Beijing  - A court in northern China's Hebei province on Wednesday tried the former head of a dairy producer at the heart of a scandal over tainted milk powder linked to the death of six infants.

The court tried Tian Wenhua, the former general manager of Sanlu, and three other senior executives on charges of "producing and selling fake or substandard commodities," state media said.

The latest cases in the Shijiazhuang Intermediate People's Court followed trials this week and last week of 17 others accused of producing, selling or adding melamine-laced "protein powder" to milk, or selling tainted milk.

Hebei courts have still not announce verdicts against the 17 defendants tried earlier.

Four defendants prosecuted Monday were charged with "endangering public security," the most serious announced since the health ministry said tainted milk powder was believed to have killed six infants and sickened nearly 300,000 babies earlier this year.

Anyone convicted of endangering public security could be sentenced to at least 10 years in jail or even to death, the official Xinhua news agency reported from Shijiazhuang.

Milk dealers reportedly added melamine-laced protein powder to raw milk that was sold to Shijiazhuang-based Sanlu, which was one of China's major dairy produce retailers until the scandal broke.

Sanlu was declared bankrupt earlier last week with debts of 1.1 billion yuan (161 million dollars) after ceasing production in September.

Government officials said Sanlu knew about the contamination of milk powder with melamine since March but didn't order a national recall of the powder until September.

Melamine is used as a binding agent and coating for particle, fibre and laminated board in furniture. It is also used to make fertilizer. (dpa)