Last year we saw a huge rise in the number of beef recalls due to E. coli O157:H7 contamination. While there were eight beef recalls in the US in 2006, the number jumped to an astounding 21 beef recalls in 2007, including the second largest beef recall in US history from Tops Meat Company. About a third of the recalls were prompted by reports of human illness, while none of the 2006 recalls were. According to a recent Washington Post article by staff writer Annys Shin, researchers at Kansas State University may have found the reason.
The study found higher levels of E. coli O157:H7 in the feces of cattle fed a diet that included an ethanol product called distillers grain.
Distillers grain is what is left after the starch from corn is removed to make ethanol. It has been around for decades, but its popularity as a feed ingredient has surged in recent years. One reason is that demand for ethanol, fueled by rising gas prices and federal mandates and subsidies, has pushed the price of corn — and in turn, corn feed — to record levels, said Darrell Mark, an economist at the University of Nebraska at Lincoln.
Distillers grain is also cheaper than corn and is high in the proteins and fats that help cattle put on more weight, said David M. Smith, a University of Nebraska researcher. For cattle ranchers, who are being squeezed by lower beef consumption and higher prices for fuel and grazing land, such benefits are important.
The researchers at Kansas State followed up with another study in which they inoculated calves with E. coli O157:H7 (which is harmless to cattle) using a modified form of the bacteria that was easier to track. They found that calves fed distillers grain had higher levels of the bacteria than those that were not. The USDA findings appear to back them up.
But the connection between distillers grain and E. coli is still far from conclusive, researchers said, for several reasons. Another study done by researchers at the University of Nebraska found that cattle fed a diet of up to 25 percent distillers grain actually had less of the bacteria than the control group, while those fed a diet that was 40 percent or more distillers grain had more of the bacteria. Another study done at Kansas State found no statistically significant increase in the bacteria in distillers-grain-fed cattle compared with the control.
T.G. Nagaraja, one of the Kansas State researchers, suggests that the variation in results may be due to differences in the distillers grain, which can depend on where it was produced.