Plant polyphenols demonstrated effectiveness against multi-drug-resistant Salmonella enterica serovar DT104, suggesting their potential in the fight against antimicrobial resistance (AMR) and foodborne illness, according to Auburn University research.
The World Health Organization lists AMR as one of the top global public health concerns, noting that in 2019, AMR was directly responsible for 1.27 million deaths globally and contributed to nearly 5 million deaths.1
“Foodborne pathogens are a leading cause of illness and death worldwide,” said Hunter Sheffield, PhD student, Auburn University, during his presentation at the 2025 International Poultry Scientific Forum.
Recognizing that developing new antibiotics is costly and time-consuming, are there ways to enhance the effectiveness of existing antibiotics?
Sheffield explored strategies to mitigate the risks of foodborne illnesses using phytopolyphenols, a plant compound that acts as a plant’s first line of immune defense.
He investigated using two phytopolyphenols, alone and in combination with antibiotics, to combat Salmonella, one of the most common foodborne pathogens. “We studied Salmonella enterica serovar DT104 because of its resistance to five antibiotics.”
In the lab
Sheffield began the study with a microdistillation assay, in which DT104 was grown in the presence of antibiotics. “DT104 was able to resist many antibiotics in varying concentrations, including ampicillin. And it was completely resistant to sulfamethoxazole,” Sheffield noted.
The second portion of his study examined the impact on DT104 of polyphenols alone and the synergistic effects of polyphenols when combined with antibiotics.
The two phytopolyphenols studied, hydroxycinnamic acid and itaconic acid, showed no antimicrobial effects when used alone. However, Sheffield observed that DT104 growth was significantly inhibited when either of the phytopolyphenols was used with antibiotics.
Real-world scenario
Sheffield investigated using polyphenols in a more realistic scenario to address foodborne bacterial illness resulting from direct meat contamination. To gather information, he tested polyphenols on store-bought chicken meat that he exposed to DT104.
He tested meat that was inoculated with DT104 and then treated with both polyphenols, as well as meat that was inoculated with DT104 and not treated with polyphenols (control).
Treated and untreated meat samples were incubated at 50° F (10° C) and 99° F (37° C). Assessing the bacterial growth on the meat, he found that the treated samples showed significantly less bacterial growth than the untreated samples.
Importantly, although individual polyphenols showed no anti-DT104 effect in the petri dishes, significant antimicrobial effects were observed in the chicken samples. “This could be due to the hurdle principle, where meat creates stress environments for DT104 in the presence of polyphenols,” Sheffield said.
Polyphenol use
Sheffield’s findings suggest that polyphenols could be important in mitigating foodborne-illness risks.
“We believe that polyphenols could be used as enhancers in food preservation,” he said. And they may provide an answer to multi-drug-resistant pathogens.
What are the challenges and next steps for using polyphenols in meat production? Sheffield identified three challenges:
- Cost
- Scaling polyphenol application for industry use
- Stability of polyphenols
He listed the next steps as:
- Broader testing on other foodborne pathogens, like Escherichia coli and additional Salmonella strains
- Investigating the molecular mechanisms of how the polyphenols work alone and in combination with antibiotics in meat samples
- Optimizing formulations for commercial use
Combatting antibiotic resistance
“This study revealed that polyphenols can enhance antibiotics and offer a novel strategy to combat antimicrobial resistance. The chicken meat analysis showed that polyphenols alone can greatly reduce microbial load of DT104,” Sheffield concluded.
“Science can be used to outsmart resistant bacteria and address public health concerns.”
1. Antimicrobial Resistance Collaborators. Global burden of bacterial antimicrobial resistance in 2019: a systematic analysis. The Lancet. 2022;399(10325):629-655. DOI: https://doi.org/10.1016/S0140-6736(21)02724-0
