New Tainted Ingredient Prompts Widened Pet Food Recall

The contaminated rice protein concentrate has also made its way into hog feed, Sundlof noted, adding that the extent of the problem isn't known.

It's also not known if hogs fed the contaminated food have made it into the human food chain, he said.

"We do understand that one of the companies that was manufacturing pet food had some pet food that was unfit for pets and it made its way into some hog feed," Sundlof said. "We are following up on that."

TheAssociated Presson Friday reported that California state agriculture officials had placed American Hog Farm in Ceres under quarantine after melamine was found in pig urine there.

Officials are investigating American Hog Farm's sales records to determine who may be affected by the quarantine, said Steve Lyle, a spokesman for the California Department of Food and Agriculture. The farm operates as a "custom slaughterhouse," which means it supplies meat only to those who want a whole pig, theAPreported.

The FDA believes that the pet food product contamination might have been intentional. Melamine can make it appear that the protein content of the wheat gluten or rice protein concentrate is higher than it actually is.

"We are aware that melamine can increase protein content," Sundlof said. "It's still a theory, but it seems to be a plausible one. The motivation would be economic in that you can take a product that is low in protein and would not qualify for the designation as protein supplement and make it appear that it has a high protein content so it can be sold at a higher price."

He noted that in the shipment of rice protein concentrate to Wilbur-Ellis, one bag was pink and was stenciled with the word "melamine."

FDA representatives are hoping to go to China to investigate the manufacturers of these products. However, they have not yet been able to clear the diplomatic hurdles that would make the trip possible.

In South Africa, meanwhile, a third ingredient imported from China appears to be involved in a major pet food recall there.

Melamine has been found in the Royal Canin pet food company's Vets Choice and Royal Canin dry dog and cat food, which are sold exclusively in South Africa and Namibia. The melamine appears to be in corn gluten imported from China, according to published reports.

And the Humane Society of the United States said Thursday it had established a pet food safety information hotline for up-to-the-minute recall information. The number is 1-800-Humane-1.

More information

For more information on the pet food recalls, visit the U.S. Food and Drug Administration.

SOURCES: April 19, 2007, U.S. Food and Drug Administration teleconference with Stephen F. Sundlof, D.V.M., Ph.D., director, Center for Veterinary Medicine; April 18, 2007, Wilbur-Ellis Co. news release;Associated Press