Most people are familiar with the massive pet food recall that occurred in 2007. The recall affected dozens of brands, and was linked to ingredients that were intentionally tainted with melamine (and unintentionally tainted with cyanuric acid due to shoddy melamine manufacturing) by human beings. The combination of ingredients sickened or killed a large number of pets.
Human-made chemicals aren’t the only contaminants that can be found in pet foods. In 2005-2006, a massive recall of Diamond brand dog food occurred due to contamination with a natural poison. That poison was aflatoxin.
Aflatoxin is created by fungus that grows on corn. Exposure to aflatoxin can lead to sudden liver failure.
A report in the May 1, 2008 issue of the Journal of the American Veterinary Medical Association discussed the symptoms, treatment, and outcome of dogs that ate contaminated food.
Different species have varying susceptiblity to aflatoxins, with dogs being highly susceptible . . . During late 2005, a serious foodborne aflatoxin contamination that was derived from moldy corn in manufactured dog food was recognized through collaborative efforts of regional New York State veterinarians and the College of Veterinary Medicine at Cornell University . . . Although product recall was rapidly announced, high rates of morbidity and mortality of dogs nevertheless was encountered in the United States.
The report goes into quite a bit of detail about the pathology that occurred in affected dogs. But the conclusion of the study was disheartening.
Despite aggressive treatment, many but not all severely affected dogs died.
For reference, the article cited in this entry is J Am Vet Med Assoc 2008;232:1329-1337.