Antimicrobial Effects of Bioactive Compounds Against Salmonella enterica Typhimurium DT104 on Chicken Meat Surfaces

Abstract

Poultry products, particularly chicken meat, represent a major reservoir for transmission of one of the leading foodborne bacterial pathogens, Salmonella enterica. Although various antimicrobial interventions, such as peracetic acid (PAA) are routinely used during processing, foodborne salmonellosis continues to occur annually, indicating limitations of current control strategies and the need for alternative or complementary antimicrobial approaches. The studies described here evaluated the antimicrobial potential of bioactive compounds 4-hydroxycinnamic acid (4HCA) and itaconic acid (ItA) against multidrug-resistant S. Typhimurium DT104 under poultry-relevant conditions. On chicken meat surfaces, both compounds demonstrated measurable inhibition of DT104, with enhanced inhibition observed when applied in combination compared to individual treatments. Inhibitory effects were maintained across multiple temperatures and treatment conditions, suggesting that the stress environment of the meat influences bacterial susceptibility. However, complete growth suppression was not observed, indicating primarily bacteriostatic activity. To assess interactions with conventional processing interventions, the additive or synergistic potential of 4HCA and ItA in combination with PAA was conducted. While select treatment combinations on chicken skin resulted in transient reductions of DT104, variability across experimental conditions limited definitive conclusions of synergism. In addition, complementary single‑cell analyses using a fluorescent reporter strain of DT104 and flow cytometry revealed treatment‑associated shifts in bacterial population physiology following exposure to the bioactive compounds and PAA. Specifically, PAA exposure induced metabolically altered, non‑proliferative subpopulations, indicative of stress‑tolerant physiological states. In contrast, the inclusion of 4HCA and ItA, individually and in combination with PAA, altered population‑level physiological responses, resulting in reduced persistence of non‑proliferative subpopulations and increased susceptibility to antimicrobial exposure. Although these changes were interpreted qualitatively, they suggest that bioactive compounds may modulate PAA‑induced stress responses at the single‑cell level. Collectively, this work demonstrates the antimicrobial potential of 4HCA and ItA for mitigating Salmonella on poultry meat and emphasizes the importance of integrating bacterial physiology into the evaluation and development of antimicrobial strategies for poultry processing systems.