BEIJING: China's health minister on Wednesday reported a third death from contaminated baby formula and said more than 1,300 babies remained hospitalized, including 158 for acute kidney failure, in what has become a rapidly widening food safety scandal.

The minister, Chen Zhu, presented the figures just a day after the government said a dangerous chemical additive had been discovered in samples of infant milk powder produced by 22 Chinese dairy companies. Before that disclosure, officials had focused their investigation on a single company, the Sanlu Group, which has acknowledged producing formula powder laced with the additive, melamine.

At a news conference Wednesday morning carried on national television, Chen said that in total 6,244 babies had been sickened so far by the tainted powdered formula. Most of the children had recovered.

On Tuesday, China Central Television, the state-run network, reported that an inspection of 175 dairy companies had found traces of melamine in some batches of baby formula at 22 of them, including Sanlu.

Dairy companies quickly began recalling products, including the country's largest dairy operation, Mengniu. At the same time, the government has sent more investigators to inspect dairy companies across the country.

The scandal is especially charged politically because government officials pledged to reform food safety regulation after a spate of problems last year. In one highly publicized case, thousands of pets in the United States were sickened by pet food made with a Chinese ingredient tainted with melamine.

Melamine is an industrial chemical used to make plastics and fertilizer. But in the past, Chinese farmers have admitted using the chemical to artificially inflate protein levels in feed or other agricultural products.

Infants sickened by the tainted formula have developed kidney stones and other ailments. On Monday, less than a week after the first disclosures about the bad formula, the Ministry of Health announced the second infant death and said that 1,253 babies had been sickened over all, including 53 still hospitalized in serious condition. The revised figures on Wednesday included 6,244 babies sickened.

The third death was reported in Zhejiang Province; the earlier ones were in Gansu Province.

Meanwhile, Hong Kong authorities announced Tuesday that traces of melamine had been discovered in frozen yogurt made by the Inner Mongolia Yili Industrial Group. In response, the Hong Kong supermarket chain Wellcome announced that it would stop selling frozen yogurt made by the company, according to news agency reports.

Public anger seems to be rising. This week, parents of sickened children have congregated outside the Sanlu Group corporate headquarters in the city of Shijiazhuang, in Hebei Province.

China News Agency, a government service, reported that the company's chairwoman, Tian Wenhua, stepped down Tuesday. The company has blamed suppliers for providing tainted milk.

Chinese officials have blamed the company for failing to come forward about the problem. Parents with sick children began complaining as far back as March, and Fonterra, a New Zealand dairy corporation that owns a large minority stake in Sanlu, said it learned of the problems in August and tried to prod Sanlu into making a public recall.

Sanlu did not do so until state media reported the problems last week.

The police have announced the arrest of two more suspects, a farmer and a milk dealer in Hebei Province. Earlier, two brothers who worked as milk dealers in Hebei were arrested.

Dairy farming is a rapidly expanding business and competition is fierce. Some dealers have admitted to diluting milk with water, but doing so lowers protein levels. As a result, melamine, rich in nitrogen, is sometimes used to artificially inflate those levels.