Police in northwestern China investigating nitrate-tainted milk that killed three infants and sickened 36 others announced Monday that the chemical was intentionally added, according to New China News Agency.
Nitrate is used for making dyes and curing meat but is not found in dairy products.
It is not clear why nitrate was added to the milk. Police have arrested two suspects and two farms have been shut down. Most of those who fell ill were younger than 14 and the deaths involved infants younger than 2.
China's dairy industry is still reeling from a milk scandal in 2008 in which melamine-tainted milk killed six infants and sickened 300,000 people.
In the current case, Xiang Jianren, 36, an oil field worker who spends weeks on end away from his family, was the father of one of the children that fell ill after drinking the milk from a local farm. He saw his nearly 3-month-old daughter for only the second time Thursday, and by the next day she was in the intensive care unit at the People's Hospital in the city of Pingliang city.
"She started throwing up 10 minutes after we fed her milk and turned very pale," he said. "There were six or seven doctors working on her. At one point they told us she would probably die."
Xiang switched to local milk after friends told him that it would be better for his daughter.
"After we heard of the tainted milk coming from Yili and Sanlu, we didn't trust the baby formula from the supermarket anymore," he said, referring to two of China's largest dairy companies that were found to be selling melamine-tainted milk.
From now on, Xiang said, he would buy only imported infant formula at a significant cost to his family.
In response to the melamine scandal, the General Administration of Quality Supervision, Inspection and Quarantine toughened standards for dairy producers and investigated dairy firms across China. Only 55% of companies inspected passed the new standards.
Despite increased vigilance by the government, the nitrate-laden milk came from a farm that was not officially licensed to sell milk and therefore not inspected by the authorities.
Haas is a special correspondent.