In a joint study, scientists at Johns Hopkins’ Center for a Livable Future (CLF) and Arizona State University found evidence suggesting that a class of antibiotics previously banned by the US Food and Drug Administration (FDA) for poultry production is still in use. The antibiotics detected—fluoroquinolones—were found in 8 of 12 samples of feather meal in a multi-state study, published in the peer-reviewed journal Environmental Science and Technology. The scientists also found caffeine, the active ingredients of Tylenol and Benadryl, and—in a companion study published in another journal—traces of arsenic in the feather meal.
In the US, antibiotics are added to the feed and water of industrially raised poultry and other farm animals, primarily to spur faster growth. In the case of poultry, once ingested such substances bioaccumulate in the birds’ feathers. After the birds are slaughtered, their feathers are ground up to make feather meal, used as a protein feed supplement for cattle in feedlots, as well as pigs, farmed fish, and other birds. So in addition to antibiotics the latter animals are purposely fed, they potentially receive a second “boost” from the feather meal.
The fluoroquinolones found in the study are broad-spectrum antibiotics that can be used to treat many types of infections, and are considered “critically important” by the World Health Organization. After a prolonged battle with Bayer (the manufacture of the fluoroquinolone, Cipro), FDA banned fluoroquinolone use in poultry feed in 2005. A primary impetus for the ban was an alarming increase in the rate of fluoroquinolone resistance among Campylobacter bacteria—implicated in human intestinal illnesses.
But the present study indicates the ban is not so airtight. David Love, CLF project director and lead author of the study, says that “The discovery of certain antibiotics in feather meal strongly suggests the continued use of these drugs [in chicken feed].…” adding that, “The public health community has long been frustrated with the unwillingness of FDA to effectively address what antibiotics are fed to food animals.”
To illustrate this point, in March, a federal district court in New York ruled that FDA must crack down on non-medical farm usage of penicillin and tetracycline because of dangers to human health, pursuant its own 35-year-old rule banning the practice. FDA has never enforced the rule because of blowback from the farm industry and pharmaceutical lobbies.
In April, in an attempt to quell the growing concerns, FDA published a guidance for industry that would require farmers and ranchers to obtain a prescription from a veterinarian before using antibiotics on farm animals. However, the agency is depending on drug manufacturers' cooperation to discourage non-therapeutic uses, and for the companies to make voluntary changes in their labeling so as to remove recommendations for “production uses” (i.e., increased weight gain and accelerated growth).
Not all remained convinced the new guidance will be effective. The Union of Concerned Scientists and the Center for Science in the Public Interest both issued statements expressing doubts. CFL study co-author Keeve Nachman did the same: “Based on what we’ve learned, I’m concerned that the new FDA guidance documents, which call for voluntary action from industry, will be ineffectual. By looking into feather meal, and uncovering a drug banned [in 2005], we have very little confidence that the food animal production industry can be left to regulate itself.”