How to check the purity of milk


Milk is consumed very popularly across the world. It has many nutrients and vitamins that allow your body to develop and grow. Besides promoting good bone and dental health, milk helps in strengthening your body’s immunity. Hence, many doctors suggest adding milk to the daily diet as well.

Drinking milk is surely a great habit but you will have to ensure that the milk is of good quality. Many sellers often adulterate the milk to increase their profits and sell poor-quality milk. You should be very careful while buying as adulterated milk can harm your health. Various items like urea, formalin, starch, and even water are used for adulterating milk. To ensure the purity of the milk and that consuming it is perfectly safe, you should perform a few purity tests. If you are not sure about how to check the purity of milk, here are a few tests you can perform to determine the purity:

  • Boiling test: To ensure that the milk is pure, boil it in a bowl for a few hours. It will turn solid over time. This solid residue is called onerous (khoya). If the residue has a rough surface, the milk is adulterated. On the other hand, a smooth oily residue is an indication of pure milk.
  • Test for synthetic milk: You must avoid synthetic milk at all costs because it contains various chemicals including soap. Hence, it is harmful to your health. You can easily identify it from its bad taste. Also, it will feel soapy when you rub it and turn yellow when heated.
  • Test for water in milk: Water is one of the most common adulterants used for adulterating milk. Although it has no such harmful effect, it will surely prove to be quite expensive. If you want to check the purity of the milk, put a drop of milk on your palm and hold it vertically. If the drop moves without leaving a white track behind it, the milk is adulterated.
  • Test for starch in milk: Starch is often used for adulterating milk. For checking the purity of the milk, take 5 to 10 ml milk in a glass and add two tbsp of salt to it. If there is the presence of starch, the iodine will turn the milk blue. Otherwise, the colour will remain unchanged.
  • Test for formalin in milk: Formalin has a transparent colour and is used for preserving items. Hence, the milk can be preserved for a longer time. If you want to check the presence of formalin, you just have to add a few drops of acid in 5 to 10 ml of milk. A blue ring will form at the top of the milk.

Although learning how to check the purity of milk can be beneficial, you do not have to worry about the quality of the milk if you buy from trustworthy brands like Lactel.