China and some other countries, however, have approved aminopterin for use as a rat poison, according to a report in the Los Angeles Times. The Food and Drug Administration (FDA) reports that the lethal concentration of the chemical is three parts per million (ppm) for rats; the amount found in the contaminated food samples was 40 ppm. There is speculation that the poison got into the chow because Chinese farmers sprayed their crops, including wheat, with it to protect them from hungry rodents.
Stephen Sundlof, director of the FDA's Center for Veterinary Medicine, says, however, that the agency's investigation is not limited to wheat gluten. "It is certainly a likely suspect," he said during a press conference, "but there are other suspects and we will continue to look at all components of the feed." Tuite, the Menu Foods spokesperson, said the company is "still trying to figure out how [aminopterin] got into the food, so I think at this stage, it would be irresponsible of us to identify exactly what ingredient it was on until we know definitively."
Sundlof noted that the FDA has the same authority over pet food as it does over most of the human food supply. "There are really no differences in the regulation of animal food and the regulation of human food," he says. "The same people that inspect human food plants also inspect pet food plants," grading the facilities as high- or low-risk, and then monitoring the high-risk venues more carefully.
"Traditionally, pet food producers are considered to be low-risk because, with few exceptions and this certainly being one of those exceptions, pet food is very safe," Sundlof adds. "We have not had a lot of illnesses in pets as a result of pet food." David Elder, director of the Office of Surveillance and Compliance in the FDA's Center for Veterinary Medicine, said during an earlier press conference that the agency relies more on testing and approving animal foods and drugs before they are put on sale, rather than on routine inspection due to "limited resources."
Details of the recall began to haunt Jim Valentine, who remembered that although he ordinarily fed Silvus dry food, he had splurged on Iams Select Bites in early February. His younger cat, Tiki, wouldn't touch the stuff, but Silvus could not get enough. Valentine alternated the fancy fare with dry food. Three weeks later, he bought a second pouch of the wet food. Then he began noticing some physical changes in Silvus after a few more of the moist meals. Most notably, the cat had developed a swollen bottom lip and had lost a considerable amount of weight. He also stopped eating. Valentine assumed Silvus was avoiding hard food because he was spoiled by the wet treat, so he offered up more of the Select Bites.
About four weeks after first purchasing the soft nuggets, Valentine took the previously healthy and now declining Silvus to the vet. The diagnosis was kidney failure. Silvus—whose weight had plummeted nearly 30 percent from 18 pounds to 13 pounds—had enlarged kidneys. He also had extremely high levels of creatinine (a by-product of the breakdown of phosphocreatine, an energy-storage molecule in muscle) normally eliminated by the kidneys and extremely elevated levels of BUN (blood urea nitrogen), which measures the amount of the waste product urea (a by-product of protein digestion).
The vet administered fluids intravenously, but the blood levels did not improve. Three days later Silvus was dead. Valentine put the rest of his cat's coveted wet food outside for the neighborhood cats to eat. Now, he is worried he may have inadvertently poisoned them, too. "[One of the recalled brands] is exactly the same brand that I had started to feed Silvus," says Valentine, who notes that product numbers on his packages of Iams wet food fell just outside of the range of recalled products. The date codes on his packages were 6256 and 6293; the recall range extends from 6339 to 7073. Nevertheless, Valentine believes that his cat was a victim of food poisoning, raising the question of whether the recall was wide enough.