Notes from the Field: Clostridium perfringens Outbreak at a Catered Lunch — Connecticut, September 2016
In September 2016, the Connecticut Department of Public Health was notified of a cluster of gastrointestinal illnesses among persons who shared a catered lunch. The Connecticut Department of Public Health worked with the local health department to investigate the outbreak and recommend control measures. Information about symptoms and foods eaten was gathered using an online survey. A case was defined as the onset of abdominal pain or diarrhea in a lunch attendee <24 hours after the lunch. Risk ratios (RRs), 95% confidence intervals (CIs), and Fisher’s exact p-values were calculated for all food and beverages consumed. Associations of food exposures with illness were considered statistically significant at p<0.05.
Among approximately 50 attendees, 30 (60%) completed the survey; 19 (63%) respondents met the case definition. The majority of commonly reported symptoms included diarrhea (17 of 18), abdominal pain (15 of 16), and headache (7 of 15). The median interval from lunch to illness onset was 5.3 hours (range = 0.4–15.5 hours) for any symptom and 7 hours (range = 2.5–13 hours) for diarrhea. Analysis of food exposures reported by 16 ill and 10 well respondents (four respondents did not provide food exposure information) found illness to be associated with the beef dish (RR = undefined; CI = 1.06–∞; p = 0.046) (Table). All 16 ill respondents reported eating the beef. Coffee was also associated with illness; however, all 13 coffee drinkers who became ill also ate the beef. Eating cake approached significance (p = 0.051); all 10 cake eaters who became ill also ate the beef.
The caterer had begun preparing all dishes the day before the lunch. Meats were partially cooked and then marinated in the refrigerator overnight. In the morning, they were sautéed 2 hours before lunch. Inspection of the facility found the limited refrigerator space to be full of stacked containers that were completely filled with cooked food, disposable gloves that appeared to have been washed for reuse, and a porous wooden chopping block.
The caterer’s four food workers reported no recent illness. Stool specimens from the food workers and from four ill attendees all tested negative for norovirus, Campylobacter, Escherichia coli O157, Salmonella, and Shigella at the Connecticut State Public Health Laboratory. All eight specimens were sent to the Minnesota Department of Health Public Health Laboratory, where additional testing was available. Two specimens from food workers were positive for enterotoxigenic Escherichia coli by polymerase chain reaction, but no enterotoxigenic E. coli colonies were isolated. Seven specimens (four from food workers and three from attendees) were culture-positive for Clostridium perfringens, and specimens from all attendees contained C. perfringens enterotoxin. Pulsed-field gel electrophoresis of 29 C. perfringens isolates from the culture-positive specimens found no matches among attendee isolates, but demonstrated a single matching pattern between two food worker specimens. No leftover food items were available for testing.
FoodWorld 