Executive Summary
Each year in the United States an estimated 9 million people get sick, 56,000 are hospitalized, and 1,300 die of foodborne disease caused by known pathogens. These estimates help highlight the scope of this public health problem. However, to develop effective prevention measures, food safety agencies and partners need to understand the types of foods contributing to the problem.
The Interagency Food Safety Analytics Collaboration (IFSAC) is a tri-agency group created by the Centers for Disease Control and Prevention (CDC), the U.S. Food and Drug Administration (FDA), and the U.S. Department of Agriculture’s Food Safety and Inspection Service (FSIS). By bringing together data from CDC, FDA, and FSIS,
and by developing sound analytical methods, IFSAC scientists can improve estimates of the sources of foodborne illness.
Using outbreak surveillance data from 1998 through 2021, this report presents annual estimates of the percentages of foodborne illness attributed to 17 food categories for Salmonella, Escherichia coli O157, and Listeria monocytogenes.
Salmonella illnesses came from a wide variety of foods. More than 75% of Salmonella illnesses were attributed to seven food categories: Chicken, Fruits, Pork, Seeded Vegetables (such as tomatoes), Other Produce (such as nuts), Beef, and Turkey.
Escherichia coli (E. coli) O157 illnesses were most often linked to two categories.
Over 80% of Escherichia coli (E. coli) O157 illnesses were linked to Vegetable Row Crops (such as leafy greens) and Beef.
Listeria monocytogenes (Listeria) illnesses were most often linked to Dairy products, Vegetable Row Crops, and Fruits. More than 75% of illnesses were attributed to these three categories, but the rarity of Listeria outbreaks makes these estimates less reliable than those for other pathogens.
Attribution estimates for Campylobacter are not presented in this year’s report. Evidence suggests the sources of Campylobacter outbreaks likely differ considerably from the sources of non-outbreak-associated illnesses caused by this pathogen. IFSAC is exploring alternative approaches for estimating the sources of Campylobacter illnesses.
IFSAC derived the estimates for 2021 using the same method used for previous estimates, with some modifications. The original method, dating back to the estimates from 2012, was described in a report, a peer- reviewed journal article, and at a public meeting. The data in this year’s report came from 47,657 illnesses linked to 1,322 foodborne disease outbreaks that occurred from 1998 through 2021 and for which each confirmed or suspected implicated food was assigned to a single food category. The method relies most heavily on the last five years of outbreak data (2017 – 2021). Foods are categorized using a scheme IFSAC
created that classifies foods into 17 categories that closely align with the U.S. food regulatory agencies’ classification needs.
Examples of foods included in each food category can be found in the appendix.
This collaborative effort to provide annual attribution estimates continues IFSAC’s work to improve foodborne illness source attribution, which can help inform efforts to prioritize food safety initiatives, interventions, and policies for reducing foodborne illnesses. These consensus estimates allow all three agencies to take a consistent approach to identifying food safety priorities to protect public health. For more information on
IFSAC projects visit https://www.cdc.gov/foodsafety/ifsac/projects/index.html.
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