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Файл:Veterinary and sanitary examination of meat and meat products. Study aid
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- consistency — by pressing, cutting, chewing;
- cross-sectional view (color of muscle and fat tissue, uniformity of color) —
visually;
- smell and taste — when testing thin slices of the product.
Fresh, good-quality products have the following organoleptic characteristics:
- appearance: the surface is clean, dry, without snatches of meat and lard,
without fringes and stubble residues, the edges are evenly trimmed;
- consistency is elastic, dense;
- cross-sectional view: muscle tissue is pale pink to dark red, evenly colored;
fat is white or with a pinkish tint, without yellowing;
- smell and taste: the smell is pleasant, aromatic, smoked — for smoked
products, ham — for boiled ones; the taste is salty, spicy — for smoked products,
ham, moderately salty — for boiled products; without foreign taste and smell.
Products of questionable freshness have organoleptic indicators:
- appearance: the surface is somewhat moist, sticky in some areas, covered
with mucus;
- the consistency is somewhat softened;
- cross-sectional view: muscle tissue is unevenly colored, there are separate
areas of grayish color; the bacon has turned yellow in some areas;
- smell and taste: the smell is slightly musty, sour, there is a smell of burning
fat; the taste is sour.
For stale products:
- appearance: the surface is covered with mucus or mold that has penetrated
into the muscle tissue;
- soft consistency;
- cross-sectional view: in the muscle tissue there are areas of gray, and in
places adjacent to the bones — greenish; adipose tissue (fat) is yellow in color;
- the smell is unpleasant, putrid, moldy, rancid.
Biochemical and microscopic examination of products from meat
of slaughtered animals for freshness
When meat products spoil, as a result of decarboxylation of amino acids,
organic bases accumulate, shifting the pH of muscle tissue to the alkaline side.
The pH of meat products is determined in an aqueous extract of 1:4 using the
same method as the pH of meat (see pp. 19–22 of the book).
Fresh meat products have a pH of 5.8–6.4; questionable freshness — 6.5–6.6;
stale — 6.7 and above.
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Reaction to primary protein breakdown products
with copper sulfate in broth
The method is based on the precipitation of water-soluble protein breakdown
products from the broth with copper sulfate, which accumulate in muscle tissue when
the product is damaged.
Preparation of broth. A sample of muscle tissue weighing 10 g is ground into
minced meat, placed in a flask, poured with 60 cm3 of distilled water, heated to a boil
and boiled for 10 minutes. The flask is cooled to room temperature under running
water, the broth is filtered through a paper filter.
Analysis procedure
2 cm3 of filtrate is poured into a test tube and 3 drops of a 5 % solution of
copper sulfate are added. The test tube is shaken, placed in a stand and in 5 min the
results of the reaction is evaluated.
The reaction is considered negative and the product is considered fresh if the
contents of the tube remain transparent; questionable, and the product is of
questionable freshness if the broth becomes cloudy; positive, and the product is stale
if a jelly-like clot or large flakes form in the broth.
Determination of volatile fatty acids in meat products
The analysis procedure is similar to the procedure for determining VFAs in
non-canned meat (see pp. 22–23 of this publication).
The results are assessed in the same way as in the study of non-canned meat:
fresh meat products contain up to 4 mg KOH per 100 g of product, products of
questionable freshness — from 4 to 9 mg KOH per 100 g of product, stale — more
than 9 mg KOH per 100 g of product.
Qualitative reaction to ammonia according to Ebert
The method of carrying out the reaction and recording its results are similar to
the method used in the examination of sausage products (see pp. 82–83 of this
publication).
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Qualitative reaction to hydrogen sulfide
The method of carrying out the reaction and recording its results are similar to
the method used in the examination of sausage products (see p. 83 of this publication).
Microscopic examination of meat products
Imprint smears are prepared from the surface and deep layers of the product,
fixed over the flame of an alcohol lamp, stained with Gram and microscoped (see pp.
26–27, 84 of this publication).
Prints from fresh products are weakly colored; in the field of view of a
microscope, single microbial bodies (mainly cocci) are found in the print from the
surface layer; there is no microflora in the deep layers.
Imprint smears from a product of questionable freshness are more clearly
colored in the field of view of the microscope in the imprint from the surface layer —
up to 20 microbes, from the deep — up to 10 microbes, cocci and rods.
Prints from stale products are intensely colored; in the field of view of a
microscope, in a print from the surface layer there are up to 30 or more, from the
deep layer there are up to 20 microbial bodies, mainly rods.
Technochemical testing of products made from meat
of slaughtered animals
During technochemical testing of products made from the meat of slaughtered
animals, indicators are determined that are regulated by the relevant regulatory and
technical documentation (GOST, TU, OST, etc.).
Determination of the mass fraction of moisture in meat products
The study is carried out using the same method as determining the mass
fraction of moisture in sausages (see pp. 84–85 of this publication).
The indicator of the mass fraction of moisture is regulated only for some raw
smoked pork products: neck (mass fraction of moisture no more than 45 %) and
sirloin (mass fraction of moisture no more than 60 %).
Determination of the mass fraction of table salt in meat products
The study is carried out using the same method as determining the mass
fraction of table salt in sausages (see pp. 85–86 of this publication).
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The mass fraction of table salt in meat products should be no more than
1.3–6 %, depending on their name.
Determination of the mass fraction of sodium nitrite in meat products
It is carried out using the same method as determining the mass fraction of
sodium nitrite in sausages (see pp. 86–88 of this publication).
The mass fraction of residual nitrite in meat products should be no more than
0.003–0.005 %, depending on their name.
Determination of the mass fraction of fat in meat products
In a sample of product weighing 10 ± 2 g, weighed to the nearest 0.1 g, adipose
tissue is separated from other tissues and weighed. Next, formula (9) determines its
percentage in the product:
М
Ж
× 100
Ж = , (9)
М
0
where:
Ж is the mass fraction of fat in a sample of the product, %;
MЖ — mass of adipose tissue in a sample of product, g;
M0 — mass of the product sample, g;
100 is the conversion factor to percentage.
The value of the indicator should be no more than the value established by the
standard (usually no more than 25–65 %, depending on the name of the product). The
indicator is regulated for most products made from pork, beef, lamb, and horse meat.
Determination of the thickness of subcutaneous fat in meat products
The indicator is determined by simple measurement using a ruler. It is
standardized by regulatory documentation and can be from 1 to 4 cm: for some
products — no less than 1.5–5 cm, for others — no more than 0.5–2 cm, depending
on their name.
Determining the mass of a product unit
Determined by weighing. The weight of the product, depending on its name, should
be no more or no less than the value established by the standard (from 0.5 to 7 kg).
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Justification for veterinary and sanitary assessment of products from meat
of slaughtered animals, depending on the results of the examination
Fresh products that meet standards for all regulated indicators are released for
free sale.
Products of questionable freshness, as well as those that do not meet the
requirements of regulatory and technical documentation for at least one regulated
indicator, are subject to industrial processing.
Stale meat products are subject to technical disposal.
Test questions and assignments
1. What organoleptic indicators are regulated by the normative and technical
documentation for products made from meat of slaughtered animals?
2. Describe the organoleptic characteristics of a meat product of questionable
freshness.
3. Describe the results of a bacterioscopic examination of a meat product of
questionable freshness.
4. What physical and chemical indicators are regulated by the normative and
technical documentation for products made from meat of slaughtered animals?
5. Describe the method for determining the mass fraction of fat in products
from meat.
6. For which meat products is the moisture mass fraction regulated?
7. In what cases are meat products not allowed for free sale, but subject to
industrial processing?
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CHAPTER 11. VETERINARY AND SANITARY EXAMINATION
OF CANNED MEAT
Canned meat is meat products packaged in hermetic containers (tin or glass)
and subjected to heat treatment in order to suppress the vital activity of microflora
and reduce the activity of tissue enzymes in meat.
Rules for sampling canned meat for research
The quality of canned meat is established for each homogeneous batch based
on inspection and test results of product samples taken from this batch. A
homogeneous batch is considered to be a certain number of canned goods of the same
type and variety, in containers of the same type and size, the same date and
production change, manufactured by one facility, intended for simultaneous delivery,
acceptance, inspection and quality assessment.
From a batch of product, the number of packaging units (boxes) indicated in
the table 8 is selected for opening.
Table 8
Number of units of transport packaging selected from a batch of canned food
Number of packaging units in a
homogeneous batch, pcs.
Number of packaging units selected
for opening
Up to 500
3 %, but not less than 5 units
Over 500
2 %
Packaging units are selected from different locations in the lot. From each
selected and opened unit of packaging, 10 units of consumer packaging (cans) are
selected.
A sample of individual packaging units is combined and constitutes the
original sample.
The initial sample is subjected to external inspection to determine the number
of cans that are wrinkled, leaky in appearance and with other external defects.
Bombageand leaking cans are replaced with others selected from this batch.
To compile an average sample, the number of packaging units indicated in the
table 9 is selected from the original sample.
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Table 9
Number of cans selected to compile an average sample of canned food
Container
capacity, cm
3
Number of selected cans
for organoleptic
evaluation
for physical and
chemical tests
for bacteriological
analysis
Total
From 50 to 100
4
10
3
17
From 100 to 200
4 5 3
12
From 200 to 300
2 3 3
8
From 300 to 1,000
2 2 3
7
More than 1,000
I I I
3
Assessing the appearance of canned meat containers
The appearance of canned meat containers is assessed visually. Selected
packaging units are inspected. At the same time, the presence and condition of a paper
label or lithographic print, the content of the label inscription, as well as container
defects are noted: seal failure, drips, swelling of lids and bottoms, “birds,” slamming
lids, etc. In metal cans, deformation is especially noted: housings, lids and bottoms,
rust spots and the extent of their distribution, defects in longitudinal and seam seams;
whether glass containers have cracks, leaks, and rusty spots on metal lids.
The varnished, lithographed or unvarnished surface of the cans must be clean,
smooth, without cracks, scratches, rust, black untinned spots, without breaking the
half on the folds and longitudinal seams, without sharp deformations, teeth marks,
nicks, or “birds.” The bottoms and lids should be concave or flat, the rubber paste
should not protrude from under the folds of cylindrical cans and may protrude
slightly from under the folds of shaped cans. Lacquered jars must be coated with a
continuous layer of heat-resistant varnish. On the surface of the cans, light shoots,
dullness, imprints from rollers, surface dots with a diameter of up to 1 mm, streaks
and light surface scratches without compromising the integrity of the tinker, small
grains of tin, well-tinned pockmarks and bubbles (no more than three) with a
diameter of up to 2 mm are allowed. On varnished cans, minor external damage to the
varnish in the form of scratches is allowed.
It is allowed (provided that they are sealed) to sell cans that have vacuum
deformations in the form of dents with non-sharp edges, external soldering of folds
(for shaped cans), slight sagging of soldering along the seam, minor teeth marks and
notches in the amount of no more than two around the circumference of each fold.
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Glass jars must be transparent, clean, without internal and surface bubbles,
burrs and cracks. The body of the jar should be smooth, without bulges or
depressions, with uniform wall thickness. Dark green color, slight folds and waviness
are allowed.
The following are not allowed for sale: canned food in metal cans — bombage,
punctured, with “birds,” black spots (places not covered by half), as well as those
with sharp bends in the tin, dented folds and cans with “slamming lids” (swelling of
the bottom or lid); canned food in glass containers — with significant folds and
waviness, with colored stripes that distort the appearance of the contents.
Cans must have a paper label pasted on them or a label inscription must be
applied lithographically. It, according to GOST R 51074-2003, must indicate the
name of the manufacturer, its address and trademark, product name, grade, net
weight, standard or specification number, conditions and shelf life (for products
requiring special conditions), composition, information about the nutritional and
energy value of canned food, method of consumption. It is allowed to re-stamp the
name of the manufacturer, grade and net weight on the label, as well as re-stamp the
grade — higher to lower, weight — higher to lower.
The label should cover the body of the jar. On large-capacity cans, the label
may be in the form of a parcel.
Symbols are applied to the lids of cans using relief marking or indelible paint
in the following order:
- production number — 2 digits (up to the ninth inclusive, 0 is set in front);
- month of production — 2 digits (up to the ninth inclusive, 0 is set in front);
- year of production — last 2 digits;
- shift number — 1 digit (if the manufacturer operates in one shift, the shift
number is not indicated);
- assortment number of canned food — 1–3 digits; for premium canned goods,
the letter “B” is added to the assortment number;
- index of the system in charge of the manufacturing enterprise: 1–2 letters
(“A” — meat industry, “M” — dairy industry, “KП” — food industry, “K” — fruit
and vegetable farming, “ЦС” — consumer cooperation, “МС” — agricultural
production, “ЛХ” — forestry);
- manufacturer number — 1–3 digits.
Markings are placed in 2 or 3 rows (depending on the diameter of the can) on
the lid or partially on the lid, and partially on the bottom, without breaking the
symbols in the area limited by the first bomb ring (or rigidity ring).
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For example, canned food with assortment number 509, produced by meat
industry manufacturer No. 214 on May 31, 2015 during the second shift, are labeled
as follows:
310515 310515 on the cover:
2 509 A214 or 2 509 or 310515
А214 2 509
on the bottom:
A214
When designating an assortment number with one or two characters, a gap of 2
or 1 character is left between it and the shift number, respectively.
Determining the tightness of canned meat containers
Metal cans are first removed from labels and washed. The jars are placed in
one row in water preheated to boiling so that after immersing the jars the water
temperature is not lower than 85 °C. Water is taken in 4 times the amount relative to
the weight of the cans, so that the layer of water above the cans is at least 25–30 mm.
The appearance of a stream of air bubbles in any place of the can indicates its
leakage. The jars should be kept in hot water for 5–7 minutes, placed in a vertical
position on the bottoms, and then on the lids. Only sealed jars are selected for further
testing.
Determination of the conditions of the inner surface of metal cans
After opening the cans and removing the contents from them, the cans are
washed with water, wiped dry and the condition of their inner surface is assessed. At
the same time, the following is noted: the presence and extent of distribution of dark
spots formed from the dissolution of tinker and exposure of iron or from the
formation of sulfur and other compounds; presence and extent of distribution of rust
stains; the presence and size of soldering deposits inside the cans; the degree of
preservation of the varnish on the inner surface of the varnished container, as well as
the condition of the rubber gaskets or sealing paste at the bottom and lids of the cans.
The inner surface of the cans should be smooth, glossy, without damaging the
varnish coating, bubbles or untinned gaps. Unevenness of the coating thickness
within 2 microns, changes in the color of varnish or enamel along the longitudinal
seam (the result of exposure to high soldering temperatures), cracks in the coating in
100
places of bend with a width of no more than 0.1 mm, and sagging areas of no more
than 50 mm2 are allowed.
Organoleptic examination of canned meat
Organoleptic evaluation of canned meat is carried out after obtaining
satisfactory results of microbiological analysis.
The evaluation of canned meat is carried out heated (stewed meat, goulash,
fried meat), chilled (tongue in jelly, ham, tourist breakfast) or at room temperature
(pate) — in accordance with the method of eating this product. In the first case, after
an external inspection, the closed jar is immersed in boiling water for 20–30 minutes
(depending on the size of the jar and the type of canned food). Heated canned food is
immediately served for organoleptic evaluation; cooling is not allowed.
The entire contents of the jar are subjected to organoleptic evaluation by
placing it in a vessel (plate, porcelain cup).
Organoleptic indicators are determined in the following sequence: appearance,
color, smell, taste and consistency.
The organoleptic characteristics of canned food products are determined by
examining and testing an average sample in accordance with the requirements of the
standard or technical specifications for the corresponding type of product.
Technochemical testing of canned meat
Determination of the mass fraction
of the constituent parts of canned meat
In canned meat, the ratio of components is determined no earlier than one day
after production.
In products, the net weight and, depending on their name, the mass fraction of
meat, fat, broth, jelly, sauce, etc. are determined.
The study is carried out in the following order.
1. The label is removed from the tin can, can is thoroughly washed and wiped.
2. Determine the gross mass of canned food — weigh it on a scale with an
accuracy of up to 1 g.
3. Open the jar for ⅔ or ¾ parts, place it in a water bath (temperature 60–70 °C)
and heat the contents until the fat is completely melted.
4. While pressing the lid, the melted fat and broth are poured into a beaker for
2 minutes; easily separated fat from meat is also added.
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