Salad is often synonymous with wholesome consuming. Besides now, because the US grapples with an increasing outbreak of cyclosporiasis that’s sickened greater than 7,100 folks in Michigan alone, doubtless attributable to iceberg lettuce provided by Taylor Farms.
Actually, leafy greens are steadily implicated in situations of foodborne sickness. There was a 2022 multistate E. coli outbreak tied to romaine served on Wendy’s sandwiches and 173 circumstances of norovirus linked to Illinois eatery D.C. Cobb’s. In 2021, BrightFarms recalled packaged salad greens offered in a number of states after 31 folks bought salmonella. And in 2019, a complete of 167 folks had been contaminated with E. coli after consuming romaine harvested from the Salinas Valley area in California. This is not even the primary cyclospora outbreak linked to lettuce: In 2020, Contemporary Specific salad kits had been linked to greater than 700 circumstances of individuals stricken with the parasite.
The Facilities for Illness Management and Prevention estimates that produce is accountable for virtually half of the reported foodborne sickness circumstances, with leafy greens topping the checklist. So what’s it that makes lettuce a serious supply of America’s foodborne tummy troubles?
One massive cause is just because a number of folks eat it. Lettuce is the second-most-consumed vegetable within the US behind potatoes. (The most recent outbreak ensures potatoes will stay the king of US veggies. Plus, french fries.) Wraps, subs, tacos, you identify a quick meals sandwich and it’s virtually definitely bought lettuce on it. Salad-slinging chains are fixtures throughout the US. Grocery retailer coolers are stocked with salad kits, on prime of the unadorned heads of iceberg lettuce and containers of spinach.
These ready-to-eat salads and blends of spring combine pose a very acute threat as a result of they include a number of sorts of leafy greens, which might come from totally different farms and areas. If one kind of lettuce within the combine is contaminated, it might contaminate the entire bag. And since that contaminated lettuce will get packaged into heaps and many bagged salad, it has the potential to unfold germs far and vast.
How lettuce is grown may also expose it to a big selection of pathogens. A 2025 research by researchers at Cornell College who studied E. coli outbreaks in romaine lettuce discovered that quite a lot of contamination originates from irrigation with untreated floor water utilized by overhead spray irrigation methods. There are methods to decrease that threat, together with switching to irrigation methods that don’t straight contact the leaves, however that may require upgrades and downtime.
Lettuce’s satisfying crunch can also be what makes it susceptible to pesky pathogens. Because it’s eaten uncooked—actually, who needs wilted lettuce?—there’s no alternative to prepare dinner off any lingering contaminants. Like different uncooked fruit and produce, leafy greens don’t undergo what’s referred to as a “kill step”—heating, pasteurization, or freezing—which is designed to eradicate pathogens throughout the meals manufacturing course of.
The feel of lettuce is a further think about its capacity to unfold illness.“Many lettuce varieties have quite a lot of crevices and folds,” says Jeanne Marrazzo, CEO of the Infectious Ailments Society of America. “It’s very simple for these tiny pathogens to get in there.”
Even prewashing procedures at manufacturing amenities don’t all the time take away microbes, which might cling tightly to leaves. Within the case of cyclospora, the parasite has thick outer partitions, making it extremely immune to most meals sanitizers. Consultants say vigorous washing that entails scrubbing is one of the simplest ways to do away with cyclospora.
“In case you do not wash these merchandise effectively, you are going to find yourself ingesting no matter is on the lettuce,” says Amira Roess, an epidemiologist at George Mason College.
