Prevention and control

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Information obtained through a foodborne outbreak investigation may be used to implement various prevention and control measures, such as intervening at food premises, recalling a food product, and informing and educating the public. Prevention and control activities can be directed at either control of the implicated source (e.g., food) or control of transmission of the pathogen (e.g., person-to-person transmission, food safety and hygiene practices).

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Prevention and control measures

Control measures are often implemented concurrently with the ongoing outbreak investigation and are often initiated before all laboratory results and investigative activities are complete. Interventions such as a food recalls, seizures, or the closure of a food premise can have serious economic and legal implications; therefore, investigators must balance the responsibility to protect public health with the need to respect business interests. The following are examples of interventions that may be employed to control the source and spread of an outbreak:

Interventions at the food premises

If implicated foods are associated with a specific food premise, there are several prevention and control measures that may be implemented. Examples of interventions at food premises include cleaning and sanitization of the facility, food safety training for employees, employee screening and exclusion (until they produce negative laboratory results for the pathogen), modification of a process/recipe, re-organization of working practices, and improvements in temperature control. In some cases, closure of the food premise and/or seizure/hold of food product(s) may be necessary.

Food recalls

A food recall is an action taken by a company to remove a potentially unsafe food product from the marketplace. It is the responsibility of industry to remove the product from sale or distribution. Regulatory authorities, such as the Canadian Food Inspection Agency (CFIA) have the responsibility to inform the public, oversee implementation of the recall, and verify that industry has removed recalled products from store shelves.

In Canada, if a potential food item has been identified, Health Canada may be requested to perform a health risk assessment (HRA). The risk assessment is guided by the Weight of Evidence document, which assesses the risk to the public based on epidemiologic, food safety, and laboratory evidence.

Public messaging and education

Public messaging can be used to educate the public on how to protect themselves against enteric illness. The decision to notify the public, as well as the timing and the content of the messaging, should be agreed upon by all investigative partners. Additional information on coordinating public communications during outbreaks is discussed in further detail in the “Communication and coordination” background page (read more).

Public messaging may include:

  • General or specialized food safety advice on food storage or preparation in the home;
  • Personal hygiene advice to prevent secondary transmission (e.g., food handlers, childcare workers, infection control practitioners in hospitals/institutions);
  • Advice specific to at-risk groups (e.g., pregnant women and immunocompromised persons should avoid consumption of unpasteurized milk products; persons with liver disease should avoid consumption of raw oysters and other foods that may transmit Vibrio bacteria).

Examples of public messaging:

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CFIA: How Canada’s Food Safety System Works

  • This webpage provides links to various CFIA activities and resources related to food safety such as the Hazard Analysis Critical Control Point (HACCP), meat and poultry inspection, food complaints, food safety investigations, and food recalls.

CFIA restaurant and food service inspection in Canada

  • This resource provides information on the restaurant and food service inspections carried out in local/regional jurisdictions by province/territory.

CFIA food recalls overview

  • This CFIA webpage provides an overview of the five step process to investigate and recall product in Canada including the triggers for investigation, the food safety investigation, the health risk assessment, the recall process and follow-up activities.

Food Traceability for Dummies Book

  • Food Traceability For Dummies, Carlisle Technology Edition, is a free PDF book for food producers and processors to show what food traceability is, how it works, and how companies can add traceability to internal plant processes. 

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Council to Improve Foodborne Outbreak Response (CIFOR). 2014. Guidelines for Foodborne Disease Outbreak Response (2nd edition). Council of State and Territorial Epidemiologists, Atlanta, GA. Available at: