IFSAC Unveils 2021 Report: Diverse Food Sources Linked to Salmonellosis Cases

The Interagency Food Safety Analytics Collaboration (IFSAC), a collaborative initiative involving the U.S. Food and Drug Administration (FDA), the U.S. Centers for Disease Control and Prevention (CDC), and the U.S. Department of Agriculture’s Food Safety and Inspection Service (USDA’s FSIS), has released its 2021 report on the attribution of foodborne illnesses. The report sheds light on the sources of Salmonella, Escherichia coli O157, and Listeria monocytogenes, highlighting the role of various foods in causing illnesses.

Annually, an estimated 9 million people in the U.S. experience foodborne illnesses, leading to 56,000 hospitalizations and 1,300 deaths from known pathogens. To formulate effective prevention measures, IFSAC, comprised of federal agencies, conducts an annual source attribution report to identify which foods contribute significantly to the issue. By consolidating data from CDC, FDA, and FSIS, and employing robust analytical methods, IFSAC aims to enhance estimates of foodborne illness sources.

The report, drawing on outbreak surveillance data spanning from 1998 to 2021, presents annual estimates of the percentages of foodborne illnesses attributed to 17 food categories for Salmonella, E. coli O157, and L. monocytogenes. While Campylobacter is a priority pathogen for IFSAC, the 2021 report omits attribution estimates for Campylobacter due to observed limitations. IFSAC is actively exploring alternative approaches for such estimates.

Salmonella, E. coli O157, L. monocytogenes, and Campylobacter are prioritized by IFSAC due to the frequency and severity of associated illnesses, with targeted interventions proving effective in reducing these cases.

Based on data from CDC's Foodborne Disease Outbreak Surveillance System, IFSAC's analysis covers 1,322 outbreaks from 1998 to 2021, with 987 attributed to Salmonella, 275 to E. coli O157, and 60 to L. monocytogenes. Notably, over 75 percent of Salmonella cases were linked to seven food categories, including chicken, fruits, pork, seeded vegetables, other produce, beef, and turkey.

For E. coli O157, more than 80 percent of illnesses were attributed to vegetable row crops and beef. Vegetable row crops, particularly leafy greens, exhibited a significantly higher estimated attribution percentage than other categories, while beef surpassed all categories except vegetable row crops. Notably, no E. coli O157 cases were linked to eggs or oils-sugars.

In the case of L. monocytogenes, over 75 percent of illnesses were associated with dairy, vegetable row crops, and fruits. However, the credibility intervals for dairy, fruits, and vegetable row crops were broad due to a limited number of outbreaks. Strikingly, no listeriosis cases were attributed to other meat/poultry, game, seafood, grains-beans, oils-sugars, or seeded vegetables.

The IFSAC report underscores the varied sources of foodborne illnesses, emphasizing the need for targeted preventive measures across a spectrum of food categories.