chemical tests for meat

1. Chemical Tests for
Differentiation of
Meat
Meat Hygiene and
Public HealthDr. M. Wasim Usmani
Dept. of Pathology, FVS-UAF

2. Chemical Tests
• Fat Test
• Iodine value Test
• Refractive Index of Fat
• Biological Tests
• Compliment
Fixation test
• Precipitation
• Anaphylactic test
• Glycogen Test

3. Fat Test
• To identify horse fat
• Beef/Mutton
• 1-2% Linoleic acid
• Omega-6 fatty acid
(18-C Unsaturated)
• Minimum (Never
higher than 0.1%)

4. Iodine Value Test
• Detection of horse fat
• Iodine value
• Number of saturated and unsaturated
fatty acid
• Amount of iodine absorbed by
unsaturated fatty acids present in fat
Goat 36-45%
Sheep 35-46%
Hog fat 52-65%
Horse 71-86%
Ox 38-48%

5. Refractive Index
• Estimation of fat
• Liquefied by heat & converted into oil
• Every lipids have specific refractive
index
Fat of Horse = 53.5
Fat of Ox = 40

6. Biological Tests
• Antibodies production in blood
• Repeated infection of blood serum from
another animal
• Species specific antibodies used to
identify antigens
• Precipitation
• Horse flesh identification
• Infect rabbit with blood serum of
horse
• Blood serum from infected animal
• Filtered extract of suspected meat
• Turbidity of solution followed by
precipitation

7. Glycogen Test
Introduction/Objective
• Animal starch
• Reserve polysaccharide
• Liver (4-8%)
• Muscles (0.5-1%)
• Horse/Foetal flesh
• D, 1-4 & D, 1-6 Glucosidic
linkages
• Molecular weight is 4,000,000
• Recognition or Estimation of
glycogen in meat products or
sausages

8. Significance
Less desirable and even objectionable for
eating purpose
Horse flesh is not permitted to be sold by
butchers (specific purpose)
Differentiation of meat

9. Important Features
• Doubtful that weather consumption
would be prejudicial to health but sale is
unjustifiable due to,
• Consumption of flesh of unborn animals is
repugnant
• To prevent the entry of Brucella abortis
• Cow suffering from tuberculosis metritis
• Stillborn calves effected with congenital
tuberculosis
• Flesh must be condemned

10. Limitations
• Glycogen disappears from meat due
to its decomposition
• Glycogen content should be more
than 2% of dry matter (horse flesh)
• In sausage (high % of glycogen)
• Difficult to sort out liver, fetal or
horse flesh

11. • Iodine solution forms an
adsorption complex with
glycogen molecule
• Appearance of Color
• Intensity of color
• Strength of complex
• Complicated branching of
glycogen
• Dark brown
• Wine red
• Straight glycogen
• Blue