Mycotoxin Trends in US Corn Grain and Corn Distiller’s Dried Grains with Solubles

Paige N Gott, Lan Zheng, Erin F Schwandt, Chasity M Pender, Ursula Hofstetter, April W Levy

Mycotoxins are secondary fungal metabolites which may affect animal health and performance and are frequently detected in various feedstuffs. Mycotoxin occurrence and contamination levels in US corn grain and corn distiller’s dried grains with solubles (DDGS) samples were monitored in this study. Samples were analyzed via LC-MS/MS for six major mycotoxin groups: aflatoxins, type A trichothecenes, type B trichothecenes (B-Trich), fumonisins (FUM), zearalenone (ZEN), and ochratoxin A. The presence of clinical health or performance concerns on-farm was reported for each sample. Results from samples without clinical concerns that were above the limit of detection for each respective mycotoxin group were analyzed using the GLIMMIX procedure (SAS 9.4, Cary, NC) to test the effect of harvest year on mean contamination level. Results are presented in Table 1. Of the 219 samples of 2021 corn grain screened in the current data set, 69% were positive for some level of B-Trich, an increase from 58% positive in 2020. Fumonisins (61%) and ZEN (27%) were the next most frequently detected mycotoxins in 2021 samples. Although numerically lower, mean B-Trich level (parts per billion, ppb) was similar to 2020 crop while contamination with FUM was elevated (P = 0.0001) compared to the prior year. Mean ZEN levels are numerically greater, but similar to 2020 samples. Out of 35 corn DDGS samples, occurrence of B-Trich, FUM, and ZEN remained high at 100, 100, and 94%, respectively. Mean B-Trich and FUM concentrations were similar year-to-year across the study period for DDGS while current mean ZEN level was similar to 2020, but lower than 2019 (P < 0.001). Preliminary results of the 2021 US corn grain and DDGS survey suggest increased mycotoxin occurrence with comparable mean contamination levels to those observed in 2020. Continued surveillance is suggested to assess contamination in common livestock feed ingredients.