China's Health Ministry said in Beijing on Friday that it has launched a nationwide investigation into the infant kidney stone cases with a domestic milk powder, Sanlu formula, involved and asked all local health agencies to report relevant cases immediately.

The number of cases as to 24:00 September 11 should be reported to the ministry by 17:00 September 12, the ministry said in a notice issued on Friday.

"Similar cases in the future shall be reported anytime they were discovered," it said.

One baby have died of kidney stones and more than 50 others were reported suffering from kidney stones in northwest China's Gansu and other provinces this year. Investigations showed that most of the baby patients had drunk the Sanlu formula.

Sanlu Group, a leading Chinese dairy producer, said on Thursday it had found in its self-check that some of its baby milk powder products were contaminated by tripolycyanamide.

The contaminated powder was all produced before Aug. 6 this year, and about 700 tonnes have been shipped, the company said. It has decided to recall all the baby milk powder it had produced before that date.

The Health Ministry, based on investigations by relevant government departments, also said it strongly suspected that Sanlu, based in Shijiazhuang of Hebei Province, had produced milk powder contaminated by the chemical.

Health experts said tripolycyanamide, a chemical raw material, could lead to stone formation in the urinary tract of the human body.

The Health Ministry said that on-the-spot investigations are going on at the Sanlu milk power production base and those responsible for the infant kidney stone cases will face "heavy punishment".

"A joint investigation team led by the Health Ministry has reached the milk power factory. Investigations are going on. Those responsible will face serious punishment," Mao Qunan, spokesperson of the Ministry told Xinhua.

The joint investigation team consists officials from the Ministry of Agriculture, the Ministry of Public Security, the General Administration of Quality Supervision, Inspection and Quarantine, State Administration for Industry and Commerce, State Food and Drug Administration and medical professionals, according to the Health Ministry.

China's quality watchdog, the Administration of Quality Supervision, Inspection and Quarantine, is carrying out nationwide check of other baby milk powders' quality.

The Health Ministry urged the public to immediately stop consuming the Sanlu milk powder formula and go to doctors if they find babies who have drunk it have difficulty in urinating.

The ministry has also issued a treatment scheme on its official website (www.moh.gov.cn) to help local hospitals treat such sick babies.

The ministry said it has notified the development to the World Health Organization and relevant countries. Any new development of the case would be publicized immediately, the ministry promised.

(Xinhua News Agency September 12, 2008)