WASHINGTON (AP) – Tainted infant formula from China may be on sale at ethnic groceries in this country, even though it is not approved for importation, federal officials warned on Thursday.

However, the Food and Drug Administration stressed that the domestic supply of infant formula is safe.

FDA officials are urging U.S. consumers to avoid all infant formula from China, after several brands sold in that country came under suspicion of being contaminated with melamine, a chemical used in plastics. Officials said there have been reports from China of babies developing kidney stones as a result. There have been no reports of illnesses in the U.S.

“We’re concerned that there may be some infant formula that may have gotten into the United States illegally and may be on the ethnic market,” said Janice Oliver, deputy director of the FDA’s food safety program. “No infant formula from China should be entering the United States, but in the past we have found it on at least one occasion.”

After hearing of the latest food safety scandal in China, the FDA checked with formula manufacturers who have approval to market here. But none receive formula or ingredients from China. Formula manufacturers get close scrutiny from the government. They are required to register with the FDA and comply with specific nutritional standards.

“We want to assure the American public there is no threat of contamination to the domestic supply,” said Oliver.

But officials are concerned that some Chinese formula may be on sale at Asian groceries, particularly in places like New York, San Francisco, Los Angeles and Boston that have large numbers of Chinese immigrants. The FDA is working with state officials to spread the word in immigrant communities to remove any Chinese formula from store shelves and to warn consumers not to feed it to their children.

“We want people in those communities, if they are in the habit of buying those Chinese products, not to use them,” said FDA spokeswoman Judy Leon. “We are doing this to be proactive.”

Melamine is the same chemical involved in a massive pet food recall last year. It is not supposed to be added to any food ingredients, but unscrupulous suppliers in China sometimes mix it in to make foodstuffs appear to be high in protein. Melamine is nitrogen rich, and standard tests for protein in bulk food ingredients measure levels of nitrogen.

AP-ES-09-11-08 1729EDT