THE MILKY WAY-ADULTERATED WITH VERY DANGEROUS MILK
Maneka Gandhi
Since you will
not stop drinking milk, and since 70 -100 per cent of the milk has been
adulterated with very dangerous adulterants according to Food Safety Standards
Authority of India FSSAI, you should learn how to make out real milk from
synthetic. Milk samples from all over the country were checked for fat (%), SNF
(%), neutralizers, acidity, hydrogen peroxide, sugar, starch, glucose, urea,
salt, detergents, skimmed milk powder, formalin and vegetable fat. Most of the
samples were found to be adulterated.
This is how
synthetic milk is made: Vegetable refined oil is taken in a wide mouthed
container along with a suitable emulsifier and thoroughly mixed till it becomes
a thick white paste. Water is slowly added to the paste until the density of
the liquid is similar to that of milk. Then is added urea or sodium sulphate or
glucose or maltose or sometimes any one of the commonly available fertilizers
after dissolving in hot water. The refined oil in synthetic milk acts as a
source of fat whereas the hot solution of any one of the substances above
mentioned acts as a source of solids not fat (SNF). The ingredients that go in
to the making of synthetic milk are calculated in such a way that the fat and
SNF percentage is similar to mixed milk. Hence it easily passes the tests
carried out at the village level dairy co-operative society (fat and lactometer
reading etc.). This is the difference between real and synthetic milk. The
colour of both is white. But on storage real milk remains white, synthetic milk
or adulterated milk turns pale yellow. If rubbed on the palm, synthetic milk
becomes foamy. Real milk does not. Real milk does not change colour on heating.
Synthetic milk turns yellow on boiling. The pH value of real milk is 6.6 – 6.8
and of synthetic milk 10-11 (extremely alkaline). The fat content is the same
in both: 4.5 – 5 per cent, the SNF (Solid Not Fat) is also the same 8-9 per
cent.
1. Detection of Neutralizers in milk —
Rosalic acid test (Soda Test). Neutralizers like hydrated lime, sodium
hydroxide, sodium carbonate or sodium bicarbonate are added to milk. Take 5 ml
of milk in a test tube and add 5 ml alcohol followed by 4-5 drops of rosalic
acid. If the colour of milk changes to pinkish red, then the milk is
adulterated with sodium carbonate / sodium bicarbonate and unfit for human
consumption. 2. The alkaline condition of the milk for the presence of soda
ash. Take 20 ml of milk in a silica crucible. Evaporate the water and burn the
contents in a muffle furnace. The ash is dispersed in 10 ml distilled water and
it is titrated against decinormal (N/10) hydrochloric acid using
phenolphthalein as an indicator. If the titre value exceeds 1.2 ml, then it is
construed that the milk is adulterated with neutralizers. 3. Detection of
hydrogen peroxide. Take 5 ml milk in a test tube and then add 5 drops of
paraphenylene diamine and shake it well. Change of the colour of milk to blue
confirms that the milk is added with hydrogen peroxide. 4. Test for detection
of formalin. Formalin (40 per cent) is poisonous. It is added because it can
preserve milk. Take 10 ml of milk in test tube and add 5 ml of concentrated
sulphuric acid on the sides of the test tube without shaking. If a violet or
blue ring appears at the intersection of the two layers, then it shows the
presence of formalin. 5. Test for detection of sugar in milk. Sugar is mixed in
milk to increase the solids not fat content of milk. It increases the
lactometer reading of water diluted milk. Take 10 ml of milk in a test tube and
add 5 ml of hydrochloric acid along with 0.1 g of resorcinol. Shake the test
tube well and place it in boiling water for five minutes. Appearance of red
colour indicates the presence of added sugar in milk. 6. Test for detection of
starch. Addition of starch also increases the SNF content of milk. Apart from
the starch, wheat flour, arrowroot, rice flour are also added. Take 3 ml milk
in a test tube and boil it thoroughly. Cool the milk to room temperature and
add two to three drops of 1 per cent iodine solution. Change of colour to blue
indicates that the milk is adulterated with starch. 7. Test for detection of
glucose. Usually poor quality glucose is added to milk to increase the
lactometer reading. There are two tests available to detect the adulteration of
milk with glucose. Take 3 ml of milk in a test tube and add 3 ml Barford's
reagent and mix it thoroughly. Keep it in boiling water for three minutes and
cool for two minutes by immersing in tap water. Add 1 ml of phosphomolybdic
acid and shake. If blue colour is visible, then glucose is present. Take a
strip of diacetic and dip it in the milk for 30 seconds to one minute. If the
strip changes colour, then it shows that the sample of milk contains glucose.
If there is no change in the colour of the strip, then glucose is absent. 8.
Test for detection of urea. Urea is added to raise the SNF value. Five ml of
milk is mixed well with 5 ml paradimethyl amino benzaldehyde (16 per cent). If
the solution turns yellow in colour, then the milk is contaminated. Take 5 ml
of milk in a test tube and add 0.2 ml of urease (20 mg/ml). Shake well at room
temperature and then add 0.1 ml of bromothymol blue solution (0.5 per cent).
Appearance of blue colour after 10-15 minutes indicates adulteration. 9. Test
for detection of ammonium sulphate. Sulphate in milk increases the lactometer
reading. Put 5 ml of hot milk in a test tube and add citric acid. The whey will
separate. Collect the whey in another test tube and add 0.5 ml of 5 per cent
barium chloride. A precipitate indicates the presence of ammonium sulphate. 10.
Test for detection of salt. Addition of salt increases the lactometer reading.
Take 5 ml of silver nitrate (0.8 per cent) in a test tube and add two to three
drops of 1 per cent potassium dichromate and 1 ml of milk and mix. If the
contents turn yellow in colour, then milk contains salt in it. If it is
chocolate coloured, then the milk is free from salt. 11. Test for detection of
pulverized soap. Take 10 ml of milk in a test tube and dilute it with equal
quantity of hot water and then add one – two drops of phenolphthalein
indicator. A pink colour indicates soap. 12. Detection of detergents in milk.
Take 5 ml of milk in a test tube and add 0.1 ml of bromocresol purple solution.
A violet colour indicates detergent in milk. Unadulterated milk samples show a
faint violet. 13. Detection of skim milk powder in milk. If the addition of
nitric acid drop by drop in to the milk sample results in an orange colour, it
indicates skim milk powder. Pure milk shows yellow colour. 14. Detection of
benzoic and salicylic acid in milk. Five ml of milk is taken in a test tube and
acidified with concentrated sulphuric acid. 0.5 per cent ferric chloride
solution is added drop by drop and mixed well. A buff colour indicates benzoic
acid and violet colour indicates salicylic acid. 15. Detection of borax and
boric acid in milk. Add 1 ml of concentrated hydrochloric acid to five ml of
milk in a test tube and mix well. Dip the tip of a turmeric paper into the
acidified milk and dry in a watch glass at 100°C or over a small flame. If the
turmeric paper turns red, it indicates the presence of borax or boric acid. Or
add a drop of ammonia solution on the turmeric paper. If the red colour changes
to green, it shows boric acid. If I were a business person, I would start
marketing home chemical kits for milk testing: Chemicals, lactometer, test
tubes, droppers, gas burner, measuring cylinders, beakers and bottles. If I
were a school chemistry teacher, I would make my students bring milk from home
and test once a week. As a householder I would — and have — simply ban milk
from the house.
Prof. John Kurakar
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