acute myeloid leukemia
chronic lymphocytic leukemia
+ undifferentiated leukemia
acute lymphocytic leukemia
chronic myeloid leukemia
/ \\ 173. In the pathogenesis of a violation of the coagulation mechanism of hemostasis, it matters
platelet count reduction
platelet dysfunction
vasopathy
+ factor VIII deficiency
-defect of platelet receptors IIb-IIIa
/ \\ 174. Thrombocytopenia is characteristic
deficiency of plasma coagulation factors
- prolongation of coagulation time
hematoma type of bleeding
+ petechial type of bleeding
- bleeding time is normal
/ \\ 175. Platelet adhesion and aggregation decreases with
excess of calcium and magnesium
Deficiency VIII f coagulation
-increase in blood ADP concentration
excess thromboxane A2
+ von Willebrand factor deficiency
/ \\ 176. Hereditary deficiency of procoagulants occurs with
+ hemophilia
deficiency of vitamin K
liver failure
formation of antibodies to procoagulants
Violation of carboxylation of prothrombin complex factors
/ \\ 177. Hemophilia A is characteristic
autosomal recessive inheritance type
IX coagulation deficiency
petechiae, ecchymoses
+ hemarthrosis
- prolongation of bleeding time
/ \\ 178. For von Willebrand disease is characteristic
-reduction of the duration of capillary bleeding
- shortening of blood coagulation time
-increased platelet aggregation ability
Violation of the synthesis of factor VIII
+ decrease in procoagulant activity of factor VIII
/\\ 179.In the pathogenesis of hypercoagulation in DIC - it matters
+ activation of the "external" and "internal" mechanisms of blood coagulation
-hypofibrinogenemia
-activation of the fibrinolytic blood system
excess of antithrombin III
thrombocytopathy
/ \\ 180. In the pathogenesis of hypocoagulation in DIC, it matters
+ coagulopathy and thrombocytopenia consumption
excess of procoagulants
- the entry into the blood of a large amount of tissue thromboplastin
-activation of fibrinolysis inhibitors
antithrombin III deficiency
/ \\ 181. The most pronounced stage of DIC in newborns
+ hypocoagulation
hypercoagulation
transitional
-recover
-terminal
/ \\ 181. The clinical manifestations of hemorrhagic disease of the newborn include
+ melena, umbilical wound bleeding
- yellowness of the skin and mucous membranes
nuclear jaundice
hyperbilirubinemia
libraries
/ \\ 182. With hemophilia A is disturbed
+ The formation of active prothrombinase
Transition of prothrombin to thrombin
- Transition of fibrinogen to fibrin
Second phase of blood coagulation
Third phase of blood coagulation
/ \\ 183. Hypercoagulation of blood is observed with
Excess Protein C
Excess Protein S
Excess Antithrombin III
+ Factor V resistance to protein C
-afibrinogenemia
/ \\ 184. Etiological factors of exogenous origin, causing damage to the nervous system
+ alcohol intoxication
damage to neurons in hepatic coma
ischemia of the brain
hypoglycemia
damage to neurons in uremia
/ \\ 185. The nerve conduits enter the nervous system
streptococcal exotoxin
-meningococci
pneumococci
enteric stick
+ rabies virus
/ \\ 186. Cause of spongy vector-borne encephalopathy
Cytomegaloviruses
Enteroviruses
Rabies viruses
Herpes virus
+ Prions
/ \\ 187. Viruses that form intracellular inclusions in neurons
Cytomegaloviruses
Enteroviruses
+ Rabies viruses
Herpes virus
Polymyelitis virus
/ \\ 188. Braking deficit is
+ exit of the underlying departments of the central nervous system from the control of the overlying departments
-reduction of nerve effects on postsynaptic structures
/ \\ 189. Denervation syndrome is
Violation of trophogen transport and the formation of pathotrophogens
-reduction of afferent impulse in a neuron
-the exit of the underlying departments of the central nervous system from the control of the overlying departments
+ reduction of nerve effects on postsynaptic structures
group of hyperactive neurons
/ \\ 190. Primary inhibition deficiency develops as a result of
Excessive stimulation of the nervous system
+ disturbances in the structure and function of inhibitory neurons
-increasing the synthesis of exciting mediators
/ \\ 191. Secondary inhibition deficiency develops as a result of
+ actions of depolarizing agents of excitatory amino acids, leading to excessive activity of neurons
Violations of the structure and function of inhibitory neurons
Violations of the structure and function of excitatory synapses
-reducing the synthesis of exciting mediators
-excess of downward inhibitory effects in the destruction of parts of the nervous system
/ \\ 192. The effect of disinhibition syndrome may be
-development of dystrophic changes in neurons and innervated structures
+ formation of GPUV (pathologically enhanced excitation generator)
-development of denervation syndrome
-development of organ atrophy
-development of deafferentation syndrome
/ \\ 193. The pathologically enhanced excitation generator (GPUV) is
+ aggregate of hyperactive interacting neurons producing an uncontrolled flow of pulses
- a set of cascade membrane and intracellular processes
-complex changes in synaptic structures
Violation of trophism due to loss or change of nerve effects
The complex of changes that occur in postsynaptic neurons, organs and tissues after loss of nerve effects on these structures
/ \\ 194. The importance of the formation of GPUV
-promotes the formation of spilled braking
+ is a determinant of the pathological system and contributes to the formation of the pathological system
promotes the formation of a physiological system
- strengthens the trophic effect of a neuron on innervated structures
- inhibits the development of neuropathological processes
/ \\ 195. Slow Hyperkinesis
cramps
+ athetosis
-tics
-chorea
-tremor
/ \\ 196. Neurosis can lead to development
+ duodenal ulcer
-meningitis
spongy vector-borne encephalopathy
Encephalitis
Alzheimer's disease
/ \\ 197. For central paralysis is characteristic:
-saving arbitrary movements
-weakening of tendon reflexes
+ strengthening tendon reflexes
lack of pathological reflexes
muscle tone reduction
/ \\ 198. For peripheral paralysis is characteristic
amplification of spinal reflexes
-appearance of pathological reflexes
muscle hypertrophy
+ muscle hypotension
hypertonicity of muscles
/ \\ 203. Pain mediators
physiological concentrations of adrenaline
enkephalins
endorphins
+ bradykinin
dynorphin
/\\ 204. A sensation of pain forms in
nociceptors
nerve trunks
spinal cord
reticular formation
+ neurons of the thalamus and cerebral cortex
/ \\ 205. Most susceptible to pain
+ skin and mucous membranes
-liver
-brain
-spinal cord
myocardium
/ \\ 206. Phantom pain is pain
-in the left hand and left shoulder blade with an attack of angina pectoris
over the collarbone in acute hepatitis or irritation of the parietal peritoneum
for diseases of the brain
+ in a missing part of the body, most often after amputation of limbs
Pancreatitis
/\\ 207. In the pathogenesis of phantom pain are important
-increase nociceptor sensitivity
-increased conduction of nerve trunks
-increase the excitability of the cerebral cortex
The formation of amputation neuroma and the formation of a pathologically enhanced excitation generator in the spinal cord
inhibition of the excitability of the brain stem
/\\208.To the antinociceptive system
bradykinin
+ gelatinous substance
ions N, K
-histamine
-substance P
/\\ 209. Decrease in pain sensitivity during skin rubbing and massage due to
-reducing nociceptor sensitivity
blockade of nerve conductors
-reducing the excitability of neurons in the reticular formation
suppression of the excitability of thalamus neurons
+ activation of the gelatinous substance of the spinal cord
/ \\ 211. The leading link in the pathogenesis of diabetic hyperosmolar coma is
+ hyperglycemia
ketosis
lactatacidemia
hypoxia
hyperazotemia
/ \\ 212. The cause of ischemic stroke may be
+ thrombosis or embolism of cerebral vessels
rupture of cerebral aneurysm
cerebrovascular dystonia
arterial hyperemia of the brain
- decrease in blood coagulability
/ \\ 213. The cause of hemorrhagic stroke may be
+ arterial hypertension
-stenotic cerebral arteriosclerosis
thrombosis and embolism of cerebral vessels
cerebrovascular angiospasm
-increase hematocrit
/ \\ 214. In ischemic stroke, in contrast to hemorrhagic stroke, the clinical picture often predominates
Brain edema
+ Focal symptoms
-Blood in cerebrospinal fluid
-Compression of brain tissue
-Increased intracranial pressure
/ \\ 215. Cerebellar ataxia, memory disorders for current events, nystagmus, dysarthria, dysphagia, hiccups, dizziness are characteristic of damage
+ Vertebral artery (posterior lower cerebellar artery)
Anterior cerebral artery
- Middle cerebral artery
- posterior cerebral arteries
-Pial arteries
/ \\ 216. Paresis or spastic paralysis of the limbs (proximal arm and distal leg), loss of sensation on the opposite side of the lesion is observed with damage
Vertebral artery (posterior lower cerebellar artery)
+ Anterior cerebral artery
- Middle cerebral artery
- posterior cerebral artery
-Pial arteries
/ \\ 217. Patient M., 64 years old, diagnosed with ischemic stroke, revealed: positive Babinsky reflex on the left, loss of sensation on the left side of the body.
Research of meat of sick and compelled-killed animals
It is known that meat and slaughter products obtained from sick animals can be a source of human infection with zooanthroponic diseases and the occurrence of foodborne diseases. Therefore, the main task of a veterinarian is to ensure the production of meat and meat products that are safe for human life and health.
Healthy animals that have undergone planned diagnostic tests are allowed to slaughter from settlements that are safe for infectious diseases. Animals sent for slaughter are subject to veterinary examination with selective thermometry at the discretion of the veterinarian.
Slaughter of animals sick and suspected of contracting an infectious disease or threatened with death (severe injuries, fractures, burns and other injuries) is permitted in cases provided for by the relevant instructions, as well as the Rules of veterinary inspection of slaughtered animals and veterinary sanitary examination of meat and meat products (from 1988).
It should be remembered that there are often cases when meat suppliers intentionally try to sell meat obtained from corpses, sick and animals killed in an agonal state. Therefore, one of the most important tasks of a vetsanexpert is to identify the meat of sick animals and corpses. To solve this problem, a set of measures is used, consisting of the study of supporting documents (veterinary certificate or certificate, etc.), organoleptic and laboratory studies.
The purpose of the lesson: to develop methods for determining the meat of sick animals; establish from which animal the meat was obtained: healthy, sick or dead.
Work plan:
1. Examine accompanying documents for meat.
2. Conduct an organoleptic examination of meat, lymph nodes of the internal organs and meat broth 1: 3.
3. To conduct a physico-chemical study of meat (determination of pH, reaction to peroxidase, formalin test, reaction with copper sulfate).
4. Prepare smear prints from the deep layers of meat, lymph nodes and organs, stain them according to Gram and Olt and conduct microscopy.
5. Issue a research protocol and, based on the results of organoleptic and laboratory studies and the study of supporting documents, give a veterinary and sanitary assessment of meat.
Material support: hourglass for 2 min, 100 ml heat-resistant flasks with a cap and 200 ml (2 pcs), glass sticks, 2 and 5 ml pipettes, pear, funnels, cotton filter, paper filter, 100 ml measuring cylinder , burette, tripod, mortar, pestle, enamelled cuvette, scissors, anatomical tweezers, scalpel, microscope, test tubes (10 pcs.), slides, bacteriological loop, bacteriological bridge, clotted milk, gas burner (spirit lamp), meat samples 100 g each from healthy, sick animals and corpses (set for 2-3 people), analytical balance eskie (accuracy - 0.01 g), digital pH meter, Michaelis kit, electric stove, water bath, distilled water, 5% copper sulfate solution, 0.2% benzidine solution, 1% hydrogen peroxide solution, neutral formalin, 0 , 1 n. caustic soda solution, 5% oxalic acid solution, immersion oil, fuchsin, gentian violet, iodized alcohol, Lugol's solution, 2% safronin, filter paper, hand disinfection solution.
Study of accompanying documents
When delivering animals for slaughter, the supplier must submit a veterinary certificate - form No. 1 or a veterinary certificate - form No. 4 (when transporting within the area). Studying this document, special attention should be paid to the epizootic state of the locality from which the animals arrived, the timing and results of planned diagnostic tests (for tuberculosis, brucellosis, etc.) and vaccinations. When referring to forced or diagnostic slaughter of sick animals, the diagnosis must be indicated in the accompanying document.
Laboratory sampling
Sampling for physico-chemical research and microscopy is carried out after organoleptic examination of the carcass and organs. Three samples of meat, 200 g each of the front, middle and back parts of the carcass, are taken. For the preparation of smears, it is additionally possible to select lymph nodes and pieces of internal organs (liver, kidney, spleen, lung).
Organoleptic research
Carcass bleeding rate
Poor bloodless meat has a darker color. To determine the degree of bleeding of meat, blood filling of blood vessels, which are especially clearly visible on the serous membranes, is looked at. In addition, you need to see the presence of blood on the surface of a fresh cut of meat, to determine the moisture content of the cut, use a strip of filter paper.
There are four degrees of meat bleeding: Good - there is no blood in the blood vessels, the cut surface is dry, a small amount of meat juice is possible.
Satisfactory - a small amount of blood is found in small blood vessels, there is no blood in the muscles, the incision surface is wet.
Bad - detect blood in small and medium blood vessels, when pressed on the surface of the incision, blood drops are released.
Very bad - they detect blood in small, medium and large blood vessels, the serous membranes are purple-red in color, blood is released on the surface of the incision.
The meat of corpses has a very poor degree of exsanguination, the meat of seriously ill animals killed in an agonal state is bad or very bad.
Definition of hypostases
In corpses and poorly bloodless carcasses, blood seeps through the walls of blood vessels and collects in the lower part of the carcass, forming hypostases - blood-saturated areas of blue-red color. Since hypostases form in the lower part of the carcass, the upper part of the carcass of the corpse can be satisfactorily bled. Therefore, by the part of the carcass or a piece of meat it is impossible to judge the bleeding of the whole carcass.
Determination of the location of the cut
The place of the cut is checked if the slaughter was carried out in an open way. If the animal at the time of slaughter was healthy, then the place of the cut will be uneven and saturated with blood. This is due to the fact that muscles do not die immediately after slaughter, individual muscle fibers relax, and others contract, in addition, bleeding takes place through the incision site. When simulating the slaughter of a corpse, the notch site is even and not saturated with blood. Therefore, private individuals supplying meat to the market are forbidden to clean the place of cutting.
Determination of the condition of the lymph nodes
In carcasses and organs obtained from healthy animals, lymph nodes are yellow or gray. In corpses and animals killed in an agonal state, due to poor bleeding and hypoxia, the lymph nodes are pink to purple. In sick animals, with the development of inflammatory processes, the lymph nodes can be enlarged, while the edges of the section turn out, and hemorrhages and other pathological changes can be on the surface of the section.
Determination of fatness of carcasses and organs
When determining the fatness of animals, special attention is paid to the presence of signs of exhaustion. In contrast to emaciation, dystrophic and degenerative changes in muscles and adipose tissue occur during exhaustion. In depleted animals, the consistency of fat becomes gelatinous. It is most convenient to determine the state of adipose tissue between the vertebrae after dividing the carcass into half carcasses.
The meat of depleted animals is sent for technical disposal.
Determination of pathological changes in organs and tissues
Laboratory research
when determining the meat of sick animals
When determining the meat of sick animals, the following physicochemical studies are carried out: determination of meat pH, reaction to peroxidase (benzidine test), determination of the products of primary protein breakdown (formol test and reaction with copper sulfate), cooking test. In addition, microscopy of smears of fingerprints stained according to Gram and capsules of B. anthracis is also carried out.
Before determining the pH, staging the reaction to peroxidase, as well as the formol test and the reaction with copper sulfate, the meat must be aged for at least 20-24 hours to mature.
In the study of meat of sick animals, a microbiological study of meat and internal organs is carried out to identify the causative agent of the disease and second microflora (Salmonella, E. coli, Proteus, etc.).
Imprint smear microscopy
Technique for making a smear print. Smears are prepared from the upper and deep layers of each sample. A piece of meat with a size of at least 1.5 x 2.0 x 2.5 cm is cut from a profiled sample with sterile scissors, the surface of the slices is applied to a sterile glass slide (three prints on two glass slides). Smears are circled on the back of the slide with a wax pencil, then dried in air, fixed over the flame of a gas burner and stained by Gram and capsules of anthrax according to Olta.
Gram stain. Carbolic gentian violet is poured onto fixed smears through a strip of filter paper, after 2 min the paint is poured and the smear is washed with water, then Lugol's solution is poured for 2 min, then iodized alcohol is poured for 1 min, in conclusion, the smear is washed with water and stained with fuchsin for 2 min . Then the smear is washed and dried with filter paper.
Coloring by Olga. The fixed smears are stained with freshly prepared warmed 2% safranin solution for 1-2 minutes (anthrax bacteria are stained in brick red and yellow in capsules).
The smear is microscopic at a large magnification of the microscope (630-900 times) under emersion. On one slide, 25 fields of vision are examined.
In fresh meat obtained from a healthy animal, microflora should not be.
Physico-chemical studies
Cooking sample
Statement of the reaction. Prepare a meat broth 1: 3. On a laboratory balance (Fig. 15), 20-30 g of meat is weighed. Then a portion of the meat is ground with scissors to the state of minced meat, placed in a 100 ml conical flask. Using a measuring cylinder, 60-90 ml of distilled water is measured and added to a meat flask. The flask is closed with a watch glass and placed in a boiling water bath for 10 minutes.
Accounting for the reaction. To account for the reaction, the glass is lifted and the aroma of the broth vapor is determined. After that pay attention to the transparency of the broth: the meat of a healthy animal - the broth remains transparent, the aroma is specific; meat of a sick or killed animal in an agonal state - clouding of the broth is noted, the aroma is weakened, extraneous odors (medicinal, etc.) are possible; corpse meat - a muddy broth with cereal, a musty or putrid smell.
Determination of primary protein breakdown products in meat
The reaction with copper sulfate. The essence of the method lies in the fact that the products of the primary protein breakdown contained in the broth filtrate and copper sulfate form complex compounds that precipitate.
Statement of the reaction. Prepare a meat broth 1: 3, for this, add 20 g of minced meat to a conical flask, add 60 ml of distilled water and mix thoroughly. Cover the flask and heat for 10 minutes in a boiling water bath. Then the hot broth is filtered through a dense layer of cotton wool with a thickness of at least 0.5 cm into a test tube placed in a glass of cold water. If the filtrate contains flakes, then it is again filtered through a paper filter.
After filtration, 2 ml of filtered broth is poured into a test tube and 3 drops of a 5% copper sulfate solution are added, shaken 2-3 times and incubated for 5 minutes.
Accounting for the reaction: meat of a healthy animal - the broth remains transparent; meat of an animal killed by them in an agonal state
There is clouding of the broth, and in the broth of frozen meat
Intense turbidity with the formation of flakes; corpse meat - flakes are formed in the broth, falling into a jelly-like precipitate.
Formula test (used only in the study of beef). The essence of the method consists in the precipitation of the products of the primary degradation of the protein with formaldehyde.
Statement of the reaction. Prepare the hood 1: 1. To do this, take a sample of 10 g of muscle tissue without fat and connective tissue and place it in a mortar, where it is ground with scissors to a state of minced meat, then 10 ml of a 0.9% sodium chloride solution and 10 drops of 0.1 N are added there. sodium hydroxide solution. The contents of the mortar are carefully rubbed with a pestle to a creamy consistency and transferred to a flask. The flask is heated on an electric stove, stirring with a glass rod to precipitate proteins (to gray). The flask is cooled with cold tap water. The contents of the flask are neutralized with 5 drops of a 5% solution of oxalic acid and filtered through a paper filter. 2 ml of the obtained meat extract filtrate were taken into a test tube and 1 ml of neutral formalin was added.
Accounting for the reaction: meat of a healthy animal - meat extract remains transparent; meat of a sick or killed animal in an agonal state - the meat extract becomes cloudy, a flocculent precipitate falls out; corpse meat - a jelly-like clot forms in the meat extract.
Peroxidase reaction (benzidine test)
Peroxidase is an enzyme that is found in the tissues of an animal and destroys peroxide compounds formed during metabolism. The essence of the reaction lies in the fact that peroxidase decomposes hydrogen peroxide, and the atomic oxygen generated in this process quickly oxidizes benzidine to paraquinodiimide, which forms a blue-green compound with a benzidine residue that turns brown.
Statement of the reaction. Prepare meat extract 1: 4. A sample of 10-20 g of meat chopped with scissors to the state of minced meat is placed in the flask, 40-80 ml of distilled water are added and extracted for 15 min, stirring the contents of the flask with a glass rod or using a magnetic stirrer (Fig. 16), and then filtered through a paper filter.
Fig. 16. Magnetic stirrers
2 ml of filtered meat extract is added to the tube, 5 drops of a 0.2% alcohol solution of benzidine are added, the contents of the tube are shaken, and then two drops of a freshly prepared 1% hydrogen peroxide solution are added.
Accounting for the reaction: meat of a healthy animal - the hood acquires a blue-green color, turning in brown-brown within 1-2 minutes (positive reaction); meat of a sick or killed animal in an agonal state - the hood acquires a blue-green color, turning within a few seconds into brown-brown (dubious reaction); corpse meat - the hood either does not acquire a specific blue-green color, or a brownish-brown color immediately manifests itself (negative reaction).
Determination of pH of meat
the pH of the meat is determined by potentiometric and colorimetric methods.
Potentiometric method. The pH of meat is determined using an analog or digital potentiometer (pH meter) directly in the meat with a special electrode-knife (Fig. 17) or in an aqueous extract prepared in a ratio of 1:10. The extract is infused for 15 minutes with periodic stirring and filtered through a paper filter. Determination of pH is carried out according to the instructions (passport) for operation of the potentiometer (pH meter). In the process, periodically check the accuracy of the instrument using standard buffer solutions.
Colorimetric method using the Michaelis comparator.
Statement of the reaction. Prepare meat extract 1: 4. A 20 g sample of meat chopped with scissors to forcemeat is placed in the flask, add 80 ml of distilled water and mix vigorously for 15 minutes, after which it is filtered through a paper filter.
Fig. 18. Michaelis Comparator
the pH is determined using color standards sealed in test tubes and a comparator with six sockets (Fig. 18), arranged in 2 rows of 3 in each. Test tubes are inserted into the nests of the comparator and filled as follows: 2 ml of meat extract are added to the test tubes of the first row, then 5 ml of distilled water are added to the outer tubes, and 4 ml of distilled water and 1 ml of indicator are added to the central one (0.1% paranitrophenol solution). 7 ml of distilled water is added to the central tube of the second row, and standards are inserted into the extreme nests, selecting them so that when observing through horizontal holes, their color matches the color of the contents of the middle tube. The pH of the meat will correspond to the number indicated on the label of the standard.
Accounting for the reaction: the pH of the meat of a healthy animal is 5.6-6.2; the pH of the meat of a sick animal is 6.3; The pH of the meat of the corpse is shifted to the alkaline side - above 6.4 and can reach 7 and above.
Veterinary and sanitary assessment of meat of sick animals and corpses
The meat is considered to be obtained from a healthy animal in the presence of good organoleptic characteristics of the carcass, the absence of pathogenic microbes in the smears, a pH value in the range of 5.6-6.2, a positive reaction to peroxidase and negative indicators of the formalin test and the reaction with copper sulfate.
The meat of patients, as well as overworked animals, has insufficient exsanguination, a pH in the range of 6.3–6.5, a dubious reaction to peroxidase, and flakes are formed during the formulation of the formaldehyde test and the reaction with copper sulfate.
The meat of animals killed in a state of agony has poor bleeding, a lilac-pink or cyanotic color of the lymph nodes, pH 6.6 and higher, a negative reaction to peroxidase, and a formalin test and a reaction with copper sulfate are accompanied by the formation of a jelly-like clot.
Meat and slaughter products obtained from corpses and animals killed in an agonal state are sent for technical disposal.
The issue of the use of meat and slaughter products obtained from sick animals is resolved after a diagnosis is established in accordance with the Rules for the pre-slaughter inspection and the post-mortem veterinary examination of meat and meat products (from 1988) and other applicable regulatory documents.
The meat of healthy animals is used without restriction.
2 ml of the filtrate, 5 drops of a 0.2% alcohol solution of benzidine and 2 drops of a 1% solution of hydrogen peroxide are poured into a test tube.
An extract from fresh meat of healthy animals acquires a green-blue color, which turns brown in a few minutes. In extracts from the meat of sick, overworked and killed animals in agony, the color does not change, but sometimes a green-blue color appears, with a long delay and quickly turns into brown.
The reaction to peroxidase can be set without preparation of the extract: 2 drops of 1% solution of hydrogen peroxide and 5 drops of 0.2% solution of benzidine are applied to a fresh meat incision. The appearance of a blue-green spot with a subsequent transition to brown is regarded as a positive reaction, the absence of a colored spot is considered a negative reaction.
FORMULA REACTION
The meat of animals killed after prolonged agony or a serious pathological condition can be recognized by the formal reaction indices ..
A meat sample is freed from fat and connective tissue. A sample of 10 g is placed in a mortar, thoroughly crushed with scissors, pour 10 ml of physical. solution and 10 drops of 0.1 n sodium hydroxide. Grind the meat with a pestle. The resulting slurry was transferred with a glass rod to the flask and heated to boiling to precipitate the proteins. The flask is cooled with tap water, after which its contents are neutralized by adding 5 drops of 5% solution of oxalic acid and passed into a test tube through filter paper. The turbid extract is filtered again or centrifuged.
The progress of the reaction. 2 ml of extract is poured into a test tube and 1 ml of neutral formalin is added.
An extract from the meat of an animal killed in agony, seriously ill, or butchered after death, turns into a dense clot; in the extract from the meat of a sick animal, cereals fall out, the extract from the meat of a healthy animal remains liquid and transparent, sometimes a slight turbidity appears.
Formalin is preliminarily neutralized with 0.1 N sodium hydroxide according to an indicator consisting of an equal mixture of 0.2% aqueous solutions of neutralrot and methylene blue until the color changes from violet to green.
Sanitary assessment of meat
It is carried out according to the results of the study and is recorded in the workbook.
If signs are found that indicate that the animal was killed during the agony (hypostases, poor bleeding, lack of reaction at the site of infection), carcasses and organs are subject to technical disposal.
In meat from a healthy animal there are no pathogenic microorganisms, the pH is in the range of 5.7-6.2, the reaction to peroxidase is positive.
Meat at pH 6.3 and above and a negative reaction to peroxidase are considered to be suspicious in originating from a sick or compulsory killed animal.
SPECIAL MEAT ACCESSORIES
An attempt to pass off the meat of one type of animal for the meat of another type of animal, as a rule, more valuable is called species falsification and may take place in markets in the distribution network and catering establishments. Therefore, a veterinarian must be able to determine the species of meat. Typically, for species falsification, carcasses of animals of similar size, shape and other characteristics are used. So horse meat is usually tried to be passed out for beef and vice versa (in some countries where horse meat is valued higher), carcasses of large dogs are given out as mutton, cats are tried to be given out for rabbits and nutria. To determine the species of meat, objective and subjective methods are used.
Subjective methods for determining the species of meat. Subjective methods include such as configuration, morphological and organoleptic characteristics of meat, etc.
Organoleptic indicators
Meat color determination
The color of meat and the structure of muscle tissue depend on age, sex, fatness of animals and other reasons.
The meat of cattle can be from light red to dark red, in the cross section it is coarse-grained.
Horse meat dark red
After cooking, the meat of pigs and calves becomes white or light gray, the meat of cattle, sheep and horses - dark gray.
In the presence of hydrogen peroxide and peroxidase, benzidine forms a more complex compound of two molecules, colored in blue. It gradually decomposes to form a brown substance.
The disadvantage of the benzidine reaction is its diffusivity. To eliminate it, ammonium molybdenum acid is added to the reagent, which precipitates the colored substance.
Reagents
1) 0.85% solution of sodium chloride.
2) 0.1% solution of ammonium molybdenum acid in saline.
3) A saturated solution of benzidine in saline.
4) 20% hydrogen peroxide solution.
5) A mixture of hydrogen peroxide with benzidine at the rate of 1 drop of hydrogen peroxide per 2 ml of benzidine (mix before use).
Reaction
1. Place slices in a 0.85% sodium chloride solution at 4 ° C in a watch glass for 3 minutes.
2. Treat the sections with a solution of 0.1% ammonium molybdenum acid in saline for 5 minutes.
3. Treat the sections with a solution of benzidine, mixed before use with hydrogen peroxide, for 5 minutes (until a blue color appears).
4. Rinse the slices with fresh chilled saline.
5. Observe the localization of the blue color.
The results of the reaction (tab. 28, 29)
Blue crystals drop out in the cabbage leaf at the sites of active peroxidase accumulation. The reaction occurs in all tissues of the leaf with a noticeable intensity, moreover, more or less evenly throughout the parenchyma. In beams, the phloem part is especially intensely colored. Cambium stains much weaker. The abundance of peroxidase in the phloem, apparently, is explained by the fact that plastic substances moving through the cells undergo partial oxidation and are spent on the synthesis of substances from new cells formed by the cambium.
In corn kernels, the reaction proceeds with insignificant intensity. The color in the embryo is almost as weak as in the endosperm. A more intense color characterizes the conductive elements. The staining of the cytoplasm of the cells giving the reaction is uneven, the plastids stain much more strongly than the cytoplasm.
Meat is classified as perishable food. During storage, it can undergo various changes. These changes occur under the influence of the own enzymes of the meat itself (tan) or in the process of the vital activity of microorganisms (mucus, mold, redness, blueness, glow, rotting). The most dangerous type of meat spoilage is rotting, since protein is destroyed and substances harmful to the body are formed.
Organoleptic and laboratory methods are used to determine the freshness of meat. According to GOST 7269 - 79 "Meat. Sampling methods and organoleptic methods for determining freshness ”evaluate the appearance, color, texture, smell of meat, the state of fat and tendons, as well as the transparency and aroma of the broth (cooking sample). Each sample taken is analyzed separately. GOST 23392-78 "Meat. Methods of chemical and microscopic analysis of freshness ”involves the determination of volatile fatty acids, the reaction with a 5% solution of copper sulfate in broth, and bacterioscopy of fingerprint smears.
These GOSTs apply to beef, lamb, pork and meat of other types of slaughter cattle, to meat offal (except for the liver, lungs, kidneys, spleen and brain).
By the degree of freshness, meat and meat offal can be fresh, of dubious freshness and stale.
SAMPLE SELECTION. Three pieces of muscle with a mass of at least 200 g each in the area of \u200b\u200bthe incision opposite the 4-5th cervical vertebra, in the area of \u200b\u200bthe scapula and from the group of posterior muscles are selected from the carcass or part thereof. From chilled or frozen blocks of meat and offal or from individual meat blocks of dubious freshness, a whole piece is also taken weighing at least 200 g. Each sample is wrapped in parchment paper or cellulose film. It is allowed to pack samples in plastic wrap. Each sample is marked with a simple pencil indicating the tissue or organ and the number of the carcass. All samples taken from one carcass are packed together in a paper bag and placed in a metal box that can be closed. The box is sealed or sealed if the veterinary laboratory is located outside the sampling location. An accompanying document is attached to the selected samples indicating the date and place of sampling, the type of meat or offal, carcass number, reasons and purpose of the study, and the signature of the sender.
Microscopy of smear prints. The surface of the studied muscles is burned with an alcohol swab or sterilized with a hot spatula. Using sterile scissors, cut pieces 2x1.5x2.5 cm in size. Slices are applied to a pre-laminated glass slide (3 prints on two glass slides). Imprint smears are dried in air, fixed over the burner flame, stained according to Gram (GOST 21237-75 "Meat. Methods of bacteriological analysis") and microscopic.
Meat and meat offal are considered fresh if there is no evidence of muscle tissue breakdown (poor staining of the preparation), microflora is absent, or single (up to 10 cells) cocci and rods are visible.
Meat and meat offal are classified as of doubtful freshness if they show signs of muscle tissue decay, the transverse striation of the fibers is weakly distinguishable, the nuclei of muscle fibers are in a state of decay, and 11-30 cocci or rods are found in the field of view of the smear imprint.
Determination of products of primary protein breakdown in broth (reaction with copper sulfate)
The method is based on combining copper ion with the primary products of protein breakdown, resulting in flakes or a jelly-like precipitate of bluish or greenish color appearing in stew from stale meat.
The essence of this method is the precipitation of proteins by heating and the formation in the filtrate of complexes of copper sulfate with the remaining products of the primary decomposition of proteins, which precipitate.
20 g of minced meat prepared from the test sample, placed in a 100 ml conical flask, pour 60 ml of water, mix thoroughly, cover with a watch glass, put in a boiling water bath and bring to a boil. The hot broth is filtered through a dense layer of cotton wool with a thickness of at least 0.5 cm into a test tube placed in a beaker with cold water. If protein flakes are visible in the broth after filtration, it is additionally filtered through filter paper. 2 ml of the filtrate is poured into a test tube and 3 drops of a 5% copper sulfate solution are added. The tube is shaken 2-3 times and put in a tripod. The reaction is read after 5 minutes.
The result of the reaction. Meat and meat offal are considered fresh if the broth remains clear when a copper sulfate solution is added. Meat and meat offal are classified as of doubtful freshness, if the broth of the broth occurs when adding a solution of copper sulfate, and in the broth of thawed meat - intense clouding with the formation of flakes.
Meat and meat offal are considered fresh if, when a solution of copper sulfate is added, a jelly-like precipitate is formed, and large flakes are present in the thawed meat broth.
The reaction with formalin (formalin reaction). The method is based on the oxidation of benzidini by hydrogen peroxide in the presence of a meat enzyme, peroxidase.
A meat sample is freed from fat and connective tissue. A sample of 10 g is placed in a mortar, thoroughly crushed with scissors, 10 ml of physiological saline and 10 drops of decanormal sodium hydroxide solution are added. The meat is ground with a pestle, the resulting slurry is transferred with a glass rod to the flask and heated to boiling to precipitate the proteins. The flask was cooled with tap water, after which the contents were neutralized by adding 5 drops of a 5% solution of oxalic acid and filtered through a filter paper into a test tube. If the hood is cloudy, it is again filtered and centrifuged. 2 ml of the extract prepared as described above is poured into a test tube and 1 ml of neutral formalin is added to it.
The result of the reaction. If the filtrate is clear or slightly cloudy, the meat is considered obtained from a healthy animal; if it turns into a dense clot or flakes form in it, the meat is considered to be received from a sick animal or killed in a state of agony.
Peroxidase response In the presence of the peroxidase enzyme, hydrogen peroxide oxidizes benzidine, forming paraquinondamide, which gives a blue-green compound that turns brown. In extracts from fresh meat (benign), the reaction to peroxidase is positive. The indicators of this reaction for assessing the freshness of meat are as important as determining pH.
2 ml of extract prepared from minced meat and distilled water in a ratio of 1: 4 are added to the test tube, 5 drops of a 0.2% alcohol solution of benzidine are added, the contents of the tube are shaken, and then two drops of a 1% solution of hydrogen peroxide are added.
The result of the reaction. The meat is fresh if the hood acquires a blue-green color, turning in brown-brown within 1-2 minutes (positive reaction); stale, if the hood either does not acquire a specific blue-green color, or brown-brown immediately appears (negative reaction).
Microbiological methods- determination of the amount of substance in raw materials based on the use of microbiological cultures in biological experimental animals. These methods are based on the fact that an environment of optimal composition is necessary for the vital functions, growth and reproduction of microorganisms (6).
