60 Occurrence of Mycotoxins in US Corn Gluten Products and Wheat Middlings

Abstract Secondary fungal metabolites which may affect animal health and productivity are known as mycotoxins. These naturally occurring metabolites are often detected in a variety of feed ingredients. Mycotoxin occurrence and contamination levels in corn gluten products and wheat middlings or “midds” were monitored in this study. Samples submitted from the US were screened 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 (OTA). 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 included in the study. Out of 14 corn gluten product samples reported as 2021 crop year, 100% were positive for both B-Trich and FUM, while 71% were positive for some amount of ZEN. These mycotoxin groups were also the most frequently detected in 2020. Mean contamination levels (parts per billion, ppb) for 2021 were 1,314 ppb, 443 ppb, and 132 ppb, respectively. Of the 24 samples of 2021 wheat midds, B-Trich were detected in 92% while 54% were positive for OTA with mean contamination levels of 665 ppb and 3 ppb, respectively. Ergot alkaloids were not screened for in the current year, however, previous analyses have identified these metabolites frequently occur in wheat midds samples. Although represented by limited data sets to date, analysis of 2021 corn gluten products and wheat midds indicate mycotoxins frequently occur in these by-product feeds. High feed costs may drive increased feeding of alternative feeds, including these and other by-products, in addition to established routine usage in pelleted feeds and other diets. Therefore, continued screening is suggested to assess mycotoxin exposure in livestock diets.