Two publicly-listed Chinese dairy companies on Wednesday issued written apologies to consumers over the tainted baby formula scandal, and promised to pay double the state-set compensation to victims.

Both Yili and Mengniu, two dairy products company groups based in north China's Inner Mongolia Autonomous Region, were found by the State Administration of Quality Supervision, Inspection and Quarantine (AQSIQ) to have produced baby milk powder contaminated with melamine. A further 20 companies were also named by the AQSIQ as having produced contaminated baby formula products.

The scandal was exposed after some babies who fed on milk powder produced by Hebei Province-based Sanlu Group were found to have developed kidney stones.

The exposure then triggered a nationwide investigation.

The contamination has so far killed three babies. There were at least 6,244 infant victims of the contaminated baby milk powder scandal, among whom 158, or 2.5 percent, have acute kidney failure, the Ministry of Health said Wednesday morning.

The AQSIQ said they carried out test samples involving 491 batches of products sold by all the 109 companies that produced baby milk powder in the country.

The inspectors found chemical melamine in 69 batches of baby milk powder produced by 22 companies, including four of 28 batches of baby milk powder produced by Mengniu, and one of the 33 product batches made by Yili.

The melamine content in the Sanlu brand reached 2,563 mg per kg, the highest among all the samples. In other samples, the range was from 0.09 mg to 619 mg per kilogram.

The chemical was not found in dairy products served for the Beijing Olympics and Paralympics, which were supplied by Yili Group.

The government has ordered a halt to the sale of the contaminated products in China.

Yili Group said in a written apology that it had recalled all the unsold contaminated baby formula for three to six-year-olds after it was told of the inspection result by AQSIQ on Tuesday.

"For consumers who have bought this problematic batch of children formula, please feel free to contact us to return it," said Yili in the document.

In a related development, Mengniu also promised in a written statement to take back all the types of contaminated baby formula products, and added that it would bear all the costs of doing so.

Baby milk powder production lines were halted, and changes in production would take place, said Mengniu in the written apology, without specifying what those changes would be.

In a vaguely-worded statement, Mengniu also said it would pay double the state-set compensation amount to all consumers who fall ill within five years of consuming the three types of contaminated baby formula products made by the company.

Yili is listed on the Shanghai Stock Exchange, and Mengniu has gone public with the Hong Kong bourse.

Melamine is used in plastics and other industries and is strictly forbidden in food processing. Experts say it is added to raw milk so the protein content of the milk appears higher than it actually is.

So far four people have been arrested in connection with the contamination of Sanlu products.

The government has so far seized 2,176 tonnes of milk powder in warehouses of the Sanlu group, based in Shijiazhuang, capital of Hebei. About 8,218 tonnes of Sanlu milk powder currently on the market had been recalled, said Shijiazhuang Vice Mayor Li Jinlu on Monday.

(Xinhua News Agency September 17, 2008)