Recent research has found that cattle fed distiller's grain, a byproduct of the ethanol distilling process, have an increased prevalence of E. coli 0157 in their hindgut. This particular type of E. coli poses a health risk to humans.
The growth in ethanol plants means more cattle are likely to be fed distiller's grain. The prevalence of 0157 is about twice as high in cattle who are fed it.
It is possible that changes in the animals' hindgut occur as a result of feeding distiller's grains to cattle, or it could be that the byproduct provides a nutrient for the bacteria.