A massive recall of pet food broadened to certain treats and a dry diet, along with more wet products. At press time in April, investigators had not concluded how the food could be causing kidney failure in cats and dogs.
The situation was worrisome to veterinarians and pet owners alike.
"As veterinarians, we chose our life's work because of the gratification we receive from the human-animal connection," said Dr. Roger K. Mahr, AVMA president. "To hear about and in many cases treat these unsuspecting, sick, suffering dogs and cats has been heartbreaking.
"Most veterinarians are pet owners as well, and we have the same concerns for our pets as our clients have. Until all information about the recall and specific cause of illness is known, we will all share some anxiety.
"However, as pet owners, we should not panic. We can be assured that the source of the toxin has been removed from the pet food chain, and the foods not listed in the recall should be perfectly safe."
The scope of the situation
The food subject to the recall contains wheat gluten from a supplier in China. The Food and Drug Administration suspected contamination of the supply, and the agency identified melamine in the wheat gluten. Melamine has uses as a fertilizer in Asia and for the production of plastics worldwide. Dr. Stephen F. Sundlof, director of the FDA Center for Veterinary Medicine, announced during an April 5 press conference that investigators had now traced all of the suspect wheat gluten.
"In the wheat gluten itself, we found in some cases very high concentrations of melamine. I think the highest one so far has been 6.6 percent," Dr. Sundlof said.
"Now, take that into consideration, but also take into consideration that the amount of wheat gluten actually used in the manufacture of pet food is relatively small, 5 percent or less. So we have a high concentration in the wheat gluten, at least in some of the lots of wheat gluten that were analyzed, but it represents a small portion of the pet food."
Dr. Sundlof said the melamine itself was "the most likely suspect" for causing kidney disease but that the agency was now trying to determine whether the problem was the melamine or another contaminant that carried through with the melamine. Dr. Sundlof said the FDA has found a strong association between the finding of melamine in the wheat gluten and the illness in animals.
The FDA continued to investigate how the contamination occurred. In an April 6 interview with CNN, Dr. Sundlof responded to a question about whether anyone would add melamine to wheat gluten on purpose. He said someone might have added melamine to the wheat gluten to increase "what appears to be the protein level," but that is just one theory the agency is investigating.
"Wheat gluten is a high-protein substance, and by trying to artificially inflate the protein level, it could command a higher price," Dr. Sundlof said.
Dr. Sundlof did not elaborate, but seemingly, the purposeful addition of melamine to wheat gluten becomes plausible if investigations do not turn up any other components of fertilizer in the samples than melamine. Theoretically, one could improve the marketability of a product to distributors and also make the content label more appealing to consumers by boosting the protein reading.
Several companies recalled additional products that could contain some of the suspect wheat gluten. Hill's Pet Nutrition pulled Prescription Diet m/d Feline dry food. Nestlé Purina PetCare recalled Alpo Prime Cuts in Gravy wet dog food for specific dates. Del Monte Pet Products pulled certain cat and dog treats, dog snacks, and wet dog food. Manufacturer Sunshine Mills recalled several brands of dog biscuits, including Ol'Roy, for specific dates.
Menu Foods, a Canadian contract manufacturer of wet pet food, expanded the product dates of the original recall in which it had pulled cuts and gravy-style food because of concerns about the effect of the products on the renal health of cats and dogs. Before the problem surfaced, the company had changed suppliers of one ingredient, wheat gluten. The recall encompassed almost 100 brands of products from two U.S. plants that received the ingredient from the same supplier out of China.
The suspect wheat gluten
According to the Pet Food Institute, the United States imports about 70 percent of wheat gluten for human and pet foods from Europe and Asia. Wheat is the major source of starch in those regions, whereas corn is the major source of starch in this country. Manufacturers of pet food also import other ingredients when U.S. commodity producers can't meet demand, according to the institute. These imports include fish meal, lamb meal, vitamins, and minerals.
The FDA began screening all incoming shipments of wheat gluten from China and from the Netherlands, a country that ships Chinese wheat gluten. According to the agency, Xuzhou Anying Biologic Technology Development supplied the suspect wheat gluten. The agency has been detaining all shipments of wheat gluten from the company. In general, food imports must meet the same standards as domestic foods. The FDA inspects imports on the basis of risk and inspects some foreign facilities.
ChemNutra of Las Vegas, which specializes in importing ingredients from China, imported the wheat gluten from Xuzhou Anying. ChemNutra has recalled all the suspect wheat gluten, which went to three manufacturers of pet food and one distributor that provides wheat gluten only to manufacturers of pet food.
The chemical aminopterin was the main lead earlier in the investigation. Aminopterin is a cancer drug that the United States has banned for use as a rodenticide. The New York State Food Laboratory reported identifying aminopterin in food subject to the recall, but the FDA has not been able to confirm the finding.
The American Society for the Prevention of Cruelty to Animals had noted that calls to the ASPCA Animal Poison Control Center seemed to indicate that clinical signs in cats that ate food from the recall were not fully consistent with ingestion of aminopterin.
"Ironically, melamine itself has a relatively high safety margin," said Dr. Steven Hansen, toxicologist and ASPCA senior vice president.
"Studies have shown that at significant doses, it causes a pronounced diuretic effect in dogs and rats, as well as the development of crystals in their urine, but without evidence of kidney damage. Should doses exceed those in published studies, we may start seeing additional adverse effects in dogs.
"Cats, however, are a very sensitive species, and can react adversely to many chemicals and drugs even at lower doses. Because of their unique physiology, we suspect that they may also be more sensitive to the adverse effects of melamine. However, further investigation is required to prove this theory."
The safety of pet food
The pet food contamination has brought attention to a variety of issues relevant to pet food—including regulations, recalls for other reasons, home preparation, ingredients in commercial foods, and the accountability of manufacturers in cases of contamination.
At press time, Sen. Dick Durbin of Illinois had arranged for a Senate hearing April 12 on the safety of pet foods. He asked the FDA for an analysis of the agency's oversight of facilities that manufacture pet food and its actions following the recall of pet foods containing suspect wheat gluten.
In a different recall, two companies recently pulled dog treats because of Salmonella contamination. Petrapport, a New Jersey manufacturer of dog treats, recalled pig ears it imported from a Chilean company in late 2006. Eight In One, a division of United Pet Group, recalled Dingo Chick'n Jerky treats for dogs along with Dingo Kitty Chicken Jerky and Dingo Ferret Chicken Jerky.
Reports about a letter from the FDA to Iams led to confusion regarding Eukanuba Veterinary Diets, which are not subject to a recall. Iams is, however, removing an ingredient from the manufacture of some of the food. The FDA noted in the letter that no regulation exists to prescribe conditions for safe use of chromium tripicolinate. Iams had added the ingredient to help manage glucose metabolism for diabetic, overweight, and senior dogs. The company will not include chromium tripicolinate in future formulations.
All these developments have led to more pet owners attempting home preparation of dog and cat food. Early April 5, a cookbook for dog food was among the top 10 best sellers on Amazon.com. At the same time, four books about dog or cat food were among the top 25 movers and shakers, by gain in sales rank in 24 hours. Three of the top 25 best sellers in the cooking category were cookbooks for dog food.
A number of pet owners also have joined class-action lawsuits against Menu Foods. Lawyers for Dawn Majerczyk of Chicago, the plaintiff in one of the earliest lawsuits, have amended the complaint to include charges of fraud. The complaint alleges that Menu Foods acted recklessly in delaying the recall.
The new charges are noteworthy because successful fraud suits could lead to punitive damages, which are intended to punish a wrongdoer, usually in cases of intentional misconduct. Under current law, suits for the wrongful death of a pet in cases where negligence is alleged usually result only in economic damages.