The FDA officially concluded its investigation into the Cyclospora outbreak linked to shredded iceberg lettuce sourced from Central Mexico, announcing on October 2 that two positive environmental samples were found — one from a processing facility's outgoing wastewater tank and another from a drainage ditch at a lettuce grower identified through traceback. The agency said these findings add to strong epidemiological and traceback evidence linking the outbreak to recalled product, though they don't conclusively establish exactly how contamination occurred.
Mexican authorities, including COFEPRIS and the Government of Guanajuato, acknowledged the findings but emphasized that positive environmental samples alone don't establish agricultural products as the contamination source, citing their own negative test results. The FDA met with senior Mexican public health officials in September and sent a letter to industry calling for supply chain collaboration on Cyclospora prevention.
Ahead of the 2027 growing season, FDA outlined ten specific prevention activities it plans to implement. For anyone buying or selling iceberg lettuce from Central Mexico, this is the most concrete official update yet on where the investigation landed — and what the regulatory environment will look like going into next season.