McDonald's Is Phasing Out Chicken With Antibiotics

It will also offer milk to customers without artificial growth hormone.

— -- McDonald's, the world's largest fast food chain, said it's phasing out the use of chicken with antibiotics over the next two years in the U.S.

In an announcement today, McDonald's said it will only source "chicken raised without antibiotics that are important to human medicine."

McDonald's U.S. restaurants will also offer customers milk from cows that are not treated with rbST, an artificial growth hormone.

"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.

Jonathan Kaplan, director of NRDC's food and agriculture program, points out that McDonald's "Global Vision" statement doesn't include a ban on the use of all medically-important antibiotics in routine disease prevention, which some say can contribute to antibiotic resistance.

"Hopefully, chicken is just the start - the Big Mac and McRib may be next," Kaplan said, adding that he hopes McDonald's closes this "loophole" and applies their new U.S. chicken antibiotics curbs to all their restaurants globally.

In late 2013, the FDA announced a plan to phase out antibiotics in feed for growth promotion to prevent antibiotic resistance. But the announcement indicated farmers could still claim antibiotics were being used for illness prevention.

Rep. Louise Slaughter, D-NY, who has worked to “save antibiotics” and is the sole microbiologist in Congress, has previously proposed removing antibiotics from farms.

“Today’s announcement from McDonalds is encouraging, but until there is an enforceable, verifiable limit on agricultural antibiotic use, we will have no way to verify whether chicken raised on medically important antibiotics has been truly phased out," she said in a statement. "Furthermore, I have called on McDonald’s to also phase out beef raised on medically important antibiotics, and I will continue to press them on that front."

When asked if the company has similar plans for its beef supply, a spokeswoman for McDonald's said in a statement to ABC News, "We continue to look at our menu and how we can evolve it based on what our customers tell us is important to them. We are proud of these initial steps we have announced today related to chicken and will be doing more going forward."

As part of the company announcement today, McDonald’s USA was announced as a founding member of the newly formed U.S. Roundtable on Sustainable Beef, which includes organizations like Cargill, Walmart, World Wildlife Fund and The Nature Conservancy.