In the United States, some consumer groups called for stricter regulation as well.

“It is now clear that China has exported dairy products like powdered milk and milk protein products around the globe and we know that some of them came to the United States,” said Wenonah Hauter, executive director of Food and Water Watch. “It is time for the F.D.A. to take this issue seriously and stop the import of dairy products from China until this situation is under control.”

The United States has imported two million pounds of a milk protein called casein this year, along with other powdered milk proteins that are used as ingredients in many processed foods, according to figures from the United States Department of Agriculture. This includes 293,000 pounds that were imported in July. The Food and Drug Administration did not immediately return calls for comment on Thursday.

Melamine is a chemical used in plastic manufacturing that can be added to foods to artificially increase their protein content in testing. Its presence was detected in pet foods originating from China last year.

Even if present in foods in Europe, milk powder contaminated with melamine is not likely to cause the kind of public health disaster that is occurring among Chinese infants. In China, babies drank contaminated milk powder as their sole source of nutrition for weeks if not months, and a handful have died.

Because the harm caused by melamine is related to someone’s weight, it is far less harmful to older children and not likely to be dangerous for adults. Also, for children and adults in Europe, melamine-contaminated milk powder is one small component of a broader diet. The toxic effects of melamine are cumulative, creating kidney stones that can in severe cases lead to kidney failure. Still, children who eat very large quantities of sweets could be at risk.

This week, a number of countries and companies that had previously removed Chinese dairy products from supermarket shelves have started removing snack foods containing milk powder as well. On Thursday, members of the Philippine Association of Supermarkets removed Chinese food products with milk ingredients.

In an increasingly globalized food economy, manufacturers use raw ingredients from all over the world, often making it difficult to track the origins.

For example, Kraft Foods, the maker of Oreo cookies, recently moved one of its large cookie factories from Australia to China. But Claire Regan, a spokeswoman for the company, said that most of the products Kraft made in China were distributed within China, although a limited number were exported. Most do not contain milk products from China, she said, and, when they do, the levels of such ingredients are very low. The Oreo product line does not contain milk ingredients from China, Ms. Regan said.