Experts at Consumer Reports say while some fast-food restaurants are making improvements when it comes to antibiotic-free beef, others are lagging behind.
For decades, antibiotics have been used on livestock and poultry to prevent disease and promote growth in crowded and unsanitary mass production facilities.
"We have a crisis with resistance to antibiotics. Antibiotics are not working for people the way they used to. In fact, the Center for Disease Control has estimated that 23,000 people a year are dying from infections that should have been cured by antibiotics but the drugs aren't working," explained Jean Halloran, director of food policy initiatives at Consumers Union.
Former Purdue farmer Craig Watts said he believes the antibiotics were overused, and the proof is the superbugs that have formed.
Fast-food chains are among the largest meat buyers in the country, which means they can demand certain things from their supplies, like pushing meat producers to use antibiotics responsibly.
"In the fast-food chains, which includes companies like McDonald's, there's been huge improvement in terms of getting the antibiotics out of chicken production, but the beef industry has lagged behind," Halloran said.
Out of 25 burger chains surveyed, 22 received an F grade for failing to make meaningful commitments to address antibiotic misuse in their beef supply chains. Those failing chains include Burger King, Sonic and McDonald's, the largest purchaser of beef in the country. No burger chain got a grade in the Bs or Cs. Wendy's received a D-, for making only a modest step in its sourcing of beef.
Two up-and-coming chains, Shake Shack and BurgerFi, received an A grade for getting medically important antibiotics entirely out of their beef supply.
"What this shows is that this can be done," Halloran said. "So we hope that the other companies in the industry will learn from their example and follow suit."