Storage of Midwest corn causing mycotoxin concerns

January 10, 2017

2016 brought a bumper corn harvest thanks to favorable weather conditions throughout the U.S. that resulted in a record amount of corn available for export. However, with the good also comes the bad. Because such a large amount of corn was produced, a large amount also had to be stored — typically in outside piles — that are vulnerable to weather extremes, especially heavy snow and rain.

Now, due to the wet weather conditions most of the Midwest is experiencing, reports are surfacing of wet corn stored in piles turning sour, and in some cases, sprouting.

According to the U.S. Grains Council’s (USGC) annual corn quality survey, the average U.S. aggregate moisture content recorded at the elevator in the 2016 samples was 16.1%, higher than 2015 (15.7%). While this is on par with the five-year average, USGC noted that general moisture storage guidelines suggest that 14% is the maximum moisture content for storage up to six to 12 months for good-quality, clean corn, and 13% or lower moisture content is recommended for storage of more than one year.

“Because of higher moisture in 2016 than in 2015, and higher total damage levels in 2016 than in previous years, care should be taken to monitor and maintain moisture levels sufficiently low to prevent possible future mold growth,” USGC stated in its report.

Of particular concern for some areas in the Midwest is vomitoxin, also known as deoxynivalenol or DON, which can grow quickly in wet conditions. According to an article, this is catching some off guard as end users did not originally have every load tested during harvest due to the favorable weather conditions. Now, the levels are creeping up and it’s becoming extremely important to test the product for mycotoxins.

In addition, Charles P. Woloshuk, a botany and plant pathology professor at Purdue University, mentions in the article that current weather conditions it will also be important to test and be prepare for the appearance of aflatoxins.

“The fungus that produces aflatoxin can grow at a moisture content at about 16%, and if the temperature is right, aflatoxins will accumulate,” he said in the article. “There is also a higher potential for storage fungi that will grow at 16% moisture. These fungi will destroy the grain as it warms.”

Woloshuk added that the grain should be properly dried to 14% to 15.5%; 13.5% if it is to be carried into the summer. “If there are farmers that have 16% grain in their bins, it should be sold before the weather begins to warm in the spring,” he said.

Angie Setzer, vice president of Grain Citizens LLC in Michigan explained that we won’t know the full extent of how badly the stored corn may or may not be infected until the corn really starts to move off the farm, “but at this point,” she said, “in my particular trade area, it seems to be a rapidly growing problem.”

For more information, click here.

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Category: Food Safety