Consider testing corn and corn silage for aflatoxin this year

By Dean Malvick, University of Minnesota Extension, and Mike Murphy, College of Veterinary Medicine

ST. PAUL, Minn. (10/18/2007)-- Not only have conditions such as drought and hail affected corn yields in Minnesota this year, these stress conditions have also favored the development of molds that can produce aflatoxin, a chemical toxic to animals and humans.

Fields at greatest risk of Apergillus ear rot are likely to be in the most drought prone areas of Minnesota, where summer temperatures were above average.

Prevention of the potential for aflatoxin residues in food products is the primary aim of checking commodities for the presence of more than 20 parts per billion.

Aflatoxin may develop from Aspergillus ear rot, a disease typically uncommon in Minnesota that can become more common under high temperatures and low moisture. However, the presence of Aspergillus ear rot does not mean corn has high levels of aflatoxin. The grain must be tested to determine how much aflatoxin is present.

Grain samples can be sent for analysis of aflatoxin, fumonisin and other mycotoxins to: Dairyland Laboratories (http://www.dairylandlabs.com), 919 Lincoln Ave., Sauk Rapids, MN 56379, (320) 240-1737; or the NDSU Veterinary Diagnostic Laboratory (http://www.vdl.ndsu.edu), 174 Van Es Hall, Fargo, ND 58105-5406, (701) 231-8307.

Check with your testing laboratory for the optimal sample collection for your analysis. Generally, samples for mold and yeast counts should be collected in a paper bag, kept cool on ice, but not frozen, and delivered to the laboratory within 24 hours. Samples of dry grain may be send in a paper bag for nutritional analyses, mold and mycotoxins testing.

To assist with diagnosis of ear rots as well as other corn diseases, a useful book ‘Field Guide to Corn Diseases’ with multiple color photos of many diseases can be purchased for $15, plus shipping, at www.shopextension.umn.edu (search for item 08324).

The following online articles and publications provide more information on corn ear molds and mycotoxins:“Moldy Grains, Mycotoxins, and Feeding Problems,” http://www.oardc.ohio-state.edu/ohiofieldcropdisease/Mycotoxins/mycopagedefault.htm:

• “Potential Problems for Livestock Producers to Consider in 2007,” http://www.extension.umn.edu/dairy/Publications/DroughtHailToxins_Murphy.pdf
• “Hot and Dry Summer Conditions in Minnesota Are Favorable for Corn Ear Rots and Mycotoxin Production,” http://www.extension.umn.edu/cropenews/2007/07MNCN42.html
• “Drought-Stressed Crops Used for Feed Should First Be Tested for Toxicity, Nitrate and Nutritional Value,” http://www.extension.umn.edu/dairy/dairystar/10-28-06-Murphy.htm
• “Mycotoxins,” http://www.geaps.com/proceedings/2004/Hawk.cfm
• Aflatoxins: Hazards in Grain, Aflatoxicosis and Livestock, http://agbiopubs.sdstate.edu/articles/FS907.pdf
• “Aflatoxins in Corn,” http://www.extension.iastate.edu/Publications/PM1800.pdf
• “FDA Regulatory Guidance for Toxins and Contaminants,” http://www.ngfa.org/toxinsPDF-1.pdf
• “Moldy Grains, Mycotoxins, and Feeding Problems,” http://www.oardc.ohio-state.edu/ohiofieldcropdisease/Mycotoxins/mycopagedefault.htm

Any use of this article must include the byline or following credit line:
Dean Malvick is a plant pathologist with University of Minnesota Extension and Mike Murphy is a toxicologist with University of Minnesota College of Veterinary Medicine.

Media Contact: Julie Christensen, U of M Extension, (612) 626-4077, reuve007@umn.edu

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URL: http:// www.extension.umn.edu/extensionnews/2007/2007aflatoxin.html  This page was updated Oct. 25, 2007 .
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