Salmonella Typhimurium Outbreak at a Fire Department Fish Fry Fundraiser, Tennessee, 2016

BACKGROUND: On September 19, 2016, the Rutherford County Health Department and the Mid-Cumberland Regional Office (MCRO) were notified of seven Salmonella cases at a local hospital. Concurrently, the Tennessee Department of Health (TDH) received a report of illnesses after a community fundraiser. Preliminary interviews of hospitalized cases identified the common exposure as the monthly fish fry hosted by the volunteer fire department. MCRO and TDH launched a joint investigation.

METHODS: A volunteer contact list and TDH Facebook post were utilized for initial case and control finding. Local news coverage encouraged attendees to contact TDH. A case-control study was conducted using a meal-specific questionnaire to capture food and exposure history. Unadjusted and adjusted odds ratios (OR) and confidence intervals (CI) were calculated in EpiInfo 7. An environmental assessment was conducted at the fire station.

RESULTS: A total of 117 (24%) interviews were completed among an estimated 480 attendees. Among these, 74 cases and 43 controls were identified. Fifty-one percent of cases were male with median age of 57 years (range: 1 – 97). Eighteen persons (24%) were hospitalized. Common symptoms included diarrhea (99%), cramps (85%), fever (69%), and fatigue (69%). In unadjusted analyses, illness was associated with eating white beans (OR 13.2), fish (3.1), and coleslaw (2.6). After adjustment, the odds of eating white beans were 11 times higher among cases than controls (OR 11.3 [CI 3.9 – 33.2]) and the only statistically significant exposure reported. In considering only cases with laboratory evidence (22 cases), odds of eating white beans were even stronger (OR 13.9 [CI 2.9 – 67.1]). The venue was not a regulated food establishment, however, the environmental assessment identified that the preparation of white beans was altered from the standard practice, potentially allowing for inadequate cooking and holding temperatures.

CONCLUSIONS: This was a large S. Typhimurium outbreak in a small community, sickening at least 74 persons and hospitalizing 18. Community and fire department cooperation were essential to the successful investigation of this outbreak. Although a prepared food sample was unavailable for testing, the epidemiologic evidence strongly implicated white beans and was supported by the environmental assessment. The outbreak team presented findings and food safety recommendations to fire department staff. This outbreak highlighted the importance of adhering to established food handling practices in unregulated settings and fostered communication between the health department and community to ensure long-standing events can safely continue in the future.