A lipophilicity-based strategy: Curcumin-mediated photodynamic inactivation combined with eugenol for enhanced bacon preservation.

Foodborne spoilage bacteria are the key factor causing food deterioration, seriously restricting the shelf life of food and threatening consumer safety. In this study, we investigated the synergistic bactericidal effect of curcumin-mediated photodynamic inactivation technology (Cur-PDI) combined with eugenol (Eug) on two typical f foodborne spoilage bacteria Leuconostoc mesenteroides and Carnobacterium maltaromaticum, and further evaluated its application in bacon preservation. The results indicated that under the combined treatment conditions (20 μΜ Cur, 25 μg/mL Eug, 20 min of light exposure), the viable bacterial counts of two bacteria decreased significantly by 7.11 log CFU/mL and 7.12 log CFU/mL compared with the blank control. As both Cur and Eug are lipophilic, the combination exhibited a stronger bactericidal effect in a lipid system than the water-soluble photosensitizer erythrosine (ERY). Mechanistic studies revealed that, compared with PDI alone, the combined treatment more significantly disrupted bacterial membrane integrity, induced higher levels of reactive oxygen species (ROS), and severely interfered with antioxidant defense and energy metabolism. In the bacon preservation experiment, the combined treatment effectively reduced the initial colony count of the product and continuously inhibited the growth of microorganisms during storage for 25 days. This study systematically clarified the synergistic antibacterial mechanism of Cur-PDI and Eug, and verified its potential in the preservation of bacon, providing a theoretical basis for the development of natural and efficient preservation strategies for foods rich in fat.