Friday, December 14, 2007

Ethanol, Clean Energy and E. coli O157:H7

The U.S. Congress has been trying to agree on an energy bill. One of the provisions of this bill, which has already been passed in the House of Representatives but which is stalled in the Senate, provides incentives for alternative fuels, such as cellulosic ethanol.

Cellulosic ethanol can be produced from a variety of plant material. At present, about 80% of it is made using corn. But the production process doesn't use up all of the corn. What is left behind after the fermentation and clean-up is a by-product known as "spent grain" or "distiller's grain".

Distiller's grain is not without its uses, especially to the cattle industry. Feedlot operators have been feeding this relatively inexpensive grain to their cattle. And distillers are enjoying the windfall revenue from what would otherwise be waste material. There is, however, a cloud on the horizon.

Recently, researchers at Kansas State University announced that feeding distiller's grain to cattle resulted in a higher incidence of E. coli O157:H7 in the hindgut of the animals. This contradicts findings reported by another major agricultural school, the University of Nebraska - Lincoln. Nebraska researchers did not find any indication that adding distiller's grain to the diet produced an increased incidence of E. coli O157:H7.

So there you have it - one of those situations that turns a microbiologist's hair gray. The USDA's Agricultural Research Service lab in Clay Center, NE is in the midst of a similar study, which is scheduled to be completed by the end of 2008. Best two out of three, anyone?

The process of raising cattle for slaughter has undergone many changes over the decades - in feedlot environment, types of feeds, and handling of manure and runoff. Unfortunately, thought is usually only given to the microbiological impact of these changes after the fact. For once, it would be nice to see data supporting the microbiological safety or benefits of a significant change before that change is implemented.

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