Melamine and Cyanuric Acid Interaction May Play Part in Illness and Death from Recalled Pet Food

May 1, 2007

Tests conducted on contaminated pet food and necropsies from affected animals have resulted in a new theory to explain how animals are being adversely affected by contaminated pet foods. A chemical reaction between melamine and cyanuric acid is suspected of forming crystals and blocking kidney function.

The investigation into contaminated pet food has focused on melamine contamination of ingredients imported from China, such as wheat gluten, rice protein concentrate and corn gluten (imported into South Africa). It is now believed that cyanuric acid, as well as melamine, has been found in urine samples from animals that died.

Analysis of the crystals in the kidneys of affected animals have revealed that they are approximately 70 percent cyanuric acid and 30 percent melamine, and are extremely insoluble. Furthermore, tests mixing melamine and cyanuric acid in samples of cat urine resulted in almost immediate formation of crystals that were identical to crystals found in the kidneys of affected animals. Two other melamine-related substances — ammelide and ammeline — may also play roles and are under investigation.

As the recalls continue, the AVMA reminds pet owners and veterinarians that over 98 percent of pet foods are still deemed safe and haven’t been recalled. The FDA is currently testing 100 percent of wheat gluten, rice protein concentrate, corn gluten, corn meal, soy protein, and rice bran being imported from China for these contaminants. The most recent pet food recalls have been undertaken proactively, due to association with involved ingredients and suppliers rather than as the result of complaints that animals that have consumed the food and become ill.

Most affected cats and dogs are recovering through use of standard fluid therapy and supportive care. The AVMA urges all veterinarians who have seen animals they suspect have been affected by a contaminated pet food to submit their findings to an ongoing survey. This survey is being conducted by the American Association of Veterinary Laboratory Diagnosticians (AAVLD).

A comprehensive Pet Food Recall List is available at American Veterinary Medical Association (AVMA) web site. The AVMA Pet Food Recall List contains all recall information that has come to the attention of the AVMA, but it is not guaranteed to be complete. The AVMA encourages all concerned to contact the specific manufacturer regarding the status of any particular pet food or treat.