BEIJING — The number of children in China sickened by dairy products tainted with the banned industrial chemical melamine has jumped to nearly 53,000, the government said Sunday as it vowed to crack down on those responsible for one of China's worst food safety scandals in years.
More than 80 percent of the 12,892 children hospitalized in recent weeks were 2 years old or younger, the Health Ministry said in a statement posted on its Web site late Sunday. Four children have died and 104 of the hospitalized children are in serious condition.
Another 39,965 children received outpatient treatment at hospitals and were considered "basically recovered," the ministry said.
The Health Ministry said that most of the hospitalized were sickened by powdered milk and baby formula. It said most of the sick children consumed baby formula from one company, the Shijiazhuang Sanlu Group Co. The dairy is at the center of the scandal.
"The hospitalized children basically consumed Sanlu brand infant milk powder. No cases have been found from ingesting liquid milk," said the ministry statement.
Over the weekend, the Chinese territory of Hong Kong reported the first known illness outside mainland China — a 3-year-old girl who developed kidney stones after drinking Chinese dairy products. She was discharged from the hospital, the Hong Kong government said.
Singapore said Sunday that it had found traces of melamine in another Chinese-made dairy product, milk-based White Rabbit brand candy. "Retailers and importers have been instructed to recall these products and withhold them from sale," Singapore's Agri-Food and Veterinary Authority said in a statement.
In the two weeks since the government acknowledged the contamination, it has issued recalls for dairy products from 22 companies after tests turned up traces of melamine.
Melamine is used in making plastics and is high in nitrogen, which registers as protein in tests of milk. Though health experts believe ingesting minute amounts poses no danger, melamine can cause kidney stones, which can lead to kidney failure. Infants are particularly vulnerable.
Some of the farmers who sell milk to Chinese food companies are thought to have used melamine to disguise watered-down milk and fatten profit margins hurt by rising costs for feed, fuel and labor.
In Hong Kong, parents of the 3-year-old girl took her for a checkup because she had been drinking milk made by Chinese dairy Yili Industrial Group Co. every day for the past 15 months. Yili was among the 22 companies whose products were recalled for melamine contamination.
The ministry did not say why the number of hospital cases had suddenly doubled from 6,200 on Saturday, but it suggested that health officials were combing through hospital records from May through August to trace the origins of the contamination. The deaths of three infants linked to tainted infant formula occurred in those months.
The Chinese government has launched high-profile efforts to show it is on top of the crisis, with Premier Wen Jiabao appearing on state-run television Sunday.