Several fast food chains have made headlines recently announcing that they’ll stop serving meat raised with antibiotics, but a new new report (PDF) from Consumers Union, the policy and advocacy arm of Consumer Reports, and five other consumer organizations finds that 20 of the 25 top restaurant chains have made no commitment to limit antibiotic use.

The routine use of antibiotics in raising meat—including cattle, chicken, and other animals—contributes to the problem of antibiotic resistance. That's when bacteria evolve to become immune to these life-saving drugs. “As consumers become aware of the problem, they’re increasingly seeking out meat that has been raised without antibiotics, both when they shop at the supermarket and when they dine out,” says Jean Halloran, director of food policy initiatives at Consumers Union. “This new report gives them the info they need to make better restaurant choices.” 

The report, "Chain Reaction: How Top Restaurants Rate on Reducing Use of Antibiotics in Their Meat Supply," provides consumers with a score card of the top 25 fast food and fast casual restaurant chains, grading each restaurant’s current antibiotic policy. The companies were sent a survey and their responses, along with public statements by the companies either in the press or on their websites were used to calculate the score. 

Chipotle and Panera Bread received A’s. Not only have they adopted policies that prohibit the use of antibiotics in raising meat, their policies apply to all types of meat they serve, and, with only a few exceptions, they’ve implemented those policies.

Chick-fil-A received a B. The company pledged in 2014 to stop sourcing chicken raised with antibiotics over five years, and currently 20 percent of the chicken they serve meets that goal.

Dunkin’ Donuts and McDonald’s got C’s. Dunkin’ Donuts has adopted a good policy, but has not set a timetable for implementation. McDonald’s policy only applies to chicken, and the company has not indicated the current percentage of poultry served that’s raised without antibiotics, according to the report.

The other 20 restaurants received a failing grade, including Starbucks, KFC, Burger King, and Subway, the largest fast food chain the world. 

“Chain restaurants have been pushed to serve healthier food and people usually think that means fewer calories or less sugar,” says Halloran. “But serving meat raised without antibiotics is a vital public health goal and one that we believe these companies must strive for.”