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Indicator name
Characteristics of rabbit meat (carcasses)
fresh
dubious freshness
stale
resulting hole is leveled
out slowly (within 1
min); the fat is soft, in
thawed carcasses it is
slightly loosened
carcasses it is loose and
greasy
Smell
Specific, characteristic
of fresh rabbit meat
Musty, most pronounced
in the abdominal cavity
Putrid, most pronounced
in the abdominal cavity
Broth clarity and
aroma
Transparent, fragrant
Transparent or cloudy
with a slight unpleasant
odor
Cloudy, with a lot of
flakes, with a strong
unpleasant odor
Determining the degree of freshness of rabbit meat by laboratory methods
Only rabbit meat that is recognized as being of questionable freshness based on
the results of an organoleptic study is subjected to laboratory (biochemical,
microscopic) studies.
Determination of the content of volatile fatty acids in rabbit meat
The analysis is carried out according to the method described on pp. 22–23 of
this publication.
Rabbit meat is considered fresh if chilled meat contains up to 2.25 mg KOH of
volatile fatty acids, and frozen meat contains up to 4.5 mg KOH.
Meat is considered to be of questionable freshness if chilled meat contains
2.25–9.00 mg of volatile fatty acids; frozen meat contains 4.5–13.50 mg KOH.
Stale meat contains over 9.00 and 13.50 mg of KOH volatile fatty acids
respectively.
Reaction to ammonia and ammonium salts with Nessler's reagent
Analysis and evaluation of its results are carried out according to the
methodology described on p. 25 of this publication.
Reaction to products of primary breakdown of proteins
with copper sulfate in broth
Analysis and evaluation of its results are carried out according to the
methodology described on pp. 24–25 of this publication.
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Microscopic examination of rabbit meat
Microscopic analysis and evaluation of its results are carried out according to
the method described on pp. 26–27 of this publication.
Rationale for veterinary and sanitary assessment of rabbit meat
depending on freshness
According to the “Rules for veterinary inspection of slaughter animals and
veterinary and sanitary examination of meat and meat products,” veterinary and
sanitary assessment of fresh rabbit meat is carried out on a general basis.
Rabbit meat of questionable freshness, after preliminary cleaning (removal
and disposal of altered areas) and, if necessary, washing, is processed into boiled
sausages or boiled.
Stale rabbit meat is disposed of.
Test questions and assignments
1. Describe the rules for sampling rabbit meat for research.
2. What organoleptic indicators are determined when assessing the freshness of
rabbit meat?
3. What should be done with rabbit meat if, according to the results of an
organoleptic study, it is found to be fresh, of questionable freshness, or stale?
4. What biochemical indicators of rabbit meat are determined when assessing
the degree of its freshness?
5. How many VFAs are contained in rabbit meat of varying degrees of
freshness?
6. How many microbial bodies are contained in prints from the deep layers of
rabbit meat of varying degrees of freshness?
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CHAPTER 5. VETERINARY AND SANITARY EXAMINATION
OF SICK ANIMALS’ MEAT
The procedure for forced slaughter of animals, veterinary and sanitary
examination and use of slaughter products
In the practice of a veterinary and sanitary expert, there are often cases when it
is necessary to establish the origin of meat — whether it was obtained from the
slaughter of a sick, overworked or slaughtered animal in an agonal state. It is likely
that in these cases, during their lifetime slaughter products may be contaminated with
microflora, including pathogenic ones.
Taking the life of an animal due to illness is referred to as forced slaughter. It is
carried out in cases where further treatment is not economically feasible or effective.
Forced slaughter of animals is most often carried out in cases of severe injuries, bone
fractures, acute gastrointestinal diseases, pathological birth, poisoning, etc.
Cases of forced slaughter do not include:
1. Slaughter of clinically healthy animals that cannot be fattened to the required
conditions, are lagging in growth and development, are unproductive, are barren, but
have a normal body temperature.
2. Slaughter of healthy animals that are at risk of death as a result of a natural
disaster (snow drifts on winter pastures, etc.).
3. Slaughter of animals that were injured before slaughter at a meat processing
plant, slaughterhouse, or slaughterhouse.
When deciding on forced slaughter, it is necessary to clearly understand the
diseases and other conditions in which the slaughter of animals for meat is prohibited.
Animal slaughter, including forced slaughter, is not permitted in the following cases:
1. Animals are sick and suspected of having anthrax, emphysematous
carbuncle, rinderpest, camel plague, rabies, tetanus, malignant edema, bradzot,
enterotoxemia of sheep, bluetongue of cattle and sheep (blue tongue), African swine
fever, tularemia, botulism, glanders, epizootic lymphangitis, meliodosis (false
glanders), myxomatosis and hemorrhagic disease of rabbits, avian influenza.
If for some reason (latent period, oversight, etc.) a sick animal is killed, then
the slaughter products are subject to destruction (burning).
2. Animals that are in an agonal state, regardless of the reasons that caused this
state. The agonal state is characterized by a sharp decline in cardiac activity, absence
of reflexes to irritation, clouding of the cornea, a decrease in body temperature by
1–2 °C and is diagnosed by a veterinarian or paramedic. An animal killed in agony is
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considered a corpse and must be disposed of or destroyed depending on the disease
that caused the condition.
3. Young animals for slaughter (calves, piglets, lambs, kids), under 2 weeks of
age, foals — 4 weeks of age. If animals are slaughtered before these dates, all
slaughter products are disposed of.
4. Animals within the first 10 days after vaccination with anthrax vaccines or
treated with anthrax serum and within 21 days after vaccination against foot-andmouth disease in areas unfavorable for this disease. In some cases, with the
permission of a veterinarian, it is possible to slaughter them earlier than the specified
period, provided that the animals had a normal temperature and there were no
reactions (complications) to the vaccination. The carcasses of these animals are
subjected to bacteriological and biochemical studies. Their meat is subjected to
neutralization depending on the results of laboratory analysis.
5. Single-hoofed animals (horses, mules, donkeys, etc.), not subjected to
malleinization at a meat processing plant or slaughterhouse. If they are slaughtered
without pre-slaughter malleinization, carcasses and other slaughter products are sent
for disposal. At the slaughterhouse, single-hoofed animals and camels are examined
for glanders using a single ophthalmomalleinization method. An animal that reacts to
mallein must be disposed of.
6. Animals for 30 days, and poultry for 10 days after the last feeding of fish,
fish waste or fish meal. When animals are slaughtered before these dates, carcasses
and internal organs have a pronounced fishy smell and are disposed of.
7. Animals that were treated with antibiotics for therapeutic and prophylactic
purposes during the period specified in the “Manual on the use of antibiotics in
veterinary medicine.”
8. Animals treated with pesticides, before the expiration of the periods
specified in the “List of chemicals recommended for treating farm animals against
insects and ticks” and the limitation period in accordance with the instructions for
their use. Animals with clinical signs of brucellosis and tuberculosis, with an
unknown diagnosis of the disease, or with low or high body temperature cannot be
sent to the slaughterhouse; a bird sick with psittacosis, influenza, or Newcastle
disease.
Permission for forced slaughter is given only by a veterinary specialist with the
obligatory execution of an act indicating the reason for the slaughter.
Forced slaughter of animals is carried out at sanitary slaughterhouses of meat
processing plants and at slaughterhouses on farms. Pre-slaughter holding of the
animal is excluded. Carcasses of sheep, goats, pigs, and calves are not dismembered
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during slaughter on the farm; carcasses of large animals may be divided into half
carcasses and quarters. Each carcass (half carcass, quarter) is tagged. Then, samples
of muscles and internal organs are taken (spleen, kidney, liver lobe with an emptied
and bandaged gall bladder, 2 lymph nodes; from pork carcasses — three) and sent to
a veterinary laboratory with an accompanying document for organoleptic,
biochemical biological and bacteriological research.
Only fresh material is suitable for laboratory research. Meat of questionable
freshness and stale meat is not subject to further laboratory research, since
biochemical, microscopic, bacteriological indicators characterizing stale meat and
meat of questionable freshness may be similar to the values of indicators of meat
obtained from the slaughter of sick animals.
During the biological examination, the presence of pathogens of anthrax and
human food diseases — salmonella, etc. — in slaughter products is excluded. If
poisoning is suspected, an additional toxicological study is carried out in the
laboratory. Until the laboratory test results are obtained, the meat is stored in a
separate refrigerator; in its absence, the meat can be preserved with table salt, with
each carcass being salted in a separate container.
If, according to the results of laboratory tests, the products of forced slaughter
are found suitable for food purposes, they are sent to a meat processing plant for
disinfection (cooking, processing into canned meat, meat loaves). The release of meat
and offal of forcedly killed animals in raw form for sale or into the public catering
network without prior neutralization is prohibited.
Determining the degree of meat exsanguination
Method for visually determining the degree of meat exsanguination
There are 4 degrees of meat exsanguination: good, satisfactory, bad and
very bad.
When externally examining a carcass to identify the meat of a sick animal,
killed in an agonal state or a dead animal, first of all, the degree of its exsanguination
is visually established — the carcass of a sick animal is exsanguination worse than a
healthy one due to several reasons, the main of which are:
a) increased blood viscosity;
b) weakening of cardiac activity;
c) decreased vascular tone.
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All of the above reasons lead to a slowdown in blood flow in the vessels, its
stagnation and exit outside the vessels, and therefore to poor exsanguination.
When determining the degree of exsanguination of a carcass, it is necessary to
take into account that it depends not only on the general physiological state of the
animal, but also on a number of other factors (the method of exsanguination, the
degree of cutting of blood vessels in the neck). With the vertical method,
exsanguination occurs much better than with the horizontal one. With horizontal
exsanguination, some of the blood may remain on the side on which the animal lies.
When visually determining the degree of exsanguination of a carcass, the
following must be taken into account.
1. Condition of the cut site. In animals that are sick or killed in a state of
agony, the cutting site is smooth and even, the surrounding muscle tissue is saturated
with blood to the same extent as the rest of the muscles. If the stabbing site is cleared
or chopped off, this indicator is not taken into account.
In healthy animals, the cut site is uneven, there are tissue fragments, and the
surrounding muscle tissue is saturated with blood to a greater extent than the muscles
of other parts of the carcass.
2. Blood supply to muscles, organs, blood vessels. In sick animals, the
internal organs are filled with blood; with a longitudinal section, blood-filled vessels
are visible, and with a transverse section of the muscles, drops of blood protrude, the
cut surface is sticky; in large vessels under the serous membranes (pleura,
peritoneum) blood is visible.
3. Presence of hypostases. Hypostases (accumulations of blood in tissues in
the form of dark red areas) are formed as a result of stagnation of blood in the vessels
and its release into the surrounding tissues due to increased porosity of the vessels,
while the surrounding tissues are painted in a dark red or bluish color. Hypostases are
observed in the carcasses of seriously ill or agonal animals, as well as in corpses. As
a rule, they are located on the side on which the animal lay, therefore, during a
veterinary and sanitary inspection, carcasses must be turned over to the other side;
4. Changes in the lymph nodes. In healthy animals, the cut surface of the
lymph nodes is light gray or light yellow; in sick animals and those killed in a state of
agony, it is lilac-pink. The reason for this is blood accumulated in the small vessels of
the lymph nodes, which penetrates through the walls of the vessels into the sinuses
and colors the node pink. Inhibition of oxidative processes in the body and
accumulation of carbon dioxide in organs leads to cyanotic (blue) staining of tissues.
In addition, changes typical to a specific disease may be observed in the lymph
nodes: atrophy, hypertrophy, necrosis, hemorrhage, edema, etc.
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5. Color of muscle and fat tissue. In sick animals, the muscles are dark red
with a bluish tint, and the fat is pink. Inhibition of oxidative processes in the body of
sick animals leads to the accumulation of carbon dioxide, which causes cyanotic
(bluish) staining of tissues.
In addition, visually established:
- presence of blood in muscles and small blood vessels;
- condition of small vessels under the serous membranes;
- color of fat and bone marrow;
- carry out the test with filter paper.
With good exsanguination, there is no blood in the muscles and blood vessels,
small vessels under the pleura and peritoneum are not visible. The color of the fat is
specific to the type of animal; the bone marrow of the tubular bones is yellow. The
carcasses of healthy animals are well bled.
With satisfactory exsanguination, a small amount of blood is found in the
blood vessels; in the muscles, blood is absent or appears in small droplets when
pressing on the transverse incision. The vessels of the pleura and peritoneum are
faintly visible. The color of fat and bone marrow is slightly pinkish. Carcasses of
tired, old, and rarely sick animals have a satisfactory degree of exsanguination.
With poor exsanguination, there are isolated bloody areas on the muscle
section, there are blood residues in the vessels, and when pressing on the muscle
cross section, dark drops of blood appear. Small blood vessels of the pleura and
peritoneum are clearly visible. The color of fat and bone marrow is pink. As a rule,
the carcasses of sick animals are poorly bled.
With very poor exsanguination, large and small vessels of the carcass are
filled with blood. On a cross section of the muscles there are many dark red areas and
large dark drops of blood protrude. The blood vessels of the pleura and peritoneum
are injected with blood, the serous membranes are violet-red. Fat and bone marrow
are colored red. Carcasses of animals killed in a severe pathological or agonal state
are always very poorly bled.
When visually assessing the degree of exsanguination, a test is carried out
with filter paper, a muscle incision is made, a strip of filter paper is inserted there,
pressed for 3–5 seconds, after which the color of the paper and the degree of its
saturation with blood are assessed.
With good exsanguination, the color of the filter paper is pink, the paper is
saturated with muscle juice.
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With satisfactory exsanguination, the filter paper is saturated with muscle
juice and blood (red dots on a pink background), but not above the level of contact
with the meat.
If exsanguination is poor, the filter paper becomes saturated with blood 2–3 mm
above the incision level.
With very poor exsanguination, the filter paper is intensively saturated with
blood above the cut level by 5 mm or more.
The filter paper test is not used to determine the degree of exsanguination of
thawed meat with high humidity.
Laboratory methods of determination the degree of meat exsanguination
The degree of meat exsanguination can be determined using the following
laboratory methods.
According to Roder, to carry out the reaction, use a reagent consisting of
0.1 cm3 of Loeffler's blue, 40 cm3 of distilled water and 0.05 cm3 of a saturated
alcohol solution of fuchsin, diluted 10 times with water.
Analysis procedure
3–5 g of meat is minced, placed in a test tube and 3–5 cm3 of Roeder’s reactive
agent is added. The contents of the tube are thoroughly mixed and the degree of
exsanguination is assessed by the color of the reagent. The reaction is taken into
account through 5 minutes.
With good exsanguination, the color of Roeder's reagent remains unchanged —
blue, with satisfactory exsanguination — blue-green, with poor exsanguination —
brownish-green, with very poor exsanguination — brownish-brown.
According to Lubyanetsky, using curved scissors, several cuts of an oat grain
size are made along the muscle fibers. The sections are placed between the glasses of
the compressorium and minced. Under low magnification of a microscope, capillaries
are found in a darkened field of view and the degree of their blood filling is assessed.
With good exsanguination of meat, red blood cells are located along the walls
of blood vessels in 1–2 rows, with satisfactory exsanguination — in 2–4 rows, there
are no traces of blood in the surrounding tissues. With poor exsanguination, the
capillaries are almost completely filled with red blood cells, in the center of the
vessels there is a lumen in the form of a thin line, blood is present in the surrounding
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tissues. With very poor exsanguination, red blood cells completely fill the vessels,
there is no lumen, and there is blood in the surrounding tissues.
The technique is not used to determine the degree of exsanguination of frozen
and thawed meat in which red blood cells are hemolyzed.
According to Zagaevsky, a sample with a total weight of 25 g is cut out from
various parts of the carcass, minced with scissors, ground in a mortar, 5 cm3 of a
0.2N solution of hydrochloric acid is added and the grinding continues until the
extract becomes brick-red in color. The extract is squeezed out through a gauze cloth.
0.5 cm3 of the extract is poured into a graduated test tube of a Sali hemoglobin
meter and a 0.2N solution of hydrochloric acid is poured into it drop by drop until the
color of the extract becomes the same as the color of a standard test tube. The upper
division of the test tube, corresponding to the level of the solution, will show the
percentage of hemoglobin in 0.5 cm3 of the extract.
The degree of exsanguination of meat is judged as follows: good — up to
50 units (divisions), satisfactory — 51–65, bad — 66–85, very bad — more than
86 units.
The hemoglobin content in 0.5 cm3 of meat extract from forcedly killed
animals is from 60 to 80 units, and the muscle of a corpse is 100 units or more.
Hemoglobin-peroxidase test (according to Schonberg). A small piece is cut
out of the meat being tested and placed in a porcelain cellule. A 5 % double tincture
is poured there and the meat is kneaded with a glass rod. Then exactly 2 drops
(0.1 cm3) of a 2 % hydrogen peroxide solution added. After a few seconds, oxygen
bubbles are released under the influence of catalase.
The reaction is read no later than 5 minutes after adding the hydrogen peroxide
solution. A piece of meat is moved in the solution several times with tweezers and
removed from it. Depending on the degree of exsanguination, the solution acquires a
different color: with good exsanguination — yellow-brown, satisfactory — light
green or green, bad — blue, very bad — dark blue and cloudy.
Determination of meat from sick animals by laboratory methods
Only fresh material is suitable for microscopic and biochemical studies. Meat
of questionable freshness and stale meat is not subject to laboratory testing, since
microscopic and biochemical indicators characterizing meat of questionable freshness
and staleness may be similar to the values of indicators of meat obtained from the
slaughter of sick animals.
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Determining the degree of freshness of meat sample submitted
for examination according to organoleptic indicators
Described on pp. 16–17 of this publication. Only fresh meat is suitable for
further laboratory research.
Microscopic recognition method of meat, obtained
from the slaughter of sick animals
Microscopic examination of meat is of great importance for identifying the
causative agents of certain infectious diseases (anthrax, emphysematous carbuncle,
erysipelas and pasteurellosis of pigs, diplo- and streptococcal infections).
For bacterioscopy, 2 lymph nodes are cut out from cattle carcasses — the
superficial cervical and iliac medial (deep inguinal), and from pig carcasses — also
the submandibular lymph nodes and specimens are prepared for microscopy. In
addition, fingerprint smears are made from internal organs (spleen, liver, kidneys)
and muscle tissue.
The technique for preparing and staining Gram smears is described on pp. 32–34
of the publication.
During bacterioscopy of fingerprint smears, the following indicators are
assessed:
- color intensity;
- morphology of microflora;
- the amount of microflora in the field of view of the microscope.
Color intensity of fingerprint strokes. In the meat of a sick animal, tissue cells
are unstable, so they quickly disintegrate after the animal is slaughtered. Decay
products leave a clear mark on the glass slide, so a smear-imprint of the meat of sick
animals will be colored more intensely than the imprint of the meat of healthy
animals. The imprint from the meat of old and tired animals will be of medium
intensity, and the meat of animals killed in an agonal state will be intensely and
densely colored with a visible residue of disintegrated tissue.
Morphology of microflora. When assessing the quality of microflora, attention
is paid to the presence of specific microflora typical to any disease (salmonella,
E. coli, anthrax bacilli, causative agents of emkar, erysipelas, pasteurellosis, etc.),
their Gram stain, the presence of spores, capsules, etc., location in smears are
assessed.
In the meat of sick animals, intensive breakdown of proteins occurs with the
accumulation of corresponding breakdown products. This creates conditions for the
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