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As the use of antibiotics in farming and raising livestock has increased, new antibiotic resistant bacteria, or “superbugs” are emerging. Here’s what you need to know about antibiotics in your food and eating antibiotic-free food.
Last fall I flew halfway across the country to go grocery shopping with Everly Macario. We set out from her second-story apartment in Hyde Park near the University of Chicago and walked to the supermarket to buy a couple of rib steaks that Macario planned to serve to her husband and two children, ages 7 and 13. Macario, who is 46, holds a doctorate in public health from Harvard University and has spent decades as a consultant, working to prevent deaths from chronic conditions such as cancer and cardiac disease.
Yet she believes that what she buys-or more accurately, refuses to buy-in the supermarket is the most important action she takes, not only for her family’s health but for the health of every person in this country. “I am determined that no product from an animal that has been fed antibiotics will ever enter my home,” she said as we walked along the meat counter peering at beef, poultry and pork. “I look for labels that read ‘certified organic,' ‘no antibiotics' or ‘raised without antibiotics.'”
It’s not the antibiotics themselves that are troubling: animals pass the drugs through their systems long before they are slaughtered and animal products are tested for traces of antibiotics. What really worries Macario is the increasing wave of antibiotic-resistant bacteria that might be traveling on her food.
This article was produced in collaboration with theFood & Environment Reporting Network, an independent, non-profit news organization producing investigative reporting on food, agriculture and environmental health.
No one knows how Simon contracted the bacteria. He had never been to a hospital, once thought to be the primary incubators of MRSA. He had a robust immune system. He wasn’t in child care. He had no cuts through which the bacteria could infect him. The germs that killed him were “community-acquired” MRSA-CA, meaning that he came in contact with them through everyday living, as opposed to “hospital-acquired” MRSA, a strain that is associated with medical centers and nursing homes.
While it remains unclear how MRSA infected Simon, what is known is that these antibiotic-resistant bacteria are on the rise. According to the Centers for Disease Control and Prevention, the incidence of MRSA in the United States more than doubled between 1999 and 2005, from 127,000 to 280,000, and MRSA-related deaths rose from 11,200 to 17,200. Perhaps it’s no coincidence that while the quantity of antibiotics given to humans has remained stable, the amount fed to livestock has soared. According to Food and Drug Administration records, antibiotic use on farms grew from about 18 million pounds in 1999 to nearly 30 million pounds in 2011.
Today 80 percent of the antibiotics used in the United States are fed to livestock. Theirs is a diet laced with low “subtherapeutic” doses of antibiotics, not to cure illness but to make the animals grow faster and survive cramped living conditions. The low doses kill many bacteria, but some develop mutations that make them immune to the same drugs that once destroyed them.
“It is very hard to prove that a specific antibiotic given to an animal for food production led to the development of a resistant bacterium in a specific patient,” said Stuart Levy, M.D., president of the Alliance for the Prudent Use of Antibiotics and a professor at Tufts University School of Medicine. “But it is a truism that antibiotic use leads to resistance, and the more antibiotics you use, the more resistance you get.”
By avoiding foods from animals that have been fed antibiotics, Macario believes she is doing more than just protecting her family from direct exposure to these “superbugs.” She is attacking the plague at its source.
That Which Does Not Kill Me…It’s hard to imagine that until World War II, infectious diseases such as pneumonia and tuberculosis were dreaded killers in this country. Beginning with the introduction of penicillin in the 1940s, these scourges could finally be cured with antibiotics. It was nothing short of a miracle. But scientists have always been aware that the miraculous antibiotics could become useless if they were underdosed and failed to knock out an infection completely. Bacteria are reproductive dynamos; a singleStaphcan divide every 30 minutes, meaning that one resistant bacterium is able to erupt into a colony of more than 1 million in less than a day. In the presence of a nonlethal dose of antibiotics, bacteria can mutate to become resistant, breeding a new strain. Which is exactly what began to happen on farms across the U.S.
In the early 1950s, drug companies began marketing antibiotics for livestock after studies showed that low doses of penicillin, tetracycline, bacitracin and other drugs used to cure infections in humans made animals grow more quickly. Unfortunately, within two decades there was persuasive scientific evidence that the low-dose antibiotics were a recipe for disaster. In a seminal 1976 study, Levy administered small amounts of the antibiotic tetracycline to a flock of chickens. Soon, the chickens were carryingE. colibacteria that were resistant not only to tetracycline, but to other antibiotics as well. Within weeks, the farmers who tended those birds also carried resistant bacteria.
A year later (1977), the Food and Drug Administration, the federal agency mandated to protect Americans' health, announced plans to ban feeding livestock low doses of antibiotics, which, according to the FDA, hadnotbeen “shown safe for widespread, subtherapeutic use.” But bowing to pressure from legislators and agribusiness, the FDA failed to act on its recommendation, even after the American Academy of Pediatrics, the Centers for Disease Control and Prevention, the National Academy of Sciences, the U.S. Department of Agriculture and the World Health Organization identified subtherapeutic use of antibiotics as a human health issue. More than 30 years later, when the Natural Resources Defense Council and other groups sued in 2011, the FDA revoked its recommendation and said that a “voluntary” effort would be more effective.
Hog Heaven, Hog HellIf there is a ground zero for the abuse of antibiotics in the United States, it’s probably Iowa, where hogs outnumber humans seven to one. During the 90-minute drive up I-35 from Des Moines to visit one farm, I was rarely out of sight of rows of long, low barns-each home to at least 2,000 pigs confined shoulder-to-shoulder in pens-known as CAFOs (Concentrated Animal Feeding Operations). In 2009, Tara Smith, Ph.D., a researcher at the University of Iowa, published a study that found that nearly half of the hogs at two large Iowa farms carried MRSA. More worrisome, 45 percent of the workers at those farms harbored the bacteria.
“We are calling on retailers and grocery stores… to commit to stopping these practices and stocking only meat that was raised without feeding antibiotics to healthy animals,” Jean Halloran, director of food policy initiatives at the Consumers Union, said in a statement accompanying the release of the report.
But it is virtually impossible to find a microbiologist unaffiliated with industry who agrees with him. “There are decades of evidence linking antibiotic use in food production with the emergence of drug resistance,” said Lance B. Price, a professor at George Washington University’s School of Public Health and Health Services. “There’s very clear, sound science showing that the multi-drug-resistant strains emerged from drug use in food animal production then spread to humans. Anyone saying that there’s no data is either deceiving themselves or lying.”
Price led a team of 33 researchers from 19 countries who tracked the origins and evolution ofStaphassociated with pigs and other meat animals. They discovered a nonresistant strain ofStaphthat originated in humans and was transmitted to livestock. There, it quickly became resistant to antibiotics and was passed back to humans as a virulent form of MRSA, according to a paper they published in 2012.
A Better Solution?So could keeping antibiotics off the farm keep humans out of the hospital? In 2009, Tara Smith of the University of Iowa sought to answer that question. As part of the study, she took nasal swabs from Sarah Willis, Willis’s 11-year-old daughter, mother and father and their farm workers to test for MRSA. Smith was interested in the family because Sarah’s father, Paul Willis, founded Niman Ranch’s pork collective in the late 1990s. The operation has since grown to include more than 500 family farmers. Niman farmers never administer antibiotics to livestock nor do they confine their animals in CAFOs. On the day I visited Sarah Willis, the pigs on her family’s 800-acre property were playing chase with each other or snoozing in the late-autumn sunshine of their paddocks-a rare sight in Iowa.
Smith also tested nine other farmers who did not use antibiotics. And she tested nine farmers who did administer the drugs to their animals. The results? Even though all the farmers in her tests ran large, commercial pig operations, not one of the producers who avoided antibiotics tested positive for MRSA, while nearly half the farmers who routinely used antibiotics on their pigs carried resistant bacteria. In other words, avoiding the drugs on the farm might be one way of reducing the prevalence of these virulent strains.
The findings resonated with Sarah Willis. One of those pig CAFOs is less than a mile from her house. In 2011, there were seven cases of MRSA in her daughter’s school district. It took two rounds of antibiotic treatment to cure the youngsters. “I avoid meat raised on antibiotics due to health concerns,” Willis said. “But it’s more important to me that I am voting with my dollars. I would rather spend my money on food that is raised responsibly.”
A Demand for Drug-FreeFor Willis, though, “it was a customer issue. My biggest customers pushed for the animals to be free from antibiotics, so I banned drugs.” Companies that now refuse to sell meat produced with antibiotics include Whole Foods Market and Chipotle Mexican Grill, and the list is growing. Hyatt Hotels now offers antibiotic-free options at all its restaurants. At a time when sales of most meat and poultry products are flat, antibiotic-free-meat sales are climbing at a rate of 10 to 15 percent annually and sales from antibiotic-free pork alone now approach $500 million a year, according to Kevin Kimle, a faculty member in the economics department at Iowa State University.
Everly Macario is convinced that conscientious shoppers are the key to boosting those numbers. “If we buy only antibiotic-free meat, then demand for conventional meat will drop and more farmers will stop drugging their animals. It’s something every shopper can do.” She does not stop at shopping: Macario helped found the MRSA Research Center at the University of Chicago Medical Center. She also became the leader of Supermoms Against Superbugs, which met with food-policy legislators in Washington, D.C., in 2012 to discuss ways to keep antibiotics viable.
“I love meat,” Macario said during our visit to the supermarket. “I crave it. I’m originally from Argentina. My grandfather raised cattle.” At the store, Macario zeroed in on Rain Crow Ranch grass-fed steaks. The package was not labeled “antibiotic-free,” but Macario had researched the company and its farms and was confident that they never used antibiotics. The steaks, at $21.99 a pound, were pricier than the same cuts raised with antibiotics (though theConsumer Reportssurvey found that many antibiotic-free meats cost the same or in some cases less). All the other meats, dairy products and eggs she chose had similar assurances of avoiding antibiotics.
“When I shop for food, I always try to remember what one consumer advocate in Washington told me,” Macario said. “Congress and big agricultural interests are scared to death of moms.”
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