Salmonella Food Poisoning Outbreak at a School in Kaohsiung County in 2010

Tzu-Fen Chen, Min-Nan Hung, Su-Hua Huang ,Mei-Man Hsu, Hui-Chen Lin, Chi-Chuan Huang, Chao-Ching Chang, Li-Jen Lin

2011 Vol.27 NO.9

Correspondence Author： Tzu-Fen Chen

Abstract：

From the dawn of July 5, 2010, many students at School X began having food poisoning-like symptoms, such as fever, nausea, vomiting, abdominal cramps, and diarrhea. In order to find out the source of this food poisoning outbreak, as well as to provide preventive recommendations, we conducted a retrospective outbreak investigation on students and employees who were at school on the day before the outbreak.
This study was based on self-reported questionnaires. The response rate was 93.3% (475/509). The analysis of data (male 462, female 13) showed the range of age is from 18 to 33, and the median is 19. There were 64 people matched with the case definition, and the main clinical symptoms were as follows: fever (n=54, 84.4%), abdominal cramps (n=48, 75%), headache (n=40, 62.5%), diarrhea (n=24, 37.5%), nausea (n=17, 26.6%), chills (n=15, 23.4%), and vomiting (n=12, 18.8%).
After analyzing the three meals they had on July 4 (the date before onset), statistically significant association appeared between food poisoning and these dishes – Malar Cake for breakfast, steamed egg custard with dried bonito flakes and popcorn chicken for lunch, and crisp fried pig’s ears for dinner. Salmonella was isolated from the leftovers of steamed egg custard with dried bonito flakes and cabbage with bacon. Besides, 24 people had isolated Salmonella from rectal swab among 29 symptomatic individuals. According to the symptoms, incubation time, and laboratory findings, we infer that the steamed egg custard with dried bonito flakes for lunch was the main source of this Salmonella food poisoning outbreak.