How to Test the purity of Milk

1) How to test Starch in Milk?

Starch is a carbohydrate. It is commonly found in potatoes. When starch is added to milk the concentration of starch increases and the concentration of fat decreases in the milk. To check if your milk is adulterated with starch, add two tablespoons of salt to about 5 ml of the milk, if the mixture turns blue, it is confirmed that it contains starch.

2. How to test the water in milk?

You are paying for the milk, not for water. So, if you want to check the presence of water in milk, put a drop of the milk on your fist or an elevated surface and let it move down. If the drop leaves behind a trail, water has been added to the milk.

3. How to test synthetic milk?

Chemicals, soap, detergents and added to natural milk to produce synthetic milk or to increase its quantity. If milk tastes bad or different, it could be a synthetic one. Furthermore, if it feels soapy on rubbing or turns yellowish in color on heating, it is synthetic milk.  

4. Heating test to test milk?

Take around 100 ml of milk and boil it at low flame for two to three hours until it solidifies. If the residue left after heating is rough, hard and solid, the milk has been adulterated. However, if the residue is oily, the milk is pure.

5. How to test urea in milk?

Urea is added to milk to increase its shelf life. To detect urea, mix one tablespoon of milk with soyabean or arhar powder and shake well. Then after five minutes, put a litmus paper in the mixture for around 30 seconds. If the color of the paper changes from red to blue, your milk has been adulterated with urea.