Improving Outbreak Investigations

For Public Health

At a glance

Preventing foodborne outbreaks in restaurants requires us to know how and why they happen. During an outbreak investigation, an environmental assessment is an important part of uncovering how and why the outbreak happened. Use our resources to improve investigations in your community.

Person holding a paper in a restaurant as part of an outbreak investigation.

Finding outbreak causes

During environmental assessments, investigators apply system theory to help find clues in the food safety system to understand and address the outbreak's environmental causes. These causes are also known as contributing factors and root causes (environmental antecedents).

Investigator holding a clipboard talks to a chef in a restaurant kitchen.
Environmental Assessments
Use environmental assessments to respond to outbreaks of foodborne illness.
Graphic of a hamburger with a thermometer in the meat.
Contributing Factors
Identify contributing factors in foodborne illness outbreaks to help stop and prevent them.
Icons representing foods, people, equipment, economics, and processes.
Root Causes of Outbreaks
Use our resources to identify root causes of foodborne illness outbreaks.
Food workers in a kitchen.
Key Findings from Investigation Data
Explore key findings about the environmental component of foodborne illness outbreak investigations.

Resources

The skills needed to investigate outbreaks of foodborne illness in restaurants are different from those needed to inspect restaurants.

Image of two food workers from a training.
Training and Resources
Learn how to address environmental causes of foodborne illnesses with our free food safety training.
NEARS graphic
National Environmental Assessment Reporting System
Use NEARS to capture environmental assessment data from foodborne illness outbreak investigations

More information

Foodborne outbreaks (CDC)

National Outbreak Reporting System (NORS) (CDC)

Food Code (Food and Drug Administration)

Outbreak investigation reports (Food and Drug Administration)

Guidelines for foodborne outbreak response (Council to Improve Foodborne Outbreak Response)

Learn more about our work to improve practices

Use our resources to improve food safety practices in restaurants, banquet facilities, schools, and other institutions.
Improving Practices
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Content Source
National Center for Environmental Health
About This Page
Published: May 15, 2024
Updated: August 20, 2026

This page was last updated on this date. Updates may include minor edits, image changes, or other modifications to page content.

Reviewed: August 20, 2026

The information on this page was last reviewed by subject matter experts to ensure accuracy.