Investigators from the Washington State Department of Health and the Tacoma-Pierce County and Thurston County Health Departments joined together to investigate the E. coli outbreak, ultimately identifying three clusters of E. coli illnesses: three E. coli cases at Pacific Lutheran University; three E. coli cases from a banquet at La Quinta Inn in Tacoma; and four E. coli cases amongst students in the Olympia School District.
California Romaine Lettuce Identified as E. coli Outbreak Source
Through interviews, the health departments determined that Romaine lettuce was the only common food consumed by all E. coli outbreak victims. Invoices from PLU, the La Quinta Inn, and Olympia School District pointed to a common supplier of the E. coli-contaminated lettuce, and further trace-back revealed that the lettuce came from California’s Salinas Valley.