It seems like everywhere we turn, there’s more evidence of industrial agriculture’s reckless use of antibiotics. The latest example: antibiotics in ethanol production.
As we reported recently here on Grist, this isn’t just a waste of important medicines. It may also contribute to the rise of antibiotic-resistant bacteria. And that’s because the main by-product of the ethanol production process, the leftover corn mash known as distillers grains, has become a major ingredient in animal feed over the last decade. More than 30 million metric tons of the made-in-the-USA stuff are fed to beef cattle, dairy cows, and pigs here and abroad every year.
While the Food and Drug Administration (FDA) does not track exact figures, meaning there’s no way to know exactly how much is used, the agency’s own research has shown antibiotics like penicillin and erythromycin, which are important for human medicine, at detectable levels in distillers grain. A 2010 study by the FDA’s Center for Veterinary Medicine found enough erythromycin present in samples of the distillers grains it tested to cause resistance to develop in certain bacteria — compelling evidence that the risks of using antibiotics to make ethanol are real.