Mycotoxin Survey in US corn: February 2020 Update

Our February update from the annual Biomin® PROcheck mycotoxin survey in corn harvested in 2019 includes 319 samples from 22 states. The survey results represent samples sent in for surveillance testing only and does not include any sample submitted following clinical signs (92 samples). Of the sample pool, 70% are corn samples (224 samples), 14% are corn by-product (44 samples), and 16% are corn silage (51). Of the total sample pool, 98% tested positive for at least one mycotoxin, equivalent to 2018, while 68% of samples had more than one mycotoxin compared to 74% in 2018. Below we discuss preliminary trends of each of these feed ingredients regarding mycotoxin prevalence and contamination levels. 

Corn 

  • 98% of ground corn samples are positive for at least one mycotoxin, similar to 2018
  • 68% of samples have more than one mycotoxin, vs 73% in 2018
  • Aflatoxin prevalence in dry corn decreased to 2% vs 10% in 2018, with average contamination levels decreasing significantly.
  • Prevalence of type B-Trichothecenes (B-Trich), fumonisin (FUM), and zearalenone (ZEN) are similar to 2018 corn.
  • Average contamination levels for B-Trich have decreased by 25% from 2018
  • Average contamination levels for FUM have increased 36% from 2018.
  • Average contamination levels for ZEN have increased by 45% from 2018 corn.
  • Overall, challenges seem very similar to last year with variation from region to region.

Corn By-Product

  • Although there are limited sample numbers, consistent risk from type B-trichothecenes, fumonisin, and zearalenone has been observed.
  • Average contamination levels from B-Trich have decreased by 13%.
  • Average contamination levels for FUM have more than doubled.
  • Average contamination levels for ZEN have increased by 12% from 2018
  • Nivalenol, a type B-Trichothecene more toxic than deoxynivalenol has been consistently observed in DDGS (data not shown). This is likely from 2018 corn.

Corn Silage

  • 98% of samples are positive for at least one mycotoxin, vs 93% in 2018
  • 39% of samples have more than one mycotoxin, vs 66% in 2018, representing an improvement in co-contamination prevalence. This is still above 2017 levels (27%).
  • Aflatoxin prevalence negligible in this sample pool, but producers in Southern regions should still be vigilant of aflatoxin risk.
  • Type B-Trichothecene prevalence has increased slightly to 96% vs. 89% in 2018, with similar contamination levels.
  • Fumonisin prevalence and contamination levels have decreased to 4% vs 22% in 2018, with average contamination levels dropping 8-fold.
  • Zearalenone prevalence decreased to 37% vs 55% in 2018, with average contamination level decreasing by 63%.

These contamination levels present MEDIUM to HIGH risk for all livestock and poultry species depending on toxin and feed ingredient type. The risk profile of 2019 corn is currently highly dynamic due to the number of samples submitted. Overall, producers in the Midwest should be on the lookout for the impacts from deoxynivalenol and zearalenone, while Southern states should be vigilant regarding fumonisin and aflatoxin contamination.