On August 14, 2020, the FDA announced an update to its investigation of the cause of an outbreak in Cyclospora illnesses that were first reported in May 2020 and were initially linked to salads manufactured by Fresh Express containing iceberg lettuce, red cabbage, and carrots. As of the date of the announcement, the outbreak has resulted in 690 people across 13 states falling ill.

Though traceback of cases has revealed that the likely source of contamination was iceberg lettuce from California and red cabbage from Florida, environmental sampling was unable to confirm these results. The Californian farms growing the iceberg lettuce linked to the outbreak tested negative for Cyclospora, while the Floridian farm suspected of being the source of the red cabbage was not in production at the time of testing and the FDA was not able to verify that the Cyclospora present in a nearby canal was a genetic match to the clinical cases.

FDA’s announcement demonstrates the technological progress that it has made in Cyclospora detection, including a test method validated last year which allows the Agency to test agricultural water for the presence of Cyclospora. Furthermore, FDA’s announcement states that the Agency intends to issue proposed rules this year which will (1) enhance product traceability and (2) revise certain agricultural water requirements in the Produce Safety Rule.

The outbreak highlights the importance of preventative measures to mitigate the risk of food-born outbreaks—including through ensuring the safety of irrigation water used on produce— as well as the FDA’s commitment to improving its ability to investigate food-born illness outbreaks, both through advances in technology and changes to the regulatory frameworks in place. Keller and Heckman will continue to monitor and report on updates to this and other food-born illness outbreaks.