Foodborne disease outbreaks in United States schools

The objective of this study was to describe the epidemiology of foodborne disease outbreaks in schools and to identify where preventive measures could be targeted.

Reports by state and local health departments of foodborne disease outbreaks occurring in primary and secondary schools, colleges and universities from January 1, 1973, through December 31, 1997, were reviewed. Data from ill persons identified through foodborne outbreak investigations and subsequently reported to the Centers for Disease Control and Prevention in the Foodborne Outbreak Surveillance System were examined. The number and size of foodborne disease outbreaks, as well as the etiologic agents, food vehicles of transmission, site of food preparation and contributing factors associated with outbreaks were also examined.

From 1973 through 1997, states and local health departments reported 604 outbreaks of foodborne disease in schools. The median number of school outbreaks annually was 25 (range, 9 to 44). In 60% of the outbreaks an etiology was not determined, and in 45% a specific food vehicle of transmission was not determined. Salmonella was the most commonly identified pathogen, accounting for 36% of outbreak reports with a known etiology. Specific food vehicles of transmission were epidemiologically identified in 333 (55%) of the 604 outbreaks. The most commonly implicated vehicles were foods containing poultry (18.6%), salads (6.0%), Mexican-style food (6.0%), beef (5.7%) and dairy products excluding ice cream (5.0%). The most commonly reported food preparation practices that contributed to these school-related outbreaks were improper food storage and holding temperatures and food contaminated by a food handler.

Strengthening food safety measures in schools would better protect students and school staff from outbreaks of foodborne illness. Infection control policies, such as training and certification of food handlers in the proper storage and cooking of foods, meticulous hand washing and paid sick leave for food handlers with gastroenteritis, could make meals safer for American students.