An Investigation of Food Poisoning Outbreak among Meeting Attendees in Pattaya City, Thailand, following Post-pandemic Kitchen Reopening, August 2022

Abstract

On 9 Aug 2022, meeting attendees at Hotel B in Pattaya City developed gastrointestinal symptoms during a tourism reopening after Thailand had transitioned to the post-COVID-19 phase. We investigated to confirm the diagnosis, describe outbreak characteristics, identify possible sources and risk factors of the outbreak, and provide recommendations. A food poisoning case was an individual staying in Hotel B on 8–9 Aug 2022 and experienced at least one of the following symptoms: diarrhea, nausea, vomiting and abdominal pain. We sent a self-administered questionnaire to all attendees and interviewed the cases. Food preparation and processing were examined. We swabbed kitchenware and food handlers’ hands and collected water samples for bacterial culture. We conducted a retrospective cohort study and used Poisson regression with a robust standard error model. Fifty-five percent of the attendees responded to the questionnaire; the attack rate was 34%. Common symptoms were diarrhea (100%) and abdominal pain (80%). The median incubation period was 7–13 hours. Stewed pork leg with kale had the highest adjusted risk ratio of 27.82x10⁶ (95% CI 9.06x10⁶–85.44x10⁶). It was reported as cold with an unusual smell and taste. We found Bacillus cereus and Aeromonas spp. on kitchenware and in filtered water. The incubation period, symptoms, and laboratory results suggested that Bacillus cereus was the most likely pathogen from the stewed pork leg. We recommended sanitizing the kitchen and kitchenware, promoting food sanitary awareness, and ensuring the quality of water supply system, particularly for hotels preparing to reopen after prolonged closure.

Keywords: Bacillus cereus, food poisoning, outbreak, Pattaya City, Thailand