NEW YORK (AP) — McDonald's plans to announce it will start using chicken raised without antibiotics important to human medicine and milk that is not treated with rbST, an artificial growth hormone.

The announcement comes as the fast-food giant struggles to shake its junk food image amid intensifying competition from smaller rivals positioning themselves as more wholesome alternatives.

McDonald's has long battled negative perceptions about its food, but the issue has become a bigger vulnerability as more people shift toward options they feel are made with natural ingredients.

The "clean label" movement has prompted companies across the industry to purge ingredients with unrecognizable chemical names from their recipes, even while standing by their safety.

McDonald's has been struggling to boost sales and saw customer visits to U.S. stores decline two years in a row.