BEIJING -- Mildewed feed given to cows caused the high levels of a cancer-causing toxin found in milk from China's biggest dairy company and a smaller one, according to a government safety agency investigating the troubled dairy industry's latest scandal.
An expert review identified the mildewed feed as the cause of the excessive levels of aflatoxin in milk from industry giant Mengniu Dairy Group and the Fujian Changfu Dairy Industry Group, the quality supervision and inspection agency said in a statement posted on its website late Monday.
The agency ordered the dairies to destroy the tainted products, and it advised the public that the contamination will end once the cows stop eating the rotten feed.
Aflatoxin is produced by a fungus that commonly grows on grain and legume crops such as peanuts, soybeans, corn and wheat. The toxin turns up in the milk of animals that eat affected crops.
Though at low doses it is not considered harmful to humans, high doses are linked to cancer, especially in the liver.
Both Mengniu and Changfu have issued public apologies. Mengniu said that the tainted products were produced at a subsidiary in Sichuan province and none had entered the market. Changfu said it recalled the affected products immediately after inspectors told the company.
While once a rarity in the Chinese diet, dairy has become a staple as incomes have risen, and the industry's booming growth has been accompanied by persistent quality issues. In the worst scandal, at least six infants died and 300,000 children were sickened in 2008 from drinking infant formula and milk products made with melamine, an industrial chemical that was being added to watered-down milk to elevate protein levels in quality tests.