Earlier this month, the McDonald’s chain of fast-food restaurants announced it would phase out within two years the sale of chickens that had been treated with antibiotics commonly used to treat human illnesses.

Scientists and doctors have for years been warning about antibiotic-resistant germs. Health experts believe that part of the problem is linked to farm animals being fed antibiotics while in overcrowded chicken barns or cattle feed lots. The chickens and cows are fed antibiotics to help them resist diseases that they are vulnerable to because they are living in cramped, confined and often disease-fostering conditions. The agriculture community also discovered that feeding livestock antibiotics helps them grow to market weight faster, thus increasing profits.

But the impact on human health of agricultural antibiotics use is a growing concern, as the current arsenal of antibiotics, once considered miracle drugs, are sometimes ineffective at knocking out human infections. The idea is that by eating chicken or beef grown with excessive antibiotics, many humans are carrying low levels of antibiotics, which allows germs to evolve, developing resistance over time.

The news from McDonald’s is important, not only because the fast food chain is a major seller of chicken, but because its decision could change the way the poultry industry operates. McDonald’s is the largest buyer of chicken in the United States, consuming about 4 percent of total chicken production in the United States. But its decision will probably impact a much larger part of the industry.

The increasing popularity of chains such as Chipotle’s and Panera Bread, which both emphasize healthy meals and also promote the fact that they buy antibiotic-free chickens, could be part of the reason for McDonald’s shifting toward healthier chicken production practices.

It also could be a sign that Steve Easterbrook, McDonald’s new CEO hopes to reverse months of slumping sales by shaking things up and moving strongly in the direction of healthier foods, which is something a large segment of the American public has been requesting.

McDonald’s plan to purchase antibiotic free chicken will probably bring more change to the chicken industry. It would not be surprising to see other fast food chains follow McDonald’s — and the farms or corporations that raise chickens will see that they need to change how they do business — if they intend to stay in business.

The shift in public thinking has been gradual, but it’s gaining momentum. The 2008 documentary film titled “Food, Inc.,” deserves credit for showing millions of Americans some of the unpleasant details behind how the food they eat is produced. Since the widespread showing of the film, more Americans are expressing concerns about the health and environmental aspects of food production. In particualar, there is growing concern over antibiotics fed to livestock raised on large, factory farms.

McDonald’s and other fast-food restaurants are seeing that fast and cheap are not the only qualities that matter to many people when it comes to their food. There is growing interest in healthy and humanely produced food.

The plan by McDonald’s is more evidence of positive changings coming to food production in America.