Additional 31 batches of milk powder were found to contain melamine while most products of this kind on the market were safe, the country's food safety watchdog said on Wednesday following a nationwide special check on the chemical.

The State Administration of Quality Supervision, Inspection and Quarantine said it had tested 265 batches milk powder produced by 154 different companies prior to September 14, and found 31 batches produced by 20 domestic dairy companies were tainted with melamine.

The new batches being tested were mostly milk powder products for adults. The melamine content in the Sanlu brand reached 6,196 mg per kg in its so-called high iron and zinc formula, the highest among all the samples.

The State Administration for Industry and Commerce (SAIC), which supervises product quality at the retail level, on Wednesday ordered all the tainted products to be immediately removed from shelves.

The contaminated products were to be sealed at the site and kept from re-entering the market, said the SAIC on its website.

Industry and Commerce organs at all levels were asked to post notices that include brand and batch number of the tainted milk powder in shopping malls, supermarkets and other dairy markets, in a bid to inform and warn the consumers.

Chinese inspectors have found the chemical melamine in 69 batches of baby milk powder produced by 22 companies nationwide in the mid-Sept. The authorities then ordered a halt to the sale of the tainted products which included such well-known brands as Sanlu, Mengniu, Yili and Yashili, among others.

Relevant departments have begun an investigation of the implicated companies to find out the problematic source and punish those responsible.Tian Wenhua, board chairwoman and general manager of Sanlu Dairy, was detained by police for questioning and fired from her posts in the wake of the tainted milk powder scandal.

China's food quality has been criticized recently, as 13,000 infants nationwide were hospitalized with kidney problems and at least three were killed after drinking baby formula tainted with melamine, a toxic chemical added to raw milk so the protein content of the milk appears higher than it actually is.

(Xinhua News Agency October 3, 2008)