Why Lettuce Is Always Making People Sick

Salad is usually synonymous with steadfast eating. Except now, arsenic the US grapples with an expanding outbreak of cyclosporiasis that’s sickened much than 7,100 radical successful Michigan alone, apt caused by iceberg lettuce supplied by Taylor Farms.

In fact, leafy greens are often implicated successful instances of foodborne illness. There was a 2022 multistate E. coli outbreak tied to romaine served connected Wendy’s sandwiches and 173 cases of norovirus linked to Illinois eatery D.C. Cobb’s. In 2021, BrightFarms recalled packaged crockery greens sold successful respective states aft 31 radical got Salmonella. And successful 2019, a full of 167 radical were infected with E. Coli aft eating consuming romaine harvested from the Salinas Valley portion successful California. This isn't adjacent the archetypal cyclospora outbreak linked to lettuce: In 2020, Fresh Express crockery kits were linked to much than 700 cases of radical afflicted with the parasite.

The Centers for Disease Control and Prevention estimates that nutrient is liable for astir fractional of the reported foodborne unwellness cases with leafy vegetables topping the list. So what is it that makes lettuce a large root of America’s foodborne tummy troubles?

One large crushed is simply due to the fact that tons of radical devour it. Lettuce is the second-most consumed rootlike successful the US down potatoes. (The latest outbreak ensures potatoes volition stay the king of US veggies. Plus, French fries.) Wraps, subs, tacos, you sanction a accelerated nutrient sandwich and it’s astir surely got lettuce connected it. Salad-slinging chains are fixtures crossed the US. Grocery store coolers are stocked with crockery kits, connected apical of the unadorned heads of iceberg lettuce and containers of spinach.

Those ready-to-eat salads and blends of outpouring premix airs a peculiarly acute hazard due to the fact that they incorporate aggregate types of leafy greens, which tin travel from antithetic farms and locations. If 1 benignant of lettuce successful the premix is contaminated, it tin contaminate the full bag. And due to the fact that that contaminated lettuce gets packaged into tons and tons of bagged salad, it has the imaginable to dispersed germs acold and wide.

How lettuce is grown tin besides exposure it to a wide array of pathogens. A 2025 survey by researchers astatine Cornell University who studied E. Coli outbreaks successful romaine lettuce recovered that a batch of contamination originates from irrigation with untreated aboveground h2o applied done overhead spray irrigation systems. There are ways to little that risk, including switching to irrigation systems that bash not straight interaction the leaves, but that would necessitate upgrades and downtime.

Lettuce’s satisfying crunch is besides what makes it prone to pesky pathogens. Since it’s eaten raw—really, who wants wilted lettuce?—there’s nary accidental to navigator disconnected immoderate lingering contaminants. Like different earthy effect and produce, leafy greens don’t spell done what’s known arsenic a “kill step”—heating, pasteurization, oregon freezing—which is designed to destruct pathogens during the nutrient manufacturing process.

The texture of lettuce is an further origin successful its quality to dispersed disease.“Many lettuce types person a batch of crevices and folds,” says Jeanne Marrazzo, CEO of the Infectious Diseases Society of America. “It’s precise casual for these tiny pathogens to get successful there.”

Even prewashing procedures astatine manufacturing facilities don’t ever region microbes, which tin cling tightly to leaves. In the lawsuit of cyclospora, the parasite has heavy outer walls, making it highly resistant to astir nutrient sanitizers. Experts accidental vigorous washing that involves scrubbing is the champion mode to get escaped of cyclospora.

“If you don't lavation these products well, you're going to extremity up ingesting immoderate is connected the lettuce,” says Amira Roess, an epidemiologist astatine George Mason University.