Aflatoxins in Food


David McCluggage, D.V.M., C.V.A.

When certain types of fungus grow on food, they produce minute amounts of toxins called mycotoxins. Most fungi-produced mycotoxins are harmless, and even helpful. For example, the antibiotic penicillin came from a fungus, and it is a mycotoxin.

Some of these fungi (primarily Aspergillus flavus) produce the very lethal mycotoxins called aflatoxins. Aflatoxins are remarkably potent, often causing disease even when ingested in minute amounts. Aflatoxins can cause disease throughout the body, but are most commonly known for causing acute or chronic liver disease and liver cancer.

Other common mycotoxins include ergotamine, ergot, and ochratoxins. Ergot is especially known for causing gangrene, while ochratoxin is primarily a liver toxin. Although any of these mycotoxins may cause problems, aflatoxins are the most likely to appear in a bird's diet. Also, birds are known to be more sensitive to aflatoxins and their resulting damage to the bird's liver. Very small amounts, ingested over time, can weaken the liver's functions. The liver has numerous functions, including detoxification, digestion, and immune function. Thus, aflatoxin damage to the liver can produce outright liver disease or can lead to other chronic disorders.

Chronic exposure to aflatoxins can damage the liver, which can produce:

Liver inflammation (hepatitis)

Other chronic disorders including:

  • Immune deficiency
  • Increased susceptibility to infections
  • Cirrhosis of the liver
  • Liver cancer

This liver toxicity can produce a cumulative effect over time, and can eventually lead to diseases of the liver including hepatic fibrosis, cirrhosis, and fatty liver disease. Aflatoxins are also carcinogenic, causing a variety of different cancers. They can cause blood disorders where small arteries are blocked due to blood clots. These clots can even lead to necrosis or death of part of the bird's toes.

Once a fungus grows on a plant (fruits, vegetables, grains and nuts) and produces it's aflatoxin, a real concerns is that these poisons are completely heat stable, so neither cooking nor freezing destroys the toxin. They remain on the food indefinitely.

A common misconception is that preservatives such as ethoxyquin and Vitamin E preserve food from the growth of bacteria and fungi. This is not true. Ethoxyquin is an antioxidant which inhibits oxidative degradation of the food, but does not inhibit growth of bacteria or fungi.

Aflatoxins grow mainly on grains and legumes. The peanut is a legume that is notorious for the growth of aflatoxins. In peanuts intended for human consumption, the levels of aflatoxins are measured. However, there is no requirement for testing aflatoxin levels in animal foods. Other common foods we feed birds that often contain aflatoxins include corn, walnuts, pecans, and even milk.

Aflatoxins grow on grains and legumes mostly during storage, so the grains and legumes must be stored correctly to limit this problem. Some foods will be more likely to contain aflatoxins, so one might consider not feeding any of these foods to animals that have preexisting liver disease or other chronic disorders. These products include:

  • Peanuts
  • Whole grains
  • Nuts, especially older nuts (they taste stale), and those in grains
  • Non-human grade foods
  • Commercial diets that contain higher levels of cottonseed oil, fish meal, and peanut oil
  • Foods from countries that have substandard storage elevators for grains

All commercial diets that are made for birds, dogs, and cats will have some aflatoxins, and, fortunately, the body can normally detoxify small amounts. Some diets will contain excessive aflatoxin levels, and, especially over time, can produce significant problems for birds.

Many commercial diets like to call themselves "natural" and possibly "organic," which may have beneficial properties in general, but "organic" or "natural" products do not necessarily reduce the amount of aflatoxins. This is one of the reasons I recommend that birds be fed as much whole foods and fresh foods as possible, instead of processed diets. For more information on feeding birds,click here to read "Feeding Your Bird."

Also, read our information on Juicing for Birds

WHAT TO DO:

  • First, feed fresh seeds and grains whenever possible. Nuts are only produced once a year, in the late summer to fall. Grains are usually only produced once a year as well. When buying nuts and grains that are from the last year's harvest (e.g.. Buying nuts and grains in the spring and summer), look carefully for signs that the grains and nuts have been stored properly. Visually inspect the nuts and grains for freshness and taste them to see if they are acceptable before feeding them to your birds
  • Limit the amount of any commercial food in the diet to no more than 10-20%.
  • Have your bird tested to see if there are any health problems that might be related to aflatoxins.
  • Use herbal antioxidants, and hepatoprotectant and hepatorestorative herbs. You will find these products listed in the "Products" page, under liver support and liver repair products.
  • Liver disease is very serious, we recommend that you see a local avian veterinarian and call us for a phone consult.
  • Some of the products we recommend for birds include: