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Fast Facts: Aflatoxin Contaminated Grains
Dr. Gavin MeerdinkOctober 20, 2005
- Aflatoxin is a mold toxin produced during production in the field and in improperly stored grain (i.e., moisture greater than14 percent). Aflatoxin is not formed in properly ensiled feedstuffs (oxygen free environment).
- The visual appearance of mold and mold spore counts are not useful in determining aflatoxin presence.
- Black light fluorescence from a corn sample is from a metabolite created by the mold, but the agent is not aflatoxin. There is some correlation between a black light positive test and the occurrence of aflatoxin in the grain. However, specific tests for aflatoxin in grains are necessary to confirm presence and to determine aflatoxin concentration. These tests are readily available from commercial laboratories, veterinary diagnostic laboratories and some grain companies.
- Proper sampling is paramount in obtaining an accurate estimate of aflatoxin concentration. Toxin presence is usually variable. Multiple random samples are essential for accuracy.
- The FDA has established guidelines for acceptable maximum levels of aflatoxin in corn: 300 ppb for finishing beef cattle; 200 ppb for finishing swine (greater than100 lbs.); 100 ppb for breeding beef cattle, breeding swine and mature poultry; and 20 ppb for other animal feeds. Toxic effects from aflatoxin are influenced by the quality of the diet.
- Dairy cattle diets should not contain more than 20 ppb. This is because of the cows metabolism of B1 to aflatoxin M1 that is excreted in the milk. M1 residues over 0.5 ppb render the milk unsalable for human consumption.
- Na Ca aluminosilicate (i.e. NovasilPlus", Trouw Nutrition) has been shown to bind aflatoxin. Other binding agents, e.g., clays or bentonites, have produced mixed, often disappointing results. Feed inclusion rates depend on species, age, toxin concentration, etc.
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