Food Hygiene and Veterinary Public Health I (VPHI) PDF

FOOD HYGIENEAND VERTERINARY PUBLIC HEALTH I (VPHI) DVM Students Class Year 4 Course code: Vetm4141 1  Objectives of this class  Student will be able to define veterinary public health  Describe the duties and responsib...

FOOD HYGIENEAND VERTERINARY PUBLIC HEALTH I (VPHI) DVM Students Class Year 4 Course code: Vetm4141 1  Objectives of this class  Student will be able to define veterinary public health  Describe the duties and responsibilities of Public health veterinarians  Define food from two sense  Define and differentiate different types of food contamination 2 INTRODUCTION  Veterinary public health (VPH): stems from veterinary medicine which is considered as the broadest and the most comprehensive of health profession because it involves large number of species.  The ultimate objective of veterinary public health is to promote the quality and well being of human life. Human health is linked to animal health and production particularly in the developing countries of the world. This is because people live with animals in close contact.  VPH provides the linkage between agriculture and public health. It is a discipline which deals with contribution of veterinary medicine to public health. 3  The term VPH describes the concept and responsibility of veterinary medicine for the health of the public.  In its widest sense, it is defined as a component of public health activities devoted to the application of veterinary profession skills, knowledge and resource:  to the protection and improvement of human health and nutrition by controlling and preventing zoonoses,  decreasing malnutrition and improving hygiene and sanitation. A new definition for VPH was suggested by WHO  “The contribution to the physical, mental and social well being of humans through understanding and applications of veterinary medicine science” 4 Duties and Responsibilities of VPH Veterinarian  The activities of VPH veterinarians can be described as follows: 1. In animal production and health  Diagnosing and treating diseased animals; and prevention, control and eradication of diseases of animals.  Prevention of occupational hazards and diseases associated with live animals and their products  Control of quarantine stations used to reduce outbreaks of livestock diseases 5 2. In food hygiene and zoonoses  Food hygiene is a branch of VPH which includes all measures necessary to insure safety, soundness, wholesomeness of food at all stages from its growth, production or manufacture to its final consumption. From farm/Production, Processing to Consumption a. Prevention and control of zoonoses and other diseases which are transmitted through food of animal origin b. Advising on the construction of premises where foods of animal origin and by-products of animals processed and inspection of food premises operation and products including processing, storage and distribution. c. Ante mortem and post-mortem inspection of meat and meat products 6 d. Prevention of chemical or drug residues in food animals e. Supervision of the hygienic aspect of foods those are imported and exported f. Cooperation with epidemiological services in disease surveillance and dissemination of data with medical professionals for the control of communicable diseases 7 3. VPH activities related with the environment Supervise the proper collection and disposal of dead animals, condemned meat and meat products and other animal wastes thereby control zoonotic diseases of environmental origin like anthrax, leptospirosis, etc Control of vertebrate and invertebrate vectors of zoonoses like mosquito in rift valley fever and snails in faciolosis, sand fly in leishmaniasis 8 4. In biomedical research a. Development of improved diagnostic procedure on the production of vaccines or biological products b. Ecological and epidemiological research on the resources of infections c. Comparative medicine and biology between animals and humans d. Laboratory animal production and medicine for the safety and efficacy of medicines including vaccines, diagnostic sera and antigens 9 5. In disaster medicine: This includes intervention and preventive measures in case of: → Outbreaks of exotic disease → Natural and man made disasters including safeguarding of food and water supplies 6. In mental health: The use of companion animals in helping persons with mental problem and it develops man-pets relationships 10 Contamination of food with microorganisms Food implies anything that is ingested (including drinks) by human being in general sense but From veterinary sense it means meat and meat products, milk and milk products, fish and fish products, egg and egg products and game (wild animals). It can be processed or semi processed or row. All these products contain protein, fat, carbohydrate, etc Food Safety: Assurance that food will not cause harm to the consumer when it is eaten. Wholesome food: is a food that is sound, clean and free of adulteration (of any substance that is unacceptable to the consumer) or it is a food suitable for human consumption. 11  Criteria of food safety and hygiene The food should be:  Healthy and palatable  Attractive and pleasant  It should not show decomposition and adulteration  It should not contain other substances  Should have high quality standards: i.e. nutritious, hygienic and psychologically acceptable by the consumer 12  Contamination of food Food contamination: The presence of objectionable levels of organisms, chemicals, foreign bodies, taints, or unwanted, diseased and decomposed material.  Food can be contaminated either by a primary source (when contaminant is obtained from the animal) or a secondary source (when contamination occurs after the healthy animal is slaughtered).  The primary contamination can be by microbial agents, chemical residues or the discharges from infected animals.  Secondary contamination can be obtained from infected human, other animals (vertebrate or invertebrates), fomites (contaminated air, substances, water, soil or plants) 13 Microorganisms in food Microorganisms in food Wanted Unwanted MO MO Intentionally Spoilage Naturally Pathogenic occurring added MO 1.Food borne infection 2.Food borne intoxication 14 Objectives : At the end of this class you will be able to: 1. Differentiate b/n food borne infection and intoxication 2. List food borne infection and intoxication causing pathogens 3. List the different factors influencing bacterial growth in food and explain how they affect 4. Define food spoilage 5. Discuss the causes and signs of food spoilage 6. Discus methods of detection of food spoilage 15  Unwanted Microorganisms A. Food Borne Intoxication Food infection occurs when a person or animal ingests the food together with viable microorganism. But food intoxication occurs when one ingests preformed toxin produced by pathogenic microorganisms. Food intoxication is important than food infection, because: 1. Even though the food is cooked and the microorganisms are killed, the preformed toxins may remain in the food resisting the heat inactivation 2. Incubation period is very short in case of FBI when compared to food-borne infection, because preformed toxins may be absorbed by the intestinal tract immediately whereas infection must wait multiplication of the organisms to cause disease. 16  Examples of MO that can cause food borne intoxications are:  S. aureus,  Clostridium botulinum,  Bacillus cereus,  Clostridium perfringens etc. B. Food Borne Infection  It is caused by the ingestion of viable pathogenic microorganisms together with food 17  Examples of microorganisms which cause food borne infection are: Bacteria Virus Fungus Salmonella Spp Infectious hepatitis Ergot fungus Streptococcus virus Aspergillus spp Mycobacterium poliovirus poisonous Listeria others mushrooms Brucella spp. others Campylobacter Anthrax Other Parasites Taenia spp. T. saginata and T. solium, Trichinella, Diphyllobothrium latum and Others 18 Types of contamination A. Classification from the agent point of view  Microbial contamination: due to living agents (bacteria, fungus, virus, parasite etc.)  Non microbial contamination: due to residues or chemicals B. Classification with regard to temporal (time)  Primary contamination: begins directly from the food animals Ex. Animal infected with anthrax or due to antibiotic treatment  Secondary contamination: results from the environment, other animals, man or water or contaminated materials (fomites) and plants (toxic plants e.g wild onion) 19 C. Types of bacteria contained in foods of animal origin  Psychrophilics: grow at low temperature (< 10oC) – pseudomonas, Aeromonas  Mesophilics: propagate at room temperature (30–40oC)- Listeria, staph, E.coli  Thermophilics: grow and multiplies at very high temperature (> 40oC) –Bacillus, Thermus aquaticus D. Classification with regards to the type of fermentation into two groups  Homofermentative: which produce only one product e.g. Lactic acid  Hetrofermentative: which produce more than one products. e.g. Contamination with yeast results in CO2 and alcohol production 20 Effect of microorganism on food  Food spoilage means the original nutritional value, texture and flavor of the food are changed, the food becomes harmful to people and unsuitable to eat.  Food spoilage is a metabolic process that causes foods to be undesirable and unacceptable for human consumption due to changes in sensory characteristics.  Food Spoilage can be microbial, enzymatic, physical or chemical changes.  Microorganisms attack or metabolize proteins, fats and carbohydrates found in foods. 21 Spoilage of food by microorganisms could be: 1. Proteolytic Spoilage- degrade protein 2. Lipolytic Spoilage- degrade fats 3. Glycolytic Spoilage- degrade carbohydrates 1. Proteoytic Spoilage: Proteolytic MOs degrade proteins into Amino acids.  Protein Bacterial enzyme  polypeptides  peptide  amino acids  H2S + NH3 (foul smelling)  The production of H2S, CO2 & NH3 are signs of food spoilage.  Examples of microorganisms which cause proteolytic spoilage are Pseudomonas, Proteus spp., Bacillus spp, Clostridium spp, etc. 22 2. Lipolytic Spoilage: Lipolytic MOs degrade fats into Fatty acids and Glycerol and cause food Rancidity  Fat Bacterial enzyme Fatty acids + Glycerol  Rancidity +(unpleasant smell) e.g. of lipolytic bacteria includes Pseudomonas, Aeromonas, Micrococci, E. coli, etc. 3. Glycolytic Spoilage: Carbohydrates (Glycogen in meat/lactose in milk) Sachrolytics Glucose  Lactic acid, Acetic acid, Propionic acid, alcohol, CO2, H2O  These products are indicators of food spoilage.  Lactobacilli, Lactococci and Pediococci bacteria can cause glycolytic spoilage.  Production of lactic acid is seen as positive effect, because lactic acid retards bacterial multiplication and prolongs the shelf life of food improving the keeping quality. It is also used in the production of yoghurt. 23 Factors Influencing Bacterial Growth in food  The parameters which affect growth of microorganisms in food can be grouped into two as Intrinsic and Extrinsic factors/parameters 1. Intrinsic Parameters: They are inherent property or nature of the food. These includes: 1. Ph of the food: This is the parameter which indicate whether the media is acidic or alkaline or neutral.  Most Microorganisms grow best at pH values around 7 (neutral).  Bacterial growth or multiplication rate decreases at lower pH of the food. 24 2. Oxidation reduction potential of the food:  The oxygen tension or partial pressure of oxygen and the reducing and oxidizing power of the food (O-R potential) influences the growth of organisms.  In relation to oxygen, bacteria can be aerobic, anaerobic or facultative, while fungi are mostly aerobic.  Yeasts are aerobic or facultative anaerobic.  A high O-R potential favors the growth of aerobic and facultative organisms.  Most fresh animal foods have low O-R potential in their interior but have higher O-R outside.  Thus, a fresh piece of meat could support the growth of aerobic organisms in the exterior and the growth of anaerobic organisms inside. 25 3. Moisture Content/ water activity of the food:  Most microorganisms grow in food with higher moisture content.  The water requirement of microorganisms is described in terms of water activity. Water activity is the amount of water found in the food which is available and essential for all living microorganisms.  Water in food, which is not bound to food molecules, supports the growth of bacteria, yeasts and moulds. The term “water activity = aw” refers to this unbound water.  The water activity of food is not the same thing as its moisture content. Although moist foods are likely to have greater water activity than dried foods, this is not always true.  A variety of foods may have exactly the same moisture content and yet have quite different water activity. addition of Salt. 26  Moisture Content= unbound free water (water activity) + bounded waters in a food  The water activity is expressed as aw and it is 1 for pure water. 4. Nutrient Content of the food:  In order to grow in/on foods, microorganisms require water, source of energy, source of Nitrogen (Nucleotides, Peptides and other proteins), vitamins and related growth factors and minerals. 27 5. Antimicrobial Constituents in the food:  Some foods may stay for a long time resisting attack by microorganisms due to the presence of naturally occurring substances that have anti microbial activity. e.g.  Cow’s milk has Lactoferin, Coaglutinin but they will be destroyed during pasteurization.  Egg contains Lysosomes, Ovotransferrin which inhibits the growth of Salmonella in egg.  Spices have oil that possesses antimicrobial activity.  Garlic contains Allicin. 6. Biological Structures of the food: The natural covering of some foods provide excellent protection against the entry and subsequent damage by spoilage MOs.  e.g The Hide of Animals, the Shell of Eggs, Testa of Seeds, outer covering of Fruits, the shell of Nuts, etc. 28 B. Extrinsic Parameters:  Extrinsic Parameters of food are those properties of storage environment and the presence of substances that affects both the food and Microorganisms. These are: 1. Storage temperature: Based on the optimum temperature requirement for growth and multiplication, MOs are grouped as: 1. Psychrophilics: grow best at low Temperature 2. Mesophilics: grow best at optimum temperature 3. Thermophilics: grow best at high temperature than the normal 29 Microorganisms Min Optimum Max. Examples T0 T0 T0 Psychrophilics 0 20 30 Alicaligenes, Corynebacterium Mesophilic 20 37 45 Shigella, Salmonella, E. coli, etc Thermophilic 45 55 85 Genera Bacillus, Clostridium, Campylobacter 30 2. Relative humidity of the environment 3. Presence and concentration of gasses in the environment: such as CO2 and O3 4. Presence and Activity of other MOs in the environment of food that produce inhibiting factors like: Antibiotics,  Bacteriocides or  Bacteriostats,  H 2 O2  Organic acids N.B: Food spoilage can be controlled by controlling the intrinsic and extrinsic factors that influence microbial growth in foods. 31 Food Spoilage  Spoilage is understood as the process of breaking down of organic matter like protein, fat and carbohydrate with microbial or intrinsic enzymes. Causes of food spoilage  Microorganisms  Physiological factors  Intrinsic enzymes  Insects’ larvae or maggots’ secretions N.B. Bacterial spoilage is marked by foul smelling of food where as spoilage due to moulds & yeasts is mostly characterized by whisker.  Intrinsic enzymes cause autolysis and spoil food after the death Signs of food spoilage: Spoiled food can be recognized by:  change in appearance, change in consistency, change in colour or change in flavour, presence of visible growth and gas production. 32  Detection of Food Spoilage/contamination 1. Organoleptic methods (using sense organs i.e. smell, taste, colour, touch...)  Microorganisms Spoil Food by metabolizing and by producing bacterial end products/metabolites/ such as Ammonia (NH3), H2S, lactic acid or other alcoholic end products which resulted/bring change in consistency, appearance, colour, flavour (taste and smell) of the food. We can be detect food spoilage by examining the food for the presence of the above changes using our sense organs. 2. Supportive tests (laboratory tests): Since it is not possible to sense minute spoilage, supportive tests are important to detect the hidden spoilage.  The tests include determination of pH, NH3, H2S volatile fatty acids, antibiotic sensitivity tests, or residue level determination test. 33  Measuring pH: The normal Ph of fresh milk lies between  6.3-6.75 and  that of fresh meat is about 5.5  pH< 6.3 in milk suggests Microbial contamination, excessive lactic acid production, but  PH > 7.5 indicate the milk is from mastitic cow  Determination of electrical conductivity: For example milk has Cl- and other electrolytes and during mastitis the electrolyte increases. 3. Culturing and bacterial load determination: By counting colony forming units (CFU) / Total aerobic Plate count (APC) 34 4. Using rapid methods PCR: This could be applied at commercial level Public health importance of food Spoilage 1. Spoilage results in food-borne infections and intoxications Eg. Contamination of food by staphylococcus bacteria 2. Economic losses can lead to food scarcity 35  MEAT HYGIENE / TECHNOLOGY Objectives : At the end of topic you will be able to: 1. Define terminologies related to meat hygiene 2. Discuss composition and nutritive values of meat 3. List sources of contamination for meat 4. List the signs of meat spoilage 5. List the different Qualitative changes in meat 6. Explain how the different Qualitative changes in meat occur 7. Discuss the importance of Differentiation of carcasses & organs of different animals 8. List the different methods used for meat Spp identification and explain how these techniques are used 36  MEAT HYGIENE / TECHNOLOGY Definition:  Meat Inspection/Hygiene: it refers to examination of meat for some abnormalities and diseases.  It is meat production with an expert supervision and with the objectives of providing wholesome meat for human consumption by excluding all factors which endanger public health. Wholesome food: is a food that is sound, clean and free of adulteration of any substance that is unacceptable to the consumer or it is a food suitable for human consumption.  It works with QSA principle: Quality, Safety and Acceptability of meat and meat products.  A proper meat inspection service consists of a veterinary examination of the live animal (ante-mortem inspection), and examination of the carcass and offal (post-mortem inspection) and where necessary, laboratory tests of body tissues and fluids 37 Meat: is the edible parts (Skeletal muscle & offal: Heart, Liver, Kidney, Tongue) of the food animals. Carcass: is meat with the two kidneys; but excluding blood, feet, head, skin and viscera (internal organs).  It is the dead body of an animal especially one slaughtered and dressed for human food purpose. Offal: also known as by-product; refers to non-carcass material, which can be classified as edible and inedible.  Edible offals: includes liver, heart, kidneys, tongue (= red offals)  stomach and intestine are termed as green offals.  Inedible offals: includes feet, horn, hoof, hide/skin, ears, etc. In general, the inclusion of offals as an edible varies throughout the world owing to custom, religion and reputation of the product. 38 Viscera: refers to organs located in the abdominal and thoracic cavity (stomach, intestine, spleen, kidneys, liver, heart, lungs etc.) Dressing Percentage (Carcass Yield):  Dressing percentage is calculated by dividing the warm carcass weight (after head, skin, feet, blood, thoracic and abdominal visceral have been removed) by the live weight of the animal and expressing the result as a percentage.  For example, suppose an animal delivered to the slaughter house weighs 300kg and after being killed, the skin, head, feet and thoracic viscera and gut are removed, the carcass then weighs 180 kg. The dressing percent of this animal will be 180 divided by 300 multiplied by 100 equaling 60 percent.  This “60 percent” represents the meat and skeletal portion of an animal compared to its live weight. 39 Carcass Yield = Body + Kidney – (head, skin, feet, blood, thoracic and abdominal visceral)  For cattle the carcass weight is expected to be about 53% of body weight. Therefore, if the life weight of the animal (bovine) is 270 kg, we expect a minimum Carcass yield of 53% which is 143.1kg.  In bovine, bone covers 20 % of the live animal body weight. (270x20%= 54kg of bone)  Therefore, Meat Weight = Carcass weight – Bone weight. 143 kg carcass – 54kg bone= 89kg of meat The carcass weight expected for different animal species is as follows:  Sheep and Goat ~ 50% of the live animal weight.  Chicken ~ 72%  In pig ~ 75 % of the live animal weight. 40  Most of the times animals which will yield a good percentage of carcasses are:  An animal with a proportion of small offal parts  Animals that have a good thickness of muscle compared with the length of body  Animals with smooth covering of fat over the whole carcass Source of Meat  The animals which furnish meat for human consumption are mostly those which are domesticated and of herbivorous type: i.e. Cattle, buffaloes, Sheep, Goat, Camel, Poultry (hen, duck, goose, and guinea fowl), rabbit, pig, guinea pigs and fish.  Although theoretically hundreds of animals could supply meat for human consumption, in practice only small number of animal spp are used today.  This may be due to restriction of the public to certain type of food animals due to their religion, culture, etc. 41  Composition of meat: Lean beef meat comprises of the following constituents 1. Water -------------------------------75 % 2. Protein------------------------------19 % 3. Non-protein nitrogen------------1.65 % 4. Lipids (fat and fatty acids)-------2.5 % 5. Carbohydrates (glycogen)-------1.2 % 6. Minerals-----------------------------0.65 % 7. Vitamins and other substances constitute minute quantities. 42 1. Protein: is the most important muscle constituent and is made up of myofibrillar, sarcoplasmic and connective tissue proteins.  Myofibril protein: elongated contractile threads found in striated muscle cells – these are actins and myosin. They gives rigidity to the muscle.  Sarcoplasmic proteins are the water-soluble proteins found in the cytoplasm of striated muscle cells.  Connective tissue proteins (Collagen, Elastin and Reticulin) – supports the muscle along with bone. 2. Lipids: mostly composed of triglycerides, which are fats and oils. (Phospholipids, Saturated, Mono-saturated, Poly-saturated fatty acids and Cholesterol). 43 3. Carbohydrate: Present mainly as glycogen, which has a major influence on muscle change after death. Glycogen is mainly present in the liver and is especially abundant in horse meat. 4. Non Protein Nitrogen: Includes Creatinine, Nucleotides, Inosine. 5. Minerals: The minerals found in meat according to their importance are: sulfur (S), Potassium (K), Phosphorus (P), Sodium (Na), Chloride (Cl), Magnesium (Mg), Calcium (Ca), Iron (Fe) & Copper (Cu). 6. Vitamins: Vitamins of the B Complexes: B1 (thiamin), B2 (Riboflavin), B3 (Nicotinic Acid = Niacin), B6 (Pyridoxine), B12 (Cyanocobalamin= found only in animal derived foods), Pantothenic acid, Folic Acid, Biotin, etc 44 Nutritive values of meat: Why people are fond of eating meat?  Meat is a valuable part of the human diet because: 1. It is the most concentrated and easily assimilable of nitrogenous foods. It contains all essential amino acids. 2. It stimulates body metabolism because of its high protein content. 3. It is also a good source of fat, carbohydrate*, bio available minerals and vitamins (Vit B Complexes and fat soluble vitamins → ADEK) and others. 4. The fat in the diet delays emptying of stomach and allays hunger. 45 5. Suitable treatment (cooking) imparts meat palatable flavour and acts as a stimulant to gastric secretion and is readily digested. 6. A vegetable diet, compared with a meat diet, is usually incomplete in essential amino acids and the vegetable proteins are less easily digested. Contamination of Meat The organisms that contaminate meat may get access through:  Infection of live animal: endogenous sources or  Contamination of Slaughtered meat: Postmortem contamination (exogenous source) 46  Sources of Contamination for Meat 1. Outer integuments (Hide, Skin, hair, feet, etc) 2. GIT contents (stomach and intestine) 3. Sticking point: if the sticking material is not clean, the bacteria may get access to get into the jugular vein, then to vena cava and finally reach to the meat 4. Physical contact with structures /premises 5. Operatives: personnel working in the slaughter house and abattoir 6. Equipments / utensils: such as knife, saws, cutters 7. Vermin: animals obnoxious to human (beast or insects) 8. Chemical contaminants: chemicals used for cleansing the materials 47  The main bacteria that cause meat spoilage are: Gram Poaitive Bacteria Gram Negative Bacteria Micrococcus Salmonella Staphylococcus (S. aureus, S. albus) Alacigenes Streptococcus (S. fecalis, S. durans) Escherchia Lactobacillus Klebsiella Bacillus (B. subtilis, B. thermophillus, B. Pseudomonas coagulans) Flavobacterium Clostridium (Cl. Histolyticum, Cl. Achromoacter Perfringens, Cl. Butyricum, Cl. Halobacterium sporogenes) Moraxiella Corynebacterium + others Mycobacterium Campylobacter: specially in chicken meat 48  Signs of Meat Spoilage  Marked change of color to grey, yellow, green  Stiffening in the consistency of the tissue  Pronounced repulsive odor  An alkaline reaction caused by the formation of ammonia (NH3) These changes can be detected by sensory analysis (organoleptic tests and/or Laboratory tests) 49  Qualitative changes in meat The difference between meat and muscle?  We talk about muscle, when the animal is alive and we discuss about meat, after the slaughtering food animal and after some biochemical changes have taken place in the muscles.  The qualitative changes which occur in meat includes Rigor mortis, Pale Soft Exudates (PSE), Dark, Firm and Dry meat (DFD) and change in water holding capacity.  Meat undergoes physical and/or chemical changes within one to two days after slaughter.  Shortly after slaughter, fresh meat appears dark, sticky and adherent when minced and water will not easily squeezed from it. It is also resistant to penetration of salt and sugar.  But after a day and so later, meat will become lighter in colour and less moist and not sticky when minced. Over 30% of the fluid can be squeezed. 50 1. Rigor mortis  It is a Latin word and literally means stiffening and hardening of skeletal muscles after slaughter/death.  It is the first and most considerable change which occurs in muscle and characterized by:  Contraction of voluntary muscles,  Loss of transparency on the surface of muscle, stiffening of the joints, and slight rise in the temperature of carcass. Mechanism of rigor mortis  Normally, in live animals the contraction of muscle is effected when the actins slide into the myosin fibers under the utilization of ATP. As the result, the space between two muscle fibers, i.e. the length of sarcomeres, shortens. Once again, under the utilization of ATP, Actins fibers slide out of myosin fibers. Consequently, the sarcomers widens and cause muscle relaxation. 51  Since energy is required to maintain muscle in a relaxed state, when the level of ATP falls to a critical low level after death, the relaxed state cannot be maintained.  Therefore, after death, actins and myosins join together to form actomyosin, whereby the muscles contracts irreversibly and joints stiffen. This stage is known as Rigor-mortis.  In live animal, there is aerobic respiration by which glycogen is converted to water and carbon dioxide. Glycolysis: The breakdown of glucose to pyruvate, with the release of usable energy.  But after slaughter, due to lack of oxygen, anaerobic respiration will takes place and results in the production of lactic acid.  the carcass PH falls from 7.0 to 5.6 (Ultimate PH). However, if the animal is stressed, an ultimate PH of 5.6 cannot be reached. 52 NB. Time taken to reach the ultimate PH of 5.6 in  pigs is 4-8 hours,  sheep 12-24 hours and  beef 24- 48 hours.  If rigor mortis enters quickly, poor quality meat is produced. The muscle becomes pale in color, Soft and drips. This leads to pale soft exudative (PSE) meat. Importance of Rigor-mortis It basically influences the meat quality and result in:  Reduced water activity or the water binding capacity of meat  Pale soft exudative (PSE) meat is produced  The meat becomes dark firm and dry (DFD) meat  Decreasing the meat tenderness 53  Nerve impulse comes through MN to synapse Trigger release of Ach contraction Ach binds on receptors and triggers impulse on the membrane of muscle Ca+ from special vesicles moves to wards myofibrils and bind to a protein called troponin Troponin moves out along actins and myosin to react The actin slide inside the myosin filament. This is repeated for each sarcomer along the muscle fiber. This causes shortening of the entire muscle An enzyme called Ach esterase present in the synaptic cleft destroys Ach shortly after it is bound to the receptor relaxation The membrane of the muscle is no longer response to impulse C+ goes off troponin and transported in to storage vesicle by ATP demanding process (muscle relaxation) During rigor mortis due to shortage of ATP this ATP demanding step of muscle relaxation will not take place b/c of this the muscle remains in 54 contracted state (rigor mortis) B. Debasement (Adulteration and substitution) I. Adulteration means adding unwanted or undesired ingredients, be it food or chemical into quality food.  Adulteration in case of meat means mixing of minced meat of one species with inferior quality minced meat of another species. It also means addition of protein of plant origin to meat product like soya to animal protein. II. Substitution refers to selling/ presenting of meat of other species than specified as food animal in that locality. e.g. presenting gazelles’ carcass as goat carcass – this is known as substitution.  Business men do debasement to disguise the true content of meat, to increase the weight of the meat or to make the meat more attractive, thereby to increase their income/profit. 55 Differentiation of carcasses & organs of different animals  Meat species specification is an utmost important field of quality control management in meat industry.  It is more challenging and revolutionary task for us as a veterinarian because by this way we can ensure the quality of meat and also helps in conservation of law existing in different countries.  For detection of meat species in adulterated/ substituted meat there are different techniques starting from simple physical tests to recent sophisticated molecular techniques. 56 1. Physical techniques: we generally go for general appearance of the meat for detection of different meat species.  It is a combined perception of color, texture, odor and presence of other body parts along with meat.  It gives the primary idea about the meat species on the basis of quality characteristics of the meat. 57  a. Organoleptic Meat color Consistency Odour Marbling Beef Dark red with slight Firm & shiny cut - Present brownish tinge surface Pork Grayish white to Very soft Urine like Present light red Mutton Dark red Firm and dense Ammoniac Absent to scanty Buffalo Dark red Firm - Absent/poorly Poultry Whitish Firm - Absent Horse Dark red with bluish Firm with - Absent meat tinge prominent fascia Camel Red Fairly firm - Absent meat Rabbit Pale, grey to grey red Firm Pronounced Absent meat 58 b. Anatomical techniques: are used on the basis of anatomical structure of different animal’s species used for meat production, we can easily identify the meat species to which it is actually belongs. But these anatomical structures must be present on the meat at the time of inspection/ examination. These include  Dental formula if teeth are attached with the carcass. The “Dental formula” for various animals helps to identify the kind of animal by counting the number of temporary and permanent sets of dentations as indicated below: Horse 2 (I3/3 +C1/1 + P 3 or 4/3 + M 3/4) = 40-42 teeth Ox 2 (I 0/4 + C0/0 + P 3/3 + M 3/3) = 32 teeth Sheep / Goat 2 (I 0/4 +C0/0 + P3/3 + M 3/3) = 32 teeth Pig 2 (I 3/3 + C1/1 + P 1/1 + M 6/6) = 44 teeth Dog 2 (I 3/3 + C ½ + p 4/4 + M 2/3) = 42 teeth  Another anatomical technique for carcass identification is on the basis of vertebrae and ribs number present on the carcass. 59  The vertebrae of different food animals Animals Cervical Thoracic Lumbar Sacral Coccyges Horse 7 18 6 5 15-21 Ox 7 13 6 5 13-20 Sheep/ Goat 7 13 6 5 12-20 Pig 7 14-15 7 4 18-23 Dog 7 13 7 3 20-23 Note: All those animals have seven cervical vertebras even the giraffe with its long neck has only the same number. Each of these animals has almost the same number of lumbar and sacral vertebral respectively. The number of tail vertebral varies in range, depending on the species of animals. The number of vertebral in the tail is greater than any vertebrae in the region. 60 2. Histological techniques: In this technique we generally measured muscle fiber length, diameter, density and pattern of the muscle fibers in different meats of animal. 3. Chemical techniques: For meat species specifications various chemical tests have immense value. In these tests we can easily estimate the amount of certain chemicals presents in the meat of different animal species. E.g. a. Carotene is absent in buffalo fat and it is b/n 0.14 - 0.225mg per gram of fat from beef meat. b. Linoleic acid is 0.1% in beef, buffalo meat, mutton and pork but it is 1-2% in horse meat c. Glycogen percentage in the meat of horse is 2.28 and it is between 0.5 and 1% in meat of other animals. 61 4. Biological techniques: These techniques are mainly based on the principles of Ag-Ab reactions. These tests are also known as immunological technique. 5. Molecular techniques: DNA based molecular techniques: DNA is molecule of choice for species specifications due to its stability during heating and processing. Polymerase Chain Reaction (PCR): is a rapid method because in this technique we can obtain multiple copies of specific piece of DNA sequence in vitro and it has high degree of selectivity and specificity. It is a qualitative test for meat species specification. 62  Production and Transportation of food animals Objectives At the end of this session you will be able to:  Explain how food animals should be Transported  List the different means of animal Transportation  Discuss the advantages and the disadvantages of the different means of animal Transportation  List the Adverse effects of Transportation on Animals  List the measures should be taken to reduce adverse effects of Transportation  Understand the importance Pre-slaughter care of animals  List pre-slaughter cares given to animals  SLAUGHTER HOUSE HYGIENE — Objectives of construction of abattoir — Planning of abattoir construction — Site selection for Slaughterhouse construction — Size of an Abattoir — Facilities In ideal Export Abattoir — Requirements on Abattoir equipments — Requirements on Building Materials — Use of Overhead rail for hygienic slaughtering operation — Plant sanitation 63  Production and Transportation of food animals  To produce a hygienic meat, the control should start from farm production in addition to the processing centres and final consumption. Food animals should be:  Raised in hygienic environment,  Free from epizootic and zoonotic diseases,  Free from residue and  Properly transported to the abattoir. 64  Transportation of food animals  Meat consumers are increasingly demanding that animals be reared, handled, transported and slaughtered using humane practices.  During transportation of food animals, they should be kept free from:  Injury and disease  Stress and loss of weight,  Unnecessary suffering while being loaded and unloaded, with inadequate fittings, bad weather and inadequate ventilation. It is essential that animals should be slaughtered as near as possible to the point of production in order to avoid unnecessary injury. (Though it is not applicable) Transportation of unfit animals and those likely to give birth during the journey should be prohibited. 65 Slaughter animals should be transported with facilities to the abattoir that ensure: 1. Soiling and cross-contamination with faecal material is minimized 2. New hazards are not introduced during transport; 3. Animal identification as to the place of origin is maintained; 4. Consideration is given to avoid undue stress. 66 Transport vehicles should be designed, constructed and maintained so that: 1. Animals can be loaded, unloaded and transported easily and with minimal risk of injury 2. Animals of different species, and animals of the same species likely to cause injury to one another, are physically separated during transport 3. Use of floor grating, crates or similar devices limits soiling and cross-contamination with fecal material 4. Minimized soiling of excreta deposited on the floor of the vehicle 5. It should be easy to clean and disinfect 6. Ventilation should be adequate to prevent suffocation 67  Means of animal Transportation Animals may be transported by the following 4 methods: 1. Driving on hoof: Can be done if animals movement is permitted Feed and water must be provided during the journey.  Advantage: It is very cheap  Disadvantage: It causes weight loss, take longer time to reach abattoir, may cause mortality; and animals may contract and transmit diseases on their way to the abattoir. 2. Transport by vehicle: It is an excellent method if the road has good standard and the vehicle is designed for the transportation of animals (with non-slippery floor, adequate ventilation, sun protected). 68 3. Transport by rail: Where the roads are poor standard, transport by rail is more reliable. 4. Transportation by ship or by plane: During live animal export  The advantage of transporting animals other than on hoof is rapid and provides protection, but there may be injury during loading and unloading.  On the other hand it requires a high investment cost. 69  Adverse effects of Transportation on Animals During transportation, animals are subjected to a number of adverse effects like: 1. Loss of body weight: It depends on the body condition of the animals, season and time of the journey and species of animal being transported.  The causes are depletion of glycogen by long, delay in transit and lack of feed and water during transportation period. 2. Injury/ trauma: It is mainly due to lack of bedding, mixing of horned and polled animals or different age groups, overloading or excessive use of beating and poor ramp design. Bruising: is a damage of the underlined tissue with the skin remained unaffected. 70  Economic implication of bruising:  Loss of meat (the bruised part has to be trimmed, even extensive bruising can result in total condemnation of the meat)  Trimming impedes slaughtering operation and also requires extra labor  The meat tests after blood  Presence of blood in the bruised carcass leads to meat spoilage 3. Disease: as a result of lack of water and feed, suffocation and contact with other animals e.g. shipping fever due to Pasteurella multosida, Salmonellosis 4. Mortality: due to suffocation, trampling and adverse climatic condition or diseases. Shoats & pigs are highly affected by suffocation. 71  Measures to reduce adverse effects of Transportation 1. Different group of animals like young and adults, females and males, horned and polled, secured and unsecured should not be transported in the same undivided vehicle. 2. Use well designed car which have non slippery floor, adequate ventilation and protection against rain and sun. The minimum floor requirement on vehicles is For pig = 335 cm2 Sheep = 213 cm2 Calf = 271 cm2 3. Loading and unloading should be using a loading ramp; the slope of the loading ramp should not exceed 300. Manual lifting for smaller species is better if used. Don’t load earlier than a few hours before departure. 72 5. Avoid unnecessary use of sticks when loading unloading and during transport on hoof 6. Avoid overcrowding but pack the animals tight enough to prevent them lying down 7. Provide water and feed during the journey and after arrival. If the journey exceeds 24-36 hrs the practice should be done at resting ground not in the vehicle and wagon 8. Insure that the animals are rested (if the journey is very long and the environment is difficult) 9. In order to prevent disease transmission, vehicles should be cleaned and disinfected before loading and after unloading. 73  Pre-slaughter Care of Animals 1. Resting: It is necessary to rest fatigued and excited animals before slaughtering at least 12 hrs or more Inadequate Resting may cause:  Reduced keeping quality of meat and facilitate early invasion of the carcass by putrefactive bacteria. (Due to incomplete development of acidity of the meat and incomplete bleeding)  The actual resting period depends on:  Species of animal  Sex, age and body condition of animals  Season of the year  Method of transportation, length of the journey  degree of fatigue  During resting period, animals must be kept under conditions, which prevent any further contamination of feet, fleeces or skins. 74 2. Watering: During detention in the lairage, animals should get ample water  This serves to lower the bacteria load in the intestine and facilitate easy removal of skin or hide. 3. Feeding: Animals having long journey should be fed and rested near the slaughter house before they are slaughtered. 4. Fasting: Animals should not be presented for slaughter with full stomach to prevent carcass contamination due to accidental incision or rupture of the GIT during the evisceration procedure. If slaughter takes place within 12 hours of animals arrival at the slaughter house, there is no need to feed the animal. 75  SLAUGHTER HOUSE HYGIENE Objectives At the end of this session you will be able to: 1. Define some terminologies related to slaughter house hygiene 2. List the objectives of construction of abattoir 3. List the criteria for construction site selection for abattoir 4. Discuss the requirements laid on building materials and equipments for abattoir 5. List the parts of an Ideal/ export abattoir 6. Explain the importance of using overhead rail for hygienic slaughtering operation 7. List the reasons for cleaning food plants 76  SLAUGHTER HOUSE HYGIENE Definitions:  Abattoir/slaughter house: is any premise, that is approved and registered by the controlling authority, in which food animals are slaughtered and dressed for their meat for human consumption. Abattoir: Should be constructed using overhead rails to avoid contact of meat with the floor or wall and also dirty and clean operations rooms are clearly separated Slaughter Slab: Should have the following facilities  Hard smooth impervious floor falling towards the center  Inspection tables with hooks for guts and livers  Viscera inspection table, wheelbarrow to transport rumen and skins, water storage tank, washing facilities for slaughter men  Should be roofed to protect butchers from rain and sun and to keep away vultures 77 Slaughter House: when the slaughter slab dose not cope with the output, it is advisable to construct a slaughter house, which contains the following units:  Trippery and guttery Hanging room for inspected meat  Shower, toilet, hide and skin room  Meat Inspector: Means a properly trained competent officer appointed by the controlling authority for the purpose of meat inspection and control of hygiene.  Potable water: Means water that is pure and wholesome at the point of usage [In accordance with the requirements of WHO guide lines for drinking water quality]. 78  Objectives of construction of abattoir The objectives of constructing abattoir/slaughter house/ slaughter slab are:  To produce wholesome and sound meat  To protect the public from zoonotic diseases  To prevent the out spread of epizootic diseases  To protect the environment from pollution/contamination  To economically utilize slaughter house by products 79  Planning of abattoir construction: The construction of abattoir should follow after consultation with authorities like:  The Municipality  Regional and Federal Veterinary Office  Health Authority  Environmental Protection Agency  Architects and  Contractors 80  Site selection for Slaughter house Construction A Suitable site for an abattoir should have the following facilities. 1. Water Supply:  There should be potable water treated with chlorine at a level of 2 ppm.  Storage tank should be available, with a capacity to hold at least one day’s consumption.  Large quantity of pressurized water is required for carcass washing, sterilization of equipments and cleaning the premise.  The recommended water requirement is: 454 liter/pig, 272 liter/cattle and 45 liter/sheep 2. Electric supply: It should have continuous electric supply. It is crucial for lighting, stunning purpose, transporting (on the overhead rail), and chilling of carcass. 81 3. Sewerage facility: To insure all the fluid waste leaving the abattoir is properly disposed the site to be selected for abattoir construction should be connected to main sewage line. 4. Access to main road: All weather, uncongested road or rail way 5. The compound should be stable ground well drained (gentle slop), free from flooding. 6. Proximity to Public: Abattoir should not be built in residential and city expansion areas. Should be far from public dwelling sites. 7. Area of land: There should be sufficient size for future expansion of the abattoir 8. Proximity to supply of varied labor and livestock market 9. The site should be free from pollution, smoke, dust, odour and from other industries. 10. It should be far from airfields to prevent bird strikes 82 Size of an Abattoir: The size of an abattoir to be constructed is influenced by a number of factors including the following:  The maximum number of animals to be slaughtered daily  Frequency of meat supply  Future plan to process meat and meat products  The plan to expand the enterprise  Abattoir  Slaughter house  Slaughter slab 83 FACILITIES/ PARTS IN IDEAL EXPORT ABATTOIR An ideal export abattoir should include the following structures: 1. Lairage: Is the place where animals are kept before slaughter. It comprises a ramp, holding pen and weighs bridge.  Ramp: is the structure where the animals are loaded & unloaded. Its slope should not exceed 300. Holding Pen: it is a roofed premise where animals are rested, fed, watered and ante mortem inspection is carried out.  Size may vary depending on the size of the abattoir.  7.6m by 6m would suffice to hold 25 head of cattle.  Floor should be concrete with hydrant points to facilitate cleaning 84 2. Slaughter - hall and other rooms:  This is a roofed hall with generous floor space, well ventilated and lighted room, fitted with overhead rails.  It is where all the slaughtering operations are carried out and it has the following areas: 2.1. Stunning Area: this in an area where animals are rendered unconscious before being bled/ slaughtered.  In modern abattoirs, animals are stunned in stunning boxes. 2.2. Bleeding area: is where animals are bleed. bleeding area is provided with concrete/ impervious material trough.  It should possess separate drain areas , 2.3. Skinning/dressing and Evisceration area: 85 2.4. Carcass Splitting Area: 2.5. Post-mortem Inspection Area: 3. Emergency slaughter unit:  It is a mini-abattoir adjacent to the main slaughter hall situated to the detention room and is in direct communication with the by-product processing unit.  Only animals suffering from acute pain or injury or approaching death are slaughtered in this section.  There should be steam or hot water, sterilizer and hand washing facilities. 86 4. Chilling and Refrigeration facilities: 4.1. Chilling room: is a room where carcass is kept at -2 to 40C.  It should be provided with thermometer fixed to the outer wall.  Carcass in chilling room should be hanged 50cm apart  In order to avoid fluctuation of internal temperature, the door should be tight and avoid frequent opening of doors. 4.2. Freezing room: Can be adjusted to different TO below 00C 4.3. Cutting room: Is a room where carcass is reduced to less than a quarter, or where carcasses are deboned and packed.  During cutting, temperature of the room should not exceed 100C.  The room should be provided with warm and hot water (830C). 87 5. Fresh meat despatch Area:  The floor level of the loading bay should be at the same level with height of vehicle or the overhead rail carrying the carcass should be at the same level with the overhead rail found in the vehicle. 6. Detained Meat room: Is a room where suspected carcass is detained and thoroughly inspected. It should be connected with the slaughter hall and Condemned meat room through overhead rails. 7. Condemned Meat room: This is a room in which condemned carcass/organ are detained or kept until further action/processing. 8. Gut and Trip Room: Is a room in which the gastrointestinal tract of the animals is emptied, cleaned and washed. 88 9. Personal facilities: For changing room, toilet with washing facilities, shower, laundry, cafeteria and clinics should be available. 10. Veterinary Office: With facilities like hand wash, toilets, meat inspection equipments, lockers for clothes and record keeping. 11. Laboratory: Adequately equipped laboratory to undertake bacteriological, parasitological and histological examinations. It is also important to control the hygiene and quality of the abattoir 12. Meat processing unit 13. Hide & Skin drying area 14. By product processing Unit 15. Car washing & Disinfection area 16. Manure and other waste collection sites 89  Requirements laid on Abattoir equipments: All equipments and utensils which come in contact with meat and meat products should be:  Be easily washable and disinfected  Have smooth (free from pits and crevices) impervious surface  Be resistant to corrosion and made of materials with non-toxic and does not transmit odour or taste  Be capable of withstanding repeated exposure to normal cleaning and disinfection  Platforms, tables, rail and similar equipments shall have non absorbent surface, which is rust-less and non-corroidible and can be easily cleaned 90  Requirements on Building Materials: 1.Premises/building: Should be built of durable materials and is vermin proof a. The floor: Made of concrete, well drained, non slippery and firm to support heavy weight equipments b. The walls: Should be built from bricks, covered at least up to 2m with porcelain tiles. Walls should be smooth (water proofed), non toxic, non absorbent, light colour and easy to clean and disinfect. Top of the walls shall be covered (above 2m) with mesh wire to prevent the entry of insects and to facilitate ventilation c. The ceiling: Should be built of solid materials and be white painted, and constructed in such a way to avoid condensation. d. The doors: Shall also be built of rust free metal and wide enough to bring in new equipments 91 2. Lighting: Adequate natural or artificial lighting must be provided though out the meat plant enabling inspectors and butchers to perform their duty with out difficulties. The overall intensity of light should not be less than  540 Lux (50 foot-candles) at all inspection points  220 Lux (20 foot-candles) in work rooms  110 Lux (10 foot-candles) in other areas 3. Adequate ventilation: Is necessary to prevent the condensation of water and to reduce accumulation of bad odour 92 Use of Overhead rail for hygienic slaughtering operation  An overhead rail facilitates the slaughtering process (i.e bleeding, flaying, evisceration, carcass splitting and transportation/loading in to vehicles/).  It enables to work continuously, avoid contamination and saves space. The cheapest rail used in slaughter slab is a flat iron bar fixed to the wall or ceiling which shows gradual decrease in slope up to meat loading ramp.  The recommended distance from the floor is 4–4.2 meter in the bleeding area and 3.2 meter in the skinning area for bovine, and 2.3 meters above floor for pig, goats and sheep. 93 Environmental sanitation Fencing: Is important to prevent entrance of dogs and other scavenger to the compound of the abattoir. This will help to break the life cycle of some parasites. Pest control:- The presence of rats, mice, insects and birds can cause problem as they may carry food poisoning microbes and pathogens responsible for zoonotic infections.  The rats and mice are attracted by the presence of food. Droppings in abattoir are indicators of their presence.  Insects are drawn into food premises by the presence of predigested food such as excreta besides near by breeding grounds (stagnant pond, sewage work, rubbish or waste tip etc).  Birds feed on meat scraps, dung, grain and food scraps. 94 Control is effected by ensuring cleanliness, absence of food scraps, use of air curtains, insecticidal spray (only to non-meat sectors), use of narcotic baits (pentabarbitone sodium) and use of special pest control firms.  waste disposal  Abattoir effluent treatment- The efficient disposal of effluent from meat plants, meat processing works, etc. is very important because of the possible pollution of watercourses.  Liquid waste discharged from a sewage system, factory, nuclear power station, or other industrial plant 95  ANTE-MORTEM EXAMINATION Objectives At the end of this session you will be able to: 1. Define ante-mortem inspection 2. List the Reasons for ante-mortem examination of food animals 3. Discuss the Guidelines and principles AMI 4. Explain the procedures of ante-mortem inspection 5. List the different Judgement categories at ante-mortem inspection 6. Explain at what condition the different Judgement categories at AMI 7. Explain how the results of ante-mortem inspection are reported. 96  ANTE-MORTEM EXAMINATION Inspection of meat has two aspects: 1. Ante-Mortem Examination (AME): Any procedure/examination or test conducted by a competent person on live animals for the purpose of judgment of safety and suitability and disposition on entry to the slaughter house 2. Post-Mortem inspection (PMI): Examination of the carcass and different body parts after slaughter Adequate/sufficient PMI is not possible without AME 97 Objectives/Reason/ for Ante-Mortem Examination of animals 1. To screen all animals destined for slaughter 2. To separate fevered and excited or dull animals 3. To isolate suspected animal & perform detailed clinical examination 4. To select and detain extremely dirty animals. 5. To reduce contamination of premises, equipments and personnel by animals affected by communicable diseases. 6. To ensure emergency slaughter for injured/suffering animals 7. To identify those animals harbouring residues, e.g. Antibiotic 8. To detect animals affected with disease, that cannot be detected during PMI. 9. To require and ensure the cleaning and disinfection of trucks used to transport livestock. 98  Guidelines and Principles  No animal shall be slaughtered without undergoing AME  AME should be made in well-lighted lairage and a crush.  All animals should be inspected within 24 hrs of delivery. If 24hrs have elapsed after AME, it should be repeated.  Every animal should be properly identified and accompanied by a certificate  The disease & management history should be recorded & reported on an AM –inspection card. information should include:  Owner's name, Origin, Species, Breed, Age & sex of the animal, number of animals in the lot, arrival time, time and date of AME, Clinical signs and body T0and Signature of inspector , 99 Procedures of Ante-Mortem Inspection:  AM inspection should be carried out where animals can be observed both collectively and individually at rest and in motion.  It is important to observe the general behaviour, nutritional status, cleanliness and signs of diseases and abnormalities of animals. General examination can be followed by systemic examination. Some of the conditions which must be checked on ante-mortem examination are: 1. The respiratory system: To detect nasal discharge (URS), cough and to determine the frequency and pattern of respiration.  Forced respiration may suggest CBPP, CCPP, Tb, Pasteurellosis and Lungworm parasites. 100 2. The digestive system: is examined to assess abnormal lesion, rumination and nutritional status.  Emaciation could be attributed to diarrhoea (Johne’s disease, Salmonellosis, infection with E. Coli, rinderpest and other viral disease).  Excessive salivation may be due to mucosal disease complex, FMD, Rinderpest, or Rabies. 3. Behavior – Abnormalities in behavior can be manifested by:  walking in circles, abnormal gait or posture, pushing head against objects, charging at various objects aggressively, showing a dull & nervous expression in the eyes.  Slow reaction/dullness could be attributed to diseases.  Excitement may suggest specific diseases like rabies, tetanus, & poisoning. 101 4. Gait: abnormal gait may be associated with pain in the legs, chest or abdomen or is an indication of nervous disease. 5. Posture: Abnormalities in posture is observed as tuck up abdomen or the animal may stand with an extended head and stretched out feet. The animal may also be laid and have its head turned along its side. Recumbence. 6. Abnormalities in structure and conformation: Swellings (abscesses) seen commonly in swine, enlarged joints, umbilical swelling (hernia or omphalophlebitis), enlarged jaw (“lumpy jaw”), bloated abdomen. 7. Abnormal discharges or protrusions from body openings: nasal discharges, excessive saliva, protruding from the rectum (prolapsed rectum), from the vagina (prolapsed uterus or afterbirth) 8. Abnormal color: (due to inflammation, gangrene, etc) 9. Abnormal odor of drugs, ketosis or abscess 102  Judgement categories during AM - inspection: The following decisions are passed during ante-mortem inspection 1. Approved for slaughter without any restriction: If no evidence of disease is found. 2. Condemned for slaughter: – When the animal is unfit for slaughter. This decision is made under the following conditions:  If specific contagious animal diseases or zoonotic diseases have been detected.  If the animal is immature/highly emaciated 103 3. Slaughter Approved under special precautions: –  When the AM inspector suspects noticeable disease or the animal is dirty that could lead to partial or total condemnation during PM inspection. S uch animal is slaughtered in a separate room o r at the end o f the slaughtering o f healthy animals. 4. Approval for delayed slaughter: This judgment is passed if:  The period of rest has not been maintained and  The animal is temporarily affected by a physiological or metabolic condition 104 5. Postponing the slaughter: The slaughtering of an animal may be postponed, if  Curable disease is diagnosed  The animal has been found treated with drugs,  Additional information or diagnostic test are required 6. Emergency slaughter ordered:  It refers the slaughter of an animal revealing an acute pain or suffering from an injury, or approaching death or if death is inevitable,  Provided that the meat quality is not affected/ does not pose public health hazards. The two reasons for this judgment?  Fracture of limbs, pelvis or ribs and extensive bruising.  Diseases like dystocia, pregnancy toxaemia in ewes, sever tympany, asphyxia and obstruction of the esophagus..causality slaughter refers to the slaughter o f animal suffering from chronic illness e.g. milk fever, obturator muscle paralysis 105 Judgments on emergency slaughtered animals: Before passing the judgment on emergency and causality slaughter, the following examination should be carried out.  Examination of blood smear taken from the ear of the animal to ensure that the animal is not suffering from any epizootic or zoonotic disease.  Examination of lymph and lymph nodes.  Inspection of the subcutaneous tissues to find extensive bruising, congestion of blood vessels and oedema.  Detailed examination of all joints.  Bacteriological examination – of samples from meat lymph nodes, muscle, Organs with distinct pathological lesions, spleen, liver including the portal lymph node and the kidney. 106 Reporting the result of AMI:– Final report of AMI shall include:  Date and time of AMI  Categorized according to species, sex and age, number of animals condemned, detained, approved and number of emergency slaughter, reasons for condemnation, name and signature of veterinarian who has carried the ante-mortem inspection.  When dead animals encountered in the lairage, Anthrax must always be suspected and careful examination should be followed. One should also keep himself & the premise from contamination. 107  THE SLAUGHTER OPERATIONS Objectives At the end of this session you will be able to: 1. Differentiate b/n the two methods of slaughtering 2. List the different methods of stunning 3. Explain the importance of stunning 4. Discuss how different factors affect bleeding 5. Discuss how efficiency of bleeding is judged 6. Explain the importance of Plant sanitation 108 THE SLAUGHTER OF ANIMALS  The moral & ethical answers to the question raised when humans kill animals for food can only be answered for each individuals according to their religious, political or economic circumstances.  The two essential things in the slaughter of food animals are that animals shall be killed without unnecessary suffering and that bleeding shall be as complete as possible. I. Methods of slaughtering: 1. Ritual (Inhumane) method of slaughtering: Slaughtering is permitted without a stunning in accordance with ritual requirements no stunning prior to Slaughtering (bleeding). e.g Kosher and Halal slaughter 2. Humane method of slaughtering: In this method, animals are first made unconscious or insensible to pain before they are slaughtered. Animals made unconscious using a method called stunning. 109 Stunning prior to bleeding The objectives of stunning are:  To reduce stress on the animal  To promote efficient bleeding  To avoid unnecessary suffering and trampling  To facilitates the butcher’s work  To prevent the butcher workers from injury The method employed in stunning animals depends on a number of factors including:  The species of animal  Efficiency of equipment  Maintenance cost and safety of personnel  Ease of operation 110 General principles that apply to all stunning methods 1. Stunning equipment must be maintained in good repair: Equipment in poor repair can interfere with the rapid and effective application of the stunning blow. This can result in an incomplete/unsuccessful/ stunning. 2. Effective stunning requires effective restraint. If an animal is not effectively restrained, it will be much more difficult to locate the stunning blow with a high degree of accuracy. 3. A well-trained and experienced employee must operate stunning devices. The employee must be able to accurately and consistently position the stunning devices so that the animal is rendered immediately unconscious. 4. Animals need to be delivered to the stunning area with a minimum of excitement or discomfort. It is more difficult to place the stunning device accurately, and the method of stunning may not work as effectively, on an excited or injured animal. 111 Methods of Stunning 1. Stunning by Striking: This method produces a physical damage or shock to the brain. It can be done using: A. Mechanical (captive bolt): There are 2 types of mechanical stunners penetrating and non-penetrating. It’s used to produce immediate unconsciousness in cattle, sheep, goats and swine. preferable  The animal should be fixed by passing the securing rope through a ring cemented to the ground. Point of shooting by captive bolt:  The point of shooting in cattle is the point of intersection of lines drawn from the base of the horn to the opposite eyes medial canthus.  In shoats, it is in the centre of the forehead between the ears.  Pigs approximately 1cm above the level of the eyes in the middle line. 112 B. Mechanical (gun shot): Another type of mechanical device used for stunning is the gun. It can be used on cattle, calves, sheep, goats and swine. C. Stabbing through Foramen magnum:  In most developing countries, including Ethiopia, animals are made unconscious by stabbing the neck behind the head (through this foramen) with double-edged knives and severing the spinal cord.  Failure to stab the right place may cause suffering to the animal.  Should be performed by well experienced personnel. 113 2. Electrical stunning:  Done by passing an alternating current through the brain.  Commonly used for stunning pigs, shoats & calves  The instrument resembles a pair of tongs  The instrument should be grounded for the operator’s safety  Disadvantages of stunning with electricity; a. It is not suitable for cattle, while the hairs interfere with the flow of current. ??? b. Low voltage causes paralysis c. High voltage kills the animal d. High electrical current damages capillaries, resulting in multiple pinpoint hemorrhages in the muscle tissue 114 3. Chemical (Carbon Dioxide - CO2):  In this method, animals are placed into a sump with a mixture of 70% CO2 and 30% air. Animal becomes unconscious after 30 sec.  It’s used on swine, sheep and calves.  Argon gas is also used. II. Bleeding: (severing/sticking)  The main purpose of bleeding is to remove all blood from the animal, so that bacteria may not decompose the carcass ( keeping Quality)  Bleeding in ruminant is effected by severing the trachea, oesophagus and jugular veins.  Pigs are bled by inserting a knife in the middle of the neck at the depression in front of the sternum. The knife should be pushed forward to sever the anterior vena cava. 115 Factors influencing the efficiency of bleeding: They are stunning, hauling & elapse of time between stunning & bleeding. 1. Stunning: Stunning causes a rise in blood pressure. An increase in blood pressure in turn leads to increased heart beat, consequently to efficient bleeding.  Stunning by using a captive bolt or by electricity is more preferable.  To obtain good bleeding the heart and respiratory system must remain in action for as long as possible.  But stunning by neither stab nor a blow in the back of the neck will injure the medulla oblongata where these functions are centred. 116 2. Hauling: Animals bleed well when their head is hung down rather than when they are left on the killing floor.  The blood flows from all tissues out of the carcass.  This then increases the keeping quality of the meat. 3. Time interval between stunning and bleeding: Animals should be bled immediately after stunning. Delay in bleeding time result in the coagulation of blood. 117 Judging the efficiency of bleeding: The efficiency of bleeding is judged by: 1. Inspecting the blood vessels: In poorly bled carcass, the small blood vessels, particularly the inter-costal veins are distinctly seen, which are not visible in well-bled carcass. 2. Inspection of the heart: in poorly bled carcass, the left ventricle is full with blood. 3. Incising internal organs & the muscle: In poorly bled carcass, blood oozes out when incision is made into organs or muscles. 4. Observing the color of the carcass  In perfectly bled carcass  meat has red color & firm consistency  In poorly bled carcass  meat is darkish red & flabby. 118  Plant sanitation:  Efficient meat hygiene practice begins from the farm and maintained during transportation, in the abattoir and also in consumers home.  Cleaning and disinfection of livestock vehicles is important not only to achieve hygienic meat but also to reduce the risk of transfer and spread of contagious diseases of animals. A heavily contaminated hide or fleece will transfer considerable amount of contamination to the carcass unless excellent care is taken during slaughtering process. 119 Moreover, hygiene in the abattoir depends on many factors such as:  Area of plant site  Its construction and lay-out  Type of equipment used  Facilities for cleansing and disinfection, (washing of hands and regular sterilisation, etc). Ample amount of pressurised hot water and detergents. Food plants are cleaned for many reasons: -  To meet national legislation  To reduce the risk of litigation  To meet customer’s quality expectations  To prolong the shelf-life of the products  To avoid food poisoning or foreign body contamination  To ensure the safety of operatives and maintenance staff, etc 120 III. Equipment Used in Hygienic Slaughtering  These are materials which are used in and outside of the abattoir for production and provision of hygienic meat to the consumers  In general, all equipments & utensils (knives, hooks, bone cutter, tables, saws, overhead rail etc) that come in contact with meat & meat products should:  Be easily washed & disinfected.  Have smooth, impervious surface and free from pits & crevices  Be resistant to corrosion, non-toxic, & dose not transmits odour or taste.  Be capable of withstanding repeated exposure to normal cleaning and disinfections.  Plat forms, tables, chutes, rail and similar equipment shall have non- absorbent surfaces which is rustles & non-corrodible and can be easily cleaned. 121