A widening outbreak of cyclosporiasis linked to iceberg lettuce supplied by Taylor Farms has sickened more than 7,100 people in Michigan alone, reviving scrutiny of why leafy greens so frequently cause foodborne illness in the US. The article explains that lettuce's popularity, the way it is grown and processed, and the fact that it is eaten raw all combine to make it an unusually persistent source of contamination, with produce responsible for almost half of reported foodborne illness cases according to the CDC.

Lettuce is the second most-consumed vegetable in the US after potatoes, appearing in countless sandwiches, wraps and salads, meaning contamination can spread widely, especially in bagged salad mixes that combine greens from multiple farms. Experts cited include Cornell researchers who traced E. coli contamination to irrigation with untreated surface water, and specialists such as Jeanne Marrazzo and Amira Roess, who note that lettuce's crevices trap pathogens and that raw produce never undergoes a "kill step" such as cooking or pasteurisation, unlike other foods. Past outbreaks referenced include a 2022 E. coli case tied to Wendy's romaine, a 2021 BrightFarms salmonella recall, 2019 romaine-linked E. coli infections, and a 2020 cyclospora outbreak from Fresh Express kits.