What is the most likely foodborne hazard contaminating improperly cleaned lettuce?

The most likely foodborne hazard contaminating improperly cleaned lettuce is indeed E. coli. Lettuce, especially when grown in fields where the soil may be contaminated by animal waste or human waste, can be a vector for this bacteria. E. coli, particularly strains such as O157:H7, can be present in the feces of infected animals and can easily transfer to leafy greens if they are not washed properly before consumption.

Improper cleaning can mean that residual soil, manure, or water contaminated with E. coli is left on the lettuce, which can lead to foodborne illnesses when ingested. Since lettuce is typically eaten raw, any pathogens present can directly affect consumers, making it crucial to ensure that these vegetables are thoroughly and properly cleaned.

While Vibrio is mainly associated with seafood, Staphylococcus aureus is often linked to foods that are handled by people, and tapeworms relate more to undercooked animal products rather than fresh produce. Therefore, the strong association of E. coli contamination with raw vegetables like lettuce underlines why it is the correct choice in this context.