An outbreak of food-borne salmonellosis linked to a bread takeaway shop in Ben Tre City, Vietnam

Abstract

OBJECTIVES: To identify the vehicle, source, and causative agent of a community-wide food-borne outbreak of gastroenteritis. METHODS: We conducted a case-control study. Cases were city residents diagnosed with gastroenteritis and hospitalized in Ben Tre City from 22 to 25 May 2013; 41 cases were selected randomly from a list of hospitalized patients. Controls were age- and gender-matched healthy neighbours of cases. Participants were interviewed using a standard questionnaire. Samples from patients and food were tested at reference laboratories. We used conditional logistic regression to calculate matched odds ratios (mORs) for the association of gastroenteritis with food items consumed. RESULTS: Of the 41 cases enrolled in the study, 61% were males and the median age was 33 years; cases resided in 12 wards of the City. Of 13 food items consumed by the cases, only stuffed bread was significantly associated with gastroenteritis (mOR 21.3, 95% confidence interval 6.3-71.8). Among the 29 cases who ate stuffed bread, the median time to illness onset was 9h. Patient stool samples and bread samples were positive for Salmonella species. CONCLUSIONS: Stuffed bread was the likely vehicle of the outbreak. The laboratory testing capacity for serotypes of Salmonella should be strengthened in Vietnam. Food-handler training in basic food safety measures should be improved.