On October 31, 2019 the FDA announced an outbreak of E. coli O157:H7 infections likely linked to consumption of romaine lettuce. At the time of the announcement, the FDA declared the outbreak to be over. A total of 23 illnesses were reported from 12 states: Arizona, California, Florida, Georgia, Illinois, Maryland, North Carolina, Nevada, New York, Oregon, Pennsylvania, and South Carolina. Eleven people were hospitalized. There were no deaths. Illnesses started on dates ranging from July 12, 2019 to September 8, 2019.

Investigators were sent to visit farms located in California’s central coast region which were identified through the traceback investigation. They collected and tested many environmental samples, and the outbreak strain was not identified. While romaine lettuce is the likely cause of the outbreak, the investigation did not identify a common source or point where contamination occurred.