Survey of Mycotoxins in US Corn Distillers Dried Grains with Solubles

Distillers dried grains with solubles (DDGS), a by-product of the ethanol industry, is commonly used as a feed ingredient for various livestock species. During ethanol production mycotoxins present in the original corn become concentrated in the resulting DDGS. These secondary metabolites produced by molds infecting crops such as corn can significantly compromise animal health. Severity of the negative effects associated with mycotoxins is dependent on the level, type, and duration of exposure and the age, species, and general health status of animals. The objective of the current study was to determine the occurrence of mycotoxins in samples of US corn DDGS and to evaluate the potential risk posed to livestock. Seventy-nine corn DDGS samples from 14 states were submitted for analysis between 2015 and 2016. Samples were analyzed using liquid chromatography tandem mass spectrometry (LC-MS/MS) for the presence of mycotoxins from the following six major mycotoxin groups: type B trichothecenes including deoxynivalenol (DON), fumonisins (FUM), zearalenone (ZEN), aflatoxins (Afla), type A trichothecenes including T-2 toxin (T-2), and ochratoxin A (OTA). All samples in the current survey were contaminated with at least one mycotoxin with 96% having more than one mycotoxin detected. The presence multiple mycotoxins may intensify the negative effects of each mycotoxin present. The percent positive samples, median, 90th percentile, and maximum contamination level of positive samples for the six major mycotoxin groups are presented in Table 1. DON was detected in 100% of samples while FUM and ZEN were also highly prevalent. DON poses the greatest threat from US corn DDGS samples to animal health due to the high prevalence (100%) and large number of samples contaminated beyond the FDA recommended level (80% of positive samples above 1000 ppb).

Table 1. Summary of mycotoxin analysis.

Parameters	DON	FUM	ZEN	Afla	T-2	OTA
Positive samples (%)	100	88	71	7	0	1
Median of positives [ppb]	2,400	2,600	150	6	0	19
90th Percentile [ppb]	5420	7100	431	26	NA	NA
Maximum contamination [ppb]	9,800	18,500	666	37	0	19