The U.S. Food and Drug Administration has decided not to withdraw penicillin and tetracyclines in animal feed, backing off the agency’s initial intention to do so. The news was not announced, but was published in the Federal Register just before the holidays.

In 1977, FDA first announced its intention to withdraw the animal drug approvals — penicillin outright and the subtherapeutic use of tetracycline — citing microbial food safety concerns, but now the agency is planning to “focus its efforts for now on the potential for voluntary reform and the promotion of the judicious use of antimicrobials in the interest of public health,” according to the notice.

The Keep Antibiotics Working coalition criticized the move. “[The decision] is just the latest evidence that the Obama Administration fails to take seriously the risk of resistant infections that occur due to the overuse of antibiotics in animal agriculture,” according to Steven Roach, the Public Health Program Director at Food Animal Concerns Trust (FACT), a member of the coalition.

“Since the FDA initially proposed the withdrawals in 1977, the data connecting antibiotic resistance with overuse in animals has only gotten stronger,” added Roach. “Yet the FDA refuses to fulfill its mandate to protect the public health and withdraw drugs that have been shown to be unsafe. As long as the Administration fails to act and continues to fall back on an ineffective voluntary approach, Keep Antibiotics Working will press the FDA to protect the public health through more meaningful measures.”

FDA said in the notice that despite this action, the agency “remains concerned about the issue of antimicrobial resistance.”

“Today’s action should not be interpreted as a sign that FDA no longer has safety concerns or that FDA will not consider re-proposing withdrawal proceedings in the future, if necessary,” said the notice. “FDA has not ruled out the prospect of future regulatory action, either with respect to the antimicrobial new animal drugs covered by the 1977 NOOHs or any others.”

The agency says it will focus on voluntary reforms and if that strategy “does not yield satisfactory results” the possibility of pursuing withdrawals is still on the table.

Maryn McKenna, public health journalist and author of Superbug, broke the story, which is likely to get lost in the holiday bustle. McKenna noted the potential political significance of the move:

“There is a lot of background to this, but here is the takeaway: For 34 years, the FDA has been contending that administering small doses of antibiotics to healthy animals is an inappropriate use of increasingly scarce drugs — a position in which it is supported by organizations as mainstream as the American Medical Association,” wrote McKenna. “With this withdrawal, it backs away from the actions it took to support that assertion — which may indicate there will be no further government action on the issue until after the 2012 election.”