Ways to test purity of Milk

Hello readers, thank you all for your responses to my last blog Pick the healthier Milk. Many of the readers requested for information on testing the purity of milk as milk adulteration is a common practice nowadays. So, I have penned down some tests that you can do at home to check if the milk procured by you is pure.

There are several ways in which milk can be adulterated. Mixing water with milk is one of the most common ways. Other ways to adulterate milk is adding urea, starch, carbonate, bicarbonate, peroxides, detergents, melamine, ammonium sulphate, white paint, glucose, salt, etc. Adulterants like salt, detergent, starch and glucose are added to increase the thickness, and viscosity of milk. Melamine and urea are added to milk to falsely increase its protein content. Some of these adulterants are extremely harmful as they are difficult to notice and can be hazardous if consumed.

Adulteration in milk is extremely dangerous. Consumption of adulterated milk/milk products can leave us with severe health issues like gastrointestinal complications, diarrhoea, overburdening of kidneys, disruption in hormones affecting reproduction, impairment of the functioning of various organs. Long term consumption of some adulterants can also lead to hormonal imbalances triggering early puberty in girls.

Hence, we must ensure that the milk should be tested before consumption. Keeping in mind the harmful impact of adulteration of primary food like milk, the Supreme Court in one of the cases handed out life imprisonment as against the existing law of imprisonment of up to six months/monetary fine.(Source article)

FSSAI, the body regulating the Food and safety standards in India has proposed draft amendments to the Food Safety and Standard Act. FSSAI has recommended stringent punishments to curb food adulteration. One of the proposed key amendments states that any act of food adulteration done by a person which renders it injurious for human consumption is a punishable offence which can lead to a maximum of life imprisonment and also fine which shall not be less than Rs.10 lakhs. (Source article)

Common ways to check the purity of milk at home

Testing for Water added to Milk: One of the easiest ways to check if water has been added to the milk is to pour a few drops of milk on a slanted surface. If it flows slowly leaving a white trail behind, it is pure milk. However, if the milk flows down immediately without leaving any trail, it is impure.

Starch in the Milk: Sometimes Starch is added to milk to increase its viscosity. The presence of starch can be detected by using iodine solution. Add a few drops of iodine to a sample of milk. If it turns blue then starch is present in the milk. You can easily buy iodine solution online and it is also available at the chemist stores.

Presence of Formalin in Milk: Formalin is added to the milk to increase its shelf life. Formalin is a colorless solution of formaldehyde and water and is very toxic. It can severely damage the liver and kidneys. To find out the presence of formalin take 10-15 ml of milk in a glass and add 2-3 drops of sulphuric acid into it. If a blue ring appears on the surface it is adulterated.

Synthetic Milk: Nowadays a lot of suppliers are making synthetic milk by adding paints, oils, etc to milk. This kind of milk can be easily differentiated from pure milk because of its bitter taste. Further, when you rub this milk in between your palms, you get a soapy feeling. This is an indicator that the milk is synthetic.

Detergent: Detergents typically contain chemicals like caustic soda, bicarbonates, sodium carbonates, etc., which are added to milk to increase its shelf life. To find out if detergent is present in the milk take about 5-10 ml of milk in a transparent glass and add an equal amount of water to it. Now shake it vigorously. If dense lather is formed on top of the solution, it is an indicator that detergent has been added to the milk.

Presence of Urea: Urea is another common adulterant. To check the presence of urea, mix some milk with powdered Arhar (Toor) dal, shake well and set aside for 5 minutes. Now dip a red color litmus paper in the solution for 30 sec. If its color changes from red to blue, then the milk is adulterated with urea. Litmus paper can be easily bought from online stores.

In its quest to battle milk adulteration, The National Dairy Development Board (NDDB) has developed and commercialized ready to use kits to check adulteration in milk. These kits are available online and are not very difficult to use. Little vigilance can help us prevent several health issues.