When melamine was first detected in pet foods that had been linked to animal deaths, veterinary toxicologists were puzzled. Melamine was never thought to be toxic to companion animals at the levels found in the contaminated products. The second contaminant, cyanuric acid, also was not known to be toxic at the levels at which it was found in the food. But the combination of the two chemicals proved deadly.
On May 1st, the University of Guelph reported that they had found the likely answer to the toxicity puzzle. Their preliminary report concluded:
Although still under investigation, it now appears that the combination of melamine and cyanuric acid has been linked to the unusual outbreak of acute renal failure in cats and dogs that have eaten the suspect products.The researchers reached this conclusion by adding both melamine and cyanuric acid to cat urine. The two chemicals, when both present in the urine, formed crystals that were identical to the crystals found in the urine of cats that had been sickened after eating the contaminated pet food. Neither melamine nor cyanuric acid alone produced these crystals.
The American Association of Veterinary Laboratory Diagnosticians commissioned Michigan State University to investigate fully the impact of the contaminated pet food and confirm the reason for its toxicity. University of Guelph and Colorado State University collaborated with MSU on the study. Their report has just been released, and the two main findings are:
- The contaminated pet food was probably responsible for the death of more than 300 cats and dogs
- The toxicity of the pet food likely resulted from the combination of melamine and cyanuric acid in the contaminated food.
Yesterday, Health and Human Services Secretary Leavitt announced that the U.S. and China had reached an agreement on food safety issues. The agreement provides for the eventual "embedding" of FDA inspectors in Chinese food processing facilities. But I don't expect this agreement to have a major impact. The FDA doesn't have nearly enough money in its budget - or trained personnel on its staff - to fulfill its domestic mandates.