How to check if your milk is adulterated

Reports of substandard and adulterated food frequent the front pages of newspapers. Samples of items we consume daily—milk, pulses, oils, vegetables, sugar, among many others—have been rated substandard.

While it is difficult to track the production process and locate the item’s source, simple tests can help you distinguish a pure sample from an adulterated one.

Food Safety and Standards Authority of India (FSSAI), under the Ministry of Health and Family Welfare, has released a list of tests to detect some common food adulterants using household ingredients. The book is a compilation of tests for Detecting Adulterants with Rapid Testing (DART) covers common adulterants like artificial and toxic colours, extraneous matter.

In the first article of a series, we look at some easy ways to test milk for adulterants.

Test 1: Water in milk

• Put a drop of milk on a polished, slanting surface
• Pure milk either stays or flows slowly leaving a white trail behind
• Milk adulterated with flow immediately without leaving a mark

Test 2: Detergent in milk

• Take 5-10 millilitres (ML) of milk sample and equal quantity of water
• Shake the mixture thoroughly
• If the milk is adulterated with detergent, it forms dense lather
• Pure milk will have a thin layer of foam

Test 3: Detecting starch in milk and milk products

• Boil 2-3 ML of the sample (milk, khoya, chenna or paneer) with 5 ML of water
• For other ghee and butter, water need not be added
• Add 2-3 drops of tincture of iodine after letting it cool
• Formation of blue colour indicates the presence of starch

Tests and images sourced from FSSAI’s booklet “DART”.

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