In the latest report by the Food & Environment Reporting Network, out today in May/June issue of Eating Well magazine, looks at the growing issue of antibiotic resistance due to the routine use of antibiotics in livestock production. Reporter Barry Estabrook, author of the New York Times bestselling book Tomatoland, details how livestock are fed a diet laced with low “sub-therapeutic” 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,” Estabrook writes, “But some develop mutations that make them immune to the same drugs that once destroyed them.” Eighty percent of all antibiotics in the U.S. are used in livestock production.

The story comes out on the heels of a new study by Consumer Reports that shows that antibiotic-free turkey is less likely to be contaminated with resistant-bacteria. The findings strongly suggest that the routine use of antibiotics in animal production has led to increased antibiotics resistance when the drugs are used to treat human illnesses. In addition, the U.S. Food and Drug Administration (FDA) released updated consumer advice this week, in which its scientists discussed the connection between treated animals and resistant strains of bacteria in humans.

Estabrook reports that incidences of MRSA, or resistant infections of Staphylococcus aureus, in the U.S. more than doubled between 1999 and 2005, from 127,000 to 280,000, and MRSA-related deaths rose from 11,200 to 17,200. He pointed out that a study published in 2011 showed that MRSA, which has been found on livestock farms that use antibiotics, was getting into meat. Researchers analyzed 136 samples of beef, poultry and pork from 36 supermarkets in California, Illinois, Florida, Arizona and Washington, D.C. Nearly one-quarter of the samples tested positive for MRSA.

Estabrook notes that a recent study tested the farmers of large hog operations for MRSA. Not one of those who avoided antibiotics tested positive, while nearly half the farmers who routinely used antibiotics on their pigs carried resistant bacteria. Not everyone who carries the resistant bacteria gets sick, however, and the article points out that proper cooking of meat will kill bacteria.

“Perhaps it’s no coincidence that while the quantity of antibiotics administered to humans has remained stable, the amount fed to livestock has soared,” he writes. According to the FDA records, antibiotic use on farms grew from about 18 million pounds in 1999 to nearly 30 million pounds in 2011.

The piece notes a seminal 1976 study, which showed that low doses of antibiotics bred E. coli resistance in chickens and also among the farmers that raised them. A year later, the FDA announced plans for a ban on feeding livestock low doses of antibiotics, but it never came to pass.

In Denmark, Estabrook explains, incidences of resistant bacteria fell dramatically in both people and animals after low-dose antibiotic usage in livestock production was banned in 2000. Meanwhile, pork production rose. The European Union banned sub-therapeutic use of antibiotics in livestock production in 2006.

In the U.S., Congresswoman Louise Slaughter, a Democrat from upstate New York and a microbiologist by training, has repeatedly tried to legislate limits on the use of the drugs in animals, without success.

You can read the full report here at Eating Well and also here on FERN’s Web site.