U.S. Meat Increasingly Contains Resistant Bacteria, Report Says
More than half of samples of ground beef, ground turkey and pork chops collected from supermarkets for testing by the federal government contained bacteria resistant to antibiotics, according to a new report.
The data, collected in 2011 by the National Antimicrobial Resistance Monitoring System (NARMS), showed a sizeable increase in the amount of meat contaminated with antibiotic-resistant forms of bacteria, known as superbugs, like salmonella, E. coli and campylobacter. NARMS is a joint program of the Food and Drug Administration (FDA) along with the Centers for Disease Control and Prevention (CDC).
The findings were published in February, but received little attention until the Environmental Work Group issued a report, "Superbugs Invade American Supermarkets."
The report was partly underwritten by Applegate, a company which sells antibiotic-free and organic "natural" meats, according to the New York Times.
"The numbers are pretty striking," said Dawn Undurraga, the nutritionist for the group, a health research and advocacy organization. "It really raises a question about the antibiotics we are using in raising animals for meat."
Academic veterinarians who work with the International Food Information Council and the U.S. Farmers and Ranchers Alliance criticized the report as misleading.
"The No. 1 misunderstanding about antibiotics in animal agriculture is that it is not understood well enough that antibiotics are used to keep animals healthy, period," said Randall Singer, a professor of veterinary science at the University of Minnesota.
The federal data included 480 samples each of ground beef and pork chops, ground turkey, and chicken breasts, wings and thighs. Singer noted it was a limited sample compared to the huge amount of meat sold in the United States.
"We should not assume that when we find resistance to antibiotics in humans, it means it was caused by the use of antibiotics in animals," he said.
Animals that are grown for meat are commonly fed diets containing antibiotics to promote growth and reduce costs, as well as to prevent and control illness. However, public health officials in the U.S. and Europe warn that the consumption of these meats can contribute to human resistance to antibiotics. Increased sales of antibiotic-free meet can be attributed to the public's growing awareness of this issue.
Almost 80 percent of all antibiotics sold in the United States are used in animal agriculture, according to the Agricultural Department. Public health authorities around the world increasingly are warning that antibiotic resistance is reaching alarming levels.
"We don't have a problem with treating animals with antibiotics when they are sick," Ms. Undurraga said. "But just feeding them antibiotics to make them get bigger faster at a lower cost poses a real problem for public health."
While the F.D.A. has recommended that the use of antibiotics in farm animals be "limited to those uses that are considered necessary for assuring animal health," the guidance is only voluntary.
The federal researchers tested the meats for enterococcus bacteria, which is an indication of fecal contamination. Enterococcus also easily develops resistance to antibiotics, and it easily can pass that resistance on to other bacteria. There are two species of the bacteria, Enterococcus faecalis and Enterococcus faecium, which are the third-leading cause of infections in the intensive care units of United States hospitals.
Research showed 87 percent of the meat contained either normal or antibiotic-resistant enterococcus, suggesting that the majority of the sample came in contact with fecal material at some point.
"That's a big percentage they're throwing around, but that organism itself on food or in an animal has little or no relationship to human health," Professor Singer said.
The chicken tested showed that 9 percent of the samples were contaminated with a variety of salmonella that is resistant to antibiotics, while 26 percent contained antibiotic-resistant campylobacter.
Ten percent of the ground turkey tested contained resistant salmonella.
The proportion of microbes identified as resistant was more shocking. Seventy-four percent of the salmonella found on raw chicken pieces sampled in 2011, were antibiotic-resistant, while less than 50 percent of the salmonella found on chicken tested in 2002 was of a superbug variety.