A new report raises concern about the number of antibiotics used in the meat and poultry supply chains for a long list of popular “fast casual” restaurants in the United States. According to a report from CNN, six consumer interest, environmental and public health organizations found that the majority of restaurants didn’t even have a publicly available policy to reduce the use of antibiotics, which can lead to an increase in bacterial resistance.

Bacteria develop defenses to antibiotics over time, and farmers that use too many risk herd and flock infection that can then potentially be passed on to human consumers. It also increases the risk that antibiotics won’t be as effective should we run into a case where they are absolutely needed.

The U.S. Centers for Disease Control and Prevention and the World Health Organization have repeatedly warned of the threats posed by antibiotic resistance. At least 2 million Americans come down with an antibiotic-resistant disease each year, resulting in an average of 23,000 deaths annually.

The WHO warned that a “post-antibiotic era,” one where everyday pathogens and minor injuries can lead to death, is a distinct possibility for the 21^st century.

The report found that Chipotle and Panera Bread scored the best in terms of supplying meat that uses few antibiotics. Chick-fil-A received a B, largely due to its announcement that it would commit to serving chicken that had never come in contact with antibiotics in 2014. Dunkin’ Donuts and McDonalds both scored Cs, while Subway, Wendy’s, Burger King, Denny’s, Starbucks, Olive Garden, Papa John’s, Taco Bell, KFC, Pizza Hut, IHOP, Arby’s and Outback were among the restaurants that scored Fs. Many of the companies announced plans to transition to antibiotic-free meat, but only time will tell if they are able to achieve this goal.