The U.S. Food and Drug Administration has warned consumers that a salmoellosis (salmonella) outbreak has been linked to certain raw tomatoes.

Though the exact source of the outbreak has yet to be determined, fast food chain restaurants like McDonald’s, Burger King, KFC, Long John Silver’s, Arby’s, A&W and others have stopped served most tomatoes as a precaution.

A manager at Jim’s Supervalu said he does not believe it has affected their supply. Local and corporate management contacted for Hy-Vee were not sure how it has affected their supplies.

The FDA has narrowed down which states or even countries the outbreak could have originated in, as well as which varieties, but retailers and restaurants can not be too safe until the source is identified.