The Shanghai Municipal Bureau of Quality and Technical Supervision said Wednesday it was investigating whether Dumex, the powdered-milk unit of France's Danone Group, had produced milk powder contaminated with melamine.
The bureau said it followed the order of the General Administration of Quality Supervision, Inspection and Quarantine to investigate the safety of Dumex milk powder that was produced before September 14 last year.
The bureau did not explain why the date was chosen. The bureau declined to give further details on the investigation.
Dumex milk powder was on sale in China on Wednesday.
Overseas media reported last month that 48 Chinese infants "recently" suffered kidney illnesses after drinking Dumex milk powder.
However, Dumex Baby Food Co Ltd external affairs director Pu Jiabin told Xinhua on Wednesday said there were no medical reports or other evidence supporting that 48 infants were sickened by Dumex milk powder.
After China's milk scandal was exposed last September, government-certified laboratories conducted spot checks on 2,651 batches of Dumex products made since April 2007, and found none of them was contaminated by melamine, Pu said.
The company official said Dumex had provided the baby milk powder for the Shanghai Municipal Bureau of Quality and Technical Supervision.
Dumex said on its Chinese Web site www.dumex.com.cn that it sold the most baby milk powder on China's market in 2005 and 2006 in terms of sales volume and revenue.
It also said on its Malaysian Web site www.dumex.com.my Wednesday that "the current situation in China has been incorrectly reported and our colleagues there have confirmed that Dumex products manufactured in China have been tested thoroughly by certified official laboratories and were found to contain no melamine."
Melamine contamination of milk powder killed at least six Chinese infants and sickened almost 300,000. More than 300 children were still in hospital at the end of last December, according to the Ministry of Health.
Two people have been sentenced to death for their roles in the contamination, while the ex-chairwoman of Sanlu Group, which was at heart of the scandal, was jailed for life.