Mycotoxin Prevalence in the 2016 Corn Crop

Mycotoxins are harmful secondary metabolites produced by fungal species capable of infesting commercial crops. These fungal species are roughly divided into two groups: those predominantly producing mycotoxins on the field (e.g. Fusarium spp.) and those predominantly occurring in storage (e.g. Aspergillus and Penicillium spp.). Mycotoxin contamination of feed materials is a global concern, as exposure to mycotoxins significantly impacts animal health and productivity. BIOMIN^® has been conducting annual corn surveys in the United States since 2012. The purpose of this study is to evaluate the mycotoxin contamination of the 2016 corn crop.

Seventy-seven corn samples, collected from mid-August to October 2016, were analyzed utilizing LC-MS/MS. Samples came from 12 states, with 85% of samples originating from the Midwest. Samples were submitted due to reproduction concerns (n=4), surveying new crop (n=59), and non-specified reasons (n=14). Six major mycotoxin groups were analyzed including aflatoxins, type A trichothecenes, type B trichothecenes (B-TRICH) such as deoxynivalenol (vomitoxin), ochratoxin-A, fumonisins (FUM), and zearalenone (ZEN) derivatives (limit of detection in ppb: 100, 100, 1.1, 100, 51.7 respectively).

Eighty-three percent of the samples contained at least one detected mycotoxin type, similar to the 2015 BIOMIN^® US corn survey (84% positive, 321 samples). However, there was a 15% increase in the number of samples contaminated with multiple mycotoxins (≥2 mycotoxins, 2016: 58%; 2015: 43%). This was primarily due to increased prevalence of FUM and ZEN (2016; FUM: 64%, ZEN: 26%) compared to the previous year (2015; FUM: 50%, ZEN: 14%). Additionally, the level of FUM in positive samples was significantly higher in 2016 (2016: median: 1100 ppb, n=77 2015; 2015: median: 400 ppb, n=321; p = 0.003, Mann-Whitney). The percent of positive samples of FUM over 1000 ppb (25 of 49 samples) increased by 24% compared to the 2015 harvest (43 of 161 samples). In contrast, the most prevalent mycotoxin B-TRICH had relatively unchanged prevalence and contamination levels (2016: 66% prevalence, 2015: 69%; 2015-16: 14% positive samples over 1000 ppb).

The preliminary results from the 2016 corn harvest suggest an increased co-occurrence with mycotoxins produced by Fusarium fungal species. This includes co-occurrence with B-TRICH and FUM (2016: 34%, 2015: 28%), and with FUM, B-TRICH, and ZEN (2016: 14%, 2015: 7.5%). Because of the high frequency of multi-mycotoxin contamination in samples thus far, multiple strategies of mitigating risk are needed beyond adsorption, including biotransformation and providing support to immune and liver function.