In September 2023, Public Health Seattle King County (PHSKC) investigated an outbreak of gastrointestinal illness among patrons of a Tacos El Guero food truck. Symptoms and timing of illness onsets were suggestive of a bacterial toxin such as Clostridium perfringens or Bacillus cereus. Thirty-four cases were identified. No one was hospitalized and no one died. The implicated meal date was September 14, 2023.

The exact food or drink that caused the illnesses was not identified. This is not uncommon for outbreaks thought to be caused by a bacterial toxin.

Environmental health investigators visited the mobile food trucks and restaurant on September 18. Investigators identified potential risks for bacterial toxin growth including inadequate refrigeration and improper cooling of food. They also observed inadequate equipment reheating, and lack of managerial oversight.