New tests by the national food quality watchdog have detected the toxic chemical melamine in 31 milk powder products from 20 mainland manufacturers.
Of the companies, 15 had not previously been identified as making adulterated milk products. The finding takes the number of dairy companies found to have distributed products tainted with melamine to 37.
One sample from the Sanlu Group contained 6,196 milligrams per kilogram of melamine, while the level of the chemical in another sample from the Shijiazhuang Baocheng Dairy Company was as high as 5,577.29mg/kg.
Melamine was also detected in samples from the Hunan Nanshan Dairy Company, with levels ranging from 2,200mg/kg to 5,624mg/kg.
Melamine is an industrial chemical. Producers and their suppliers dilute milk to make more money, and add melamine to the diluted milk to allow it pass tests for protein content. The practice has led to the deaths of at least four babies on the mainland and made more than 54,000 others ill.
The General Administration of Quality Supervision, Inspection and Quarantine said on its website yesterday that tests in the past two weeks had covered 265 products from 154 firms and found 11.7 per cent contained melamine. It said the 154 companies accounted for more than 70 per cent of the market and included Sanlu and several of its partners in Hebei province .
The contaminated samples were mostly products for adults. The administration said all of them were produced before September 14 and that batches made after that date were safe.
