Outbreak investigation: Salmonella food poisoning

BackgroundAn outbreak of food poisoning was reported from a Military establishment on 29 May 2011 when 43 cases of food poisoning reported sick in a span of few hours.MethodsA retrospective-prospective study was conducted. Data regarding the onset of symptoms, presenting features and history of food items consumed was collected. A detailed inspection of the mess for hygiene and sanitary status, cooking and storage procedure, and rodent nuisance was also carried out.ResultsA total of 53 cases of food poisoning occurred between 29 and 31 May 2011. All cases had symptoms of diarrohea followed by fever (96.2%), headache (84.9%), abdominal pain (50.1%), nausea and vomiting (49.1%) and bodyache (39.6%) respectively. Based on the Attributable Risk (AR = 46.67%) and Relative Risk (RR = 4.5, 95% CI = 1.22–16.54) Potato-bitter gourd vegetable served during dinner on 28 May 2011 was incriminated as the food item responsible for outbreak.ConclusionSymptomatology, incubation period and presence of rodent nuisance suggested contamination of Potato–bitter gourd vegetable with non-typhoidal Salmonella spp.