February 3, 2006

Healthy Pets

Aflatoxin is deadly for dogs

Stephen Tesluk

There has been quite a bit of concern among local dog owners over a recent recall of certain dog foods manufactured by Diamond Pet Foods that were found to be contaminated with a fungal toxin.

There have been reports of many deaths due to acute liver failure in dogs that were fed the contaminated diets. Several of the recalled diets are carried locally at various stores, but Diamond Pet Foods says that the tainted products originated from a manufacturing plant in South Carolina, and were not shipped west of the Mississippi River.

The specific toxin involved is known as Aflatoxin, which is produced by a fungus that can grow on several types of grain. In this case, it was present on the corn that was used in the diet.

A dry summer and wet fall led to conditions that favored growth of the fungus, and there were warnings from several state agriculture departments that last year’s corn crop had a higher than normal prevalence of aflatoxin contamination.

Pet-food manufactures, including Diamond, routinely test for the presence of aflatoxin in shipments of corn that arrive for processing, but the procedure only tests a small fraction of the corn present in any shipment, and, as happened in this case, it is possible for contaminated corn to make it into the processing plant and eventually into the dog food.

Unfortunately, Diamond Pet Foods had no testing protocol in place to test their final product for aflatoxin, but they have started a final product-testing program since the contamination was discovered.

Aflatoxins target the liver and can cause acute liver failure. The liver cleans the blood of toxins, and signs of liver failure include yellowing of the skin, vomiting, diarrhea, loss of appetite and depression. Death can result if the injury to the liver is severe.

Although the stories surrounding the recall have focused on the severe and acute results of aflatoxin consumption, aflatoxins are also a long-term threat because they are one the most potent liver carcinogens known to exist. The sensitivity of dogs to cancer caused by aflatoxins is not well understood, but it is a well-documented fact that aflatoxin exposure increases the risk of liver cancer in people.

People who study ways to make food safer recommend several layers of testing for contaminants. Raw materials should be tested at the farm and at the plant prior to processing. Manufacturing methods need to be designed to detoxify any contaminants that escape detection. Finally, the finished product should be tested as well.

This type of testing protocol will not completely eliminate the risk of contaminated food entering the marketplace, but it the best way to reduce the risk. This type multilevel testing is more expensive for the manufacturer, and it takes a type of commitment to quality that manufacturers of some economy lines of food may not be able to afford.

But that cost is nothing compared to the loss in revenue that a company like Diamond Pet Foods faces when killer contaminants make it into their food.

Dr. Tesluk practices at Ashland Veterinary Hospital.