Each year, an estimated 600 million people, or nearly 1 in 10 of us, fall ill due to foodborne illnesses from E. coli and salmonella. The death rate is particularly high among children under five. Most of these illnesses are caused by antibiotic-resistant bacteria, and most of that bacteria comes from industrially produced chicken, according to Maryn McKenna, author of Big Chicken, which was published by National Geographic.

When McKenna spoke by phone from her home in Athens, Georgia, she revealed what antibiotics are really used for, why fast food chains like KFC and McDonalds are starting to avoid them, and why French poulets taste so much better than American supermarket chicken.

View Images Courtesy National Geographic

You begin your book with a wonderful description of eating a poulet crapaudine (spatchcock) in Paris. Make our mouths water—and explain why this kind of chicken is so different from the mass-produced varieties sold in American supermarkets.

For poulet crapaudine, you take a chicken, flip it over, cut out the backbone then flip it back over and flatten it. It looks like a frog or toad, which is crapaud in French. Crapaudine is also the word for the bearing in the center point of a hinge, which makes perfect sense because once you’ve taken the backbone out and broken the breastbone, the chicken looks like the hinge in a door.

It tastes delicious! After it is flattened, the chicken is slid on a set of bars, where it resides for several hours in this radiant heat, basted by other birds dripping onto them, heavily coated in herbs and black pepper, inside this giant, portable roasting cabinet that gets rolled into the street markets of Paris. It’s very bronze and has that great caramel-y flavor.

What was extraordinary to me as an American was that the flesh actually tasted like something. [Laughs] It’s almost a joke in American English to say that when something tastes like chicken, it means first, you don’t really know what it tastes like, and second, it tastes fairly bland. But this chicken tastes like a real animal.

It spent its life running around a farm in France where it was out in the open air, scratching up bugs, getting exercise, eating herbs, and flapping its wings. It had more flavor and more chew because its muscles had been used. This is so different from the everyday chickens that one encounters in U.S. supermarkets—and increasingly across the world—that are large and flabby, pale and taste safe but don’t taste like much.

You call antibiotic resistance “the greatest slow-brewing health crisis of our time.” Give us a global overview—and how food production is at the heart of it.

It comes as news to a lot of people that antibiotics play the role that they do in agriculture because we’re used to the role of antibiotics in the context of medicine and everyday healthcare. But it turns out that the greatest use of antibiotics on the planet is not in medicine for people; it’s in agriculture for animals!

In the U.S., more than 34 million pounds per year of antibiotics go into meat animals, which is four times the amount that gets used in people. Almost all that use is not to cure infections. Overwhelmingly, antibiotics are used for a practice called “growth promotion,” which makes animals put on weight.

Animals receive these antibiotics in their feed and water just about every day of their lives. This creates antibiotic-resistant bacteria in their gut, which then leave the farm when the animals go to be slaughtered. The bacteria move out into the wider world where they cause infections just as antibiotic-resistant bacteria arising from medicine do. These infections are often far removed in time and place from the food that caused them, so the puzzle of how antibiotic use on the farm causes antibiotic-resistant infections in people was a jigsaw that’s taken years to put together. But there is now solid evidence that there’s a direct link.

TIL: We Waste One-Third of Food Worldwide That's enough food to feed the nearly 800 million people going hungry—and then some. National Geographic explorer Tristram Stuart elaborates on the many ways perfectly good food goes to waste.

The widespread use of antibiotics in America began in 1948 with a man named Thomas Jukes. Tell us about his experiment—and why it revolutionized chicken production.

Jukes was an expert in the dietary needs of chickens at a time when vitamins were beginning to be synthesized and added to chickens’ diets. He was working at one of the early pharma companies and had the idea to set up an experiment to trial different supplements—like brewer’s yeast, cod liver oil or distiller’s grains—in the diets of chickens to see which had the best effect. He also decided to test the manufacturing leftovers of one of his company’s first antibiotics, which is now known as chlortetracycline. When he ended his experiment, on Christmas Day 1948, all of the chickens that had gotten supplements gained at least a little weight. But the ones that gained by far the most weight were the ones that got the antibiotic leftovers. Out of that, an entire industry was born.

The global fight back against antibiotics began in the U.K. with a scientist named Ephraim Saul Anderson. Introduce us to him—and explain why the action taken by the British government was so revolutionary.

It only took a while of antibiotics being used in farm animals, for people to start noticing that something was happening with food-borne illness. It was becoming antibiotic resistant. A scientist named Ephraim Saul “Andy” Anderson noticed these outbreaks, first in southeastern U.K., then more seriously in Middlesbrough, in Yorkshire, where a number of children died of antibiotic-resistant E. coli.

Anderson decided that he was going to try to connect the dots between them, tracing the outbreaks back through the middlemen that sold the cattle. This large-scale outbreak of antibiotic-resistant food-borne illness had never been seen before. It was clear from his research that it could be traced back to the lavish, new use of antibiotics in farm animals creating antibiotic-resistant bacteria that moved off the farms to people. Even though this idea was still controversial, by 1971 Parliament had accepted it and England became the first nation to ban some use of agricultural antibiotics. This set the pattern for the Scandinavian countries, all of the EU, then much later the United States.

View Images Some of the environmental hazards of raising chickens are avoided on this Pennsylvania farm by letting the birds roam free. Photograph by Peter Essick, Nat Geo Image Collection

In the U.S., the Food and Drug Administration (FDA) tried to enact similar regulations in 1977. But they faced huge opposition, didn’t they?

As soon as the British government acted, attention turned to the U.S., as a much larger agricultural market and a place where growth-promoter antibiotics were first used. It happened to be at a time when an administration of reformers was coming into the American government, led by President Jimmy Carter. To head the FDA, he asked an academic from Stanford, Donald Kennedy, who was young, very fierce, and intolerant of political processes.

Kennedy declared via the usual government channels that he was going to hold a hearing and summon the manufacturers of all the agricultural antibiotics to prove to his satisfaction that the drugs being used in animals were safe. If they could not prove it to his satisfaction, he was going to yank the licenses for antibiotics being used in agriculture.

But he never got to hold that hearing. A very powerful congressman from the South named Jamie Whitten, who had a lot of agricultural interests behind him, happened to be the head of the committee that approves the FDA budget. He sent a message to the White House that, if this hearing went ahead, he would hold the entire FDA budget hostage.

The White House sent a message back down to their new FDA chief that the hearing could not go forward. After two years, Kennedy went back to Stanford, Congressman Whitten remained in the House of Representatives for more than 50 years, and the issue stayed at a stalemate for decades until, finally, things started to change with the Obama Administration.

There are some bright spots in the story. Tell us about Frank Reese, aka the Good Shepherd, and his wonderful collection of chickens in Marquette, Kansas.

Frank Reese descends from a family that migrated to central Kansas several generations ago. He’s kind of the high priest of chicken. He lives by himself in a Victorian farmhouse on a big property up on a hill, which is full of free-range chickens and turkeys from breeds that exist nowhere else in the world at this point. He’s like a seed saver or librarian for chickens, not just because he loves the birds personally. He also believes that if he maintains these genetics, someday the chicken industry will come to its senses and want them again.

Another piece of good news occurred in 2014, when Perdue announced a dramatic reversal of policy. How important was that?

For decades, poultry production and the production of other kinds of proteins, like pigs and cattle, was moving in lockstep with the use of antibiotics. Then in 2014, quite shockingly, Jim Perdue, chairman of Perdue farms and grandson of the founder, stood up at a press conference and announced that his company was not using antibiotics and had, in fact, been working on not using antibiotics for more than seven years.

Perdue, which is based in Maryland, is the fourth largest poultry company in the U.S., producing about 9 billion chickens a year. What they did by making that announcement was to break the lockstep in the industry. They moved out in front and declared that they were going to lead things in a different direction.

Their announcement was completely pathbreaking. Since 2014, company after company in food production, sales, and food service—Costco, Walmart, Tyson, Cargill, McDonald’s, Taco Bell, Chick-fil-A, Subway, and even KFC—have fallen in behind this example of turning poultry production away from routine antibiotic use.

That said, chicken in America and all around the world still suffers from a high rate of contamination of food borne illness. Countries that have already controlled antibiotics use, such as the Scandinavian countries and the Netherlands, have seen the rates of antibiotic-resistant bacteria in animals and humans go down. So we have to hope that, now things are changing in the U.S., the risk of exposure is going to reduce as well.

You end the book suggesting that consumer power can change the way we eat. Won’t cheap chicken always be the best chicken, particularly for those on low incomes?

This is the big battle that remains. How do we prevent creating a two-tiered food system in which more affluent people can afford the better, safer meat and people who are less advantaged are forced to contend with meat that’s riskier? I don’t think we know the answer to that but it’s becoming clear that it is a challenge that has to be dealt with.

This whole revolution—how antibiotics are used and how poultry is raised—is down to consumer pressure. We’ve seen a bigger movement in the U.S. even though we had less regulation than in Europe, where the regulation had been extant since at least 1999.

All the companies that rolled over and said we’re going to follow Perdue and reduce antibiotic use didn’t do it because of regulation, because regulation in the U.S. didn’t exist yet. They did it because of pressure from big buyers, like medical centers and school systems, and the advocacy of chefs, farmers, and average parents getting together to say they wouldn’t spend their money on this anymore.

This interview was edited for length and clarity.