Why McDonald's is cutting back on antibiotics

Bowing to growing consumer pressure for more natural food, McDonald's (MCD) announced today that it would phase-out sales of chicken treated with human antibiotics over the next two years. The move is a victory for public health groups who have long claimed that the use of human medicine in animals encourages the growth of drug-resistant illnesses.

Antibiotics developed for humans are used in meat production in order to encourage growth and to prevent the spread of disease. About 80 percent of antibiotics sold in the U.S. are used in this manner, according to some estimates. The practice, while legal, has been on the decline in recent years, according to chicken producers. McDonald's announcement is expected to curb their use even further since the company has 14,000 U.S. locations.

"This is a huge and very positive development," said Caroline Smith DeWaal, director of food safety at the Center for Science and the Public Interest, in an interview.

Shares of McDonald's have risen 5 percent over the past year, underperforming its peers such as Burger King parent Restaurant Brands (QSR) and Wendy's (WEN), which have both posted double-digit gains. Investors are concerned about McDonald's lackluster sales growth, which Wall Street analysts have attributed to the public's concerns about the quality of the company's food.

"Our customers want food that they feel great about eating -- all the way from the farm to the restaurant -- and these moves take a step toward better delivering on those expectations," said McDonald's U.S President Mike Andres in a press release.

McDonald's, though, is coming to the antibiotic issue late. Chipolote (CMG), which has attracted the young consumers that new McDonald's CEO Steve Easterbrook covets, has for years sourced all of its chickens from farms that don't use antibiotics. Wendy's, a rival to McDonald's in the quick service market, has long-standing policies against the use of human antibiotics by meat suppliers solely for the purposes of growth promotion.

"Our customers are our guide, and we continue to listen to their expectations regarding the quality food we serve," Wendy's spokesman Bob Bertini wrote in an email to CBS MoneyWatch.

Rival Chick-fil-A announced last year that it was working with suppliers to eliminate all antibiotics from its chicken supply over the next few years, including animal-specific medications called ionophores that aren't included in McDonald's plan. Smith DeWaal noted that ionophores are mainly used to treat parasites in animals and have no impact on humans. McDonald's wants ill animals to receive this treatment.

"It's exciting to see another major player in the industry moving forward on this issue," Chick-fil-A, a closely held chain, said in a statement to CBS MoneyWatch, adding that it will provide an update on its efforts next months. "We are also asking suppliers to work with the USDA to verify that antibiotics are never administered from the hatchery to the processing plant."

Burger King said in a statement that it "encourages good animal husbandry by adopting meaningful requirements to make certain that Burger King products are purchased from processors and farmers that comply with local government requirements and standards, including antibiotic usage restrictions. As a matter of policy the Burger King brand does not allow the use of antibiotics in poultry for growth-promotion purposes."

According to the National Chicken Council, a trade group, chicken producers have been working with the FDA, farmers and veterinarians for the past two years to reduce the amount of human antibiotics in the industry. Tyson Foods (TSN), the largest U.S. chicken producer, welcomed the announcement by McDonald's, noting that it has been cutting the use of human antibiotics by 84 percent since 2011 and stopped using the medications in its 35 hatcheries last fall.

"The vast majority of the antibiotics used to raise our chickens are never used in humans," the Springdale, Ark.-based company said in a statement. However, the welfare of these animals is very important to us, so we sometimes use FDA-approved antibiotics in a small percent of our flocks to treat or prevent disease, but only when prescribed by a veterinarian."