Assessing the Presence of Aflatoxins and DON
At least 25% of the minimum number of samples (600) across the sampling area was proportionately collected and tested to assess the impact of the 2016 growing conditions on total aflatoxins and DON development in the U.S. corn crop. The sampling criteria, described in the “Survey and Statistical Analysis Methods” section, resulted in a total number of 177 samples tested for mycotoxins.
A threshold established by the U.S. Department of Agriculture (USDA) Federal Grain Inspection Service (FGIS) as the “Lower Conformance Level” (LCL) was used to determine whether or not a detectable level of the mycotoxin appeared in the sample. The LCLs for the FGIS-approved analytical kits and used for this 2016/2017 report were 5.0 parts per billion (ppb) for aflatoxins and 0.5 parts per million (ppm) for DON. The FGIS LCL was higher than the Limit of Detection (LOD) specified by the kit manufacturer of 2.5 ppb and 0.3 ppm for aflatoxin and DON, respectively. Details on the testing methodology employed in this study for the mycotoxins are in the “Testing Analysis Methods” section.
Results: Aflatoxins
A total of 177 samples were analyzed for aflatoxins in 2016, compared to 185 and 182 samples tested for aflatoxins in 2015 and 2014, respectively. Results of the 2016 survey are as follows:
One hundred seventy-three (173) samples, or 97.7% of the 177 samples, had no detectable levels of aflatoxins (below the FGIS LCL of 5.0 ppb). This is slightly below 2015 and 2014, where 100% of the samples tested had no detectable levels of aflatoxins in both years.
Two samples (2), or 1.1% of the 177 samples, showed aflatoxin levels greater than or equal to 5 ppb, but less than 10 ppb.
One sample (1), or 0.6% of the 177 samples, showed an aflatoxin level greater than or equal to 10 ppb, but less than or equal to the FDA action level of 20 ppb.
One sample (1), or 0.6% of the 177 samples, showed an aflatoxin level greater than or equal to FDA action level of 20 ppb.
These results denote that 176 samples, or 99.4% of the 177 sample test results in 2016, were below or equal to the FDA action level of 20 ppb, compared to 100% of the samples tested in both 2015 and 2014.
While the 2016 crop season had a slightly lower percentage of samples below the FGIS LCL of 5.0 ppb than 2015 and 2014, the high percentage of 2016 samples testing below the LCL may be due, in part, to favorable weather conditions in 2016 (see the “Crop and Weather Conditions” section for more information on the 2016 growing conditions). Most of the growing area received ample moisture during pollination and grain-fill in 2016, and the corn plants were not under stress as a result.
Results: DON (Deoxynivalenol or Vomitoxin)
A total of 177 samples were analyzed collectively for DON in 2016, compared to 185 and 182 samples tested for DON in 2015 and 2014, respectively. Results of the 2016 survey are as follows:
One hundred four (104) samples, or 58.8% of the 177 samples had no detectable levels of DON (below the FGIS LCL of 0.5 ppm).
The 2016 percentage for samples that tested below 0.5 ppm (58.8%) was lower than 2015 (87%) and 2014 (80%).
Seventy-three (73) samples, or 41.2% of the 177 samples, tested greater than or equal to 0.5 ppm, but less than or equal to the FDA advisory level of 5 ppm.
All 177 samples, or 100%, tested below or equal to the FDA advisory level of 5 ppm, which was the same as was observed in 2015 and 2014.
While the samples in the 2016, 2015, and 2014 surveys were all below 5 ppm, the decrease in the percentage of samples below 0.5 ppm in 2016, compared to 2015 and 2014, may be attributed to wet weather conditions that were more conducive to DON development in 2016.