The objectives of this study were to evaluate the bactericidal effects of X-ray irradiation and gallic acid (GA) against Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes on lettuce leaves and in phosphate-buffered saline (PBS). Inoculated PBS and lettuce were exposed to X-rays (0.05, 0.1, and 0.15; 0.1, 0.2, and 0.3 kGy, respectively), and GA was applied to lettuce leaves as a solution and in PBS at concentrations of 0.5% (w/v). Combined treatment with 0.3 kGy and 0.5% GA reduced E. coli O157:H7, S. Typhimurium, and L. monocytogenes cell counts 5.41, 2.57, and 1.36 log CFU/cm² on lettuce, respectively. Combined treatment with 0.15 kGy X-ray and 0.5% GA reduced counts for the same species by 6.54, 4.24, and 1.51 log CFU/mL in PBS. The combined treatments exerted a synergistic antibacterial effect against E. coli O157:H7 on lettuce, but not against S. Typhimurium or L. monocytogenes. In PBS, the synergistic effect was confirmed in both E. coli O157:H7 and S. Typhimurium cells. Mechanistic investigations indicated that the synergistic antibacterial effect was associated with intracellular reactive oxygen species (ROS) generation and bacterial cell membrane damage. Additionally, the X-ray and GA combination treatment did not adversely affect the color, total phenol content, and texture of lettuce. These findings demonstrate that treatment with X-ray radiation and GA can enhance the microbiological safety of fresh produce.

本研究的目的是评估 X 射线照射和没食子酸 (GA) 对生菜叶子和磷酸盐缓冲盐水 (PBS) 中的大肠杆菌O157:H7、鼠伤寒沙门氏菌和单核细胞增生李斯特氏菌的杀菌效果。将接种的 PBS 和生菜暴露于 X 射线（分别为 0.05、0.1 和 0.15；0.1、0.2 和 0.3 kGy），并将 GA 作为溶液和在 PBS 中的浓度为 0.5%（w/五）。 0.3 kGy 和 0.5% GA 联合处理减少了大肠杆菌O157:H7, S。生菜上的鼠伤寒杆菌和单核细胞增生李斯特氏菌细胞计数分别为 5.41、2.57 和 1.36 log CFU/cm ² 。 0.15 kGy X 射线和 0.5% GA 的联合处理使 PBS 中同一物种的计数减少了 6.54、4.24 和 1.51 log CFU/mL。联合处理对生菜上的大肠杆菌O157:H7 产生协同抗菌作用，但对金黄色葡萄球菌没有作用。鼠伤寒杆菌或单核细胞增生利斯特氏菌。在 PBS 中，在大肠杆菌O157:H7 和S中均证实了协同效应。鼠伤寒细胞。机理研究表明，协同抗菌作用与细胞内活性氧（ROS）的产生和细菌细胞膜损伤有关。此外，X 射线和 GA 组合处理不会对生菜的颜色、总酚含量和质地产生不利影响。这些发现表明，X 射线辐射和 GA 处理可以增强新鲜农产品的微生物安全性。