Defective fresh milk from unlawful dairy farmers is to blame for the contamination of milk powder from Sanlu Group, China's largest producer of powdered milk.

At a press conference on Saturday evening, a health official said preliminary investigations have shown an industrial contaminant, melamine, was added, directly resulting in kidney stones found among babies.

Our reporter Dan Dan has the details.

"Melamine is a chemical material, which is clearly prohibited as an additive in processing food. The chemical could make the milk appear rich in protein. Putting melamine in Sanlu milk powder is an illegal act."

Gao Qiang, a senior official with the Ministry of Health, said at the press conference, that the incident of Sanlu is a serious food security accident. The Chinese government has ordered a halt of production at the Sanlu Group.

As of Friday, the country has reported 432 sick babies suffering from kidney stones. Gao Qiang said the government would take every measure possible to help cure these babies.

"The State Council has decided to offer all those sick babies medical treatment free of charge. Experts suggested that if they received treatment early enough, the babies would recover well. Plus, we'll organize more experts to go to rural areas to visit local families to find out if there are more sick babies."

It was stated that in addition to a small amount exported to Taiwan for the purpose of food processing, the majority of the baby formula produced by Sanlu was sold in the Chinese mainland.

On Thursday, the company recalled 700 tons of baby formula produced between March and August 5. In addition, the company has sealed more than 2,100 tons of milk powder that might be contaminated and recalled more than 8,000 tons as of Wednesday.

Gao Qiang said the country's quality supervision authorities have kicked off a special campaign, examining all the companies that produce baby formula across the nation.

Dan Dan, CRI news.