If grabbing a bag of prewashed lettuce or spinach feels like a healthy, convenient move, you may want to think twice before tossing it in your cart.
According to a report from HuffPost, food safety experts say bagged salad greens are among the riskiest items in the grocery store due to repeated outbreaks of contamination linked to serious illnesses. And the danger isn’t just theoretical—some outbreaks tied to prepackaged salads have led to hospitalizations, kidney failure, and even death.
“While consumers expect convenience and safety, the reality is that prewashed bagged greens remain one of the riskiest items in the grocery store due to contamination risks throughout the supply chain,” said Darin Detwiler, a professor of food policy at Northeastern University and author of Food Safety: Past, Present, and Predictions, in HuffPost’s report.
Leafy greens are frequently linked to foodborne illness outbreaks, often caused by E. coli, listeria, or salmonella. These bacteria can be introduced at multiple points in the supply chain—from contaminated irrigation water near cattle farms to unsanitary processing equipment. Once a single contaminated leaf enters the production line, it can end up affecting thousands of bags across multiple states.
According to the FDA’s Leafy Greens STEC Action Plan, outbreaks involving greens are so common that the agency made leafy greens a focus of updated safety protocols as recently as 2023. Still, the threat remains. A study published in Journal of Foodborne Illness in April 2024 reported that leafy greens account for up to 9.2% of all known foodborne illnesses in the U.S.—that’s over 2.3 million illnesses a year.
What makes this worse is that refrigeration doesn’t kill bacteria, and washing the greens again at home doesn’t help either. In fact, rinsing bagged salad could introduce new bacteria from your sink, hands, or kitchen tools.
“Prewashed greens should not be rewashed at home, as doing so can introduce contamination,” said Kimberly Baker, food systems and safety program director at Clemson University.
As for how the bacteria get there? It often starts on the farm. Runoff from nearby livestock operations, unregulated irrigation water, and close proximity to manure lagoons are just some of the ways dangerous pathogens like E. coli O157:H7 make their way onto produce. And once at the processing plant, greens from multiple farms are mixed, washed, and bagged together—making it nearly impossible to trace contamination after the fact.
So what should you do?
Experts recommend buying only what you’ll eat within a day or two, checking expiration dates, and skipping any bags with excessive moisture or wilting. They also suggest purchasing whole heads of lettuce or bunches of spinach instead of pre-cut mixes. Though it requires a bit more prep, it may significantly lower your exposure to harmful bacteria.
If you’re sticking with convenience, stay alert for recalls and keep those greens cold. Just know that when it comes to bagged salad, the cleanest-looking option on the shelf might not be the safest.
