infringements 286

Analytical methods: Technical aspects 287

Method specificity 287

Performance characteristics 288

Method validation 288

Proficiency testing 289

References 289

14 Health and safety in meat processing 291

Accident statistics 291

UK legislation 291

General duties 292

Key topics requiring risk assessment 293

Being struck by hand tools

including knives 293

Musculoskeletal disorders 294

Slips, trips and falls 298

Contact with machinery 298

Transport 301

Falls from a height 301

Substances/microorganisms 302

Zoonoses 303

Specific control measures for zoonoses 303

Animals 310

Noise 310

Cold environment 311

General requirements 312

References 316

Index 319