WASHINGTON — McDonald’s said on Wednesday that its 14,000 US restaurants will stop serving chicken raised with antibiotics ‘‘important to human medicine,’’ a significant change in food policy for the world’s largest fast-food chain.
McDonald’s said the decision is an attempt to adapt to diners’ desire for healthier food.
The company had one of its most challenging years in history in 2014 as consumers turned away from the brand, often in favor of fast-casual places like Chipotle that have long emphasized their commitment to serving only ethically raised meat.
‘‘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,’’ McDonald’s US president, Mike Andres, said in a statement.
McDonald’s said the new policy will be implemented across its US supply chain within two years.
Also, McDonald’s said that this year it will begin offering milk jugs in its Happy Meals that contain milk from cows that have not been treated with the growth hormone rbST.
Public health advocates cheered the move, and some groups, including Keep Antibiotics Working, said they had been in ‘‘close dialogue’’ with McDonald’s about the policy change.
This is the latest in a series of recent attempts by McDonald’s to bring more transparency to how its food is made.