Pet Food Contamination: Aflatoxin, Molds, and Melamine

As a companion to the guest post I wrote on the basics of cat and dog nutrition over on PawDiet, (I promise I’m not abandoning our ABCs, and K will be my next post!), today we’re going to cover the touchy topic of pet food contamination.

If you haven’t had a chance to check out PawDiet, take a peek at the Food Finder and the widgets page.  The ability to find food based on multiple criteria is essential for picking the right diet for your pet!

What is so scary about packaged pet foods?

This is a question bouncing around in people’s heads a lot lately, especially considering the food recall in 2007 and all of the buzz around switching to grain-free or raw-based diets.

There are a lot of factors that influence the quality of packaged pet food extending past the manufacturer. Ingredients shipped from distributors can become contaminated, storage of foods at the store (and at home) can affect food quality, and there are some toxins that the FDA doesn’t completely regulate. The contaminants we are going to cover today include:

• Molds such as aflatoxin and tremorgenic mycotoxins
• Melamine

Bacterial infection is an expansive topic and needs an article of its own! However, bacterial contamination is a very common type of animal food contamination.

In many cases, pet food contamination may not be directly related to the manufacturer itself, but instead a breakdown in one of many pieces in a chain of events that ends up affecting your animal.

Melamine – what happened in 2007

Melamine is a chemical used in the production of several non-edible products such as plastics and resin.  When added to wheat gluten, melamine can falsely increase the protein content when subjected to laboratory tests.  While not approved for use in any food, some companies will illegally add melamine to wheat gluten in order to falsely bump up the reported protein content of a product.

In 2007, a Chinese plant-product processor, a Chinese food product exporter, and an American food product supply company entered a contract together. From this contract, the US imported 800 tons of melamine-contaminated wheat products. When a pet food manufacturer reported several linked illnesses and deaths in the pet community, the supply companies were all brought up on federal charges.

How it’s different now:

FDA’s response was to develop an initiative called PETNet, which is a web-based network that allows for quick reporting and communication regarding illness outbreaks and pet food contamination between federal and state levels, previously a process that did not have good standards of communication.

Melamine has a wide margin of safety (meaning smaller ingestions cause fewer signs). However, the buildup of melamine in small amounts over a long period of time (called chronic exposure) causes the formation of crystals in the kidneys in both animals and humans.

The crystals lead to urinary problems, kidney stones, and eventually kidney failure.  Before everyone who has had an animal in kidney failure runs to report their pet food, this type of pet food contamination is not very common.  Due to increased regulation of food products on part of the FDA and increased awareness of melamine in the food industry, the risk of this happening is very low.  It is still a good idea to keep up-to-date on current pet product recalls through the FDA.

Aflatoxin and other molds

Certain species of Aspergillus fungi (aka, a mold) produce aflatoxin as a toxic byproduct.  While many molds tend to be tremorgenic  (meaning they cause tremors and seizures), aflatoxin directly affects the liver.

These species of molds thrive in warm weather and moist grain conditions.  They are common enough in grain storage that the FDA has reported “acceptable” levels of aflatoxin in food-based products.  As you can see, the “acceptable” levels are HIGHER for food for animal consumption than for food for human consumption.

It is not a well-kept secret that pet food companies often invest in cheaper ingredients for their pet foods. Food that has NOT passed the qualification for human consumption sometimes finds its way into pet food for animal consumption.  While the current claim is that these levels of aflatoxin in pet food are not high enough to risk the health of the animal, there is not a lot of documentation on the long-term effects of chronic exposure in pets.

Acute exposure tends to occur when improper storage leads to acute contamination that slips through the cracks of the food control process (again not a common occurrence)

Signs related to aflatoxicosis start with tummy upset and progress:

• Vomiting
• Diarrhea
• Unwillingness to eat
• Dark, tarry stools from digested blood (melena)
• Stomach pain
• Bloody diarrhea
• The buildup of fluid in the stomach (abdominal effusion)
• Increases in thirst and urination
• Dehydration and other electrolyte imbalances
• Increases in liver enzymes, liver damage, and liver failure
• Coagulopathy (excess bleeding)
• Brain damage or malfunction
• Death

As these signs are common among all toxins that cause damage to the liver, it can be very difficult to tie an affected animal to a contaminated food source.  If at any point you suspect that your pet ingested contaminated food and died as a result, insist upon a necropsy. Have samples kept of both your pet’s liver and the contents of your pet’s stomach. Bag up several samples of the food from home for laboratory testing (use gloves!).  Then, report everything to the FDA. 

Alternative to testing through the FDA (which they may or may not offer), you can have your vet send the samples off to a diagnostic testing lab for analysis.

Treatment:

There is no antidote for aflatoxin.  We treat animals supportively to help protect the liver and alleviate signs:

• IV fluids to support hydration
• Vitamin K supplements to prevent coagulopathy
• Drugs to replace the loss of antioxidants and prevent vomiting
• Liver protectants

As is often the case,  with sudden-onset liver failure, these cases can be difficult to treat and may end up being fatal.

Tremorgenic mycotoxins cause vastly different signs

In comparison to aflatoxin’s tendency to contaminate food during production, other molds grow after purchase. Improperly stored food may grow mold, leading to toxicosis (shout-out to Doctor Schell who authored this tox brief – she is one heck of a fun person and has led an interesting life). This is something that also affects animals who ingest trash, compost, or human food that is past expiration.

Signs of ingestion include:

• Vomiting
• Stumbling
• Changes in heart rhythm and rate
• Twitching
• Tremors
• Seizures
• Death

Depending on how alert you are to the fact that your dog has ingested a moldy substance, treatments can vary:

• Inducing vomiting if possible
• Gastric lavage (which is similar to a human stomach pumping)
• Activated charcoal
• Management of temperature fluctuations
• Drugs to stop tremors and seizures

Pets who ingest mycotoxins often do well if they receive treatment in time.  These animals require veterinary care, so keep the number to animal poison control handy. Alternatively, notify your local or emergency vet if you suspect exposure.

Prevent pet food contamination

As always, prevention is key to keeping your pet healthy. There are several changes you can make at home to reduce the likelihood of your pet eating spoiled or moldy foods:

• Always check the expiration date on foods you feed to your pets.
• Never feed anything that smells “off” or “funny”.
• Store dry food in an air-tight plastic container with a lid.
  • Write the food’s expiration date on a piece of masking tape and tape it to the top of the lid.  Disposed of any expired food.
• Cap and date opened cans of unused wet food.  Store them in the fridge, and toss them after 2-3 days.
• Toss all cans of expired, unopened pet food.
• Don’t keep food in the garage, or outside.
• Invest in a  trash can with a lock, or get a lid-lock.
• Throw away spoiled or moldy food in the outside trash can, and do not keep bags with moldy food inside.
  

Happy eating!