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Foodhandler-Associated Salmonella Outbreak in a University Hospital Despite Routine Surveillance Cultures of Kitchen Employees

Published online by Cambridge University Press:  02 January 2015

Najwa A. Khuri-Bulos*
Affiliation:
Jordan University Hospital, Amman, Jordan
Mahmoud Abu Khalaf
Affiliation:
Jordan University Hospital, Amman, Jordan
Asem Shehabi
Affiliation:
Jordan University Hospital, Amman, Jordan
Khaled Shami
Affiliation:
Jordan University Hospital, Amman, Jordan
*
Department of Pediatrics, Jordan University Hospital, Amman, Jordan

Abstract

Objective:

To describe an outbreak of salmonella food poisoning that probably was due to contamination of mashed potatoes by a foodhandler, which occurred despite a policy for routine surveillance stool cultures of kitchen employees.

Design:

A case control study of 223 individuals who ate the lunch meal on September 23, 1989, at the Jordan University Hospital (JUH) cafeteria.

Setting:

Tertiary care university hospital in Amman, the capital of Jordan.

Patients:

Individuals who developed loose stool or vomiting 6 to 72 hours after eating the lunch meal of September 23, 1989, at the JUH cafeteria.

Results:

Of 619 individuals, 183 fit the case definition (attack rate, 19.6%); 150 were employees, 26 were inpatients, and seven were visitors. Twelve other employees became sick 4 to 6 days later and probably were infected secondarily. The incubation period ranged from 16 to 72 hours in 183 instances. Symptoms included diarrhea (88%), fever (71%), abdominal pain (74%), dehydration (34%), and bloody stool (5%). Eighty-four were hospitalized. Cultures of eight food items were negative, but stool culture on 90 of 180 patients and 11 of 61 kitchen employees yielded Salmonella enteritidis group D.

A cohort study of 223 individuals revealed a food-specific attack rate of 72% for the steak and potato meal and 18% for the rice and meat meal (RR, 4; CI95, 2.62 to 6.24; P<0.01). Stratified analysis of the steak and potato meal revealed that the potatoes were implicated most strongly (RR, 1.93; CI95, 1.42 to 2.64; p<0.01). Cultures were obtained from all kitchen employees, and 11 of 61 grew Salmonella enteritidis group D. One asymptomatic, culture-positive employee prepared the mashed potatoes on September 23. All of these employees had negative stool cultures 3 months earlier.

Conclusion:

This outbreak probably was caused by massive contamination of mashed potatoes by the contaminated hands of the foodhandler. Routine stool culture of foodhandlers is not cost-effective and should not be used as a substitute for health education and proper hygienic practices.

Type
Original Articles
Copyright
Copyright © The Society for Healthcare Epidemiology of America 1994

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