What to know
- Warning consumers quickly about a contaminated food can prevent illnesses and save lives.
- When a food is linked to an outbreak, health officials issue outbreak notices to prevent additional illnesses.
- CDC, FDA, and USDA developed a framework for deciding when to warn consumers about ongoing multistate foodborne outbreaks.
Deciding when to communicate
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.
Level of 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
- 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 concern
- 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 of the public health concern
Specificity refers to how much we know about what food is causing an outbreak.
Examples of low specificity
No generic food item or food category has been identified as the source of the outbreak
Examples of medium specificity
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
- 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 notices
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
These 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
These 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
In the last two scenarios of the table below, 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.
Scenarios and communication approaches to consider
When CDC names businesses
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 information.
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.