So, “Who made the Romaine and Iceberg Lettuce Hybrid?”

The FDA is supporting the Centers for Disease Control and Prevention (CDC), and state and local authorities in an investigation of an outbreak of Shiga toxin-producing Escherichia coli (E. coli) O157:H7 illnesses linked to an unknown food.

A specific food has not yet been confirmed as the source of this outbreak, but according to CDC, many sick people report eating burgers and sandwiches with romaine lettuce at Wendy’s restaurant locations in Michigan, Ohio, and Pennsylvania before getting sick. Based on this preliminary information, Wendy’s has removed the romaine lettuce being used for burgers and sandwiches in Indiana, Michigan, Ohio, and Pennsylvania as a precautionary measure. Wendy’s uses a different type of romaine lettuce for salads. At this time, CDC is not advising that people avoid eating at Wendy’s restaurants in the affected states or to stop eating romaine lettuce. Additional information is available in CDC’s Investigation Notice.

The CDC is working with state and local health departments to gather information from patients and examine other evidence to identify what was commonly eaten among the people who became ill. The FDA is using this information to trace back and identify the source of suspect food(s), including romaine lettuce, to help confirm or rule out products as the source of the outbreak by identifying any convergence, or commonalities, in the supply chain and to help identify any potential source(s) of contamination.

Investigators are working to confirm whether romaine lettuce is the source of this outbreak, and whether romaine lettuce served at Wendy’s restaurants was served or sold at other businesses. This is an ongoing and rapidly evolving investigation and additional information will be provided as we learn more about the potential source of this outbreak. Additionally, FDA will issue an Outbreak Advisory when and if an FDA regulated product is confirmed as the source of this outbreak.

Based on preliminary information, Wendy’s has removed the romaine lettuce being used for burgers and sandwiches in Indiana, Michigan, Ohio, and Pennsylvania as a precautionary measure. The romaine lettuce used on Wendy’s burgers is a romaine and iceberg lettuce hybrid that is smaller than regular romaine heads and is not the same type of lettuce used in Wendy’s salads. The product being replaced was identified as a product of interest based on available meal information from ill people and commonalities in the product source and supply chain. This is an ongoing investigation and state and federal partners continue working to confirm whether this lettuce is the source of the outbreak.