超声联合香芹酚纳米乳灭活鼠伤寒沙门氏菌的作用机制及其在卷心菜中的应用

Synergistic Bactericidal Effect and Mechanism of Ultrasound Combined with Carvacrol Nanoemulsion on Salmonella typhimurium and its Application to Cabbage

摘要:

为了寻求安全有效的鼠伤寒沙门氏菌（Salmonella typhimurium, S. typhimurium）控制方法，探究超声（Ultrasound, US）联合香芹酚纳米乳（Carvacrol Nanoemulsions, CN）对S. typhimurium的协同杀菌作用机制及其在卷心菜中的应用。该研究采用超声乳化法制备CN，探究了US和CN联合处理对S. typhimurium的杀菌作用以及对其菌体细胞形态、细胞内容物泄露程度、活性氧水平（Reactive Oxygen Species, ROS）、N-苯基-1-萘胺摄入量（N-phenyl-1-naphthylamine, NPN）和丙二醛（Malondialdehyde, MDA）含量、对卷心菜表面S. typhimurium的杀灭效果及对卷心菜色泽和硬度的影响。研究表明：US和CN联合处理相比各自单独处理具有显著的协同杀菌作用，杀菌协同值分别为1.35和1.33。联合处理破坏了S. typhimurium的细胞膜并增加其通透性、使细胞皱缩干瘪、并使得ROS水平和MDA含量分别显著提高到1866.99和1.25 nmol/mL，增加了氧化应激程度；此外，该处理还可使卷心菜表面S. typhimurium的存活量显著降低0.89~2.01 log CFU/g，且对卷心菜色泽和硬度无明显影响。该研究表明，US和CN联合处理能够协同灭活S. typhimurium和提高生鲜农产品安全性，为食品工业提供了一种安全高效并具备极大发展潜力的灭菌方法。

Abstract:

To explore safe and effective control methods for Salmonella typhimurium (S. typhimurium), the synergistic bactericidal mechanism of ultrasound (US) combined with carvacrol nanoemulsions (CN) against Salmonella typhimurium and its application in cabbage was investigated. CN was prepared using the ultrasonic emulsification method and the bactericidal effects of US and CN combined treatment on Salmonella typhimurium was evaluated, as well as. changes in bacterial cell morphology, intracellular content leakage, reactive oxygen species (ROS) levels, N-phenyl-1-naphthylamine (NPN) uptake, and malondialdehyde (MDA) content. Additionally, the efficacy of this treatment in reducing Salmonella typhimurium on cabbage surfaces and its impact on cabbage color and firmness were investigated.The results demonstrated that the combined treatment of US and CN was found to exhibit significant synergistic bactericidal effects against Salmonella typhimurium, with synergy index values of 1.35 and 1.33, respectively, compared to individual treatments. Also, the bacterial cell membrane was damaged and increased permeability were observed, along with cell shrinkage and collapse. ROS levels and MDA content were significantly elevated to 1866.99 and 1.25 nmol/mL, respectively, indicating intensified oxidative stress. Furthermore, a reduction in Salmonella typhimurium survival on cabbage surfaces by 0.89~2.01 log CFU/g was achieved by the combined treatment, while no significant alterations in cabbage color or firmness were detected. This study demonstrates that the combined treatment of US and CN effectively inactivates Salmonella typhimurium and enhances the safety of fresh agricultural products. It provides a safe, efficient, and highly promising sterilization method for the food industry.