A significant outbreak of the parasite Cyclospora is affecting the United States, with authorities linking it to iceberg lettuce grown in Mexico.
The parasite, which causes severe diarrhea and other gastrointestinal symptoms, is transmitted through food or water contaminated with feces. Its protective oocysts make it resistant to standard washing and sanitization methods.
Bagged salads may be a vector for the recent Cyclospora outbreak in the US. (Toni Jardon/iStock/Getty Images Plus)
Bagged salad greens are a primary vector because they are often consumed raw, allowing multiple points for potential contamination.
Experts state that washing produce does not reliably eliminate Cyclospora due to its resilient shell. "Washing is great. Washing with a vegetable brush is even better, but you still cannot definitively say that you have removed and/or killed the parasite," said Dr. Rotonya De Latour of NYU Grossman School of Medicine.
Health officials recommend avoiding bagged and boxed salads from stores and restaurants. The safest alternative is to choose whole heads of lettuce, discard outer leaves, and wash the rest thoroughly. Cooking greens to at least 158°F (70°C) reliably kills the parasite.
The Centers for Disease Control and Prevention advises washing all produce under running water and scrubbing firm items with a clean brush before preparation.