How CDC Investigates Foodborne Outbreaks

What to know

  • The first goal of investigating outbreaks is to stop the outbreak and prevent more people from getting sick.
  • When an outbreak is detected, public health and regulatory officials work quickly to collect information and find out what is making people sick.
  • CDC works closely with many partners to identify the contaminated food and take actions to stop the outbreak.

Detecting an outbreak

Outbreaks of foodborne illness are usually detected by PulseNet, CDC's national laboratory network for detecting bacterial enteric (intestinal) disease outbreaks. Other public health partners may also receive reports about possible outbreaks from sick people, healthcare providers, and others, and report it to CDC.

What CDC and partners do to respond

Identifying the source

When a foodborne outbreak is detected, public health and regulatory officials work quickly to collect as much information as possible to find out what is making people sick. They use data to determine what food is causing the outbreak and once confirmed, take actions to protect the public.

The three types of data are epidemiologic, traceback, and food and environmental testing.

Epidemiologic data

  • Where and when did people get sick? Has the same germ caused outbreaks before? If it has, what made people sick in those outbreaks?
  • What foods did people eat before they got sick?
  • What restaurants, grocery stores, or events did sick people go to?

Traceback data

  • Is there a common point in the distribution chain where the food could have gotten contaminated?
  • Is there anything about the food production facilities, farms, or restaurants that made germs likely to spread?

Food and environmental testing data

  • Is the germ causing the outbreak also found in a food item or in the food production environment?
  • Do the germs found in the food or food production environment have the same DNA fingerprints as germs found in sick people?

Keep in mind

Investigators don't solve every outbreak. Sometimes outbreaks end before enough information is gathered to identify the contaminated food. Outbreak investigators are constantly developing new ways to investigate and solve outbreaks faster.

Stopping the spread

Outbreak investigators take actions to protect the public when there is clear and convincing information showing that people got sick from the same contaminated food.

  • Health officials warn the public
  • Companies recall contaminated products
  • Restaurants or food production facilities close temporarily
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Content Source:
National Center for Emerging and Zoonotic Infectious Diseases (NCEZID)