Food is supposed to provide nutrients so that those who partake in it can maintain health and grow stronger.  Over thousands of years, the human race has concerned itself with the preservation of foods to prevent spoilage and the preparation of foods to reduce contamination.  In general, the same biotoxins that have been problematic for us have been problematic for our pets as well.

There are two types of biological contaminants: bacteria and toxins.

Bacteria can cause infection themselves or they can produce toxins, which make us sick. In general, toxins make us sick in a matter of a few hours after ingestion. Bacteria require more like 1-6 days.

Contamination can occur at any stage of food production and it should be noted that the nutrients present in foods are just as nutritive to contaminating bacteria as they are to us. Bacteria are able to double in numbers every 30 minutes depending on the environmental conditions. 

What are common toxins to be concerned about?

First, there are mycotoxins (toxins produced by fungi or molds).  An example of a common type mycotoxin would be the “Aflatoxins.”  These toxins attack the liver and can produce upset stomach all the way to a life-threatening hepatitis depending on exposure.  They come from the bacterial species called “Aspergillus” which is the white and gray fluffy mold that is commonly seen on spoiled foods.  A typical exposure scenario might involve a dog that got into some moldy trash.  The extra bad news is that aflatoxins are stable in heat which means that cooking does not destroy them.

Another toxin to know is “Vomitoxin” which produces upset stomach especially in dogs. This toxin is produced by “Fusarium” bacteria growing in grain, especially wheat and barley.  This toxin is also heat stable.  Because of this toxin, the FDA has established a guideline that the grain and grain by-product composition of pet food should never exceed 40% thus restricting the amount of toxin that could be present in food.  The FDA’s advisory level of this toxin is 5 parts per million in pet food though many dogs can detect this toxin in amounts as low as 2 parts per million. In 1995, it was the presence of vomitoxin in contaminated grains that led to the recall of 16,000 tons of Nature’s Recipe dog food and created much embarrassment for this company.

What are common bacteria to be concerned about?

Salmonella is a common bacteria of concern. While this bacteria is likely not to be a problem for young healthy individuals it can be very harmful for those who are weak or debilitated.  It usually causes diarrhea due to a toxin it produces but if it gains access to the systemic circulation it can cause blood poisoning (“septicemia.”)  This bacteria is carried harmlessly in 36% of healthy dogs and 17% of healthy cats.  Classically, the source of Salmonella is felt to be meats contaminated by the fecal matter from a carrier animal (generally the same animal that provided the meat) but more recently fresh vegetables have been implicated as well. Salmonella bacteria and their toxins are readily destroyed by cooking.  Washing the food is helpful in removing harmful bacteria but dipping vegetables in dilute chlorine has been advocated.

For more information on Salmonella (from the Center for Disease Control), click here.

Clostridium botulinum is the anaerobic bacterium that produces botulism toxin, one of the most powerful biotoxins in the world.  Cats are resistant to this toxin but dogs and humans have certainly become paralysed from it.  The bacteria themselves are destroyed in cooking but the devestating toxin they produce is not.

For more information on clostridium botulinum (from The Food Safety Home Page by Donald L. Zink), click here

How is pet food safety regulated?

First of all, no pet food company will knowingly risk its reputation and credibility by instituting inferior inspection and production.  This is an important driving force in the pet food industry. Most companies have extensive quality control in this regard. 

But because pet foods are transported across state lines, the federal government regulates their safety through the Food and Drug Administration (the presence of insecticides is separately regulated by the Environmental Protection Agency).  Additives can be issued a “tolerance,” an “action level” or an “Advisory level.” The tolerance level is an actual legal regulation while the other action and advisory levels are just guidelines.  The USDA and FDA are responsible for enforcing these guidelines.

How safe is pet food?

The good news is that pets are primarily fed commercially prepared food that has been properly treated to minimize contamination, and because of this treatment, food poisoning is rare except in dogs that forage garbage and carrion.  In a 1992 survey of Poison Control Centers, food poisoning accounted for only 1.7% of all poisonings. Risks are higher for dogs than for cats as dogs tend to eat things first and ask questions later.  Warm weather, hunting season, Thanksgiving, and Christmas seasons all pose extra risks for food poisoning in pets for obvious reasons.

RECOMMENDATIONS
To minimize the risk of food poisoning in pets, the following simple guidelines have been established:

• Do not allow the pet access to garbage or carrion
   
• Cover and refrigerate unused portions of wet food
   
• Be vigilant for the presence of molds in dry foods left out
  for free feeding
   
• If the temperature is greater than 50 degrees, discard
  uneaten wet food after 2-4 hours
   
• Use stainless steel bowls and utensils and clean them
  after each use
   
• If home cooking pet food, use only human grade ingredients
  that look unspoiled and unblemished. Cook all foods to a measured temperature of 180 degrees for a minimum of 10 minutes.
   
• Store dry foods in a cool dry location free of pests.

Bon Appetit!