NEW YORK (Reuters) - U.S. officials said on Friday that melamine, a chemical used in fertilizers in Asia and forbidden in pet food, has been detected in the wheat gluten used by Canada-based Menu Foods.
"The association between the melamine in the kidneys and urine of cats that died and the melamine in the food they consumed is undeniable," said Stephen Sundlof, director of the U.S. Food and Drug Administration's Center for Veterinary Medicine, during a press conference.
Melamine should not be in pet food at all, but its presence has not been confirmed as the cause of sickness or deaths in pets, because there is little research on its effects on those animals, the FDA said.
"So it is very difficult to determine a level that would be harmful or lethal," Sundlof said.
FDA officials said the wheat gluten was imported from China but was not yet known to be used in human food. All wheat gluten coming from there will now be reviewed, they said.
On March 16, Menu Foods recalled 60 million cans and pouches of "cuts-and-gravy" style wet pet food after it was blamed for the deaths of at least 14 animals -- mostly cats.
The company makes pet foods that are sold under a variety of labels such as Iams, Eukanuba, President's Choice and Nutro Max Gourmet Classics, store brands sold at Wal-Mart Stores Inc. and Safeway Inc. and at specialty pet stores including Petsmart Inc.
Many companies pulled the pet food brands in question off shelves following complaints from pet owners. Over 8,000 pet owners have called the FDA to report that their pets had fallen sick or died.
Some have even started blaming dry pet food for sickness in their pets, according to various media reports.
One company that makes dry pet food may have received a shipment of the contaminated wheat gluten but doesn't seem to have used it to make any finished products, the FDA said. Until dry pet foods test unsafe, owners can feed it to their pets, officials said.
Procter & Gamble Co. said on Friday that its dry Iams and Eukanuba foods are safe since they do not contain melamine or wheat gluten and are not manufactured by Menu Foods.
Production of all wet foods at the affected Menu Foods plant in Emporia, Kansas was suspended on March 14, P&G said.
Separately, New York state officials, who said they discovered aminopterin -- a substance used in rat poison -- in tainted pet food last week, said they have no doubt that melamine is present in the recalled food.
"Since neither aminopterin nor melamine are compounds that should be found in pet food, it is important for full public disclosure," said New York State Department of Agriculture and Markets Commissioner Patrick Hooker.
The FDA, however, has still not confirmed the presence of aminopterin in the recalled pet food.
Aminopterin is forbidden for use in the United States since it is known to cause kidney failure in cats and dogs. It is also known to cause cancer and birth defects in humans.
Menu Foods scheduled a press conference for later on Friday to respond to the latest developments.