How to check if your milk is adulterated

Some simple tests to check milk and milk products for common adulterants 

Many instances of milk adulteration have been reported

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

Credit: FSSAI

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

Credit: FSSAI

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

Credit: FSSAI

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