Issuing Foodborne Outbreak Notices

Warning consumers quickly about a contaminated food can prevent illnesses and save lives.

Public health and regulatory officials work quickly to find the source of foodborne disease outbreaks so they can take action to prevent more people from getting sick. When there is clear and convincing information linking illness to a food found in stores or in people’s homes, health officials issue outbreak notices to prevent additional illnesses.

The information on this page describes how CDC decides to issue a notice, the types of notices CDC issues, and why CDC names businesses linked to outbreaks.

Framework for Risk Communication Decisions

Multistate foodborne outbreak investigations are complex and involve many partners at local, state, and federal health and regulatory agencies. CDC makes the decision to communicate about an outbreak with input from these partners.

One challenging part of communicating about an ongoing foodborne outbreak is deciding when to issue an outbreak notice. CDC works to balance the need for releasing information quickly with the need for an accurate, specific, and actionable message. Inaccurate or confusing messages, such as warning the public about the wrong food, can

  • cause illnesses to continue because the contaminated food remains on the market,
  • damage the credibility of public health agencies,
  • lead to food waste,
  • cause panic if initial messaging is inaccurate, and
  • cause negative consequences for companies or industries.

To aid in these decisions, CDC, the U.S. Food and Drug Administration (FDA), and the U.S. Department of Agriculture’s Food Safety and Inspection Service (USDA-FSIS) established a risk communication framework for evaluating when to warn consumers about ongoing multistate foodborne outbreaks. In this framework, CDC and its partners assess two main factors about an outbreak: the level of public health concern and the specificity of the public health concern.

Level of concern refers to how serious the outbreak is. CDC and its partners look at things like the size of the outbreak, whether it is growing rapidly or slowing down, and how severe the illnesses are.

  • Examples of lower concern include
    • Unclear if outbreak is ongoing
    • Number of new illnesses reported is low and most recent illness was several weeks ago
    • Lower number of more severe outcomes (e.g., lower hospitalization rate, no deaths)
    • Food linked to illness is known, but the food is likely no longer available in stores or in people’s homes
  • Examples of higher public health concern include
    • Illnesses continue to be reported (outbreak is ongoing)
    • Number of new illnesses is increasing rapidly
    • Illnesses are unusually severe (e.g., higher hospitalization rate, deaths)
    • A specific group of people is at higher risk for illness
    • Food linked to illness is known, and the food is likely still available in stores or in people’s homes

Specificity refers to how much we know about what food is causing an outbreak.

  • Example of low specificity include
    • No generic food item or food category has been identified as the source of the outbreak
  • Examples of medium specificity include
    • Generic food item (e.g., ground beef) or food category (e.g., leafy greens) identified as the source of the outbreak, but no specific products or brands have been linked to illness
    • Germ causing illness in people has been found in a food, food facility, or farm, but no interview or traceback data confirm a link to ill people
  • Examples of high specificity include
    • Specific food item (e.g., brand, lots, “best by” dates) identified as the source of the outbreak
    • Germ causing illness in people has been found in a food or food environment, and interview data or traceback data confirm a link to illnesses

Once these factors are assessed, the team decides on the most appropriate type of outbreak notice and message. The framework is used throughout the investigation process as outbreak data are collected and analyzed. New data can change the communication tool and message.

Types of Outbreak Notices

CDC is most likely to issue an outbreak notice when the level of public health concern is higher and the public health threat is more specific. In scenario 5 or 6 in the table, there are specific, clear, and actionable steps people can take to protect themselves from a contaminated food. However, CDC issues outbreak notices in the other scenarios if there is an actionable message for consumers or retailers or the level of public health concern is higher.

Scenario Level of Concern Specificity of Concern Communication Approaches to Consider
CDC, the U.S. Food and Drug Administration (FDA), and the U.S. Department of Agriculture’s Food Safety and Inspection Service (USDA-FSIS) established a risk communication framework for evaluating when to warn consumers about ongoing multistate foodborne outbreaks.
1 Lower concern Low specificity Gather more information
2 Lower concern Medium specificity Issue investigation notice
3 Lower concern High specificity Issue food safety alert
4 Higher concern Low specificity Gather more information, or issue investigation notice
5 Higher concern Medium specificity Issue investigation notice or food safety alert
6 Higher concern High specificity Issue food safety alert

If the decision is made to notify the public of an outbreak, CDC announces the outbreak using either a food safety alert or an investigation notice. These notices tell people what they can do to protect their health.

Food safety alerts provide urgent, specific advice to people and businesses about foods to avoid eating or selling. This advice may include information about a recall or specific products to avoid.

Investigation notices provide information about an outbreak not yet linked to a source or an outbreak linked to a general type or category of food, rather than a specific food.

Both types of outbreak notices typically include:

  • How many people are sick in each state and when their illnesses started
  • Signs and symptoms of the illness
  • Advice to consumers and retailers
  • Other investigation details, including food testing results, if available

CDC posts updates during outbreak investigations to ensure the website reflects the most accurate and current information. Updates are posted as needed, and the timing differs depending on the outbreak.

CDC posts a final update once an investigation ends.

CDC also notifies the public through the following social media channels when a foodborne outbreak is announced or when new information is released:

A list of current and past outbreak notices can be found on the CDC Foodborne Outbreaks website. This website provides information about foodborne outbreaks in which CDC led the epidemiologic investigation.

CDC works with FDA and USDA-FSIS during multistate foodborne outbreaks to develop actionable advice about foods linked to illness. FDAexternal icon and USDA-FSISexternal icon release information on their respective websites about outbreaks they are investigating.

State and local health department websites often provide information on local foodborne outbreaks they investigate. The National Outbreak Reporting System (NORS) receives reports on local, state, and multistate foodborne outbreaks reported to CDC. Any multistate foodborne disease outbreak investigation that CDC coordinates is also reported through NORS.

Naming Businesses Involved in Outbreaks

When investigating foodborne outbreaks, public health investigators often find that the way people got sick involved a business where they ate or shopped or a particular brand of product they bought.

CDC has a long-standing practice of regularly disclosing names of businesses implicated in ongoing infectious disease outbreaks to protect public health. These disclosures have helped the public reduce their health risks and have helped businesses improve the safety of their products. In some situations, federal law dictates whether CDC can disclose or must protect the identity of businesses, such as a requirement to protect confidential commercial informationexternal icon.

Generally, the decision to disclose names of businesses is made with regulatory agency partners (e.g., FDA or USDA-FSIS) and affected states. Long after an outbreak is over (e.g., in peer-reviewed articles or in conference presentations), CDC typically refers to any implicated businesses anonymously (e.g., “Restaurant A” or “Supplier B”), because naming the specific business in such settings does not add to the body of public health knowledge and there is no ongoing public health threat. These peer-reviewed articles and presentations provide information for people interested in food safety topics, such as the media, food safety educators, and consumer advocacy groups, as well as for food industries and regulatory officials as they work to make food safer.