Back to Pre-Pandemic, Still Off Target: Foodborne Infections in 2022

In 2020 and 2021, foodborne infections in the United States fell — not because food got safer, but because of pandemic-era changes in behavior, public health measures, and how people sought care and got tested. By 2022, most of those measures had ended, outbreaks and international travel resumed, and the numbers came back. CDC's Foodborne Diseases Active Surveillance Network (FoodNet) found that 2022 incidence had returned to 2016–2018 levels, or higher, and that no progress was visible toward the national targets.

Nationally, major foodborne pathogens cause an estimated 9.4 million illnesses, 56,000 hospitalizations and 1,350 deaths a year.

Visual abstract. CDC.

How FoodNet counts

CDC, 10 state health departments, the USDA's Food Safety and Inspection Service (FSIS) and the FDA track every laboratory-diagnosed infection with eight pathogens in a catchment of about 51 million people — about 15% of the U.S. population — in Connecticut, Georgia, Maryland, Minnesota, New Mexico, Oregon, Tennessee and selected counties of California, Colorado and New York. The 2022 figures are preliminary, and are compared with the 2016–2018 average, the baseline for the Healthy People 2030 targets.

2022 by pathogen

In all: 25,479 infections, 5,981 hospitalizations (23.5%) and 170 deaths (0.7%).

Salmonella deaths stood out: 62 (0.7%) in 2022, against an annual average of 37 (0.4%) in 2016–2018, with serotypes and characteristics similar to before. The five most common serotypes — Enteritidis, Typhimurium, Newport, Javiana and I 4,[5],12:i:- — have led every year since 2010.

Other shares barely moved from the baseline: hospitalization 23.5% (vs 23.8%), outbreak-associated 4.3% (vs 3.9%), international travel 12.4% (vs 12.8%).

Against the 2030 targets

Healthy People 2030 targets count only domestically acquired infections. For every pathogen that has one, 2022 was above it — and none showed a significant decrease:

Poultry is the most commonly identified source of Campylobacter in many countries, and the estimated leading U.S. source of Salmonella. The authors call for cutting contamination during poultry slaughter and processing, and of leafy greens through safer agricultural water. Regulators have moved: FSIS issued guidelines to control Campylobacter in raw poultry in 2021, proposed a new framework to control Salmonella in poultry in 2022, and in 2023 proposed declaring Salmonella an adulterant in not-ready-to-eat breaded and stuffed chicken products.

A testing shift that muddies the picture

Culture-independent diagnostic tests (CIDTs) — rapid, highly sensitive tests — were used for 73% of bacterial infections in 2022, up from 49% in 2016–2018, and 41% were diagnosed only by CIDT (up from 26%) — 77% for Yersinia. They probably find infections that used to go undetected, which is part of why some rates rose. But without a cultured isolate there is no genome to sequence, which makes outbreaks and antibiotic-resistance genes harder to spot. The share of reflex cultures yielding an isolate fell most for Yersinia, from 48% to 24%. For STEC, 55% of 2022 infections could not be classified as O157 or non-O157, against 43% in 2016–2018; among those typed, O157 was most common (301), then O103, O26 and O111.

Hemolytic uremic syndrome, a kidney complication of STEC, struck 72 children and adolescents in 2021, 41 of them under 5 — no change from the baseline.

Limits. Some ill people never seek care or aren't tested, while false positives can inflate counts; the reasons behind hospitalizations and deaths are not always known; and deaths after discharge, or more than a week after specimen collection, may be missed.

Sources

Based on Delahoy MJ, Shah HJ, Weller DL, et al., "Preliminary Incidence and Trends of Infections Caused by Pathogens Transmitted Commonly Through Food — Foodborne Diseases Active Surveillance Network, 10 U.S. Sites, 2022," MMWR Morbidity and Mortality Weekly Report volume 72, number 26, Centers for Disease Control and Prevention; a work of the United States government in the public domain. The imported copy was cut short; the missing text is from the report's full text in PubMed Central (PMC10328488).