Donald Kennedy was commissioner of the U.S. Food and Drug Administration from 1977 to 1979. He is professor emeritus of environmental science at Stanford University.

When I was commissioner of the U.S. Food and Drug Administration (FDA), the agency’s national advisory committee recommended in 1977 that we eliminate an agricultural practice that threatened human health. Routinely feeding low doses of antibiotics to healthy livestock, our scientific advisory committee warned, was breeding drug-resistant bacteria that could infect people. We scheduled hearings to begin the process of curtailing the use of penicillin and other antibiotics for this purpose, but Congress halted the effort before it started.

Today, the science is even clearer that antibiotic overuse in agriculture is dangerous — yet the same risks persist. Fortunately, the FDA appears poised to act by instituting a measure known as Guidance 213. This voluntary policy instructs pharmaceutical companies to stop marketing certain antibiotics for animal production purposes. Some public health advocates want the agency to make the restrictions mandatory, but voluntary guidance can work — if it is finalized. The agency issued a draft version of its policy in April 2012 and received public comments, as required, but the comment period closed about a year ago. Drugmakers have been left awaiting further instruction.

The new guidelines cannot come soon enough. More antibiotics were sold for use in food animal production in 2011, the last year for which complete data are available, than in any prior year. The FDA annually examines bacteria on retail meat and poultry, and each year the bugs show more resistance to antibiotics. Moreover, several new studies using genetic analysis demonstrate with great precision the evolution and transmission of resistant pathogens not traditionally linked to food. Methicillin-resistant Staphylococcus is a troublesome new source of livestock-associated infections, and the E. coli that cause drug-resistant urinary tract infections can also be transmitted to people via food.

Representatives of the livestock and drug industries try to dismiss part of the problem by saying that overuse of antibiotics in hospitals is responsible for the evolution of superbugs. Medical overprescribing is surely one piece of the puzzle. But those concerned with human health cannot dismiss or ignore the overwhelming evidence that agricultural practices also contribute to the problem.

About 80 percent of the antibiotics sold in this country are intended for food animals, not people. Consumers and the public health community would like to know more but, unfortunately, the FDA is not authorized to collect data from pharmaceutical manufacturers, feed mills or livestock producers to demonstrate exactly how many antibiotics are being used and for what specific purpose. Until it has the data, the agency cannot be certain that its voluntary approach can be effective. FDA officials have initiated a process to obtain that information, but whether it will work, and how long it will take to complete, is not certain.

In 2012, during his reelection campaign, President Obama said that his “administration is taking steps to limit antibiotic use for livestock. This will help ensure that antibiotics are used only [to] address diseases and health problems, and not for enhancing growth and other production purposes.”

The Obama administration isn’t the first to be concerned. Those of us at the FDA in Jimmy Carter’s day were worried, too. But “production purposes” introduce a more complex note that the FDA should clearly define. Many animals are raised in conditions that pose a constant threat to their health — a symptom of a sick system. Agricultural businesses should be able to treat animals in ways that promote efficiency and profit, which includes giving the drugs to livestock that are actually infected. But the FDA should not allow extensive uses of antibiotics in confined animals for prophylactic protection; doing so threatens to undermine those same drugs that are critical to human medicine.

A far better solution would be to improve the crowding and poor sanitation that make food animals susceptible to disease in the first place. Action by the FDA would be the initial step to encourage companies to make such changes and stop relying on massive overuse of antibiotics.

The FDA should finalize Guidance 213, tell the public how data will be collected to ensure that its voluntary strategy is working and then, if antibiotic misuse continues unabated, apply the full force of regulation. It has been 36 years since the agency moved to restrict injudicious antibiotic practices that threatened the public’s health. It should not wait any longer to finish the job.

Read more about this issue:

The Post’s View: Cruelty to farm animals demands exposure

The Post’s View: Resistance to antibiotics is becoming a crisis

The Post’s View: Meat and ‘superbugs’