Consumer groups give many of the top restaurant chains in the United States failing grades for their policies regarding antibiotics used in their beef supply for burgers and other beef dishes.
The report is the result of a combined effort from the U.S. Public Interest Research Group Education Fund, the Natural Resources Defense Council, Consumer Reports and the Milken Institute School of Public Health at George Washington University, among others.
"Overuse of antibiotics in the beef industry threatens our health, and fast-food companies need to do more," said Matt Wellington, a co-author and antibiotics campaign director for the U.S. PIRG Education Fund.
At issue is the rise of drug-resistant bacteria, which occurs when the antibiotics used to control and kill germs are overused or used incorrectly.
"Improving antibiotic prescribing and use is critical to ensure that bacteria don’t become resistant to antibiotics," the Centers for Disease Control and Prevention says. "Prescribers should only treat people and animals with antibiotics when they need them for medically sound reasons."
Drug-resistant bacteria in animals used in the food supply can affect humans if people eat raw or undercooked contaminated meat, or come into contact with animal waste through contaminated drinking or swimming water.
The new report looked at whether the restaurants even had a policy to restrict antibiotic use in their beef supply chains, or a plan to phase it out, as well as how they're implementing those actions.
Arby's, Burger King and Jack in the Box received failing grades for having no policies for antibiotics in beef. Taco Bell and Wendy's earned Ds, due to what the report authors called insufficient plans to reduce antibiotic use.
"Restaurants are committed to protecting the health and safety of our guests," Jeff Solsby, vice president of advocacy communications for the National Restaurant Association, said in a statement to NBC News.
"This is a key reason why so many restaurants offer nutrition and ingredient information and are increasingly sharing animal welfare and supply chain policies—including the responsible use of antibiotics important to animal and human health," he continued.
Chipotle and Panera Bread earned top marks in the new report. Both received As for actively seeking out beef suppliers that only use antibiotics in animals when they get sick.
According to Chipotle's website, "antibiotics and hormones are given to a majority of livestock to increase production" but that Chipotle only buys meat from farmers who use antibiotics responsibly.
McDonald's earned a C grade this year — up from an F in 2018 — for its recent commitment to "curtailing routine medically important antibiotic use across its vast global supply chain and set concrete reduction targets by the end of 2020," according to the report.
"McDonald's believes antibiotic resistance is a critical public health issue, and we take seriously our unique position to use our scale for good to continue to address this challenge," Keith Kenny, global vice president for McDonald's Sustainability, wrote in a statement to NBC News.
A spokesperson for the National Cattlemen's Beef Association said that the group "promotes the judicious use of antibiotics to keep potential risk of developing antibiotic-resistant bacteria extremely low." The group has programs to advise ranchers on "guidelines for antibiotics, such as avoiding using antibiotics that are important in human medicine," according to the statement.
Starbucks also received a failing grade in the new report, despite the fact that the coffee chain does not offer many beef products on its menus. The F grade was given because Starbucks does not have a policy on antibiotic use in its beef supply chains, though it does have such a policy for poultry.
The fast-food industry has already made strides with chicken overall. Last month, Chick-fil-A announced that none of the meat sold at its more than 2,400 restaurants had been treated with antibiotics.
"When we look at chicken, we’ve seen incredible progress over the last 5 years with restaurants on getting antibiotics out of their supply and that has rippled throughout the entire chicken industry," Wellington said.
Still, humans, not animals are perhaps the biggest culprit in the rise of drug-resistant bacteria. Taking antibiotics for illnesses for which they have zero impact, such as those caused by fungi (like vaginal yeast infections) or viruses (like the flu) drive drug resistance upwards. Antibiotics are only effective for illnesses caused by bacteria, including strep throat and urinary tract infections.
The World Health Organization calls antibiotic resistance one of the top 10 threats to global public health, and issued a dire warning earlier this year: drug-resistant infections could cause 10 million deaths a year by 2050 if no action is taken.
In the U.S., the Centers for Disease Control and Prevention estimates drug-resistant infections such as E. coli and MRSA already sicken more than 2 million and kill 23,000 people every year.