Salmonella infection rates in the United States held roughly steady in 2024 compared with the reference period used to track federal food safety goals. That flat line hides a substantial change in how the data are counted.
According to FoodNet's preliminary surveillance data for 2024, released by the Centers for Disease Control and Prevention on April 29, 63.8 percent of Salmonella infections in the surveillance network were diagnosed by rapid molecular panels, compared with 29.7 percent during the 2016 to 2018 reference period. The tests are faster and detect infections that older methods missed, which means a stable rate does not translate cleanly into a stable amount of illness.
For households, the practical issue is not the statistic. It is what happens after a positive test. Rapid panels tell a clinician which pathogen is present, but they do not produce the bacterial isolate that public health laboratories use to fingerprint strains and connect scattered cases into a recognized outbreak.
Rapid Panels Now Detect Most Salmonella Cases
FoodNet sites reported 24,624 infections overall in 2024, including 6,746 hospitalizations and 178 deaths. Salmonella accounted for 9,219 of those infections, along with 2,769 hospitalizations and 63 deaths.
Infections identified by culture alone fell from 70.3 percent of Salmonella cases in the reference period to 36.2 percent in 2024. Across all bacterial pathogens FoodNet tracks, excluding Campylobacter, 78 percent were diagnosed by these panels in 2024 versus 47 percent in the reference period.
The agency is direct about what this does to trend lines. CDC notes that increased use of these tests allows laboratories to detect infections that would previously have been missed, that more sick people may be tested because the panels are fast and easy to use, and that most of the additional detections are true infections. The adjusted incidence rate ratio for Salmonella in 2024 was 1.03, with a credible interval spanning 1.0, which CDC describes as similar rather than increased.
One further caveat applies to the same report. Starting in 2024, FoodNet stopped collecting data on Campylobacter infections diagnosed by rapid panel alone, so 2024 Campylobacter counts cannot be compared with earlier years and no incidence was calculated for it.
Fewer Isolates Mean Slower Outbreak Fingerprinting
The trade-off appears in the serotyping numbers. Among the 9,219 Salmonella infections reported, 7,314, or 79 percent, yielded a positive culture, and laboratories fully serotyped 6,066 of those isolates, or 83 percent of the cultured group.
That leaves a large group that arrived without a name. Cases recorded as Salmonella, not serotyped, numbered 3,153, with an incidence rate ratio of 2.15 against the reference period. Success rates for reflex culture also slipped: among samples cultured after a positive rapid panel, 59 percent grew the organism in 2024, down from 71 percent in 2016 through 2018.
Five serotypes remained dominant, unchanged since 2010: Enteritidis with 1,535 infections, Newport with 582, Typhimurium with 515, Javiana with 433, and I 4,[5],12:i:- with 270.
Serotype and genomic data are what allow investigators to link a cluster of illnesses in three states to a single supplier. Without an isolate, a case counts toward a total but contributes little to an investigation. An earlier FoodNet analysis of testing practices makes the same point, and CDC continues to ask clinical laboratories to culture samples after a positive rapid result, and asks test developers to make new panels compatible with culture-based methods.
Ten Sites Are Counting for the Whole Country
FoodNet is not national. To keep comparisons with past reports valid, the 2024 report uses only the historic surveillance area, which covered about 15 percent of the U.S. population, roughly 51 million people, across Connecticut, Georgia, Maryland, Minnesota, New Mexico, Oregon and Tennessee plus selected counties in California, Colorado and New York.
Readers in Baltimore, Atlanta, Denver, Minneapolis and Portland are inside that catchment. Readers in Houston, Phoenix, Chicago and Miami are not, which is one reason state and county health department dashboards remain the better local source. With Colorado fully included since 2023, the current surveillance area reaches about 16 percent of the population, or almost 54 million people, and improved representation of rural counties and several racial and ethnic groups.
The network itself has narrowed. For data collected on or after July 1, 2025, reporting is optional for every pathogen except Salmonella and Shiga toxin-producing E. coli. CDC says the change reflects in part a surveillance landscape that has shifted since the collaboration began in 1995.
Because the 2024 data were collected before that change took effect, this report still covers all eight pathogens. Future reports will not look the same.
Steps Households Can Take While the Counting Gets Sorted Out
Salmonella causes diarrhea, fever and stomach cramps, typically beginning six hours to six days after exposure. Most people recover in about a week without antibiotics. Signs that warrant prompt medical attention include diarrhea lasting more than three days, a fever above 102 degrees, bloody stools, persistent vomiting that prevents keeping liquids down, and signs of dehydration such as little urination, dry mouth, or dizziness on standing.
Highest risk falls on children under 5, adults over 65, pregnant people, and anyone with a weakened immune system. Those groups should seek guidance earlier rather than waiting out symptoms.
If a clinician orders testing, it is reasonable to ask whether the laboratory performs reflex culture after a positive panel. That single step is what converts an individual diagnosis into usable outbreak intelligence. CDC's food safety guidance remains clean, separate, cook and chill, and recalled products should be discarded rather than cooked.
Case counts here are preliminary and cover the historic catchment only. The next preliminary report will be the first to reflect the narrowed pathogen list.
Frequently Asked Questions
Did Salmonella infections increase in 2024? No. CDC reported incidence similar to the 2016 through 2018 reference period. Interpreting that as no change in real illness is not straightforward, because testing practices shifted substantially over the same span.
What is a culture-independent diagnostic test? It is a rapid molecular panel that detects a pathogen's genetic material directly from a stool sample, usually within hours. It does not grow the organism.
Why do isolates matter if the test already found the bacteria? Serotyping and genomic sequencing require a living isolate. Those techniques are how investigators link cases across states to a common food source.
Is FoodNet nationwide? No. The 2024 report covers a historic catchment of roughly 51 million people across 10 sites. Your state or county health department is the better source for local counts.
Which Salmonella serotypes are most common? Enteritidis, Newport, Typhimurium, Javiana, and I 4,[5],12:i:- have been the top five since 2010.
When should I see a doctor for suspected Salmonella? Seek care for diarrhea beyond three days, fever above 102 degrees, bloody stools, persistent vomiting, or signs of dehydration. Higher risk groups should seek guidance sooner.
What changed about FoodNet itself? For data collected on or after July 1, 2025, reporting became optional for every pathogen except Salmonella and Shiga toxin-producing E. coli.
