Milk Adulteration Tests: What Dairy Farmers and Vendors Should Know

Milk adulteration means that something has been added to milk that does not belong in it, such as water, urea, detergent or starch. Simple lab tests can find the common ones. For a dairy farmer, a vendor or a cooperative, they give useful information about a sample, but they do not replace official food-safety testing.

Why does milk get adulterated?

Some people add water or other substances to make milk go further, to make it look thicker, or to hide that it has turned sour or dirty. Others add preservatives or neutralisers so that milk keeps longer in hot weather. Some of these additions are harmless in small amounts, and some can harm people, especially children and the sick. A farmer who adds nothing can still be blamed when a collection centre finds a problem, so a clean, documented test of the milk as it left the farm can be valuable.

Which adulterants do the tests look for?

The lab can check for several common ones, often as a group:

• Added water, which dilutes the milk and can be found by how the milk freezes.
• Urea, which can be added to raise the solids reading.
• Detergent, which makes milk look foamy and thick.
• Starch, sugar and salt, used to add body or weight.
• Neutralisers, hydrogen peroxide and formalin, used to hide souring or to preserve milk.

The Milk Adulteration Screening Panel typically checks for several of these at once, and the exact list is confirmed when you book. Single tests can also be asked for, such as the Milk Urea (Adulteration) Test, the Milk Detergent Test and the Milk Added Water (Freezing Point) Test. The freezing-point test works because water added to milk raises the temperature at which it freezes.

What does a result mean?

A negative result means the lab did not find that substance in that sample, using that test. A positive result is a reason to look further, for example by testing a fresh sample again. Results are for your information, as an owner. They do not replace the testing done by the food-safety authorities and approved laboratories, and the lab does not quote legal limits. Bad cleaning, old milk or dirty containers can also affect some readings, which is why careful sampling matters.

How should the sample be taken?

Take the sample from well-mixed milk. Wash your hands, and use a clean, dry, lidded container that has not held anything else. Fill it, label it with the animal or farm name, the date and the time, and keep it cool. Bring or send it quickly, because milk changes as it stands. If the milk is from several animals mixed together, say so on the label. Do not add any preservative unless the lab tells you to.

Who benefits most from testing?

Dairy farmers who sell to a dairy or directly to households can show that their milk was checked. Vendors and collection centres can screen the milk they buy before it is mixed with other milk. Cooperatives can look at supplies from many members. The Milk Quality & Adulteration Pack groups composition, adulteration, residue, bacteria and cell count checks for these buyers and sellers.

When should you see a vet?

If milk looks clotted, stringy or bloody, or the udder is hot and swollen, the animal may have mastitis, and a vet should examine her. That is a health problem in the animal, not adulteration, and it needs its own tests. A registered veterinarian can examine the animal and read any health test together with her signs and history.

Read next

Milk problems often start in the herd. For a disease that can pass to people through milk, read Brucellosis in Cattle and Buffalo: Why Herd Testing Matters, and for the safety side of handling herds, see Brucellosis in Herds: Testing, Safety and What to Tell the Vet.

Testing in Bhopal

The lab at C-200, C Sector, Shahpura, Bhopal accepts milk samples, and sample collection is free anywhere in Bhopal. Call or WhatsApp +91 88175 01118; the lab confirms the method, sample needs and reporting time when you book, and other districts can send chilled samples by courier or through their vet.