Six Pathogens Caused 9.9 Million Foodborne Illnesses in U.S. in 2019, Per CDC’s Latest Estimates
Image credit: Freepik
The U.S. Centers for Disease Control and Prevention (CDC) has updated its estimates for the burden of foodborne illness in the U.S. based on a newly published analysis of data for 2019.
CDC’s estimates are based on the number of illnesses, hospitalizations, and deaths caused in 2019 by seven major foodborne pathogens: Campylobacter, Clostridium perfringens, Listeria monocytogenes, norovirus, nontyphoidal Salmonella, Shiga toxin-producing Escherichia coli (STEC), and Toxoplasma gondii. The majority of the dataset comprised laboratory-confirmed reports of illness, hospitalizations, and deaths (adjusted for underreporting) gathered from CDC’s Foodborne Diseases Active Surveillance Network (FoodNet) for the years 2017–2019, the Listeria Initiative surveillance system for the years 2016–2019, and Foodborne Disease Outbreak Surveillance System (FDOSS) for the years 2010–2019.
Together, six of the seven foodborne pathogens included in the dataset (excluding T. gondii) caused an estimated 9.9 million domestically acquired foodborne illnesses in the U.S. in 2019. All seven pathogens (including T. gondii) together caused approximately 53,300 hospitalizations and 931 deaths in 2019. CDC did not estimate the numbers of T. gondii illnesses because most infected people were asymptomatic, and the number of persons experiencing mild illness was unknown.
The top five contributors to foodborne illness were norovirus (5.5 million cases), Campylobacter (1.9 million), Salmonella (1.3 million), C. perfringens (889,000 cases), STEC (357,000 cases), and L. monocytogenes (1,250 cases), together causing 37.6 million cases of illness. Of the foodborne illnesses caused by Salmonella, 297,000 (23 percent) were estimated to be caused by S. Enteritidis, followed by S. Newport (14 percent), S. Typhimurium (11 percent), S. I 4,[5],12:i:- (7 percent), and S. Javiana (7 percent). Additionally, more STEC illnesses were caused by all non-O157 serogroups (271,000, or 76 percent) than by STEC O157 (86,200, or 24 percent).
Norovirus was also the leading cause of hospitalizations (22,400 cases), followed by Campylobacter (13,000), Salmonella (12,500), and C. perfringens (3,150). The order of Salmonella serotypes causing most hospitalizations was the same as that for illnesses. Additionally, STEC O157 caused more hospitalizations (1,730, or 55 percent) than all non-O157 STEC serogroups (1,410, or 45 percent), although the overall number of hospitalizations caused by non-O157 STEC was slightly higher.
Salmonella was the deadliest foodborne pathogen, causing 238 fatalities, followed by Campylobacter (197 deaths), norovirus (174), L. monocytogenes (172), and STEC (66). The greatest number of salmonellosis deaths were caused by S. Enteritidis (26 percent), followed by S. Typhimurium (17 percent), S. I 4,[5],12:i:- (11 percent), S. Newport (7 percent), and S. Javiana (2 percent).
CDC Also Publishes Data on Contributing Factors of Foodborne Illness Outbreaks
Another recent analysis, published by CDC in March 2025, covers the causes of foodborne illness outbreaks that occurred between 2014 and 2022, based on FDOSS data. CDC estimates that approximately 800 foodborne illness outbreaks occur in the U.S. each year, causing approximately 15,000 illnesses, 800 hospitalizations, and 20 deaths. This differs from the number of foodborne illnesses that occur in a year, as not all illnesses are outbreak-associated. A detailed summary of CDC’s findings can be read here.
Looking for quick answers on food safety topics?
Try Ask FSM, our new smart AI search tool.
Ask FSM →
An overall trend observed by CDC included that many foodborne illness outbreaks occur because of contamination of food by an animal or environmental source before arriving at the point of final preparation. Additionally, most viral outbreaks (e.g., norovirus) are caused by contamination from ill food workers. The data also showed that common contributing factors to bacterial outbreaks are: 1) allowing foods to remain out of temperature control for a prolonged period, and 2) inadequate time and temperature control during cooking.
New CDC Foodborne Illness Source Estimates Webpage
In tandem with the publication of its foodborne illness burden estimates, CDC published a webpage on foodborne illness source estimates—albeit based on a much older analysis that was originally conducted in 2013 and covered data from 1998–2008. The 2013 report was the first time CDC attempted such a comprehensive set of estimates for foodborne illness; since then, this estimation work has been the responsibility of the Interagency Food Safety Analytics Collaboration (IFSAC), a collaboration among CDC, the U.S. Food and Drug Administration (FDA), and the U.S. Department of Agriculture’s Food Safety and Inspection Service (USDA-FSIS). The new CDC webpage summarizing data from the 2013 report links to IFSAC reports for the most recent foodborne illness source estimates, which focus on four priority pathogens (Salmonella, E. coli O157, L. monocytogenes, and Campylobacter).
Read a detailed summary of IFSAC’s most recent foodborne illness source attribution estimates, covering 2022, here.
For more information about IFSAC’s approach to foodborne illness source attribution estimation, read an article written by IFSAC scientists for the December 2024/January 2025 issue of Food Safety Magazine here.
