Photo by the University of Missouri Extension.

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.