Your corn crop is going to yield about half of what it normally does — or maybe less — and now you wake up in a cold sweat in the middle of the night that your corn is infected with—gulp—aflatoxin. Now your income has gone from minimal to dismal. Your corn cannot be used for feed, or food, or even ethanol because of the fungus that prefers droughty corn. There is a growing bitter taste in your mouth, but Garrison Keillor is not going to come to your house with a piece of rhubarb pie.*

Aflatoxin is nothing to joke about, particularly its devastating financial impact on the value of infected corn; however, aflatoxin is a peril that is covered by crop insurance. And anyone with droughty corn, and who suspects aflatoxin may be lurking inside the husks, must determine whether or not that is the case prior to harvest. After the grain is on the truck or in the bin, it is too late. If you think you may have aflatoxin or any other kind of mycotoxin, get it tested, and call your crop insurance agent.

USDA’s Risk Management Agency has produced a fact sheet on aflatoxin and specifically says that adjustors must see the problem in the field. Once in the bin, tests on the grain are no longer valid. The adjustor may come to your field and take samples, or provide instructions for leaving representative strips of standing corn in the field for testing when it is possible.

Gary Hachfeld at the University of Minnesota says the weather we have had this year is perfect for aspergillus fungus development which can produce aflatoxin and other toxins, “High daytime temperatures of 90° F or greater and relative humidity of 80 percent or greater can also cause aflatoxin. Corn can be contaminated with aflatoxin and aflatoxin can grow and spread while in storage when corn moisture is above 13 percent and warm temperatures are present.” He also reports you will encounter challenges in disposing of corn that tests positive for aflatoxin. “There are also special guidelines for grain production that has in excess of FDA 300ppb aflatoxin as well as grain that is deemed having zero market value. In addition, farmers may encounter claim settlement delays because elevators may not buy the contaminated grain nor will they supply a reasonable value for the grain. Contact your insurance provider for questions regarding these situations.” 

One of the first decisions you will need to make is where to have the grain tested, if you think there may be a problem. The Midwest RMA office provides this list, or you can use an Internet search engine to find a more local facility. Call to ask the procedure for submitting the sample, what tests will be conducted, and what results will be provided, as well as the cost.

Just because the elevator will not take corn with aflatoxin because of the liability for someone’s livestock to be sickened or killed, does not mean you can blend it for your own feeding purposes. The veterinarians at Iowa State University provide guidance on what level of aflatoxin is federally approved for feed or processing use, which turns out to be very small amounts. They say, “Low levels of aflatoxin in feeds - sometimes less than 1 part per million (ppm) – can cause poor growth, interfere with the immune system and result in liver damage and bleeding. High dosages cause acute loss of appetite, depression, hemorrhage, diarrhea and death.” For corn being fed to swine, beef cattle, and dairy cattle, the amounts of allowable aflatoxin levels are measured in a few parts per billion.

The use of aflatoxin-infected corn for ethanol is also a problem because it infects the germ, and stays in the corn gluten or distillers dried grain, and is not destroyed in the starch refining and fermentation process.

*According to the Prairie Home Companion, “Nothing gets the taste of fear and humiliation out of your mouth like a slice of rhubarb pie.”
Although there may not be any confirmed reports, farmers should be on the lookout for ear molds in corn that produce mycotoxins such as aflatoxin. Environmental conditions have been conducive for aflatoxin development which could severely damage the value of any corn that is infected with it. Tests should be conducted if molds are suspected, and crop insurance agents alerted. Aflatoxin is covered by crop insurance, but only if the crop is still in the field. Disposal of the corn may be a problem because its level of contamination may be above what can be fed to livestock and used for ethanol production.

Source: Stu Ellis, FarmGate Blog