Aflatoxin has been discovered in some corn harvested this fall in northwest Iowa and southeast South Dakota. As of today, the discoveries of the tainted corn in northwest Iowa have been only a few cases—and they have been limited to the Plymouth and Sioux county area.

"Grain elevators in that part of Iowa have been testing incoming loads of corn," notes Bill Northey, Iowa secretary of agriculture. "The samples of corn that have tested positive for aflatoxin have only been found sporadically. This isn't very widespread, at least from what we've seen so far. Our department has also been testing corn samples submitted to us from other areas too."

Aflatoxin tends to show up in areas where the growing season was very hot and dry—and this area in the northwest corner of Iowa had those conditions this past summer. "This discovery of aflatoxin this fall is not completely unexpected and shows that grain elevators are prepared for it and they are taking the necessary precautions to make sure affected corn is used appropriately," says Northey.

Elevators are handling the situation.

"The levels of aflatoxin being found are not especially high and there is a lot of corn that it can be blended with to make sure it won't cause any problems when fed to livestock," says Northey. "I think it's important the public knows that we are aware of the situation and taking the necessary steps to make sure it doesn't cause any health issues for animals or humans."

Aflatoxins are a result of naturally occurring mold that can infest an ear of corn during the growing season. Aflatoxins are harmful or fatal to livestock when the corn is consumed in high quantities and aflatoxins are considered carcinogenic to animals and humans. "Hot, dry summers are most likely to produce aflatoxin infection in the corn, and the affected area this year was very dry before the heavy rains began in mid-August," notes Northey.

As a result of the recent reports, area grain elevators have been testing loads received from the at-risk areas.

Follow FDA guidelines for feeding tainted corn.

The federal Food and Drug Administration has approved the feeding of corn that has certain levels of aflatoxin. FDA says an aflatoxin level of under 300 parts per billion (ppb) can be used in cattle feed and under 200 ppb in hog feed. They say corn with an aflatoxin level of under 100 ppb can be safely used to feed breeding beef cattle, hogs and mature poultry.

Levels of under 20 ppb are allowed for feeding young animals and levels of under 20 ppb are allowed in corn that has an unknown destination. However, the FDA does not allow any level of aflatoxin in milk, which means that you can't feed any aflatoxin-tainted corn to milking dairy cows.

Most reports in Iowa have been in the 20 to 100 ppb range, which means this corn can still easily be used in feed for cattle.

Ethanol plants in the area have been notified and all do some testing of the incoming loads of corn so they ensure they are not buying corn with aflatoxin. "Ethanol plants have to be cautious because of the distillers grains that are used for cattle feed," explains Northey. "Due to the processing of the corn, aflatoxins if they are present in the corn, can become concentrated at higher levels in the distillers grains. Distillers grains are a co-product of ethanol production and are often used as a supplement for cattle feed."