For nearly 40 years, public health officials and scientists have been pushing the Food and Drug Administration (FDA) to limit the use of antibiotics fed to animals raised for meat, a practice many worry is contributing to the rise of potentially deadly, drug-resistant infections.

Now, the agency is trying a different approach: asking companies to do so voluntarily.

The new policy comes at a time when the global health community has watched with alarm as many common antibiotics developed to fend off human illness have been rendered either ineffective or obsolete due to overuse. The Centers for Disease Control and Prevention estimates that more than 20,000 people die each year due to antibiotic-resistant infections, and as many as 2 million get sick. The FDA’s worry is that antibiotics used on the farm may be partly to blame.

Most antibiotics aren’t used by humans. Data compiled by the Pew Charitable Trusts, which advocates to limit antibiotic use on farms, shows that in 2011, 7.7 million pounds of antibiotics were sold to treat sick people, while a whopping 29.9 million pounds were sold for use in food animal production. In 2012, that figure grew to 32 million pounds, according to a report released earlier this month by the FDA.