Three companies have been found selling milk products tainted with melamine, the industrial chemical responsible for the deaths of six children and injuring 300,000 in 2008.

Three batches of milk products have been ordered off shelves by the health department in Guizhou Province because they contain melamine, local media reported.

These products are: A batch of products produced by the Shandong Zibo Lusaier Dairy Company Ltd on April 25, 2009; a batch of popsicles produced by the Liaoning Tieling Wuzhou Food Company Ltd on April 9, 2009; and a batch of popsicles produced by the Laoting Kaida Refrigeration Plant at Tangshan, Hebei province on March 19, 2009.

It follows the country's most notorious food scandal in Sept 2008, when the chemical melamine was found in the milk products of 22 dairy companies around the country. The industrial chemical causes kidney stones and kidney failure among children.

The National Business Daily reported that melamine-tainted products were found and banned in Sichuan province and Jiangsu province last December.

An official who participated in the investigation in Mianyang of Sichuan said a government body in Beijing ordered the investigation.

Wang Dingmian, former chairman of the Guangdong Provincial Dairy Association, said the products likely contained tainted milk recalled after the 2008 scandal but which somehow made its way back into the market.

"After the 2008 scandal, most tainted milk products were recalled. However there were still some leftovers in the dealers' hands that nobody cared about. The problems were not totally solved. From this point, it's inevitable to see new problems popping out," he said in an interview yesterday.

According to local media reports, the three companies said their products contain melamine because they bought milk powder as a raw material to use in their products.

"The companies were just shirking their responsibilities. The companies should have been required to test each and every batch of milk powder they bought," Wang said.

Wang said the latest scandal exposed weak government regulation of the market because it involved leftover tainted milk.

"The government should be more responsible and avoid bureaucracy. You can't just assume that everything is fine," he said.