What are Common Adulterants in Milk and How to Detect Them?

What is Milk Adulteration?

When is Milk Considered Adulterated?

What are the Common Adulterants in Milk?

What is the Difference Between Milk Adulteration and Contamination?

Despite their many differences, adulterating and contaminating milk have detrimental health impacts. See the table below to gain a better understanding.

Milk Contamination

Milk Adulteration
The term "milk contamination" describes the process of declining material quality. "Milk adulteration" describes adding certain lawfully allowed compounds to milk.
This can occur organically or due to numerous environmental factors, including heat, humidity, etc. Artificial factors are the reason behind this. This is a profitable technique carried out by merchants or businesspeople.
Detection methods include microbiological testing, chemical analysis, and sensory evaluation to identify harmful contaminants. Requires specialised laboratory tests and analytical techniques to identify and quantify contaminants accurately.
It can lead to foodborne illnesses, infections, toxicity, or other adverse health effects. If consumed, depending on the type and concentration of contaminants present. Depending on the nature of the adulterants, it may pose health risks due to the addition of harmful substances, such as toxins, allergens, or chemical residues.
It can occur due to unsanitary conditions during milk production, processing, or storage, leading to microbial growth or chemical contamination. To increase volume, mask quality deficiencies, or enhance certain properties of milk.
Contaminants may include pathogenic bacteria (e.g., Salmonella, E. coli), antibiotics, pesticides, heavy metals, and toxins from environmental sources. Adulterants such as water, urea, starch, sugars, and synthetic chemicals may be added to milk.
It is unintentional and often unavoidable, typically due to environmental contamination or improper handling. Intentional and deceptive acts aimed at deceiving consumers and maximising profits.

How to Check Adulteration of Milk at Home?

Consumers often need help in identifying contaminated or adulterated milk. Fortunately, several simple yet effective methods can be employed at home to detect potential adulterants and assess milk quality.


Ways to Detect
Water Participants in this test must aim for a milk drop at any slanted surface. Pure milk will flow slowly and leave a trace; thus, if it flows quickly, it must contain water. There will undoubtedly be no trace of tainted milk.
Starch Boli 2 to 3 millilitres of milk with 5 millilitres of water. Once it cools, add 2 to 3 drops of iodine tincture. If the mixture turns blue, it has starch in it.    
Urea The taste of milk remains unchanged, and it is difficult to identify the presence of urea. As a result, people must combine a tablespoon of milk with soybean powder and shake thoroughly to determine whether the milk they drink daily contains urea. 
They must then dip a litmus paper for a brief period. The sample contains urea if the colour shifts from red to blue.
Detergent Many detergents are used to degrade milk. To determine whether detergent is present in milk, people must shake 5–10 millilitres of milk well with equal water at home. 
If they observe that mixing milk and water creates a thick foam, it indicates possible adulteration in milk. Pure milk forms a thin film of foam.
Synthetic Milk Synthetic milk may taste a bit more bitter than pure milk. When you rub the synthetic milk between your fingers, the texture of the liquid becomes soapy, and when you heat the synthetic milk, it starts turning yellow.    

Laboratory Methods to Test Milk for Adulteration

These sophisticated analytical techniques, conducted in accredited laboratories by trained professionals, provide reliable milk quality and authenticity assessments.


Laboratory Test
Vanaspati Lab workers must add three millilitres of milk, ten drops of hydrochloric acid, and one tablespoon of sugar to a test tube. After five minutes of resting the mixture, they must check for colour changes. If the combination becomes red, vanaspati is present in the milk.
Formalin Lab personnel must add 10 millilitres of milk to a test tube. Next, they must carefully pour 5 millilitres of concentrated formalin out the side of the test tube wall. The acid must be properly poured without being shaken. 
A reddish-purple ring formed at the interface between two layers indicates the presence of formalin in the mixture.
Hydrogen Peroxide To specifically detect hydrogen peroxide during a milk adulteration lab test, lab personnel will fill a test tube with three drops of para phenylene diamine and five millilitres of silver nitrate reagent.
They will then thoroughly shake the mixture. The milk includes hydrogen peroxide if the hue turns blue.
Salt To find salt in milk, laboratory professionals place 5 millilitres of silver nitrate reagent in a test tube and add two to three drops of the potassium dichromate reagent. 
They will then add one millilitre of milk and thoroughly mix it. There is salt present if the mixture becomes yellow.
Boric Acid Lab workers will take 3 millilitres of milk and put 20 drops of hydrochloric acid in a test tube to determine whether or not the milk contains boric acid. They will then give the mixture a good shake. They will dip a yellow paper strip in the mixture and let it sit for a minute. 
After adding one drop of ammonia solution, milk contains boric acid if the combination changes from red to yellow and then back to green.
Ammonium Sulphate Lab workers must fill a test tube with heated milk (5 millilitres) and citric acid to finish the lab testing of tainted milk. The generated whey will then be separated and filtered.
Subsequently, they must transfer the whey to an additional test tube and incorporate 0.5 millilitres of 5% barium chloride. Precipitate in the test tube is a sign that ammonium sulphate is present.

Harmful Effects of Milk Adulteration

FAQs about Milk Adulteration