And we've also talked about the related issue of antibiotic residues elsewhere in the environment, in sewage and wastewater supplies.
But here's a whole new peril: Antibiotic resistance generated by ethanol production, that vast corn-based industry that has been pitched as a homegrown biofuel alternative to foreign oil.
Food-policy blogger (and farmer and chef) Tom Philpott has been doggedly following this story for more than a year at Grist. And in a study published last month the Institute for Agriculture and Trade Policy brings some important numbers-based analysis. The gist of the problem is this:
- Ethanol production uses yeast to convert corn starches into alcohol
- Bacterial contamination, usually by lactobacilli, can hijack the process and covert the starches to unusable lactic acid instead
- To prevent that from happening, ethanol producers dose their corn mash with antibiotics
- Because contamination is frequent and persistent, producers use increasing amounts of antibiotics to overcome bacteria that have become resistant
- After ethanol is extracted, the mash residue remains tainted with those resistant bacteria and with antibiotics — including penicillin, erythromycin and streptogramin (an analog of the human antibiotic Synercid)
- The dried mash residue is sold to farmers as livestock feed, exposing livestock to resistant bacteria and dosing them with unsuspected additional antibiotics as well.