Inactivation mechanisms of carvacrol on Salmonella Typhimurium and its combined inhibitory effects with blue light-405 nm for chicken meat preservation

Salmonella Typhimurium ( S. Typhimurium ) is a major contributor responsible for food contamination and foodborne illnesses. In this study, the antibacterial activity of natural compound carvacrol (CAR) against S. Typhimurium were evaluated, and the combined inhibitory effects of CAR and blue light-405 nm (BL-405 nm) were also assessed for chicken meat preservation. CAR showed efficient antibacterial activity with a minimal inhibitory concentration (MIC) at 0.5 mg/mL. CAR at 2MIC significantly compromised bacterial membrane integrity, resulting in intracellular content leakage. The combined effect of CAR and BL-405 nm achieved a remarkable 5.62 log CFU/mL reduction in S. Typhimurium viability. The antibacterial mechanism investigations demonstrated that BL-405 nm and CAR triggered the cell oxidative stress by producing highly reactive oxygen species, such as reactive hydroxyl radicals ( OH), leading to cellular destruction and ultimately resulting in cell death. In practical application test, CAR combined with BL-405 nm treatment effectively extended chicken meat shelf life by maintaining moisture content, stabilizing pH, preserving color and texture, and inhibiting microbial growth and lipid oxidation. The study provided novel insights into the antibacterial mechanisms of CAR combined with BL-405 nm against S. Typhimurium , which could offer a new strategy for extending the shelf life of poultry meat.