Add fish to the growing list of animals that have eaten tainted food.
Canadian-made fish meal contaminated with the industrial chemical melamine was exported to fish farms in the United States, federal officials said yesterday.
The fish meal was shipped to companies that breed fish that will be sold as food and to companies that breed fish that will be released into lakes and streams, officials said.
"We do not believe this poses any human health threat," said David Acheson, the U.S. Food and Drug Administration's assistant commissioner for food protection. Canadian officials are cooperating with U.S. officials in the fish meal investigation, he said.
U.S. officials would not identify the states where the contaminated fish meal was sent and would not say how many fish have eaten tainted food because the investigation is still under way.
Cats, dogs, hogs and chickens have eaten contaminated food that is involved in a massive, continually growing pet food recall that began March 16.
More than 150 pet food companies are involved.
The fish meal included what was purported to be wheat gluten, a protein source, imported from China. Contaminated wheat gluten and rice protein concentrate shipped from China initially had been identified as the ingredients that sickened and killed an as-yet unsubstantiated number of U.S. cats and dogs.
The culprit was actually wheat flour that contained melamine, Dr. Acheson said yesterday.
"The products that came to the U.S. were labeled as wheat gluten and rice protein concentrate," Dr. Acheson said. But additional testing, including tests on starch levels in animal foods, indicated the products were "actually wheat flour contaminated with melamine" and other related compounds, including cyanuric acid, which is used in this country to clean the water in swimming pools.
This discovery does not mean that all wheat gluten in the United States is actually wheat flour, Dr. Acheson said.
Melamine is a chemical used in this country in the manufacture of plastic utensils and in other countries, including China, as fertilizer. Early this month U.S. officials said testing labs found a second ingredient, cyanuric acid, in pet food. The two chemicals combined are apparently much more deadly than either would be individually, officials have said.
U.S. officials are currently in China investigating how melamine and cyanuric acid ended up in the ingredients used to make pet food and animal feed. The New York Times, in today's editions, quoted Chinese chemical producers who say the cyanuric acid may have been added to the food to boost the protein count.
China said yesterday it had found two companies guilty of intentionally exporting pet food ingredients containing melamine to the United States, according to The Times.
The country's watchdog for quality control released a statement on its Web site late yesterday saying officials at the two companies were also detained for their role in shipping tainted goods that may have contributed to the pet food recalls in the United States.
The revelations from chemical producers help address uncertainties about the presence of cyanuric acid. For instance, it has not been clear whether it is a derivative or byproduct when melamine is broken down in the animals, or whether the cyanuric acid was separately placed in the feed.
The FDA and the U.S. Department of Agriculture have been inspecting all wheat gluten and other vegetable proteins exported from China. Last week, U.S. officials starting doing "additional sampling and testing" of wheat gluten, corn gluten and rice protein concentrates exported from other countries, said Vera Adams, executive director of Commercial Targeting and Enforcement, U.S. Customs and Border Protection.
"There is no evidence at this time to suggest that the bulk of these products" pose any risk, Ms. Adams said during the news conference yesterday. Wider testing is being done "as a precaution."
The expanded testing will include a search for "antibiotic residue" in fish that are tested for traces of melamine, Dr. Acheson said.