GAINESVILLE, Ga. — Salmonella, a word and infection that gives people pause at the mere mention of it. Infections from the bacteria have become more common in recent years, and outbreaks are occurring more frequently.
The Centers for Disease Control and Prevention estimates that 1.35 million infections are caused by Salmonella every year in the United States. Additionally, from 1998 to 2022, the CDC’s Foodborne Disease Outbreak Surveillance System received reports of 3,250 outbreaks that were confirmed or suspected to be caused by Salmonella.
One cause that may be contributing to the rise in Salmonella outbreaks is the increased consumption of chicken in the country. Chicken is the primary animal protein consumed in the U.S., and Americans eat it more per person than any other country, according to the USDA Economic Research Service.
In a recent study done by Anna N. Chard and Taylor Eisenstein, with the CDC, and Andrea Cote and Selena Kremer-Caldwell, with the USDA, they looked to describe the trends in Salmonella illness outbreaks attributed to chicken and evaluate any changes in outbreak frequency over time.
To complete the study, they collected data and reports from the CDC’s FDOSS (Foodborne Disease Outbreak Surveillance System) on foodborne disease outbreaks from 1998 to 2022 and categorized the outbreaks based on the type of chicken product, such as raw chicken or ready-to-eat chicken, that caused the outbreak.
After analyzing the data, they found that 366 of the 3,250 outbreaks confirmed or suspected to be caused by Salmonella could be attributed to chicken and chicken products. Additionally, Chard et al. (2025) found that, among those 366 outbreaks, the most frequently reported food preparation locations were restaurants and private homes, highlighting the need for enhanced foodservice employee and household consumer education on cooking, safe handling and storage practices for all raw chicken.
In addition to describing the trends in Salmonella illness outbreaks attributed to chicken, Chard et al. (2025) found that the frequency of Salmonella illness outbreaks and outbreak-associated illnesses attributed to chicken has remained unchanged for more than two decades.
In fact, despite a Healthy People 2030 objective to reduce infections by Salmonella, the authors didn’t find any evidence of a statistically significant change in the number of illness outbreaks or outbreak-associated illnesses attributed to chicken from 1998 to 2022.
Surprisingly enough, USDA’s Food Safety and Inspection Service’s verification sampling data show that, overall, salmonella prevalence in raw poultry products has decreased from 1998 through 2017, but, for some reason, the illnesses caused by the bacteria have remained the same.
This lack of changes indicates that additional prevention measures along the farm-to-fork continuum are needed to reduce consumer risk of salmonellosis in chicken. Chard et al. (2025) pointed out that Salmonella contamination can be mitigated with the use of proper sanitary procedures throughout the entire production process, including vaccinating chickens against the bacteria before slaughter.
The only caveat to vaccinations is that there are so many different serotypes of Salmonella that don’t have a vaccine, which the authors believe is a problem that could be solved with enhanced surveillance of circulating Salmonella strains among broiler flocks.
Despite the thoroughness of the study, the authors know that their results are subject to limitations. For one, the FDOSS is a system with data that is always changing. Secondly, reporting outbreaks to the FDOSS is voluntary, so it’s possible that outbreaks are underreported.
Overall, Chard et al. (2025) concluded that further research on virulence genes and pathogenicity of specific Salmonella serotypes that contribute to human illness is needed to understand the public health significance and identify ways to reduce outbreaks. Salmonella-related research that could potentially mitigate illness outbreaks has already started.
Gary Closs Jr. and his colleagues with the Department of Animal Science at The Ohio State University recently published a study that was looking to find antibiotic alternatives to control Salmonella.
Before 2012, antibiotics were widely used to regulate Salmonella infections, but that year the U.S. Food and Drug Administration recommended the limited use of antibiotics in food-producing animals and then later included the phasing out of antibiotics in the production use for prevention and growth in food animals.
Closs Jr. et al. (2025) pointed out that there is a need for reducing the overuse of antibiotics to control antibiotic-resistant bacteria, but reducing the use of antibiotics can lead to an increase in foodborne and avian pathogens in poultry.
This is important to note because poultry products, such as eggs and meat, have been considered the main vehicles of Salmonella infections in humans. In fact, Closs Jr. et al. (2025) noted that poultry, specifically chicken and turkey, are frequently colonized with Salmonella without showing detectable symptoms through both horizontal and vertical transmission at the primary production level.
All this is to say that this study is addressing a need for developing and implementing effective antibiotic alternatives to reduce Salmonella in chickens, minimize human exposures, and simultaneously contribute to alleviating antibiotic resistance.
“This study could provide a framework for developing and using antimicrobial peptides to control Salmonella in chickens, thereby promoting food safety and public health,” Gireesh Rajashekara, study co-author, told the American Society of Microbiology.
Antimicrobial peptides
Closs Jr. et al. (2025) focused on antimicrobial peptides, which are short chains of amino acids, because they have the potential to kill harmful bacteria without inducing resistance to antibiotics. Additionally, AMPs include low-affinity targets, which complicates bacteria’s ability to defend against a singular resistance mechanism, as opposed to conventional antibiotics that have high-affinity targets, allowing bacteria to quickly defend and display resistance.
Out of all the positives of using AMPs, Closs Jr. et al. (2025) emphasized that AMPs don’t pose a threat to mammalian cells and possess immunomodulatory properties, which can aid in protection while simultaneously enhancing animal health and performance.
To prove that AMPs are the superior antibiotic alternative for controlling Salmonella, the study evaluated the efficacy of Lactobacillus rhamnosus GG (LGG) derived small peptides against Salmonella Typhimurium and Salmonella Enteritidis both in vitro and in chickens.
Additionally, Closs Jr. et al. (2025) tested the ability of peptides to retain inhibition qualities when heated or treated with protease, according to poultry industry standards.
In the end, their study showed that small peptides have an antagonistic effect against Salmonella.
“We identified 2 antimicrobial peptides that kill many different types of Salmonella and also reduce Salmonella load in chickens,” Rajashekara noted.
Also, Closs Jr. et al. (2025) found that the peptides reduced Salmonella colonization in the chicken small and large intestine and retain their activity upon exposure to heat and protease treatments, characteristics needed for the use of antimicrobial products in the poultry industry.
“These peptides not only can kill Salmonella but also other related bacterial pathogens such as E. coli, so they could be really valuable in controlling a broad range of pathogens,” Rajashekara added.
These study results indicate that small peptides can facilitate the development of promising approaches to control Salmonella infections in poultry, improving food safety. Despite providing much needed results, Closs Jr. and his colleagues are already thinking of ways to improve the study of salmonella in chickens.
“Our future work is to test these peptides in chickens on a large scale, optimize their delivery in water and/or feed, understand better how they kill Salmonella, and explore more peptides like these for their anti-Salmonella activity,” Rajashekara said.
Closs Jr. et al. (2025) added that future chicken trials should be conducted with broilers over an extended period of time and in conditions that mimic field settings to assess the peptides’ impact on cecal microbiota at an early age, as well as their impact on performance parameters, such as body weight gain and feed conversion ratio.
These two studies prove that the poultry industry is ready for a reliable way to fight and prevent Salmonella, and the development of a way to control it is necessary for the benefit of public health.
