Experts share insights on milk adulteration, its detection

Milk is considered a complete food that contains all the nutrients required for physical growth and there is always a high demand for milk as it is consumed daily by almost all across age groups. The demand increases during the festivities and the wedding season as it is the main ingredient in Indian sweets, an integral part of any celebration.

Recently, the Health Department seized adulterated khoya in large quantities before Diwali and since the wedding season is going on, cases of adulterated milk and milk products also increase.

Milk is said to be adulterated if its quality is degraded or affected by addition of substances which are injurious to health or by the removal of substances which are nutritious, said Ankush Proch and Kanwarpal Singh Dhillon from PAU’s Krishi Vigyan Kendra.

According to the national survey on milk adulteration conducted by food safety and standards authority of India (FSSAI) in 2011, the most common adulterant in milk is water followed by detergent.

“Water is the most common adulterant added in milk due to the convenience of its mixing to increase the volume and also to neutralise the developed acidity to increase profits. The addition of water in milk reduces its nutritional value. If the water used for milk adulteration is contaminated then the milk consumption may leads to various waterborne disease like typhoid, hepatitis, diarrhea, cholera, shigella, etc,” Ankush Proch said.

Detergent is considered one of the most indispensable parts of the so-called synthetic fluid added in milk for the purpose of emulsification of cheap foreign fat. Detergents are added to dissolve oil and give a characteristic white color of milk. The addition of detergents can cause food poisoning and other gastric complications, added Kanwarpal Dhillon further.

The kit for testing milk adulteration is available from College of Dairy Sciences and Technology, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana. By using this kit, one can easily detect many substances used for adulteration of milk. The various adulterants which can be used for milk adulteration and their harmful effects are as under.

Methods to detect:

Detection of water: Put a drop of milk on a slanting surface. If the milk flows freely then the milk is contaminated with water and if it flows slowly then it is pure.

Detection of starch: Add 2 tablespoon of salt (iodine) to 5ml of milk. If it turns blue then the milk is adulterated with starch.

Detection of detergents: Take 10 ml of milk sample and add equal quantity of water in it. The production of lather indicates the adulteration of milk with detergents.

Detection of urea: Take milk sample and add soybean powder in it. Mix up the contents by shaking the test tube. Approximately after 5 minutes dip a red litmus paper in the sample. Remove the paper after 30 seconds and observe for any change in color. If the color changes from red to blue then there is adulteration of urea in the milk sample.

5. Detection of glucose: Take a strip of diacetic and dip it in milk sample for 30 seconds. If there is change in coloration of strip then the milk is adulterated with glucose.

Detection of formalin: Take about 10 ml milk sample in a test tube and add 5ml concentrated sulphuric acid with a small amount of ferric chloride in it. Formation of violet or blue color indicates the presence of formalin in milk sample.

Detection of hydrogen peroxide: Take about 1ml milk sample in a test tube and add 1 ml of potassium iodide starch reagent and mix well. If there is appearance of blue color then the milk sample is adulterated with hydrogen peroxide.

Detection of neutralisers: Take 5 ml milk sample in a test tube and add 5ml alcohol in it followed by 4-5 drops of rosalic acid. If the color of milk changes to red then there is presence bicarbonates in milk.