Cyclospora outbreak linked to lettuce sickens thousands and underscores broader leafy-green safety concerns
More than 7,100 people in Michigan have been infected with the parasite Cyclospora, likely from iceberg lettuce supplied by Taylor Farms, highlighting the recurring role of leafy vegetables in U.S. foodborne illness outbreaks.
An ongoing outbreak of cyclosporiasis has sickened over 7,100 people in Michigan, health officials say, and investigators have traced the likely source to iceberg lettuce produced by Taylor Farms. The Centers for Disease Control and Prevention (CDC) notes that produce accounts for nearly half of reported foodborne illnesses in the United States, with leafy greens topping the list.
The current surge follows several high-profile incidents involving salad ingredients, including a 2022 multistate E. coli outbreak linked to romaine on Wendy’s sandwiches, a 2021 salmonella recall of packaged salad greens by BrightFarms, and a 2020 cyclospora outbreak tied to Fresh Express salad kits. Experts point to the widespread consumption of lettuce—ranked second among U.S. vegetables—as a key factor in its frequent association with outbreaks.
Ready-to-eat salad mixes pose particular risk because they combine greens from multiple farms, allowing contamination in a single component to spread throughout a large batch. A 2025 Cornell University study found that irrigation with untreated surface water applied via overhead sprinklers can introduce pathogens such as E. coli onto romaine lettuce, and that alternative irrigation methods could reduce this risk, though they would require infrastructure upgrades.
Because lettuce is typically consumed raw, there is no “kill step” such as cooking or pasteurization to eliminate microbes. The leaf structure—crevices and folds—can harbor bacteria and parasites, and standard pre-washing at processing facilities does not always remove them. Cyclospora, in particular, has a thick outer wall that resists many sanitizers; experts recommend vigorous scrubbing to reduce contamination.
"If you don't wash these products well, you're going to end up ingesting whatever is on the lettuce," said Amira Roess, an epidemiologist at George Mason University.
"Many lettuce types have a lot of crevices and folds. It’s very easy for these tiny pathogens to get in there," noted Jeanne Marrazzo, CEO of the Infectious Diseases Society of America.
The CDC continues to monitor the outbreak, and a voluntary recall of the implicated lettuce was issued on July 17. Officials caution that official case counts likely represent only a portion of total infections and that the situation could worsen before improving.
The episode adds to a pattern of food safety challenges associated with raw leafy vegetables, prompting calls for improved agricultural practices, better sanitation protocols, and heightened consumer awareness.