Outbreak Investigations: Foodborne Illness Outbreak Investigations

Outbreak investigations involve coordination between epidemiologists and environmental health specialists (health inspectors). Environmental health inspectors focus on evaluating the food safety practices at the restaurant or facility where the outbreak likely occurred and interviewing employees Epidemiologists coordinate patron interviews, arrange stool collection and testing, and perform data analysis to help determine if there is a specific food item that made people sick.

This model of foodborne disease outbreak investigation, with a core group of epidemiologists and an extensive network of environmental health specialists, (in coordination with local, state and federal health agencies) provides Minnesotans with an efficient foodborne disease surveillance system.

During an investigation, it is important to interview patrons who were ill, as well as those who weren’t. Information obtained from patrons during an investigation may include:

• Demographic information
• Illness history, including when illness started and symptoms
• Exposure history, including details about food and beverages consumed
• In addition, stool samples may be requested from ill patrons in order to identify the pathogen that is causing the outbreak.

Investigation of the food service establishment usually includes:

• Illness histories from all food workers and staff to identify whether a food handler may have contributed to the outbreak.
• An assessment of food preparation and storage practices to determine if a procedure may have contributed to the outbreak.
• Any necessary corrective measures such as discarded contaminated food, restricting ill employees from work until they are recovered from illness, and modifying unsafe food preparation practices.