DON outbreak highlights storage concerns for grain

DON: it’s nasty, it’s dangerous and it’s being currently found in high levels in stored grain around the Corn Belt region of the United States.

DON — a.k.a., vomitoxin — is a mycotoxin created by Fusarium molds, especially F. graminearum. When consumed, it can cause nausea, vomiting (hence the nickname), gastroenteritis, diarrhea, immunosuppression and even blood disorders. Animals affected may refuse to eat.

“In the eastern Corn Belt right now, we are seeing base corn levels around 1 part per million,” said Erin Bowers, mycotoxin sampling and analysis specialist at Iowa State University. “Grain receiving locations should be testing for these levels, or at least be aware that we are seeing higher levels this year.”

The U.S. Food and Drug Administration advises that DON not be consumed above the following levels:

  • 1 part per million (ppm) in humans
  • 10 ppm in less than 50% of the diet (5 ppm total diet) for ruminating beef, feedlot cattle and chickens
  • 5 ppm in less than 20% of the diet (1 ppm total diet) for swine
  • 5 ppm in less than 40% of the diet (2 ppm total diet) for all other animals

As the recommendations suggest, swine are especially sensitive to DON. This heavily impacts the swine industry in the Corn Belt region, which includes Iowa, Illinois, Indiana and other states in the upper Midwest.

Bowers and her colleagues have developed several resources for producers to learn about handling and sampling for mycotoxins, including a mycotoxin development model and a best practices model. Bowers is also presenting a hands-on workshop at the end of the month that will guide producers step-by-step through the testing process.

A global glut of grain

As a global glut of grain has led to mountainous piles of corn and wheat around the world, farmers and elevators need to be careful about how they store their grain. Improper storage of such a high volume means an increased risk of spoilage and contamination.

Wallaces Farmer reports that higher-than-average temperatures and dew points last fall mean that more of stored grain’s storage life was used up. This presents problems, as the current excess of grain may need to be carried over in good condition even into 2018.

Fungi and mold are likely to grow in environments where the relative humidity is higher than 65%. Keeping grains aerated and at a lower temperature can help stave off these spoilage organisms. Keeping grain in bins with roof fans is one way to avoid problems.

“Pay attention to dew point temperatures in the air,” said Charles Hurburgh, grain quality and handling specialist at Iowa State. “If we have a stretch of big storms, there will often be dry air afterward with dew points in the 30s and 40s. Run fans if grain is warmer than that, in order to keep grain cold as long as possible.”

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