Subway is joining a rapidly growing list of fast food restaurants choosing to serve antibiotic free chicken due to growing concern about antibiotic resistance from consumers.

By next year, the fast food chain will switch from using chicken treated with human antibiotics to naturally raised chickens--but that’s about all there is to know at this point, which is unsettling to some throughout the food industry.

The Center for Food Safety (CFS) has expressed some concerns with Subway’s newest venture, particularly because the fast food chain’s plans do not include a real plan--no set goals, no deadlines, no third-party auditing to check progress.

"The details of Subway's plans moving forward regarding antibiotic use in its chicken are important in order to fully appraise their recent statement.” says the organization. “CFS and other organizations working in this movement are cautiously optimistic, but without transparency there is absolutely no guarantee that Subway's statement will actually bring about meaningful reforms within the industry."

The CFS isn’t the only organization left desiring more specificity from Subway. The Consumers Union, Food Animals Concern Trust, Keep Antibiotics Working and The Natural Resources Defense Council have all expressed similar concerns.

Subway is also planning to find antibiotic free options for all meats they serve, but no timeline for that has been announced. Fast food chains including Chipotle, Chick-Fil-A, Panera Bread and McDonald’s all have been or plan to start serving antibiotic free chicken.