ost people who eat regularly at McDonald's don't think of themselves as having much impact on the shape of global agriculture. The appeal of McDonald's has always been immediate gratification, and its basic offerings — including hamburgers, Chicken McNuggets and French fries — are usually the despair of nutritionists. Yet behind the scenes, McDonald's, which buys some 2.5 billion pounds of meat a year, has made remarkable strides, influencing the practices of suppliers that provide it with beef, chicken and pork. Last year, for instance, it conducted 500 audits of meat processing facilities globally, checking everything from cleanliness to the treatment of animals.

Now, McDonald's has taken an even more important step. By the end of 2004, it will require its direct suppliers, mostly of chicken, to stop giving antibiotics in low doses to speed animal growth. And McDonald's will choose indirect suppliers that limit antibiotics over those that do not. This is the company's response to growing alarm over the routine use of antibiotics in animal production, a practice that is diminishing the effectiveness of antibiotics in humans.

The effort to reduce the amount of agricultural antibiotics — which came to some 22 million pounds in 2001 — has been blocked by a number of disputes about how much they are used as growth supplements and how harmful they are to humans. But the science strongly suggests that there are better ways to raise animals, as the Europeans, who have sharply reduced agricultural antibiotic use, have realized.

The real importance of this policy will be its ripple effect. The best way to cut back on antibiotic use on farms is to raise animals in healthier ways that do not require the use of antibiotics. And as McDonald's changes the standards of meat production, other corporations will follow suit. McDonald's may have an unfortunate effect on international eating habits, but at least it is using its market power where it can to change farming practices for the better.

Copyright 2003 The New York Times Company