Yhanhong Zhang, assistant director with the National Corn-to-Ethanol Research Center, presented survey results on DDGS contaminants at the Fuel Ethanol Workshop & Expo in Indianapolis.

“Mycotoxins are unavoidable,” she said, “they are weather related.” Harold Tilstra with Land O’Lakes Purina Feed, who spoke on the same panel titled Containing Distillers Grains Contaminants, further explained that some mycotoxins such as aflatoxins are associated with drought conditions while others, like vomitoxins (also called deoxynivalenols) are brought on by wet weather conditions.

Zhang said in 2009 predictions of greater vomitoxins present in corn were on the rise, which initiated interest at NCERC to conduct sample surveys of DDGS at various ethanol plants.

The DDGS survey took place between August 2009 and January 2011, which meant that the corn used to make the ethanol and resulting DDGS came from the 2008-’10 growing season. Eight ethanol plants were surveyed every other month between August 2009 and January 2011. The results showed that aflatoxins were found not to be an issue, but two of the eight plants sampled showed levels of vomitoxins well passed the 5 ppm Food and Drug Administration advisory level. The samples showing the highest concentration of vomitoxins were taken during Spring 2010, dying down after then. Fumonisin levels at three of the eight ethanol plants surpassed the FDA advisory level of 5 ppm as well. Zhang noted, however, that “the plants with high vomitoxins were different than the plants with high fumonisin levels.” None of the eight plants tested bimonthly during that period of time showed detectable levels of T-2 mycotoxins.

Zhang also shared data from DDGS produced with corn from crop years 2005-’07. She said 235 samples were taken from 23 dry mill ethanol plants, and the highest aflatoxin levels were at 4 ppb, meaning none were higher than the FDA advisory level. No vomitoxin levels were higher than the advisory level either, but the highest fumonisin levels were at around 8.6 ppm, and 10 percent sampled showed levels of fumonisin greater than the 5 ppm FDA advisory level.

She concluded by explaining how mycotoxin levels in corn get concentrated in DDGS, and to prove it, she took pair samples from two ethanol plants in 14 consecutive days, and monitored the results. The end result was that enrichment of contamination in DDGS from mycotoxin-contaminated corn is roughly 3.5 times. Thus, Zhang expressed, it is imperative to monitor levels of these contaminants in the incoming corn.