Author(s): Lee VJ, Ong AE, Auw M
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Abstract INTRODUCTION: Non-typhoidal Salmonellae are important causes of bacterial food-borne infection, especially in institutional settings. An outbreak of gastrointestinal infection occurred in a military camp in January 2007, and an epidemiological outbreak investigation was conducted. MATERIALS AND METHODS: A survey was conducted on soldiers in the camp on their clinical symptoms, and recent meals consumed. After determining the affected meal, a subsequent survey was conducted on those who had eaten the meal. A case-control study was then performed to determine the outbreak's likely food source. Laboratory tests were also conducted to determine the bacteriological cause. RESULTS: Of the 94 responders, 55 (58.5\%) met our case definition of gastrointestinal illness. The dinner on 9 January was the most likely affected meal, with the onset of symptoms occurring within 6 to 36 hours. The mashed potato was the most likely food source with an attack rate of 80.7\% for those who consumed it versus 32.7\% for those who did not (P <0.01). From the multivariate analysis, the mashed potato remained the only food item independently and significantly associated with infection, with a relative risk of infection 9.49 times those who did not consume it (95\% CI, 2.73-32.97). Salmonella group E was cultured from 4 individuals. Although no specific contamination was identified, the mashed potato was stored for more than 5 hours before the last serving. CONCLUSION: Risk during preparation of large quantities of food should be identified a priori, and measures taken to reduce them, to prevent outbreaks.
This article was published in Ann Acad Med Singapore
and referenced in Journal of Antivirals & Antiretrovirals