69 Occurrence of Mycotoxins in 2020 US Corn Grain and Corn By-product Feeds

Abstract Mycotoxins are fungal metabolites that limit animal health and performance through various negative effects including reduced feed intake, diarrhea, and compromised immune function. These toxic metabolites have been detected in a broad range of feedstuffs worldwide. This study investigated mycotoxin occurrence and contamination levels in U.S. corn grain samples marked as 2020 harvest year and corn by-product feed samples submitted since October 2020. Samples were screened via LC-MS/MS for six major mycotoxin groups including: aflatoxins, type A trichothecenes, type B trichothecenes (B-Trich), fumonisins (FUM), zearalenone (ZEN), and ochratoxin A. Results from samples 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. Occurrence levels of B-Trich, ZEN, and FUM in 2020 corn grain are numerically lower than those from 2019. Mean B-Trich level (parts per billion, ppb) for corn grain samples harvested in 2020 was similar to 2019 crop year. Contamination levels of FUM and ZEN were similar for 2020 crop as compared to prior harvest years. Mycotoxin occurrence in corn by-product feeds continued to be high at 99, 85, and 95% for B-Trich, ZEN, and FUM, respectively. Mean B-Trich and ZEN levels in 2020 corn by-products were similar to respective contamination levels in 2018, but were lower than 2019 samples. Mean FUM contamination in corn by-products has been similar across reported years. Preliminary results of the 2020 corn grain survey indicate mean mycotoxin contamination levels are similar to those observed the past two crop years while levels of B-Trich and ZEN in corn by-product feeds are reduced from 2019. Corn-based feed ingredients may present challenges to producers due to the presence of mycotoxin contamination, therefore, continued monitoring is warranted.