The Sanlu Group recalled about 700 tons of its baby milk food, as one of the infants diagnosed with kidney stones after being fed the food died in Gansu province yesterday.

One of the country's largest dairy products' makers said its milk food had been contaminated with a chemical called melamine. The announcement came after the company conducted an internal investigation.

A Gansu provincial health department spokesman said that altogether 59 infants have been diagnosed with kidney stones in the province this year. Reports said many of them had been fed the same brand of milk food. No infants were diagnosed with kidney stones last year or in 2006 in the province.