Banned Antibiotics in Chicken Feathers

Antibiotics banned by the FDA and arsenic found in feathers from U.S. poultry

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) Do you know what's in the chicken on your plate? You may be ingesting tiny amounts of arsenic and antibiotics that are illegal to feed chickens according to two recent studies.

Some of the antibiotics found were a type called fluoroquinolones which are typically used to treat serious bacterial infections in people that may be resistant to other antibiotics.

However, fluoroquinolones were banned for chickens by the FDA in 2005 because of fears that they may contribute to antibiotic-resistant infections.

"Consider eating organic poultry or local poultry if you know what they're fed."

The studies were led by David Love, PhD, of the Department of Environmental Health Sciences in the Bloomberg School of Public Health at Johns Hopkins University, and Keeve Nachman, PhD, Farming for the Future Program Director at the Johns Hopkins Center for a Livable Future.

Along with colleagues at Johns Hopkins and Arizona State University, Love and Nachman tested chicken feathers for traces of 59 different substances.

Feathers contain the same compounds that would be present in the rest of a chicken's body and are therefore an adequate way to measure what's present in a chicken.

However, feathers from industrial poultry farms can be hard to come by for researchers, so they tested feather meal, which is composed of ground up feathers that is often used as fertilizer and is commonly added to feed for chickens, pigs, cattle and fish.

In Love's study, the researchers analyzed 12 samples of feather meal for 59 different pharmaceuticals and personal care products; the results were positive for all 12 samples.

The most significant finding of the study were that six different groups of antibiotics were discovered in the feather meal. Each sample contained two to 10 different antibiotics.

"The discovery of certain antibiotics in feather meal strongly suggests the continued use of these drugs, despite the ban put in place in 2005 by the FDA," Love said. "The public health community has long been frustrated with the unwillingness of FDA to effectively address what antibiotics are fed to food animals."

The researchers also found caffeine and acetaminophen, the active ingredient in Tylenol, in 10 of the 12 samples. As reported by Nicholas Kristof in the New York Times, the purpose of giving caffeine to chickens is reportedly to keep them awake longer to feed them more.

"This is the first study to detect antimicrobial residues in feather meal," Love's team wrote. "Initial results suggest that more studies are needed to better understand potential risks posed to consumers by drug residues in feather meal," they concluded.

The researchers also exposed bacteria strains of E. coli to the antibiotics found in the feather samples and found that the bacteria could be resistant to some of the antibiotics.

"A high enough concentration was found in one of the samples to select for bacteria that are resistant to drugs important to treat infections in humans," noted Nachman, a co-author in Love's study.

The second study, led by Nachman, also tested feather meal and found evidence of arsenic in the feathers. Arsenic is one of the ingredients of a drug called roxarsone that used to be given to chickens to prevent a disease caused by a parasite.

The Food and Drug Administration announced last June that the manufacturer of roxarsone, Pfizer, Inc., voluntarily suspended the sale of the drug following concerns of inorganic arsenic in the food supply after an FDA study identified arsenic in chicken livers.

There are two forms of arsenic: organic and inorganic. Inorganic arsenic is a known carcinogen, which means it can contribute to cancer.

However, the FDA wrote last June that the levels of arsenic found in the chickens is very low and does not pose a health risk to people who eat chicken.

Nachman's team's research aimed to find out how much arsenic was in the feather meal. All 12 samples contained arsenic, and 37 to 83 percent of it was the inorganic form. They did not find evidence of the drug roxarsone in the samples, however.

They wrote, "Feather meal products represent a previously unrecognized source of arsenic in the food system, and may pose additional risks to humans as a result of its use as an organic fertilizer and when animal waste is managed."

However, they could not conclude how much arsenic may be in the human supply, and further study would need to determine whether these levels might be safe or unsafe.

The study led by Love appeared March 21 in Environmental Science & Technology, and the study led by Nachman appeared in the February issue of The Science of the Total Environment.

Reviewed by: 
Review Date: 
April 6, 2012
Last Updated:
April 9, 2012