Adulteration means deliberate addition or substitution by inferior substances, or the removal of some valuable ingredient, which adversely affects the nature and quality of food, thus making it unsafe for consumption. Adulterated food can be toxic when consumed or it can deprive the body of required nutrients.
Milk is one of the essential food products consumed in almost every household daily. It contains numerous micro and macronutrients required for the development of the human body. However, its demand is too high, especially in the festive seasons (in India), which apart from the financial gains makes it more vulnerable to adulteration. The other possible reason for adulteration might be the gap in the supply chain and huge demand from the public, low socio-economic status, and less affordability by people. Moreover, a large fraction of the milk sector in India is still unorganized, and people, therefore, consume whatever is available to them. People are not bothered to check or get the milk tested in either a milk testing lab, or a NABL accredited laboratory.
WHAT ARE THE ADULTERANTS GENERALLY DETECTED IN MILK?
Milk is adulterated with water, starch, urea, detergent, glucose/invert sugar, formalin, ammonium sulfate, salt, hydrogen peroxide, glucose/invert sugar, sodium bicarbonate, boric acid.
Chenna/Paneer, Khoa, and its products are often detected to be adulterated with Starch.
Vanaspati is an adulterant detected in Sweet curd and ghee, whereas Blotting paper is exposed in Rabri. Coal Tar dyes can be detected in ghee, cottage cheese, condensed milk, khoya, milk powder, etc.
DO YOU KNOW THE REASON WHY THESE CHEMICALS ARE USED FOR ADULTERATION?
Each adulterant has its specific role to deceive the testing and hoodwink the laboratory analysis results. For instance, cane sugar, starch, sulfate salts, urea, and common salts are added to increase the SNF (solid-not-fat) in milk.
Urea is a natural component of milk, and FSSAI has henceforth, set a limit for its amount on milk, which is 70mg/100ml. Synthetic urea is added to milk to increase the non-protein nitrogen content.
Melamine is similarly used as an adulterant to increase the protein content falsely.
When water is used as an adulterant, the density of milk decreases. To trick the lactometer reading, ammonium sulfate is added to maintain the density of milk.
To increase the shelf-life of milk, formalin, salicylic acid, benzoic acid, and hydrogen peroxide are added as preservatives.
To obtain financial gain, some manufacturers remove the natural fat from milk and substitute the requirement using vegetable oil. To dissolve oil in water, and provide a thick solution, people adulterate milk with detergents, that emulsify the oils.
Fatal effects of the above-mentioned adulterants, when consumed above safety limits, can be-
Melamine -Renal Failure, Death
Peroxides, Detergents – Gastrointestinal complications, leading to gastritis and inflammation of the intestine.
Excessive starch- Diarrhea, Fatal to diabetic patients.
Urea- Overburdens kidneys.
Carbonates and bicarbonates- Disruption in hormone signaling (that regulates development and reproduction)
Hydrogen peroxide leads to concerns related to the digestive system.
Formalin consumption can lead to skin problems and cancer.
HOW TO DETECT ADULTERANTS IN MILK?
FSSAI has provided simple home procedures under DART (Detect adulteration with Rapid Test) to let the common people check for possible adulterant content in milk and milk products. There are some home-based procedures and testing strips available by which one can easily detect any possible adulterant in milk.
SOME HOME PROCEDURES FOR DETECTION OF ADULTERANTS IN MILK-
Detection of water in milk
· Put a drop of milk on a polished slanting surface.
· Pure milk either stays or flows slowly leaving a white trail behind.
· Milk adulterated with water will flow immediately without leaving a mark.
Detection of Detergent in milk
· Take 5 to 10ml of the sample with an equal amount of water.
· Shake the contents thoroughly.
· If milk is adulterated with detergent, it forms dense lather.
· Pure milk will form a very thin foam layer due to agitation.
Detection of Starch in milk and milk products (Khoya, Chenna, Paneer)
· Boil 2-3 ml of sample with 5ml of water.
· Cool and add 2-3 drops of tincture of iodine.
· Formation of blue color indicates the presence of starch. (In the case of milk, the addition of water and boiling is not required)
Detection of Mashed potatoes, sweet potatoes, and other starches in ghee/butter
· Take ½ teaspoon of ghee/butter in a transparent glass bowl.
· Add 2-3 drops of tincture of iodine.
· Formation of blue color indicates the presence of mashed potatoes, sweet potatoes, and other starches.
For synthetic milk- Synthetic milk has a bitter aftertaste. It gives a soapy feeling on rubbing between the fingers and turns yellowish on heating.
SOME OTHER ADULTERANT DETECTION METHODS-
For urea-
· Take a teaspoon of milk in a test tube.
· Add half teaspoon of soybean or arhar powder
· Mix up the contents thoroughly by shaking the test tube.
· After 5 minutes, dip a red litmus paper in it.
· Remove the paper after half a minute.
· A change in color from red to blue indicates the presence of urea in the milk.
For synthetic milk-
The milk can be easily tested using Urease strips. The color chart in Urease strips helps to arrive at the quantity of urea present in the milk.
For glucose-
· Take one piece of Diacetic strip and dip it into the milk for 30 sec to 1 min.
· If the strip changes the color then it shows the sample of milk contains glucose.
· If there is no change is observed in the strip, then glucose is absent.
For starch in Chenna/Paneer, Starch, and its products-
· Boil a small quantity of sample with some water. Cool it and add a few drops of Iodine solution.
· Formation of blue color indicates the presence of starch.
These were some of the ways by which we can detect whether milk is adulterated or not, at our home. Don’t forget to apply these simple procedures before taking milk from an unorganized source, especially during the festive seasons when the rate of adulteration is overly high. Keep yourself and your family members safe.
Stay Healthy!
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