United States — Food and Drug Administration & Yum! Brands — Taco Bell

United States — Food and Drug Administration: The FDA led the investigation, linking the outbreak to Taylor Farms lettuce. It faced criticism for a false-positive test result and for potential influence by the United States — White House, but it continues to work on the investigation.

Yum! Brands — Taco Bell: Yum! Brands — Taco Bell, a subsidiary of Yum! Brands, was the main restaurant chain linked to the contaminated lettuce. It removed the affected lettuce from its supply chain, but the outbreak has led to a significant drop in customer traffic and negative publicity.

United States — Food and Drug Administration: The FDA is assisting in the outbreak investigation, focusing on food safety and potential contamination sources.

Yum! Brands — Taco Bell: Voluntarily removed limited ingredients from select restaurants as a precaution; under investigation for possible link.