J Prev Med Public Health.  2011 Mar;44(2):65-73. 10.3961/jpmph.2011.44.2.65.

Epidemiological Investigation for Outbreak of Food Poisoning Caused by Bacillus cereus Among the Workers at a Local Company in 2010

• Choi KB
• Lim HS
• Lee K
• Ha GY
• Jung KH
• Sohn CK

• KMID: 1003041
• DOI: http://doi.org/10.3961/jpmph.2011.44.2.65

Abstract

OBJECTIVES
In July 2 2010, a diarrhea outbreak occurred among the workers in a company in Gyeungju city, Korea. An epidemiological investigation was performed to clarify the cause and transmission route of the outbreak.
METHODS
We conducted a questionnaire survey among 193 persons, and we examined 21 rectal swabs and 6 environmental specimens. We also delegated the Daegu Bukgu public health center to examine 3 food service employees and 5 environmental specimens from the P buffet which served a buffet on June 30. The patient case was defined as a worker of L Corporation and who participated in the company meal service and who had diarrhea more than one time. We also collected the underground water filter of the company on July 23.
RESULTS
The attack rate of diarrhea among the employees was 20.3%. The epidemic curve showed that a single exposure peaked on July 1. The relative risk of attendance and non-attendance by date was highest for the lunch of June 30 (35.62; 95% CI, 2.25 to 574.79). There was no specific food that was statistically regarded as the source of the outbreak. Bacillus cereus was cultured from two of the rectal swabs, two of the preserved foods and the underground water filter. We thought the exposure date was lunch of June 30 according the latency period of B. cereus.
CONCLUSIONS
We concluded the route of transmission was infection of dishes, spoons and chopsticks in the lunch buffet of June 30 by the underground water. At the lunch buffet, 50 dishes, 40 spoons, and chopsticks were served as cleaned and wiped with a dishcloth. We thought the underground water contaminated the dishes, spoons, chopsticks and the dishcloth. Those contaminated materials became the cause of this outbreak.

Keyword

Epidemiology; Bacillus cereus; Food poisoning; Outbreaks; Diarrhea

MeSH Terms

Adult
Aged
Bacillus cereus/*isolation & purification
Diarrhea/etiology
*Disease Outbreaks
Female
Foodborne Diseases/*epidemiology/microbiology
Fresh Water/microbiology
Gram-Positive Bacterial Infections/*epidemiology/microbiology
Humans
Male
Middle Aged
Questionnaires
Rectum/microbiology