Cattle eating a mixture of antibiotic-free corn and hay at Corrin Farms, near Neola, Iowa. Their meat is sold by Niman Ranch. Dan Charles/NPR hide caption
antibiotic-free food
A customer holds a McDonald's Big Mac. The fast-food giant, one of the world's biggest beef buyers, has announced plans to use its might to cut back on antibiotics in its global beef supply. Environmentalists are applauding the commitment. Christoph Schmidt/Picture Alliance via Getty Images hide caption
A pig stands in a pen at an antibiotic-free pig farm in Tongxiang, China. Bloomberg via Getty Images hide caption
Chicks in the Perdue hatchery in Salisbury, Md. The company says that it is now raising all of its chickens without routine antibiotics. Only those flocks that get sick, about 5 percent of all birds, will be treated. Dan Charles/NPR hide caption
Diners wait in line at a Subway sandwich shop on September 15, 2015 in Chicago, Ill. Subway will serve antibiotic-free turkey and chicken by the end of 2016, but it may take nine years for its suppliers of beef and pork to go antibiotic-free as well. Scott Olson/Getty Images hide caption