Mainland officials said yesterday 78 people had been questioned over the melamine contamination of 700 tonnes of Sanlu milk formula suspected of killing one child and making dozens of others ill.
Late last night the Ministry of Health confirmed that tainted milk powder was responsible for the scandal, which had again put the safety of China's food under the spotlight.
A Xinhua report said the Sanlu Group had received complaints as early as March and discovered the contamination last month - but it only announced a product recall on Thursday. It did not explain the delay.
Zhao Xinchao , deputy mayor of Shijiazhuang in Hebei , said dairy farmers and milk dealers were among those questioned.
He said tripolycyanamide - also known as melamine which can cause kidney stones - was added with water to fresh milk to raise it up to 'purchasing standard' and boost profits.
He said Sanlu was aware of a problem as early as March when consumers complained of 'red' urine and kidney stones in their babies, Xinhua reported.
Sanlu, the mainland's biggest dairy producer and a state-owned enterprise, has retained 2,176 tonnes of contaminated milk powder and recalled 8,210 tonnes of the product. About 700 tonnes of milk formula was still being pulled from the market, Mr Zhao said.
