HYDERABAD: A study conducted in Hyderabad on raw milk samples collected from various markets showed presence of hexachlorocyclohexane (HCH), an insecticide. HCH residues in milk samples were higher than the Maximum Residue Limit of 0.001 parts per million (ppm) as recommended by the World Health Organisation. The study was conducted by the department of Veterinary Public Health and Epidemiology at PV Narsimha Rao Telangana Veterinary University on Tuesday.
What is HCH?
HCH are divided in alpha, beta, gamma and delta varieties. Benzene hexachloride (BHC) contained all kinds of HCH and as per reports it used to account for close to 40 pc of entire insecticide usage in India before the ban.
However, in 1997 government restricted usage of gamma-HCH, also known as Lindane to only agriculture and completely banned other HCH varieties. HCH is also a ‘persistent organic pollutant’, meaning it can stay in the environment for years together.
Not surprisingly, when milk samples were tested, all four kinds of HCH were found to be present in high amounts, especially delta-HCH.
Dr Shashi Bhushan Vemuri, former head of All India Network Project on Pesticide Residues, says, “Lindane is not much in use now and other HCHs were banned long back. A main reason behind HCHs being found in milk samples must be the residues which got accumulated in soils over several years. HCHs do not degrade easily. From the soil they spread into vegetation and water bodies. When the cattle consumes this contaminated fodder the HCH gets accumulated in their fat and gets in the milk too.”
‘Sterilisation better than boiling or pasteurisation’
Heating reduces HCH levels in milk by some percentage. The veterinary varsity tested milk samples with three heating techniques, namely, pasteurisation, boiling milk for five minutes and sterilisation. They found that sterilisation was more effective than the other two methods.