The Ministry of Health announced on Sunday that it had found no evidence of contamination in milk powder made by a Chinese company after an investigation into reports that it had caused baby girls to show signs of premature sexual development.

At a press conference in Beijing, ministry spokesman Deng Haihua said the investigation found that the contents of sex hormones in Synutra milk powder and samples of 20 other brands did not exceed the qualified amounts of either national or international standards.

The Synutra milk formula was reported earlier this month to have caused at least three infant girls in Hubei to develop prematurely.

Similar cases were reported in Guangdong, Shandong, Anhui, Jiangxi provinces and Beijing.

Deng said that 42 samples of milk powder made by Synutra were tested together with 31 samples from 20 other brands, which were collected from the home of one of the girls affected, the markets of Wuhan in central China's Hubei Province and in Beijing.

Professor Wu Xueyan, an expert in endocrine research at the Peking Union Medical College Hospital, said the three infant girls undergoing premature development should be diagnosed as "minimal puberty", which is usually seen among infant boys up to six months and in girls up to two years old.

"Minimal puberty" as a natural result of hormone secretion would make infants develop prematurely, Wu explained.

Infant girls under the age of two who are sensitive to hormone secretion could grow breasts, Wu said.

According to Wu, the experts studied the medical histories, clinical symptoms and chemical test reports on the three girls.

"The three infants did not show premature development of bones or height, and the growth of their breasts was within the normal ranges of minimal puberty," Wu said.

When asked to comment on the increasing number of cases involving premature development over the past decade, Wu attributed it to greater awareness of the problem and a rise in hospital visits.

"I believe more parents will pay attention to the problem after this incident, which might trigger a rise in hospital visits and more such diagnoses," said Wu.

Shao Bing, a researcher at the Beijing Center for Disease Control and Prevention, said experts from different medical institutes jointly tested more than 70 samples of milk powder products.

"The samples were delivered by the Ministry of Health, each was given a number, but with no trademark," Shao said. "The method of testing was widely applied during the Beijing Olympic Games and proved to be effective and safe."

Testing for the hormone content of dairy products was not a standard part of quality inspection procedures, but routine testing was feasible, though expensive, said Shao.

Plans for regulations and standard procedures to test milk formula will be formulated in the near future, Deng said.

Synutra's official website on Sunday carried a public letter written by company president Zhang Liang on Aug 12, expressing regret for the panic and the public concern over the company's products.

(China Daily August 16, 2010)