Outbreak Investigations of Restaurants, 2014–2016

Findings from CDC’s National Environmental Assessment Reporting System

Most foodborne outbreaks occur in retail food establishments like restaurants. We studied 404 of these kinds of outbreaks reported to CDC’s National Environmental Assessment Reporting System (NEARS) in 2014–2016. Most outbreaks reported to NEARS were of viral illnesses, such as norovirus, as opposed to outbreaks from bacterial contamination, chemicals, or toxins.

Waiter serving a table in busy restaurant

Learn about the outbreaks and gaps we found in retail food safety practices and outbreak investigations.

Food worker role in outbreaks. Contamination of food by ill food workers contributed to more than half of outbreaks with contributing factor data.

Gaps in policies. Most establishments with outbreaks lacked written policies for practices to keep food from being contaminated by workers.

  • About a third did not have written policies on glove use.
  • About half did not have written policies about food workers working while sick.

Gaps in outbreak investigation practices. Investigations that start within 24-48 hours are more likely to uncover important information about outbreak causes. But about 1 in 10 investigations began more than 2 days after an outbreak was identified.

What’s Next

We are working to learn more about how retail establishment characteristics and food safety policies and practices relate to foodborne outbreaks. Our goal is to provide data to help food safety programs develop effective approaches to prevent outbreaks.


Local, state, tribal, and territorial programs use NEARS to report environmental assessment data. These data come from foodborne illness outbreak investigations in restaurants, banquet facilities, schools, and other institutions.

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Find More Information

Read the report.
Access the NEARS 2014-2016 outbreak data and the NEARS 2014-2016 outbreak establishment data for this study.
Read more findings using NEARS data.
Learn 3 things restaurant managers need to know about talking with sick workers.
Check out summaries of our scientific publications on sick workers, hand hygiene, and more.