CHENNAI: “All dairy depots within the city have storage units that can store milk for two days at least. That’s how they manage sales when there’s a dairy strike,” said Ponnusamy SA, the founder and president Tamil Nadu Milk Dealers Employees Welfare Association. He, however, added that Aavin spoils earlier than other milk, suggesting that the level of adulteration maybe lower.
However, Aavin managing director C Kamaraj argued that the milk is poured into bulk cooling booths at co-operative societies. “Within 2-3 hours of milking, the milk is brought to 40 Celsius, preventing growth of microbes,” he said, adding that it is distributed within 12 hours procurement.
Responding to a question from a Tamil news channel, minister KT Rajenthra Bhalaji said the government would not remain a mute spectator in the matter. “The judges are also watching the news. Samples of private milk have been sent to Pune for scientific examination,” he said.
When pointed out that the comments might create panic among the people, and asked whether the government had any alternative plans to supply milk to them if the people stopped buying private milk, the minister said, “Aavin can supply any quantity of milk. We are manufacturing milk powder with the surplus milk. We will stop production of powder and would supply that milk to the people.”
A Quality Control researcher said urea or soap detergent is the most commonly used adulterant. “Pure milk and its products always have a shade of yellow. If the milk is white, it either means that buffalo milk is mixed in it or Urea (a chemical used in manufacture of fertilisers) is used for whitening,” Kamaraj said.
He added that pasteurised milk also loses its ability to froth when boiled or vigorously shaken. “The milk that froths usually has soap detergent in it. One may have noticed in some tea shops that froth fills half the glass,” he said.
When asked about milk that lasts longer than 20 hours, the researcher said that pasteurised milk has a shelf life of 24 hours. “Organisms called Psychrophiles can’t be killed by pasteurisation. While they don’t cause harm to humans or change the milk’s taste, they consume all healthy components of the milk and render it useless health-wise,” he said adding that any milk must be consumed in less than a day. Pasteurised milk is kept at 72 degrees Celsius for 15 seconds and chilled at 5 degrees immediately.
“Milk called UHT (Ultra High Temperature) milk has high shelf life and when refrigerated and preserved air-tight, it can be stored up to 90 days,” he said. UHT milk is briefly heated to 1250 C and chilled at 50 C immediately, and sealed in special air tight tetra packs made in sterile environments. “This milk can’t be stored in polythene bags,” he said.
While minister Rajenthra Bhalaji accused private dairy industries of adulteration, Aavin alone may not be able to meet the demand of the State. “The milk requirement in Tamil Nadu stands at 1.5 crore litres, and Aavin produces between 25 lakh and 30 lakh litres,” said Ponnusamy.
Clean or unprocessed milk
Shelf life: 6-7 hours. On exposure to air during milking, about 2,000 microbes enter the milk and double every hour. By the tenth hour, there will be a crore microbes in the milk
Shelf Life: Up to 3 days when refrigrated at 5 degrees Celsius Without refrigeration, the milk may spoil in under 12 hours. It is heated only to the extent to kill harmful pathogens and does not wipe away all microbes from the milk
Ultra-High Temperature (UHT) milk
Shelf life: up to 90 days The milk does not spoil when it’s stored in a cool air-tight environment. The milk has to be consumed within 12 hours of opening the tetra pack.