Veterinary Public Health I.pdf

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JIMMA UNIVERSITY
COLLEGE of AGRICULTURE and VETERINARY MEDICINE
SCHOOL of VETERINARY MEDICINE
Microbiology and Veterinary Public Health Team
VETERINARY PUBLIC HEALTH I
MIVP 511
Credit Hr.: 3 (2+1)
Students: Veterinary Medicine students (Year IV)
Course Instructor: Mekonnen Addis (DVM, MSc, Asst. professor)
JIMMA, ETHIOPIA

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1. Introduction to veterinary public health: Duties and responsibilities of
Veterinary Public Health at different levels
Human health is inextricably linked to animal health and production. This link between human
and animal populations, and with the surrounding environment, is particularly close in
developing regions where animals provide transportation, draught power, fuel and clothing as
well as proteins (meat, eggs and milk). In both developing and industrialized countries, however,
this can lead to a serious risk to Public Health with severe economic consequences. A number of
communicable diseases (zoonoses) are transmitted from animals to humans. Any disease or
infection that is naturally transmissible from vertebrate animals to humans and vice-versa is
classified as zoonoses. Veterinary medicine has a long and distinguished history of contributing
to the maintenance and promotion of Public Health.
The animal itself, animal health and veterinary science are related to the physical, mental and
social well-being of humans and the contribution of Veterinary Public Health (VPH) in this field
is considered fundamental. Veterinary Public Health is a fundamental part of Public Health
whereby human health and well-being are the main objectives. Veterinary Public Health
comprises the application, efforts and knowledge of Veterinary science which contribute to
secure, promote and restore human health.
Veterinary Public Health is the field of veterinary medicine that is concerned with safeguarding
and improving the health of the human community as a whole by controlling diseases of animals
that are communicable to humans or which affect the human food chain to the detriment of the
health of the consumers. It comprises all the community efforts influencing and influenced by
the Veterinary medical arts and sciences applied to the prevention of diseases, protection of life,
and promotion of the well being and efficiency of man.
Veterinary Public Health is a component of Public Health activities devoted to the application of
professional Veterinary skills, knowledge and resources for the protection and improvement of
human health. According to the WHO definition of health the following definition of Veterinary
Public Health was suggested at a WHO meeting as "Veterinary Public Health is the contribution

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to the complete physical, mental, and social well-being of humans through an understanding and
application of veterinary medical science.
The field of Public Health concerns the management of human health at the community level.
This contrasts to other aspects of medicine where treatment is frequently focused on the
individual. Public Health often involves methods of disease prevention (e.g. vaccination,
sanitation, etc.). Veterinary Public Health concerns all areas of Public Health that can be
protected or improved by Veterinary Medicine. Veterinary Public Health could include almost
all aspects of Veterinary work from treating pets (as this helps people's mental & social well-
being) to farm animal veterinary work (as this helps secure food production).

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2. Contamination of food, food spoilage and food borne illnesses
What Is Food Hygiene?
Cleanliness
PLANT PREMISES PRODUCT PERSONNEL
3 HYGIENIC PRACTICES
1: PROTECTION to protect the food from contamination
2: PREVENTION to prevent food poisoning bacteria from multiplying
3: DESTRUCTION to destroy the food poisoning bacteria to a safe level
SAFE FOOD
Foodstuffs should not contain micro-organisms or their toxins in quantities that present an
unacceptable risk for human health. When food is infected or contaminated with germs or any

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disease causing bacteria or those which may spoil the food then it is called as contaminated food.
Contamination is the presence of something harmful or objectionable in food or drink, which
creates a risk of illness, injury or discomfort. Or, anything in or on the food that should not be
there. Food contamination is when something makes the food inedible or can cause illness when
consumed. If we eat infected or contaminated food the infectious bacteria may enter our
digestive system and cause diseases. They may also enter blood streams along with the absorbed
food if they are having that ability.
The most common causes of food contamination are:
¾ improper handling of food
¾ improper sterilization methods
¾ improper cooking or boiling
¾ improper storage conditions
There are three main ways in which food can become contaminated:
¾ Biological (ants, flies, plants, bacteria, parasites, viruses, etc.)
¾ Chemical (petrol, fertilizer, cleaning products, pesticides, additives, etc.)
¾ Physical (paperclips, stones, glass, metal like lead pipes, copper saucepans, tin cans etc.)
An illness caused by eating contaminated food (food poisoning) usually occurs 1 – 36 hours after
eating. Symptoms of food contamination range from mild to serious. Symptoms usually last
between 1 – 7 days. The most common symptoms include:
¾ Vomiting
¾ Fever
¾ Diarrhoea
¾ Nausea
¾ Stomach Cramp / Abdominal Pains

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The Path to an Outbreak of Food Poisoning
Harmful bacteria are the most common cause of food borne illness. Raw meat may become
contaminated during slaughter. Fruits and vegetables may become contaminated when they are
growing or when they are processed. But it can also happen in your kitchen if you leave food out
for more than 2 hours at room temperature. High-risk groups include children, the elderly,
immune suppressed and pregnant and new mothers. The treatment in most cases is increasing
your fluid intake. For more serious illness, you may need treatment at a hospital.
CONTAMINATION
SOURCE
VEHICLES
HIGH RISK FOOD
OUTBREAK OF FOOD POISONING
VEHICLES
• Hands
• Cloths
• Clothes
• Equipment
• Utensils
SOURCES
• Intestine man
• Intestine of animals
• Raw Foods
• Refuse
• Soil
CONTAMINATION
• Direct contamination
• Indirect contamination
• Cross contamination

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Food spoilage is the deterioration of food which makes it taste and smell bad (sour, rotten or
mouldy) and/or makes it a carrier of pathogenic micro-organisms. Food spoilage means the
original nutritional value, texture, flavour of the food are damaged, the food become harmful to
people and unsuitable to eat. The most important kinds of food spoilage are:
1. Microbiological spoilage: There are three types of microorganisms that cause food
spoilage namely yeasts, moulds and bacteria.
2. Autolytic spoilage: Caused by enzymes- from within cells (responsible for respiration).
™ Intrinsic (inherent) factors affecting microbial growth and enzyme action:
¾ pH
¾ Moisture content
¾ Water activity: in general, lower water activity inhibits microbial growth. water
activity is lowered by drying and addition of salt or sugar
• osmophilic microorganisms: prefer high osmotic pressure
• xerophilic microorganisms: prefer low water activity
¾ Oxidation-reduction potential
¾ Physical structure of the food: grinding and mixing increase surface area and distribute
microbes and promotes microbial growth.
¾ Available nutrients
¾ Presence of antimicrobial agents
™ Extrinsic (from outside) factors affecting microbial growth and enzyme action:
¾ Temperature: lower temperatures retard microbial growth.
¾ Relative humidity: higher levels promote microbial growth.
¾ Carbon dioxide or oxygen: oxygen promotes growth
¾ Types and numbers of microorganisms in the food
Types of spoilage in food
¾ Slime: Due to many bacteria they touch one another.
¾ Souring: When the micro-organisms produce acids.
¾ Discolouration; Due to microbiological growth.
¾ Gas: Bacteria often produce gas as a by-product.
¾ Odour: Rotten smells develop from the breakdown of bacteria.

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Food spoilage is more likely to
happen in foods which are: Way of prevention
¾ Moist: Keep food in well-ventilated places to stop build-up of moisture.
¾ Warm: Do not keep food at warm temperatures.
¾ Low in acid: Use vinegar an acetic acid to preserve food.
¾ Low in salt or sugar: Add salt or sugar.
¾ Damaged: Check food on delivery.
¾ Old: Rotate food using a first in-first out policy.
Foodborne illness also called foodborne disease is any illness resulting from the consumption of
contaminated food. There are three types of foodborne illness: food borne infection, food
intoxication and toxin-mediated infection.
Food borne infection is a disease that results from eating food containing living harmful micro-
organisms (germs). These kinds of germs colonize the intestinal lining and invade the body,
causing food borne illness symptoms.
Food borne intoxication is a disease that results from eating food contaminated with poisons or
toxins from bacteria, molds, or chemicals. These toxins are usually odorless, tasteless and
colorless, and they can cause disease even after the disease germs in the food have been killed.
Toxin-mediated infection is a disease that results from eating food containing live germs. These
kinds of germs would colonize the stomach or intestine, making toxin as they live and grow. The
toxin produced inside the body causes the food borne illness symptoms.
When a food poisoning outbreak occurs it undermines our confidence in the food safety system
and we are quick to react. Food safety is the utilization of various resources and strategies to
ensure that all types of foods are properly handled, prepared, preserved and stored so they are
safe for consumption in ways that prevent foodborne illness. Practicing this level of food
sanitation begins with the purchase or acquisition of different food items and ends with the
proper storage of leftovers for future use.
Food preservation is the processing of foods so that they can be stored longer. Man is dependent
on products of plant and animal origin for food. Because most of these products are readily
available only during certain seasons of the year and because fresh food spoils quickly, methods

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have been developed to preserve foods. Preserved foods can be eaten long after the fresh
products would normally have spoiled. With the growth of towns, the need to preserve foods
longer increased as some people could no longer grow their own vegetables nor keep animals.
Preservation must be seen as a way of storing excess foods that are abundantly available at
certain times of the year, so that they can be consumed in times when food is scarce.
Consumption of fresh foods is always preferable, however, as preservation usually decreases the
nutritional value. In other words, preserved foods are not as healthy as fresh foods. Food
preservation is the process of treating and handling food to stop or greatly slow down spoilage
(loss of quality, edibility or nutritive value) caused or accelerated by micro-organisms.
Preservation usually involves preventing the growth of bacteria, fungi, and other micro-
organisms, as well as retarding the oxidation of fats which cause rancidity. Preservation
processes include:
¾ Heating to kill or denature micro-organisms (e.g. boiling)
¾ Oxidation (e.g. use of sulphur dioxide)
¾ Toxic inhibition (e.g. smoking, use of carbon dioxide, vinegar, alcohol etc)
¾ Dehydration (drying)
¾ Osmotic inhibition ( e.g. sugar, salt)
¾ Low temperature inactivation (e.g. freezing)
Food borne illness could be prevented by applying the following basic rules:
¾ Practice good personal hygiene
¾ Cook foods adequately
¾ Avoid cross-contamination
¾ Keep foods at safe temperatures
¾ Avoid foods and water from unsafe sources
¾ Application of HACCP
Hazard Analysis Critical Control Point (HACCP) is a systematic preventive approach to food
safety that addresses physical, chemical, and biological hazards as a means of prevention rather
than finished product inspection. HACCP is used in the food industry to identify potential food
safety hazards, so that key actions, known as Critical Control Points (CCPs) can be taken to

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reduce or eliminate the risk of the hazards being realized. The system is used at all stages of food
production and preparation processes including packaging, distribution, etc. The function of
HACCP is based on seven principles
1. Conduct a hazard analysis: Plans determine the food safety hazards and identify the
preventive measures the plan can apply to control these hazards. A food safety hazard
is any biological, chemical, or physical property that may cause a food to be unsafe
for human consumption.
2. Identify critical control points: Critical Control Point (CCP) is a point, step, or
procedure in a food manufacturing process at which control can be applied and, as a
result, a food safety hazard can be prevented, eliminated, or reduced to an acceptable
level.
3. Establish critical limits for each critical control point: A critical limit is the
maximum or minimum value to which a physical, biological, or chemical hazard must
be controlled at a critical control point to prevent, eliminate, or reduce to an
acceptable level.
4. Establish critical control point monitoring requirements: Monitoring activities are
necessary to ensure that the process is under control at each critical control point. In
the United States, the FSIS is requiring that each monitoring procedure and its
frequency be listed in the HACCP plan.
5. Establish corrective actions: These are actions to be taken when monitoring indicates
a deviation from an established critical limit. The final rule requires a plant's HACCP
plan to identify the corrective actions to be taken if a critical limit is not met.
Corrective actions are intended to ensure that no product injurious to health or
otherwise adulterated as a result of the deviation enters commerce.
6. Establish record keeping procedures: The HACCP regulation requires that all plants
maintain certain documents, including its hazard analysis and written HACCP plan,
and records documenting the monitoring of critical control points, critical limits,
verification activities, and the handling of processing deviations.
7. Verification procedures: Establish procedures for ensuring the HACCP system is
working as intended.

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3. MEAT HYGIENE
3.1. Meat and sources of meat
Meat figures prominently in what might be called the two most important transitions in human
evolution: the development of complex cultures and sophisticated technologies. Just as hunting
had a major influence in shaping human nature, the combination of agriculture and domestication
laid the foundation for high densities of humans and the subsequent elaboration of culture. By
making the human food supply more independent of the seasons and of short-term extremes in
weather, agriculture and domestication set the stage for major changes in human life.
Domestication made it possible for humans to be the only mammals that could have continued
access to the almost perfect mammal food of infancy, milk; it also frequently made meat a less
scarce resource. Just as hunting helped encourage the upright posture, the development of hand
skills and major cognitive developments, agriculture and domestication of animals freed humans
to develop a wide range of impressive technologies.
Most people in the Third World eat relatively little meat, mostly because of its cost and rarity.
They would eat more if they could. On the other hand, in some religious groups, such as
orthodox Hindus, all meat is prohibited. And within some meat-eating cultures, individuals or
groups of individuals reject meat as food. This type of vegetarianism has a history that goes back
at least to ancient Greece. Historically, this type of elective vegetarianism has been motivated
primarily by moral or religious concerns, often having to do with negative reactions to the killing
of animals or the psychological effects of consuming animals.
Within many developed cultures, vegetarians invoke, in addition to moral, religious, or aesthetic
concerns, worries about the long-term health effects of eating meat. Some vegetarians can be
classified as either health or moral vegetarians, though most long-time vegetarians express a little
of both motivations. Interestingly, moral vegetarians are more likely to find meat disgusting than
are health vegetarians. When meat becomes disgusting, it is much easier to avoid it.

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Since meat is a perishable commodity and its poor handling daily exacts a large public health and
economic toll, there can be no room for complacency over problems of meat hygiene, either in
under developed or in advanced countries. Nations can ill afford the disruption of activities in the
home and community caused by meat borne diseases, not to mention the formidable economic
wastage and nutritional losses to the population of two fundamental needs-protein and fat.
The primary purpose of good meat hygiene practice is to prevent transmission of disease to man
and to provide a safe, wholesome product for his consumption. Thus, meat hygiene is essentially
a public health function.The secondary aims, lying rather in the economic sphere, include
reduction of losses in meat and its by-products and prevention of disease transmission to other
domestic animals. These are matters of concern chiefly to trade, food and agricultural authorities.
In many countries the division of responsibility for meat hygiene supervision among government
departments is not a clear-cut. Although no standard or uniform pattern exists, it is readily
apparent that the effective operation of a meat hygiene service must be based on close working
relationship between the triad of veterinary, medical and sanitary-engineering disciplines. Since
meat hygiene is essentially a public health function and the veterinarian is usually best trained
and equipped to deal with diseases transmissible through meat, most health authorities have
found it advantageous to include a veterinary public-health branch in their services, to cover
meat hygiene needs as well as other responsibilities such as zoonoses .
The speed with which meat spoils depends on hygiene conditions during slaughtering, storage
temperature, acidity of the meat and the structure of the muscular tissue. The firm muscular
tissue of beef, for example, spoils less quickly than liver. After slaughtering, one should preserve
the meat as quickly as possible. For the production of hygienic meat:
¾ Ensure good personal hygiene: Wash hands thoroughly with hot water and soap after
using the toilet, handling cuts and doing dirty work, and before touching meat.
¾ Change towels and wash clothes regularly.
¾ Ensure proper hygiene when animals are slaughtered.
¾ Keep meat on containers which can be and are washed well (stainless steel).
¾ Keep the places where meats are stored clean.

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¾ Wash all tools used for meat regularly.
¾ Cover all meats well.
¾ Keep all pests away from the places where meats are kept.
¾ Never store leftovers at room temperature.
¾ Use clean water. If necessary, boil the water before use.
Meat is the flesh of animals and fowls that is used as food. Most often, this means the skeletal
muscles and associated fat, but it may also describe other edible tissues organs such as the liver,
brain, tongue, bone marrow, kidneys, lungs and heart. Worldwide, pork is the most widely
consumed meat; beef is second. Mutton and lamb, poultry, goat, venison (deer meat) and rabbit
are other common meats. The U.S. produces and consumes about a third of the world's meat,
while much of the world's population eats little if any meat, though it is generally prized.
Meat consumption is based largely on availability, price and tradition. Meat production is a very
complex operation depending not only on demand (which is usually based on price and income)
but on many social and economic influences such as official policy, price support mechanisms
and interrelations such as the interaction between beef and milk production, the availability of
animal feedstuffs and competition for food between man and animals.
For most human beings, meat is a highly desired food, but it is more of a treat than a staple.
Meat, whether obtained from hunted or domesticated animals, is more expensive than staple
carbohydrate-rich foods because of the investment in land and labor required in producing it.
This reality is often the justification for reserving meat, or the best parts of it, for those with
higher status. In a majority of the world's cultures, this elite is men and, sometimes, the women
and children attached to them. Furthermore, when there is enough meat to go around, the
preferred parts, usually the muscle, go to these same individuals. It is this special status of meat
that makes it of particular interest in human culture, psychology and cuisine.
Meat is digested slowly, largely because of the presence of fats. Although meat is digested more
slowly than starches or sugars, it has a high food value, with more than 95% of the protein and
fat being digested; the fattier meats take somewhat longer time to digest than the leaner ones.

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The production of animals for meat can be integrated into the overall food system without
competing directly with crops for human food. It enables utilization of land that is difficult to
cultivate and supplies valuable by-products as well as improving the fertility of the soil. Human
requirements for protein have been thoroughly investigated over the years and are currently
estimated to be 55 g per day for adult man and 45 g for woman (a higher requirement in various
disease states and conditions of stress).
The relative importance of various sources of meat in the diet varies from region to region
depending on availability and local custom. Those that are rejected for various reasons in one
culture are fully accepted in others. There are three broad categories of meat depending on their
sources. The flesh of cattle, sheep, goat, pig, camel, horse, buffalo and dog is termed red meat,
while the flesh of poultry (chicken, turkey, duck and pigeon) is termed white meat. In addition to
the common domestic animals a wide variety of wild animals are eaten - possum, deer, rabbit,
moose, bear, seals, walruses and rodents. Meat from non-domesticated animals is termed as
game meat.
3.2. Nutritional composition and quality of meat
Meat, and other animal foods such as milk, can make a valuable contribution to the diets in
developing countries. It has less nutritional importance in industrialized countries where a wide
variety of foods of all kinds is available. Many diets in developing countries are based on cereals
or root crops and are relatively bulky, especially where fats are in short supply, and this can limit
the total energy intake. This is especially true of infants after weaning and young children. The
importance of meat in the diet is as a concentrated source of protein which is not only of high
biological value but its amino acid composition complements that of cereal and other vegetable
proteins. It is also a good source of iron and zinc and several B vitamins, and liver is a very rich
source of vitamin A.
The animal carcass consists of muscle, connective tissue, fat and bone and some 75% water in
proportions depending on species, breed, size, age, etc. The chief constituents of meat are water,
protein and fat. Meat is valued as a complete- protein food containing all of the essential amino

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acids necessary for the human body. Meat is also a good source of niacin, riboflavin, vitamin B6,
vitamin B12, vitamin K, phosphorus, iron, zinc and selenium. By providing such nutrients meat
consumption can alleviate common nutritional deficiencies.
The protein of typical mammalian muscle after rigor mortis but before post-mortem degradative
changes contains about 19% protein: 11.5% is structural protein - actin and myosin
(myofibrillar), 5.5% soluble sarcoplasmic protein in the muscle juice, 2% connective tissue
(collagen and elastin) encasing the structural protein and about 2.5% fat dispersed among the
protein fibres. Myoglobin is present in relatively large quantities in heart muscle because of
heavy oxygen demand: (the highest amount of myoglobin in mammals is found in the whale to
permit prolonged submersion under water). Immediately after rigor mortis there is almost 2.5%
carbohydrates present - lactic acid and glucose.
Lipids (fats) are found at three sites in the body.
1. The largest amount by fat is in the storage deposits under the skin and around the organs.
This constitutes the obvious, visible fat in a piece of meat and can be as much as 40-50%
of the total weight in fatty meat. This adipose tissue is composed largely of triglycerides
contained in proteinaceous cells with relative little water. Clearly this visible fat can be
trimmed off the meat during processing, before cooking or at the table - a growing
practice in the western world.
2. Small streaks of fat are visible between the bundles of muscle fibres, intermuscular fat,
i.e. in the lean part of the meat; this is known as "marbling" and can amount to 4-8% of
the weight of lean meat.
3. There are small amounts of fat within the muscle structure - intra muscular or structural
fats - in amounts varying with the tissue. This can be 1-3% of the wet weight of muscle
and 5-7% of the weight of the liver.
The comparative toughness of meat depends on the character of the muscle walls and connective
tissue, the part of the animal, from which the meat is taken, and the age and condition of the
animal. Ripening meat, i.e., hanging it for a time at a temperature just above freezing (or, in a
more recently developed technique, at a high temperature) permits enzyme action and the
formation of lactic acid, which tenderizes it. Good meat may be recognized by a uniform color; a

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firm, elastic texture; being barely moist to the touch; and having a scarcely perceptible, clean
odour. The choicer cuts should be of fine texture and well marbled with fat. Cooking meat not
only softens tissues, kills parasites and microorganisms, and coagulates blood and albumen, but
makes the meat more palatable by developing its flavors or introducing new ones by means of
seasonings and sauces. Meat quality can be defined with the following parameters:
¾ PH - During post-mortem changes in muscles of slaughtered animals the PH falls from
around 7.0 - 7.2 in the muscle of living animals to 5.5 – 5.8. This final value is called
ultimate PH (PHU) and its values are reached at different post mortem times depending
on species, muscle type and stress during the pre-slaughter period. The reason for the PH
fall is the formation of lactic acid from glycogen in the anaerobic glycolysis.
¾ Colour - Colour is a very important quality characteristic of the meat. Consumers related
meat colour to the sensory properties of a product or to freshness. Factors influencing
meat colour are:
• Pigment content (myoglobin or haemoglobin)
• Ante-mortem and post-mortem conditions
• Form and type of storage
¾ Water holding capacity - is the ability of the meat to retain its water during cutting,
heating and pressing. Drip loss: is the amount of exudates in the meat surface.
¾ Texture - Texture measures the tenderness of meat.
¾ Intramascular fat and fatty acid composition - Intramuscular fat and fatty acid
composition contributes to the caloric content of meat but also have an effect on the
texture and flavor of the meat. Both components (quantity of fat and its quality) affect
consumers’ health
There are two major aspects of meat quality, nutritional quality which is objective and "eating"
quality as perceived by the consumer - flavour, juiciness, tenderness and colour - which is highly
subjective. There are considerable differences between the preferences of individuals including
preferences for different cuts of meat, lean or fatty, muscle or organ meats, methods of cooking,
etc. In the industrialized countries the demand for what is perceived as eating quality and also the
demand for particular qualities for a range of products from the meat processing industry dictate

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the breed, feed and management of the animals with intensive rearing and specially formulated
dietary supplements and a tendency to slaughter earlier. On the other hand the demand in most
developing regions of the world is for more animal products of almost any kind. The animals live
under variable conditions often of rough grazing and grow more slowly, yielding older animals
for slaughter; when animals are primarily used for draught they are very old at the time of
slaughter. Old animals yield meat that is less juicy and of a quality that differs considerably from
that demanded in the industrialized countries.
The post-mortem changes that take place in muscle have a marked effect on the quality of the
meat. After slaughter the glycogen in the muscle is converted into lactic acid causing a fall in pH
from an initial value of pH 7.0 - 7.2 to about 5.5 - 5.8 at rigor mortis. If animals are stressed
immediately prior to slaughter as when they are roughly handled or fight one another the muscle
glycogen is released into the blood stream and, after slaughter, is rapidly broken down to lactic
acid while the carcass is still warm. This high level of acidity causes a partial breakdown of
muscle structure which results in pale, soft and exudative meat (termed PSE) - a condition
mostly occurring in pigs.
Long-term stress before slaughter or starvation uses up the glycogen so that less lactic acid is
formed after slaughter resulting in an abnormal muscle condition in which it remains dark
purplish-red on exposure to air instead of a bright red colour. This is termed dark, firm and dry
(DFD) in the case of pigs and "dark cutting" in beef. The condition is rarer in lambs. Such meat
and products made with it have a pH above 6.0 and spoil quickly since the low acidity favours
rapid bacterial growth.
After slaughter as the glycogen in the tissues is exhausted rigor mortis sets in and the whole
carcass become stiff. This is due to the contraction of the muscle fibres when the actin filaments
of the muscle fibres slide inwards between the myosin filaments so shortening the myofibrils. If
the meat is cooked when the muscles are still in rigor it is extremely tough. This condition is
prevented by "aging" or "ripening" after slaughter which is achieved by storing the meat until the
muscles gradually recovers their extensibility and become more tender through partial enzymatic
breakdown of the muscles fibres. At this stage rigor mortis is said to be resolved. Rigor mortis

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affects first the muscles that have been most active and best nourished prior to death. It
commences at the head and neck extending back wards to involve the body and the limbs. The
heart is affected very easily and it appears usually within an hour of slaughter. Rigor mortis
reaches its greatest intensity in the left ventricle and this cavity is therefore usually free of blood
in post mortem examination although some blood may remain in the right ventricle. In a
physiologically normal animal rigor mortis in skeletal muscles does not appear before 9-12 hours
after slaughter. Maximum rigidity attains at 20-24 hours and then gradually declines.
Rigor is completed in cattle after 12-24 hours and is resolved by periods that depend on the
temperature:- 10-13 days at 0°C, 4-5 days at 10°C, 30-40 hours at 20°C and 10-11 hours at 30°C
The process is twice as fast in pork as beef or lamb: it is faster in young animals and slower in
"red muscles. If lamb, and to a lesser extent beef, are chilled too rapidly after slaughter the
muscles may undergo extreme contraction or "cold shortening" which results in very tough meat
when cooked. Pork is almost unaffected in this way. Cold shortening does not take place when
the carcass is cooled more slowly - the temperature must not fall below 10°C before the onset of
the rigor. To achieve this, the carcass should be kept at ambient temperature for some hours to
accelerate rigor and then rapidly chilled or frozen - a process called "conditioning".
Old animals, especially old draught animals, have a high content of tough connective tissue in
the muscle and prolonged cooking at a low temperature is needed to soften the meat by
hydrolysis of the connective tissue - a fact not always known to consumers. So it is clear that in
many areas conditions militate against good quality meat long transport of animals and poor
lairage facilities prior to slaughter reduce the glycogen in the muscles, poor hygiene, high
ambient temperature and lack of refrigeration during and after slaughter lead to heavy
contamination and growth of microorganisms and considerable losses from spoilage together
with dangers of food poisoning. All this can be aggravated by inadequate care of the meat during
transport and in the market.

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3.3. Differentiation of meat of different food animals
The differentiation of muscle and fat of animals is of great importance in connection with
possible substitution and/or adulterations malpractice. There is little difficulty in differentiating
the flesh and fat of animals in carcass form. The characteristics of meat and fat of food animals is
as follows:
1. Beef:
• Young bulls: the flesh is light red and attractive but the muscle appears darker in
latter life. It shows little intramuscular fat.
• Bullock flesh: light red in colour with well marked marbling. In bullock and
young bulls the fat is white or whitish yellow and firm. In older cows the fat tends
to be yellow
• Veal: these are few older dairy calves having pale and watery flesh. There is gely
like fat consistency however in the milk fed calves the meat becomes firmer and
white.
2. Mutton: it is light and dark red in colour with fine and firm fibers. Muscle is not
intermixed with fat. The fat is firm and white.
3. Goat: goat flesh resembles that of mutton however the kidney fat is always abundant. In
goat no fat between the muscles.
4. Pork: of all food animals pork is the least firm. The colour varies from whitish gray to red
in young pigs and to a strong red colour in boars and sows particularly in the muscles of
the back. A characteristic of pig flesh is a marked deposition of fat which is white, soft
and greasy in consistency. Pork is nearly white when cooked where as in other food
animals the meat becomes darker on cooking.
5. Horse: horse flesh is dark red and even bluish after cutting. Connective tissue fascia is
more strongly developed than any other food animals as a result of muscular exercise.
The fat may be yellow and soft. Characteristically horse flesh is not marbling.

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There is little difficulty in differentiating the flesh of various animals when it is in carcass form.
However recognition in mince/ sausage depends up on a number of biological and chemical
sources. The most common techniques use in species identification of the flesh includes;
1. Agar gel immunodiffusion test (AGID)
2. Enzyme linked immunosorbent assay (ELISA)
3. Immunoelectroforesis
4. Gas-liquid chromatography
Horse and ox carcass differentiation
Carcasses of horse and ox may be differentiated by the following details:
1. In the horse, the unusual length of the side is noticeable together with the great muscular
development of the hind quarter.
2. The thoracic cavity is longer in the horse; this animal possesses 18 pairs of ribs, where as
the ox has 13 pairs.
3. The ribs in the horse are narrower but more markedly curved.
4. The superior spinous processes of the first six dorsal vertebrae are more markedly
developed in the horse and are less inclined posteriorly.
5. In the forequarter the ulna of the horse extends only half the length of the radius; in the
ox it extends and articulates with the carpus.
6. In the hindquarter, the femur of the ox possesses no third trochanter; the fibula is only a
small pointed projection, but in the horse it extends two-third the length of the tibia.
7. In the horse the last three lumbar transverse processes articulate with each other, the sixth
articulates in similar manner with the sacrum. They do not articulate in the ox.
8. The horse carcass shows considerable development of soft, yellow fat beneath the
peritoneum. In the ox the kidney fat is always firmer, whiter and more abundant than in
the horse.
9. Horse flesh is dark bluish-red, beef lacking the bluish ting. Horse meat has a pronounced
sweet taste and well-defined muscle fibers.

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3.4. Qualitative changes in meat
Immediately after slaughter changes occur in the muscle of an animal. The changes in meat can
be retarded by method of handling and storage. They are brought about by microorganisms,
enzymes, chemical and physical means which alter the structure and chemical composition of the
meat. Muscle in the living animal is pliant, soft, gel-like, yet somewhat viscous. After slaughter
the muscles pass from this state into a stiff or rigid one known as rigor mortis, or muscle rigor.
After some time the muscles again become pliant. This stage is known as the passing of rigor.
With longer storage enzymes and chemical means bring about more extensive changes which
produce ripened meat. With bacterial action and still more extensive changes putrefaction occurs.
The passage from one stage to another is gradual with no definite dividing zone and is
accelerated at higher temperatures and retarded at lower ones. Meat undergoes certain superficial
changes as a result of storage, chief of which are:
¾ Shrinkage: occurs as a result of evaporation of water from the meat surface.
¾ Loss of weight: 1.5 – 2% of the weight of the carcass is lost in 24 hours.
¾ Sweating: denotes the condensation of water vapour on meat brought from a cold store
into ordinary room temperature. The condensation occurs because the refrigerated carcass
lowers the temperature of the air to below the dew point.
¾ Loss of bloom: this is the shiny surface of the meat. Bloom is defined as the colour and
general appearance of a carcass surface when viewed through the semitransparent layer
of connective tissue, muscle and fat which form the carcass surface. This property is lost
due to dehydration.
¾ Weeping or dripping: denotes the presence of watery, blood stained fluid which escapes
from the frozen meat when thawed. It is the result of rupture of blood vessels.
¾ Reduced protein solubility: at -2 0
C meat globulin and albumin become insoluble. They
don’t regain their solubility after thawing.
¾ Rancidity: unpleasant flavor of meat due to oxidation of carcass fat.

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4. Transportation of food animals
Food animals are transported in to the abattoir by hoof, car, rail, ship and airplane.
Transportation of food animals is of great concern due to the following reasons
1. It can cause severe stress in animals, if due welfare conditions are not provided.
2. Stressful transportation may affect adversely meat quality.
3. There is the risk of spread of infectious diseases over large distances.
4. Animal health can be impaired by various pre-transport and transport conditions.
These conditions may cause injury, reduce performance, cause increased morbidity and mortality
rate and consequently substantial economic losses due to loss of live weight and poor meat
quality. Long-term transportation of livestock by road across various ecological and climatic
zones imposes many stressors upon the transported animals. The stressors include: rough
handling during loading and unloading, deprivation of food and water, poor vehicle design, poor
road conditions, extremes of temperature and humidity, overcrowding, mixing different species
and age groups, high air velocity, noise, motion, vibration and length of the journey. The stress
reactions overtax the body systems and cause reduction in fitness of the animal by inducing
dysfunctions of the pituitary, adrenal and thyroid glands. Transportation also induces changes in
the blood composition as well as other bodily parameters like heart rate, electrolytes, hormones,
metabolites, enzymes and live weight, meat and skin quality. The effects varied with the duration
of transportation, age and breed of the animal, previous experience and the nature of vehicle and
the roughness of the road.
In order to reduce the adverse effects on food animals and the economic losses encountered
during animal transportation the following cares should be considered:
¾ Avoid shipping during extreme of weather
¾ Proper feeding prior to loading
¾ Avoid rough handling and beating
¾ Avoid excessive and loud noise as it may be stressful to livestock
¾ Avoid mixing strange animals together
¾ Avoid mixing different species and age groups of animals

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¾ Avoid overcrowding as it encourages aggressiveness and bruises
¾ Follow the recommended maximum journey time of 19 hours that must include a one-
hour break for food, water and rest after each 8-9 hours since long haul transportation
may expose animals to significant environmental changes and/or increase the length of
time they are exposed to risk factors such as heat, cold, jostling and piling
¾ Vehicles and containers used to transport livestock should be cleaned, sanitized and
equipped with suitable fresh bedding material before each new load
¾ Maintain sufficient floor space to allow for adequate ventilation and avoid overcrowding
as overcrowding can cause bruising or other injuries
¾ Handle livestock safely, humanely and in a way that minimizes stress and injury
¾ Maintain adequate bedding, ventilation and light for the livestock at all times while the
animals are on a vehicle
¾ Each animal should be able to assume its natural position for transport without coming
into contact with the roof or upper deck of the vehicle
¾ All normal, healthy animals are alert and inquisitive. every change or disturbance in
surroundings, such as noises, breezes, movement and flashes of light, should be avoided
¾ Animals should not be rushed during loading and unloading
¾ Separate livestock which are dead-on-arrival, dying, diseased or injured

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5. Pre slaughter care of slaughter animals
Husbandry of food animals for human consumption could be accepted provided that the
production methods are in compliance with best practices for humane and ethical food
production. The humane and ethical husbandry practices are those that are responsive to the five
freedoms of animal welfare:
1. Freedom from Hunger and Thirst – by ready access to diet and fresh water to maintain
full health and vigour.
2. Freedom from Discomfort – by providing an appropriate environment including shelter
and a comfortable resting area.
3. Freedom from Pain, Injury or Disease – by prevention or rapid diagnosis and treatment.
4. Freedom to Express Normal Behaviour – by providing sufficient space, proper facilities
and company of the animal’s own kind.
5. Freedom from Fear and Distress – by ensuring conditions and treatment which avoid
mental suffering.
Animal welfare issue opposes to any method of slaughter which does not quickly render the
animal totally unconscious prior to being killed. Animal welfare issue recognizes that
identification and processing of farm animals often involves castration, dehorning, debeaking,
branding, tail docking, ear tagging, nose rings and tooth pulling among other invasive
procedures. Animal welfare issue believes pharmaceuticals should be used only for the treatment
of illness, disease or injury and opposes:
¾ antibiotics in feed in sub-therapeutic amounts
¾ growth enhancing hormones
¾ any inappropriate use of pharmaceuticals for food animals
The following factors should be considered for animals that are going to be slaughtered for
human consumption:
1. The fatigued and exited animals must be given rest before slaughter. A period of 12 to 24
hours with a maximum of 36 hours detention and rest in a lairage is essential. The

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duration of resting period depends on species of the animals, age, sex, condition, time of
the year, length of the journey and method of transportation.
2. Animals should receive ample potable drinking water during their detention in the
lairage. This helps to lower the bacterial load in the intestine and facilitates removal of
the hide during dressing of the carcass.
3. Withholding food from cattle for a period of 6 hours prior to slaughter minimizes the
migration of bacteria from the intestinal tract during digestion. Moreover fastened
animals bleed better, carcass is easier to dress and has a brighter appearance.
4. Regular cleaning and disinfection of a lairage to lower the risk of cross contamination.
5. Animals should be kept in well ventilated, dry and hygienic lairage.
6. The animals which are badly soiled, dirty and doggy should be properly washed.
7. The lairage should be 10m away from slaughter house. Lairage areas for each specific
abattoir should therefore be assessed relative to expected throughput. Pen areas required
for each species are for cattle 1.7m2
/head, for pigs/sheep 0.35m2
/head and for goats
0.25m2
/head.
8. Sufficient space should be provided to each animal.
9. Aggressive animals should be isolated in lairage.
10. Females in oestrus should not be kept with males in lairage.
11. Design of lairage pen should allow free movement of stock.
12. Stock should be kept in their original social groups as far as possible and there should be
no mixing within the last 24-48 hours before slaughter.
13. Avoid pre-slaughter stress to prevent dark, firm and dry meat.

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6. Abattoir
An abattoir also called a slaughterhouse is a facility/building/place where animals are killed and
processed into meat foods. The animals most commonly slaughtered for food are cattle (for beef
and veal), sheep (for lamb and mutton), pigs (for pork), horses (for horsemeat), goats (for
chevon), and fowl, largely chickens, turkeys, and ducks, for poultry meat. The number and site
of abattoirs in one country should be geared closely to the demands of livestock production, due
attention being paid to transport (journey to be as short as possible) and the need for casualty
slaughter.
The objectives of construction of an abattoir or a slaughter house are to:
¾ Produce wholesome and sound meat
¾ Protect the public from zoonotic diseases
¾ Prevent the out spread of epizootics
¾ Protect the environment from pollution
¾ Utilize economically slaughter house by-products
The planning of the construction of abattoirs or slaughter houses should be materialized in
consultation with the following:
¾ Municipality
¾ Federal or regional veterinary officer
¾ Health authority
¾ Architects
¾ Environmental protection agency
¾ Contractors
Planning begins with the selection of the appropriate site. In practice compromises will
inevitably be needed when selecting a site. In selecting a suitable location and site for the
construction of abattoirs or slaughter houses the following points need to be considered.

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• Distance from Urban Development: The abattoir should not be located close to dwellings,
schools, churches and other public or commercial buildings due to possible nuisance from
noise, smell, congestion etc. Likely future commercial and residential developments should
also be taken into account.
• Accessibility: The site should be accessible from a permanent road to allow ready transport of
both livestock and meat.
• Water Supply: An adequate water supply is essential. While mains water is to be preferred,
well or bore water will also be suitable provided the water meets drinking water standards.
Quantities of 1000 liters per large animal, 100 liters per small ruminant and 450 liters per pig
are desirable. In some areas it may be necessary to rely on rainwater collected from the
abattoir roofs. (Under these circumstances water usage will need to be much lower than given
above and ‘dry’ slaughter systems should be adopted. The use of rainwater should however be
avoided if at all possible due to the limited supply available from this source.
• Electricity: Connection to a public electricity supply is desirable especially if chilling of
carcasses is being considered or on site water pumping is required.
• Effluent Disposal: The effluent disposal schemes should be designed based on subsurface
irrigation and soakage. Such systems are generally lower in cost and easier to operate than
other alternatives. The site should therefore be free draining and not subject to water logging
or flooding. Land used for subsurface irrigation need not necessarily be within the abattoir
boundary although control over cropping operations above subsurface irrigation trenches
would be essential.
• Solid Waste Disposal: There should be sufficient space available to bury inedible wastes and
condemned animals and provide for compost stacks, hide drying frames etc.
In general the area where abattoirs or slaughter houses are to be constructed should have the
following facilities: The compound should be of stable ground, well drained, free from flooding
and wide enough to enable future expansion, there must be uninterrupted supply of electricity
and potable water, the sewage system should be located far away from the plant to avoid
contamination, contiguity with uncongested road and rail systems it should have easy access to
the main road, proximity to supply of varied labour, freedom from pollution from other
industries’ odour, dust, smoke, ash, etc., ability to separate clean and dirty areas and access, good

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availability of stock nearby and the plant must be adequately separated from residential,
industrial, future city expansion areas, churches, mosques, public offices, latrines and any other
waste disposal system to avoid complaints about noise and smell and carcass contamination
An ideal abattoir should have the following basic facilities:
¾ Slaughter premises large enough for work to be carried out satisfactorily
¾ A room for emptying and cleansing stomachs and intestines
¾ Room for dressing guts and tripe
¾ Separate room for the storage of fat, hides and skins, horns and hooves
¾ A separate room for preparing and cleaning offal
¾ Lockable premises reserved respectively for the accommodation of sick or suspect
animals, the slaughter of such animals, the storage of detained meat and seized meat
¾ Sufficiently large chilling or refrigerating rooms
¾ An adequately equipped veterinary officer's room, preferably including a laboratory
¾ Changing rooms, wash basins, showers and flush lavatories which do not open directly
on to the work rooms
¾ Means of controlling access to and exit from the plant
¾ An adequate separation between the clean and the contaminated parts of the building
¾ animal by-products must be kept securely within the container (so that birds and vermin
cannot have access to them and they are protected from the elements)
¾ The plant must be constructed in such a way that it is easy to clean and disinfect
¾ Floors must be laid down in such a way as to facilitate the draining of liquids
¾ The plant must have adequate lavatories, changing rooms and washbasins staff
¾ Appropriate arrangements for protection against dogs, insects, rodents and bird
¾ An adequate of potable water
¾ A waste-water disposal system which meets hygiene requirements
¾ Where it is necessary for the purpose of achieving the objectives of this Regulation,
plants must have suitable temperature-controlled storage facilities of sufficient capacity
for maintaining animal by-products at appropriate temperatures and designed to allow
the monitoring and recording of those temperatures

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¾ The plant must have adequate facilities for cleaning and disinfecting the containers or
receptacles in which animal by-products are received and in which they are transported
¾ Adequate facilities provided for the disinfecting of vehicle wheels
¾ Waste water must be treated to ensure that no pathogens remain
An abattoir should entail the following different components:
1. Lairage: accommodation for animals awaiting slaughter. It comprises of a ramp, holding
pens, V-race and weigh bridge.
2. Slaughter hall: area where all slaughtering operation is carried out. It should entail
stunning, bleeding, skinning, evisceration, carcass splitting and post-mortem inspection
areas.
3. Emergency slaughter hall: is a mini abattoir built adjacent to the main slaughter hall
situated near to the detention room and is in direct communication with the by product
processing unit. Only animals suffering from acute pain or suffering from injury or
approaching death are slaughtered in the premise.
4. Chilling room: rooms where split carcasses are kept at -2 to 4 0
c until meat is exported.
Chilling rooms:
¾ Be fitted with thermometers
¾ The carcass should be cooled before chilling
¾ Hang carcasses at least 50 cm apart to facilitate ventilation
¾ Doors should not be opened frequently
5. Detained meat room: where suspect carcasses are detained and thoroughly inspected.
6. Condemned meat room: room in which condemned organs and carcasses are detained and
kept until further processing.
7. Gut and tripe room: a room where the gastrointestinal tracts of animals are emptied
cleaned and washed. It is usually provided with a macerator to remove GIT contents.
8. Cutting rooms: room where carcass is reduced to less than a quarter or deboned
9. Dispatch area:
10. Veterinary office: should be adequately facilitated with hand washing facilities, showers
and cup boards where records are kept.

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11. Veterinary laboratory: should be equipped to undertake bacteriological, parasitological
and histological examinations.
12. Personnel facilities: cloak rooms, toilets with hand washing facilities, urinals, showers,
laundry, cafeteria and clinic should be made available.
13. Hide and skin drying shade
14. By product processing unit
15. Vehicle washing and disinfection facility
16. Administrative building
The type and size of abattoir to be constructed is influenced by:
¾ Maximum number of animals slaughtered daily
¾ Intention to process meat and meat by products
¾ Frequency of meat supply
¾ Number of buildings and the plan to expand the enterprise
Slaughter slabs: These are roofed, walled or not walled concrete floorsto which 1 or 2 rings are
fixed to the floor to restrain and slaughter the animal.

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7. Slaughtering operations, Stunning, Bleeding and Slaughterhouse by-products
7.1. Slaughtering operations
Slaughter is an act of killing the animals for purpose of food. Slaughter means the process of
bleeding to induce death, usually by severing major blood vessels supplying oxygenated blood to
the brain. At the time of slaughter, animals should be healthy and physiologically normal.
Slaughter animals should be adequately rested. They should be rested, preferably overnight,
particularly if they have travelled for some times over long distances. Animals should be watered
during holding and can be fed, if required. The holding period allows for injured and victimized
animals to be identified and for sick animals to be quarantined.
There are two broad divisions of slaughter, ritual slaughter and humane method of slaughter.
Ritual method of slaughter is an act of killing of animal without stunning of the animal prior to
slaughter. It is in accordance with the ritual requirements of any religious faith that prescribes a
method of slaughter where the animal suffers loss of consciousness by anemia of the brain
caused by the simultaneous and instantaneous severance of the carotid arteries with a sharp
instrument. Animals are sensible to pain prior to shackling, hoisting, casting or cutting. In ritual
slaughter, the animal’s throat is cut from side to side with a sharp knife, deeply enough for the
major arteries and veins to be severed. There are three ritual methods of slaughter:
1. Jewish method (Shechita): meat declared fit for consumption by Jewish is called Kosher;
meat unfit for consumption by Jewish because it was not slaughtered properly is called
Nevailah.
2. Halal method/Muslim method: meat declared fit for the consumption by Muslims is called
Halal; unfit meat for the food of Muslims is called Haram.
3. Hindu method/ Jhatka method: caused by decapitation by one stroke of a sharp sword.
Humane method of slaughter is a method in which an animal is experienced minimum pain or
suffering during the act of slaughtering by stunning. The use of humane methods in the slaughter
and handling of livestock prevents needless suffering, results in safer working conditions for
packing house workers, improves the quality of meat products and decreases a significant
financial loss to meat packers. For all operations approved for the slaughter or killing of farmed

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mammals for food animals must be rendered instantaneously unconscious and insensible to pain,
prior to being slaughtered or killed by bleeding, the period of insensibility must continue until
death supervenes from bleeding and bleeding must be carried out promptly and skillfully.
7.2. Stunning
Stunning is a technical process that induces immediate unconsciousness and insensibility in
animals, so that slaughter can be performed without avoidable fear, anxiety, pain, suffering and
distress without affecting the quality of meat or offal. When ready for slaughter, animals should
be driven to the stunning area in a quiet and orderly manner without undue fuss and noise.
Animals should never be beaten nor have their tails twisted. Animals should be led in single file
into the stunning area where they can be held in appropriate restraining devices before stunning.
It is very important that slaughter animals should be properly restrained before stunning or
bleeding. Restraining means restricting the movement of an animal to ensure stability / holding
the animal in a correct position, so that stunning or sticking can be carried out accurately and
properly. The objectives of stunning are:
¾ To achieve complete bleeding
¾ To prevent unnecessary suffering from pain to animal
Precautions and the general principles that apply to all stunning methods are:
¾ Instruments used for stunning must be in a good working condition
¾ The animal must be restrained/casted properly
¾ A well-trained and experienced establishment employee must operate stunning devices
¾ Animals need to be delivered to the stunning area with a minimum of excitement or
discomfort
The acceptable methods of stunning are:
1. Sledge hammer: it contains a long handle. It is made up of iron. The weight of hammer is
around 2 kgs. It is used for striking an animal on the forehead and within few minutes the
animal becomes unconscious.
2. Captive bolts: Stunning by concussion of the brain through an impact of the bolt with the
skull of animals. Gun powder (cartridge), compressed air and spring under tension drive

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bolts through the skull of animals. This type of stunning is widely used for all farmed
animals. It is called ‘captive’ since the bolt is shot out of the barrel but remains attached to
the pistol. A captive bolt stunning gun kills the animal and reduces it instantly
unconscious without causing pain. A captive bolt gun has a steel bolt that is powered by
either compressed air or a blank cartridge. The bolt is driven into the animal's brain. It has
the same effect on the animal as a firearm with a live bullet. After the animal is shot the bolt
retracts and is reset for the next animal. A captive bolt gun is safer than a firearm. There
have been some questions about whether or not a captive bolt actually kills an animal.
Practical experience in slaughter plants indicates that cattle shot correctly with a penetrating
captive bolt have irreversible damage to their brain and they will not revive. If a non-
penetrating captive bolt is used the animal may revive unless it is bled promptly.
3. Electrical: here we use the electrical current of magnitude of 75 volts for 10 seconds. The
technique involves the application of a pair of electric tongs on either side of the animal’s
head. An electric current is then passed through the brain and this supposedly leads to the
temporary loss of consciousness.
4. Firearm (gunshot): Used for animals difficult to handle such as wild pigs, bison, deer, horses
or in emergencies.
5. Carbon dioxide: A CO2 gas chamber is designed on the principle that carbon dioxide is
heavier than normal atmospheric air. Birds may be stunned using CO2 and Argon gas while
they remain in their crates. Pigs are also gassed using CO2. Pig becomes unconscious by
70% CO2 within 20-25 seconds.
7.3. Bleeding
Bleeding (Sticking) is the act of severing or cutting the major blood vessels supplying or
draining blood in the brain. In this method a knife is stuck into the animal’s throat or neck
causing brain death from the rapid loss of blood supply to the brain. Exsanguination is the
process of bleeding the animal usually done by severing the jugular vein with a sharp knife.
Bleeding must be done quickly to avoid haemorrhaging. Haemorrhaging can cause blood spots in
the meat due to escape of blood from ruptured blood vessels caused by a rise in blood pressure.

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Quick bleeding is essential after slaughter. The animal should be stuck within 15 seconds after
stunning. Bleeding very quickly reduces blood-splash because quickly lowering the blood
pressure helps prevent small capillaries from bursting. A vertical or hanging position is achieved
by shackling below the hock of one hind leg and hoisting the animal (head down) to a convenient
height. Hoist bleeding is more hygienic and is recommended. It also facilitates collection of
blood for further use. Alternatively, the animal can be placed horizontally on a concrete slab or a
sturdy plastic pallet for bleeding.
The actual bleeding operation is made by sticking or inserting the sticking knife through the neck
behind the jaw bone and below the first neck bone. The object is to sever the blood vessels of the
neck and let out blood. If the sticking is made at a lower position than indicated the oesophagus
might be cut and the viscera contaminated. The bleeding should be as complete as possible, the
usual time for sheep and goats being about 2 minutes. Insufficient bleeding and slow death could
mean that the severance of the neck vessels is incomplete, or specifically that the arteries leading
to the head have been missed, having only cut the veins during sticking.
7.4. Carcass weight and Dressing percentage
Carcass weight refers to the weight of an animal after slaughter and removal of most internal
organs, head and skin. The normal range for carcass weight of sheep is between 48% and 58% of
the live animal weight. On average the carcass weight of beef is about 60% of the live animal
weight, for hogs it is about 73%. Dressing percentage is calculated by dividing the carcass
weight by the live weight of the animal and expressing the result as a percentage. For example,
suppose that an animal delivered to the abattoir weighs 1300 kilograms. After being killed, the
hide, head, feet and gut are removed; the carcass then weighs 767 kilograms. The dressing
percent of this animal would be 767 divided by 1300 multiplied by 100 equaling 59 percent. This
“59 percent” represents the meat and skeletal portion of an animal compared to its live weight.
The greatest factor affecting dressing percent is the fatness of the animal. A fatter animal will
have a higher dressing percent.

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7.5. Slaughterhouse by-products
Slaughterhouse by-products include gelatine, skin, brain, blood, organs, glands etc. The products
become a natural and environmental compatible raw material for the industry in
general. Slaughterhouse by-products are mainly used as additives to human or animal feed
products. The equipment for processing and drying slaughterhouse by-products has undergone
radical changes regarding environmental, health and safety requirements. The collection,
transportation and processing of slaughterhouse by-products intended for human or animal
consumption must comply with hygienic standards that are certified and controlled by health and
safety authorities. The hygienic demand calls for specialized processing factories that handle
sufficiently large volumes of product in order to ensure and certify the necessary standards.
Animal blood: Animal blood is either spray dried as regular whole blood or after separation into
plasma and red albumin. To ensure an economically feasible drying process, all blood products
are concentrated in a falling film evaporator until reaching a viscosity around 150 centipoises
viscosity before drying. All slaughterhouse by-products are dried at low temperatures in order to
prevent heat coagulation or Maillard reaction.
Animal gelatine: Animal gelatine is either spray dried as simple gelatine or hydrolysed gelatine,
i.e. partial or total splitting of the long gelatine molecules into smaller fragments. This is done
with chemical or enzymatic processes followed by refining and other unit operations for
obtaining the required product cleanness and or property. To ensure an economically feasible
drying process, all gelatine products are concentrated in a falling-film evaporator until reaching a
viscosity around 150 centipoises viscosity before drying. Again the processes and equipment are
designed with respect to raw material and final product specification.
Animal skin: Slaughterhouse skin by-products can be treated and become a good protein source
with efficient water binding properties. The skin is shredded into 3 x 3 mm pieces and washed.
The wash water is filtrated for impurities, and the dissolved proteins are concentrated in a
falling-film evaporator reaching up to 300 centipoises. The concentrated protein is mixed back to
the clean and centrifuged skin-shreds; the skin-shreds absorb the concentrated protein, and it can

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be dried in a fluid bed with a special inlet section with agitated powder layer. The dry material
will contain approximately 7 percent water and have an acceptable industrial shelf life.
Animal Mucous: Intestines are usually washed in the slaughterhouse; the intestine wash water
contains valuable mucous that can be recovered, cleaned for pathogen material, concentrated to
150 centipoises and spray dried.
Animal brain, organs, glands & ligaments: These by-products are either disintegrated to
particles less than 100 micron, concentrated to around 150 centipoises viscosity and stabilised to
become suitable feed for the spray drying process, or hydrolysed, filtered and stabilised before
spray drying.
Some of the above by-products contain high valued compounds. The high market price of these
compounds/products makes a profitable opportunity for “mining” for lipo-proteins, peptides,
enzymes, hormones, insulin, etc. that can be extracted out of glands and organs, concentrated and
dried for storage and further process or sold as raw material for other industries.
8. Meat inspection
Too many times consumers take things for granted about their food products. Meat inspection
and grading are those activities related to meat products that are important in assuring the best
product for the consumer. This involves inspection of the live animal, carcass, internal organs,
plant facilities, equipment, personnel, and transportation system. The meat inspection act works
to inspect all animals when slaughtered and processed into meat and meat products for human
consumption. Or, in short, this act made sure that meat was thoroughly inspected before reaching
its consumers. The primary goals are to prevent adulterated or misbranded livestock and products
from being sold as food, and to ensure that meat and meat products are slaughtered and
processed under sanitary conditions. Hence, Meat inspection assures the consumer that the meat
and meat products are clean, safe, and wholesome for human consumption at the time of
purchase. The four primary requirements of the meat inspection act are:
¾ Mandatory inspection of livestock before slaughter
¾ Mandatory post-mortem inspection of every carcass

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¾ Sanitary standards established for slaughterhouses and meat processing plants
¾ Trained personnel should conduct the monitoring and inspection of slaughter and
processing operations
The objectives of meat inspection programme are twofold:
a. To ensure that only apparently healthy, physiologically normal animals are slaughtered
for human consumption and that abnormal animals are separated and dealt with
accordingly.
b. To ensure that meat from animals is free from disease, wholesome and of no risk to
human health.
These objectives are achieved by ante mortem and post mortem inspection procedures and by
hygienic dressing with minimum contamination.
8.1. Ante-mortem inspection
The first line of defense in the protection of a wholesome meat supply is the recognition and
removal of clinically affected animals. The term ante-mortem means “before death.” Ante-
mortem inspection is the inspection of live animals prior to being slaughtered to avoid putting
sick or harassed animals into the abattoir buildings and the slaughter chain. Ante-mortem
examination should be done within 24 hours of slaughter and repeated if slaughter has been
delayed over a day. Some of the major objectives of ante-mortem inspection are as follows:
¾ To segregate the diseased animals from healthy stock
¾ To detect the outbreaks of infectious diseases like FMD, RP, hog cholera
¾ To prevent the pain/suffering to animal by insuring that injured animals or those with
pain and suffering receive emergency slaughter and that animals are treated humanely
¾ To diagnose some of the exotic diseases and identify reportable animal diseases
¾ To prevent food borne infections
¾ To diagnose zoonotic diseases like Anthrax
¾ To detect certain conditions, disorders and diseases which are extremely difficult to
detect the organ or carcass after slaughter, e.g. mastitis

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¾ To ensure that animals are properly rested and that proper clinical information which
will assist in the disease diagnosis and judgment is obtained.
¾ To avoid contamination of premises and meat by infective material by separating the
dirty animals and condemning the diseased animals
¾ To identify sick animals and those treated with antibiotics, chemotherapeutic agents,
insecticides and pesticides
Facilities required for conducting ante mortem inspection:
1. To restrain the animal by rope or travis.
2. Identification of the live animal, make identification either by paint, ear band, tattooing
or leg bands.
3. To require good lairage (space which should be well ventilated and properly lighted to
keep the animal for 24 hours.
4. We should have an isolation pan to separate the diseased animal from healthy animal.
5. To need an assistant staff who is confident in handling of livestock.
Both sides of an animal should be examined at rest and in motion. Animals affected with
extensive bruising or fractures require emergency slaughter. Animals showing clinical signs of
disease should be held for veterinary examination and judgment. They are treated as “suspects”
and should be segregated from the healthy animals. The disease and management history should
be recorded and reported on an AMI card. Other information should include:
1. Owner's name
2. The number of animals in the lot and arrival time
3. Species and sex of the animal
4. The time and date of ante mortem inspection
5. Clinical signs and body temperature if relevant
6. Reason why the animal was held
7. Signature of inspector
Steps required for ante mortem examination
1. We must inspect live animals at rest as well as while moving.
2. Animal showing elevated temperature and systemic disturbances should be retained for
treatment outside the meat plant.

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3. Special attention should be paid to the emergency accident and casually slaughtered.
4. Great care must be taken in handling of those animals, which are representing a source of
infection to the staff working in slaughter house.
5. Special attention must be given to the recumbent animals.
6. If dead animal is encountered during inspection then anthrax should come in to mind and
blood smear should be prepared from the ear vein.
7. An experienced and well trained veterinarian should carry out AME.
8. AME should be should be conducted in adequate day/natural/artificial light.
9. Animal suffering from metabolic infection/disorder should be first treated.
10. Animals which have recently suffered accident/injuries should be subjected to the
emergency slaughter.
11. Animal which are very doggy/dirty must be cleaned before slaughter. In such cases the
animal should be re-inspected after washing.
The ante-mortem inspection of livestock takes place in the pens. Ante-mortem inspection should
be carried out in adequate lighting where the animals can be observed both collectively and
individually. Ante-mortem inspection consists of two steps:
¾ Observe animals at rest
¾ Observe animals in motion
It is important to inspect the animals using both steps because certain abnormal signs, such as
labored breathing, are easier to detect while the animals are at rest, while other abnormalities,
such as lameness, are more easily detected while in motion. When you perform at-rest
inspection, position yourself at various locations outside the pen. Observe all of the animals and
note their general behavior while they're at rest. Look at the heads, necks, sides, rumps, and legs
of as many animals as you can see. When you perform in-motion inspection of the animals, you
should position yourself outside of the pen next to the open gate so that you can easily view the
animals as they are driven by you. Allow the animals to move all of the animals slowly and
individually out of the pen while you observe them for abnormalities by viewing the visible side
of the head, neck, shoulder, flank, legs, and rump. The general behaviour of animals should be
observed and determine if any of the animals show abnormal behavior patterns such as excessive

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VPH2011 Page 40 0f 46
excitability or severe depression. Look for their nutritional status, cleanliness, signs of diseases
and abnormalities. During ante-mortem inspection both sides of an animal should be examined.
Some of the abnormalities which are checked on ante-mortem examination include:
¾ Abnormalities in respiration
¾ Abnormalities in behaviour
¾ Abnormalities in gait
¾ Abnormalities in posture
¾ Abnormalities in structure and conformation
¾ Abnormal discharges or protrusions from body openings
¾ Abnormal colour
¾ Abnormal odour
Abnormalities in respiration commonly refer to frequency of respiration. If the breathing pattern
is different from normal the animal should be segregated as a suspect.
Abnormalities in behaviour are manifested by one or more of the following signs:
The animal may be:
a. walking in circles or show an abnormal gait or posture
b. pushing its head against a wall
c. charging at various objects and acting aggressively
d. showing a dull and anxious expression in the eyes
An abnormal gait in an animal is associated with pain in the legs, chest or abdomen or is an
indication of nervous disease.
Abnormal posture in an animal is observed as tucked up abdomen or the animal may stand with
an extended head and stretched out feet. The animal may also be laying and have its head
turned along its side. When it is unable to rise, it is often called a “downer”. Downer
animals should be handled with caution in order to prevent further suffering.
Abnormalities in structure (conformation) are manifested by:
a. swellings (abscesses) seen commonly in swine
b. enlarged joints
c. umbilical swelling (hernia or omphalophlebitis)

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d. enlarged sensitive udder indicative of mastitis
e. enlarged jaw (“lumpy jaw”)
f. bloated abdomen
Some examples of abnormal discharges or protrusions from the body are:
a. discharges from the nose, excessive saliva from the mouth, afterbirth
b. protruding from the vulva, intestine
c. protruding from the rectum (prolapsed rectum) or uterus
d. protruding from the vagina (prolapsed uterus)
e. growths on the eye and bloody diarrhoea
Abnormal colour such as black areas on horses and swine, red areas on light coloured skin
(inflammation), dark blue areas on the skin or udder (gangrene).
An abnormal odour is difficult to detect on routine AMI. The odour of an abscess, a medicinal
odour, stinkweed odour or an acetone odour of ketosis may be observed.
Since many abattoirs in developing countries have not accommodation station or yards for
animals, Inspector's ante mortem judgement must be performed at the admission of slaughter
animals. There are three possible outcomes that follow ante-mortem inspection:
¾ passed for slaughter
¾ Suspect
¾ Condemned
SN. Condition Disposition
1 Animal is clean, healthy and dry Pass for slaughter
2 Dirty and doggy animal Cleaning and re-inspection
3 Recent injury (fracture, extensive brushing, sever laceration) Emergency slaughter
4 Milk fever/ Hypo magnesium tetany Treatment
5 Brucella, TB reactors, Chronic mastitis, Actiobacillosis,
Arthritis, Salmonellosis, Neoplasm, Benign tumor
Veterinary clinical
examination
6 Anthrax, Gangrenous dermatitis, Generalized TB, Malignant
tumor
Condemnation

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8.2. Post-mortem inspection
Post-mortem inspection of a carcass is the veterinary medical examination of the dead body of
animal after the slaughter is completed. The principal purpose of post-mortem inspection is to
supplement ante-mortem inspection in identifying diseases of public or animal health
significance and to remove meat that is unfit for human consumption. Routine post-mortem
examination of a carcass should be carried out as soon as possible after the completion of
dressing in order to detect any abnormalities so that products only conditionally fit for human
consumption are not passed as food. All organs and carcass portions should be kept together and
correlated for inspection before they are removed from the slaughter floor. Carcass should be
inspected immediately after slaughter and evisceration for possible changes and lesions that
indicate unsuitability of the meat for food. Postmortem examination requires observation of all
parts of the carcass, dressing procedures, equipment, and facilities to prevent contamination of
edible parts.
The purposes of post-mortem inspection are to detect:
¾ diseases of Public Health significance
¾ diseases of animal health significance
¾ residues or contaminants in excess of the levels allowed by legislation
¾ non-compliance with microbiological criteria
¾ the hygienic dressing of the carcass
¾ visible lesions that are relevant to animal welfare
¾ evidence of animal welfare problems such as beating or long standing untreated injuries
Facilities required for conducting post mortem inspection:
1. The premises should be clean, hygienic and well ventilated
2. The equipments should be in a good working condition.
3. The staff should have proper clothing.
4. There should be a sterilizer for knives and other instruments.
5. There should be wash basin, liquid detergent, antiseptic soap, towel and free supply of
hot and cold water.

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6. There should be metal stamp or rubber stamp with marking ink for the identification of
carcass.
7. There should be well experienced and trained meat inspector.
Types of post-mortem examination
1. Visual examination: it is very important and helpful to detect haemorrhages, infarction,
fatty liver, abscesses, cysts, jaundice, penetration of foreign body etc.
2. Palpation of tissue: detect conditions like haematoma, caliculi, pneumonia, pleurisy etc.
3. Incision of organ/tissue: lymph nodes, certain glands, liver and kidney are usually
examined after incision for the presence of TB, Cysticercosis, Hydatidosis, Fasciollosis...
4. Use of inspectors’ sense of smell: ketosis, uremia, decomposition etc. can be diagnosed by
peculiar or typical smell.
5. Laboratory test: in diseases where there is no characteristic or pathognomonic
pathological lesions the specimen must be submitted to the laboratory for confirmation of
conditions such as Leptospirosis, Listeriosis, Q-fever, Salmonellosis and many protozoan
diseases.
A routine postmortem inspection should include the following procedures:
Head:
¾ Incise and visually examine the left and right mandibular, parotid, atlantal, and
suprapharyngeal lymph nodes.
¾ Examine 2 incised layers of both masseter muscles.
¾ Examine and palpate tongue.
Viscera:
¾ Examine mesenteric lymph nodes and abdominal viscera.
¾ Examine and palpate ruminoreticular junction.
¾ Examine esophagus and spleen.
¾ Incise and examine anterior, middle, and posterior mediastinal lymph nodes and right
and left bronchial lymph nodes.
¾ Examine and palpate costal and ventral surfaces of the lungs.

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¾ Incise heart from base to apex through interventricular septum and examine and cut
inner and outer surfaces.
¾ Incise and examine hepatic (portal) lymph nodes.
¾ Incise bile duct in both directions and examine contents.
¾ Examine and palpate ventral and dorsal surfaces of liver and palpate kidneys.
Carcass:
¾ Examine internal and external surfaces.
¾ Palpate superficial inguinal or supramammary and internal iliac lymph nodes.
¾ Examine and palpate diaphragm.
The inspector must ensure that condemned carcasses and parts are disposed of safely. The
following are unacceptable for human food: the lungs, thyroid glands, laryngeal muscles, and
lactating mammary glands; brains, cheek meat, and head trimmings from animals that were
stunned by lead, sponge iron, or frangible bullets; and carcasses suspected of containing
sulfonamides, antibiotics, or other residues. Spinal cords and CNS tissue must be discarded to
eliminate threat of bovine spongiform encephalopathy in the food supply.
Possible outcomes that follow post-mortem inspection:
¾ Pass the meat as fit for human consumption:- the meat will be approved for human
consumption when no disease, abnormality or residue is detected and if the slaughter
operation is performed in a hygienic manner
¾ Totally condemned for human consumption:- carcass and organs may be totally
condemned for human consumption if the food animals or their products is found to be
hazardous to consumers, food handlers and livestock, if residue beyond the normal limit
is detected and if there is severe organoleptic deviation. Condemned carcasses are
sources of infection for animals and man so must be disposed properly. Use it as animal
feed after sterilization, incineration (burn) and burry deeply.
¾ Partially fit for human consumption:- carcass may be partially condemned for human
consumption if abnormalities or defects are encountered in certain parts of the organ or
carcass. The part of the organ or carcass is passed after trimming of the defect.

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¾ Conditionally approved for human consumption:- carcass may be passed as
conditionally approved for human consumption if the carcass or organ causes hazards to
public or animal health but such hazards can be eliminated through proper treatment.
Example freezing or boiling used to kill larvae of C. bovis.
¾ Detained:- carcass or organ may be detained when discolouration due to icterus is
encountered and to perform detailed parasitological, microbiological and toxicological
examinations.
Procedures for post mortem examination
01. Head: Inspection of the gums, lips and tongue is done for detecting FMD, actinobacillosis,
actinomycosis, stomatitis etc. Incise the tongue to detect Cysticercous bovis. Incision should
be made on retropharyngeal, submaxillary and parotid lymph nodes to detect
actinobacillosis, tuberculosis and abscess.
02. Lungs: lungs are usually examined for the presence of pleurisy, pneumonia, tuberculosis,
hydatidosis and fasciolosis. Bronchial and mediasinal lymph nodes should be incised to detect
tuberculosis lesions.
03. Heart: Pericardium is looked for pericarditis, haemorarhges, hydatid cyst and cysticercosis.
04. Liver: View and palpate entire surface (both sides). Examine for fatty liver, fasciolosis,
actinobacillosis, Cysticercous bovis and certain parasitic conditions. View and incise the
portal (hepatic), lymph nodes.
05. Gastrointestinal tract: Viewing of rumen, reticulum, omasum and abomasums. The serous
surfaces of the organs are examined for tuberculosis and actinobacillosis. Reticulum should
be assessed for foreign body. Incision of the mesenteric lymph nodes should be done to
investigate lesions of lymphangitis.
06. Kidneys: examined for nephritis, caliculi and nodules. The renal lymph node is examined for
tuberculosis.
07. Spleen: palpation of spleen and viewing. The surface and substance should be examined for
anthrax, haematoma, infarction and tuberculosis.
08. Uterus: uterus should be examined for evidence of pregnancy or recent parturition. In
Brucella reactors, the uterus should not be handled or incised since the disease is highly
infectious to human.

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09. Udder: it is examined for abscess, mastitis, cowpox, pseudo cowpox, and actinomycosis.
Supramammry lymph node should be examined for tuberculosis.
10. Testes: Testes should be examined for orchitis, abscess, haematoma, haemorrhages and
ingury.
11. Carcass: Examine internal and external surfaces.
In addition to the above, cut surface of bone muscles, pleura, peritoneun and diaphragm should
also be examined for various conditions.
Time of bruising
A. By appearance
• Red and haemorrhagic…………………………………………... 0-10 hours old
• Dark coloured…………………………………………………… 24 hours old
• Watery consistency……………………………………………… 24-38 hours old
• Rusty orange colour and soapy to touch………………………… 3 days or more
B. Chemical tests
Add a sample of bruised meat and Fouche’s reagent (trichloracetic acid + ferric chloride)
• No colour reaction………………………………………………...... less than 50 hours old
• if the solution turns to light blue…………………………………… 60-72 hours old
• dark green reaction…………………………………………………. 4-5 days old

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