How the CDC Traces Food Poisoning in what is Called a Traceback Investigation
According to the U.S. Centers for Disease Control and Prevention (CDC), when a foodborne illness outbreak is detected, a traceback investigation is conducted, in order to “determine the distribution and production chain for [the] food…implicated” in the outbreak. Public health and regulatory officials collect as much information as possible, as quickly as possible, in order to determine the source of the outbreak and put an end to it. There are three types of information collected in a traceback investigation: epidemiological, traceback, and food and environmental testing.
The first type of information collected is epidemiological. Epidemiological information includes the pattern of geographic distribution of cases of illness connected to the outbreak, the onset and duration of the illnesses, and any past outbreaks linked to the same pathogen. It also looks at common types of exposure sick people had, such as the types of food they ate, or restaurants, grocery stores, or events they went to prior to falling ill.
The second type of information collected is traceback data. This step takes any information regarding common exposure points of sick persons and analyzes them more closely. For example, records, such as receipts, of restaurants or grocery stores which sick persons reported having eaten or shopped at prior to falling ill, are collected and reviewed. Additionally, any significant findings from environmental assessments and food safety protocols assessments (discussed below) of food production facilities, farms, and restaurants are analyzed to find any connection to sick peoples’ case reports.
The third type of information collected is food and environmental testing. In this process, a sample of a sick person’s stool and a sample from the allegedly contaminated food source is taken. Then, using a type of data fingerprinting technology called Whole Genome Sequencing (WGS), the two samples’ are compared to determine if they share the same germ, which, in that case, would likely be the source of the outbreak.
Health officials analyze all the information provided via these three different areas of investigation, in order to reach a reasonable conclusion regarding the source of the outbreak. Once a probable source is identified, health officials use this information to announce public recalls on any related food products and communicate the issue to the producers or processing plants implicated in the outbreak.
https://www.cdc.gov/pulsenet/pathogens/wgs.html
https://www.cdc.gov/foodsafety/outbreaks/investigating-outbreaks/index.html
