India may be the largest producer of milk in the world but is the milk really safe? A study which analysed samples in Delhi found that it contained “harmful adulterants”, the most common among them being starch, chlorine, hydrated lime, sodium carbonate, formalin and ammonium sulphate. Milk producers are known to use these substances to scrimp on milk portions and prepare “synthetic milk” by mixing urea, caustic soda, refined oil and common detergents.
Adulterated milk is linked to a range of health hazards which include gastrointestinal disorders, renal and skin diseases, eye and heart problems, and cancer, according to the study which will be published later this month in the peer-reviewed Current Science
Results of study
For their study, the researchers, led by Brototi Roy and colleagues at Maitreyi College in Delhi, randomly collected 75 milk samples (packaged and unpackaged) from different regions of Delhi, Noida, Gurgaon and Faridabad. These were tested for adulterants such as neutralisers, skimmed milk powder, urea, detergents and ammonium sulphate.
The study found that all the milk samples were adulterated with neutralisers. These are substances added to prevent curdling and increase the shelf life of milk. They could be added in the form of caustic soda, sodium bicarbonate and sodium carbonate. Packaged milk, that now forms a significant chunk of the milk delivered to homes, was found to contain a higher amount of neutralisers, solid milk products and urea. A higher proportion of unpackaged milk samples contained detergents and ammonium sulphate.
Milk adulterated with detergents is known to cause food poisoning and gastrointestinal complications. In addition, some detergents contained dioxane, a carcinogenic agent. The concentration of urea in natural milk ranges from 0.2 to 0.7 g/l whereas adulterated milk contains almost 20 times its natural concentration and stresses the kidney to the point of renal failure.
It is also reported to weaken the eyesight and trigger headaches and diarrhoea in children. In excessive quantities, ammonium sulphate can lead to coronary disease, gastrointestinal irritation with nausea, vomiting and diarrhoea.
Demand is the catalyst
Even though a majority of Indians are lactose intolerant — i.e. they lack the gene that allows milk to be digested beyond childhood — the consumption of milk and dairy products in India outstrips milk production.
At roughly 160 million tonnes annually, India accounts for a fifth of world production. This is primarily due to the overwhelming popularity of milk in north and north-west India. North-eastern States such as Arunachal Pradesh and Manipur have reduced milk consumption, according to the National Sample Survey Office. The discrepancy between production and demand incentivises adulteration.
Earlier investigations, similar to the Delhi study, have also found several instances of adulteration in other parts of the country. A 2012 report by the Food Safety and Standards Authority of India said that 68.4% of samples from across the country were found contaminated with various adulterants and fell below required milk quality standards. The study tested samples from States and Union Territories and found that barring Goa and Puducherry, all States had a significant fraction of their milk adulterated. At the other end, all the samples tested in West Bengal, Jharkhand, Bihar, Odisha and Mizoram were completely adulterated. Of these, 33.4% of packaged milk and 66.6% of unpackaged milk sold by milkmen were adulterated.