(CNN) -- China's health ministry said a clinical investigation has found no evidence that milk powder made by a Chinese company caused three infant girls to grow breasts, according to the state-run Xinhua news agency.
The health ministry launched an investigation in Hubei province after claims that milk powder led to premature sexual development in infant girls.
Ministry spokesman Deng Haihua said Sunday the hormone content of the powder was within normal limits, Xinhua reported.
According to Xinhua, Deng said food safety experts tested the residue of milk powder consumed by the three infant girls, as well 42 samples of Synutra products on the market and 31 samples of dairy products from other producers.
The deputy head of Wuhan Children's Hospital's endocrine department said three of the four children treated for the condition had never consumed baby formula made by Synutra, Xinhua reported.
A fourth baby had used Synutra formula but then switched brands, Xinhua cited the hospital official as saying.
Last Monday, Synutra Chairman and CEO Liang Zhang in a statement called media reports "highly irresponsible and based on speculation instead of evidence."
He said that the company was working with state authorities, including the Dairy Association of China and the Office of Food Safety, to test product samples.
"We do not add hormones to our products, and we have invested heavily in research, quality control, formulations and ingredients," the statement on the company's web site said.
Liang added that the company was "in the process of taking legal action to protect our brand."
New Zealand-based Fonterra, which supplies milk powder to Synutra, said last week it remained "100 percent confident about the quality of its products."
Fonterra noted that Synutra also sourced milk locally and imported whey powder from Europe.
Estrogen hormones are banned in milk powder products, Deng said.
The case is the latest to hit China's dairy industry. In 2008, a tainted milk powder scandal involving melamine left six babies dead and sickened 290,000 in China's Hebei province.
The company at the center of it -- Sanlu Group -- filed for bankruptcy. Fonterra owned a 43 percent stake in it.