Abstract：
In the present study, the synergistic bactericidal effect and mechanism of ultrasound (US) combined with Lauroyl Arginate Ethyl (LAE) against Salmonella Typhimurium were investigated. On this basis, the effect of US+LAE treatment on the washing of S. Typhimurium on the surface of onions and on the physical and chemical properties of onion during fresh-cutting and storage were studied. The results showed that treatment with US+LAE could significantly (P < 0.05) reduce the number of S. Typhimurium compared to US and LAE treatments alone, especially the treatment of US+LAE (230 W/cm2, 8 min, 71 μM) reduced S. Typhimurium by 8.82 log CFU/mL. Confocal laser scanning microscopy (CLSM), flow cytometry (FCM), protein and nucleic acid release and N-phenyl-l-naphthylamine (NPN) assays demonstrated that US+LAE disrupted the integrity and permeability of S. Typhimurium cell membranes. Reactive oxygen species (ROS) and malondialdehyde (MDA) assays indicated that US+LAE exacerbated oxidative stress and lipid peroxidation in cell membranes. Field emission scanning electron microscopy (FESEM) demonstrated that US+LAE treatment caused loss of cellular contents and led to cell crumpling and even lost the original cell morphology. US+LAE treatment caused a significant (P < 0.05) decrease in the number of S. Typhimurium on onions, but there was no significant (P > 0.05) effect on the color, hardness, weight and ascorbic acid content of onions. This study elucidated the synergistic antibacterial mechanism of US+LAE and verified the feasibility of bactericidal effect on the surface of onions, providing a theoretical basis for improving the safety of fresh produce in the food industry and to propose a new way to achieve the desired results.
摘要：
在本研究中,研究了超声（US）联合月桂酰精氨酸乙酯（LAE）对鼠伤寒沙门氏菌的协同杀菌效果和机理。在此基础上,研究了USLAE处理对鼠伤寒沙门氏菌在洋葱表面的洗涤以及洋葱在鲜切和贮藏过程中的理化性质的影响。结果表明，与单独的US和LAE治疗相比，USLAE治疗可以显着（P<0.05）减少鼠伤寒沙门氏菌的数量。特别是US+LAE(230W/cm2，8min，71μM)使鼠伤寒沙门氏菌减少8.82logCFU/mL。共聚焦激光扫描显微镜（CLSM），流式细胞术（FCM），蛋白质和核酸释放以及N-苯基-1-萘胺（NPN）测定表明，USLAE破坏了鼠伤寒沙门氏菌细胞膜的完整性和通透性。活性氧（ROS）和丙二醛（MDA）测定表明，USLAE加剧了细胞膜中的氧化应激和脂质过氧化。场发射扫描电子显微镜（FESEM）表明，USLAE处理导致细胞内容物损失，导致细胞皱折，甚至失去原始细胞形态。US+LAE治疗导致洋葱上的鼠伤寒沙门氏菌数量显着减少（P<0.05），但对颜色无显著影响(P>0.05),硬度,洋葱的重量和抗坏血酸含量。本研究阐明了US+LAE的协同抗菌机制，并验证了对洋葱表面杀菌效果的可行性。为提高食品行业生鲜产品的安全性提供理论依据,并提出新的途径,以达到预期的效果。
