FDA, through CVM, regulates the manufacture and distribution of feed ingredients and complete feeds, including pet food, as well as animal drugs. FDA first learned of a problem with pet food manufactured by Menu Foods Inc. after the company reported illnesses and deaths in cats and dogs that had eaten some of its "cuts and gravy" style products. The Canada-based manufacturer supplies cat and dog food to numerous pet food companies that sell it under various brand names. Menu Foods voluntarily recalled about 100 different brand name products made at its U.S. plants in Emporia, Kan., and Pennsauken, N.J., and its Canadian plant in Streetsville, Ontario.

Within 24 hours of learning about the pet food problem, FDA investigators were on-site at the Emporia plant to search for possible sources of contamination. FDA worked with the manufacturer to ensure that the contaminated products were removed from the market and to inform consumers of the danger of feeding their animals the suspect products.

At the same time, FDA consumer complaint coordinators around the country began taking calls from pet owners and veterinarians who reported illnesses that may have been associated with the contaminated pet food. FDA received over 14,000 such reports in the first four weeks—more than twice the number of complaints typically received in a year for all of the products the agency.

A New York State laboratory reported finding aminopterin, a form of rat poison, in some pet food samples. FDA's Forensic Chemistry Center could not confirm these findings. What the center did find, though, was melamine in the pet foods and in the wheat gluten used as an ingredient. Subsequently, FDA's field laboratories found melamine in over 130 of more than 210 samples of pet food and wheat gluten. In addition, Cornell University scientists found melamine in the urine and kidneys of cats that were part of a taste-testing study conducted for Menu Foods.

The Melamine and Wheat Gluten Connection

Melamine is a molecule that has a number of industrial uses, including use in manufacturing cooking utensils. It has no approved use in human or animal food in the United States, nor is it permitted to be used as fertilizer, as it is in some parts of the world.

Wheat gluten is a mixture of two proteins obtained when wheat flour is washed to remove the starch. It is sometimes used to thicken pet food "gravy." The wheat gluten that had gone into the pet food had been received from a new supplier in China, according to Menu Foods.

FDA is not 100 percent certain that melamine, a relatively non-toxic substance, is the cause of the spate of pet illnesses and deaths. Although some studies have shown a toxic effect of melamine in rodents, research is scarce on melamine's effect on cats and dogs.

"While the levels we've found to date in both the finished pet food product and the wheat gluten are below what would be considered toxic in rodents, there is extremely little data in the scientific literature on melamine exposure in dogs and cats," said Stephen F. Sundlof, D.V.M., Ph.D., Director of the Food and Drug Administration's Center for Veterinary Medicine (CVM).

"Regardless, the association between melamine in the kidneys of cats that died and melamine in the food they consumed is undeniable."

Now FDA must attempt to determine whether or not it is the melamine itself that is the culprit, or whether it's some other contaminant associated with the melamine. Another piece of FDA's detective work is to find out whether cats and dogs are more sensitive to melamine than rodents without actually testing the toxicity of melamine on cats and dogs.

Tracking Down Wheat Gluten

By examining import records obtained during its investigation, FDA identified the distributor of the contaminated wheat gluten as ChemNutra of Las Vegas. The firm supplies ingredients to pet food companies. Working with the firm, FDA traced the suspect product to a single supplier in China, Xuzhou Anying Biologic Technology. FDA issued an import alert focused on this supplier, and is sampling 100 percent of all wheat gluten from China—regardless of its source—coming into the United States. FDA is also sampling all wheat gluten coming from the Netherlands, since the Chinese supplier shipped some of its wheat gluten to this European country.

"At this time in the ongoing investigation, there is no evidence that any imported wheat gluten contaminated with melamine has entered the U.S. human food supply," says Michael Rogers, Director of FDA's Division of Field Investigations. As an added precaution, however, FDA has asked the Centers for Disease Control and Prevention to use its surveillance network to monitor for signs of human illness that could indicate contamination of the human food supply.

An Active Investigation

FDA's investigation remains open and active, and the agency continues to follow leads to get closer to the root cause of the pet food problem, says Rogers. "FDA will continue monitoring the ongoing recalls, conduct recall audit follow-ups to ensure an effective recall, and promptly inform the public of any additional findings regarding the recent outbreak of cat and dog illness."

As the investigation continues, FDA scientists will review blood and tissue samples of affected animals to understand how melamine contributed to the pet illnesses. "This understanding will provide valuable information about the cause of this outbreak, and what FDA and the pet food industry can do to avoid this type of problem in the future," says Sundlof.

On April 18, 2007 Wilbur-Ellis Company voluntarily recalled all lots of the rice protein concentrate the San Francisco company’s Feed Division shipped to pet-food manufacturers because of a risk that rice protein concentrate may have been contaminated by melamine, an industrial chemical used to make plastics and fertilizers that can lead to illness or fatalities in animals if consumed.

Wilbur-Ellis noted that it obtained rice protein from a single source in China and shipped to a total of five U.S. pet-food manufacturers located in Utah, N.Y., Kansas and two in Missouri.

Last Sunday, April 15, Wilbur-Ellis notified the U.S. Food and Drug Administration that a single bag in a recent shipment of rice protein concentrate from its Chinese supplier, Binzhou Futian Biology Technology Co. Ltd., had tested positive for melamine. Unlike the other white-colored bags in that shipment, the bag in question was pink and had the word “melamine” stenciled upon it. Wilbur-Ellis separated that bag and quarantined the entire shipment for further testing and since that time, no further deliveries of rice protein concentrate have been made. Samples from the white bags tested negative for melamine. However, subsequent and potentially more sensitive tests by the FDA came back positive for melamine, leading Wilbur-Ellis to voluntarily issue the recall.

Wilbur-Ellis began importing rice protein concentrate from Binzhou Futian Biology Technology in July 2006.  A total of 14 containers holding 336 metric tons of rice protein concentrate were sent from Futian to Wilbur-Ellis. Wilbur-Ellis has distributed 155 metric tons to date.

On April 16, a pet food distributor issued a voluntary recall of its pet food, believing the source of contamination to be rice protein concentrate supplied by Wilbur-Ellis. As an additional precaution, Wilbur-Ellis is urging all pet food manufacturers using rice protein concentrate supplied through Wilbur-Ellis to recall any pet food that may be on supermarket shelves.

Hammersmith Marketing Ltd. announced today (April 21, 2007) that it has stopped all shipments of protein meal products from China until the situation has been clarified.

“It is our understanding from reliable information that the products affected are a wide range of protein meals from china, including wheat gluten meal, pea protein meal, corn gluten meal and fishmeal”, Wayne Bacon said.

“The companies mentioned in the news stories produce a wide range of protein products so the list of those with melamine may increase. We do not and have not provided any corn gluten meal produced by the companies mentioned in the news but still feel it is best to stop shipments until we can be 100 percent certain of the purity and quality of the products”.