Abstract：
Listeria monocytogenes presents significant risk to human health due to its high resistance and capacity to form toxin-producing biofilms that contaminate food. The objective of this study was to assess the inhibitory effect of citronella aldehyde (CIT) on L. monocytogenes and investigate the underlying mechanism of inhibition. The results indicated that the minimum inhibitory concentration (MIC) and Minimum sterilisation concentration (MBC) of CIT against L. monocytogenes was 2 μL/mL. At this concentration, CIT was able to effectively suppress biofilm formation and reduce metabolic activity. Crystalline violet staining and MTT reaction demonstrated that CIT was able to inhibit biofilm formation and reduce bacterial cell activity. Furthermore, the motility assessment assay revealed that CIT inhibited bacterial swarming and swimming. Scanning electron microscopy (SEM) and laser confocal microscopy (LSCM) observations revealed that CIT had a significant detrimental effect on L. monocytogenes cell structure and biofilm integrity. LSCM also observed that nucleic acids of L. monocytogenes were damaged in the CIT-treated group, along with an increase in bacterial extracellular nucleic acid leakage. The proteomic results also confirmed the ability of CIT to affect the expression of proteins related to processes including metabolism, DNA replication and repair, transcription and biofilm formation in L. monocytogenes. Consistent with the proteomics results are ATPase activity and ATP content of L. monocytogenes were significantly reduced following treatment with various concentrations of CIT. Notably, CIT showed good inhibitory activity against L. monocytogenes on cheese via fumigation at 4 °C.This study establishes a foundation for the potential application of CIT in food safety control.
摘要：
单核细胞增生李斯特菌由于其高抗性和形成污染食品的毒素产生生物膜的能力而对人类健康存在重大风险。本研究的目的是评估香茅醛（CIT）对单核细胞增生李斯特菌的抑制作用，并探讨其潜在的抑制机制。结果表明，CIT对单核细胞增生李斯特菌的最低抑菌浓度（MIC）和最低杀菌浓度（MBC）为2μL/mL。在这个浓度下，CIT能够有效抑制生物膜形成并降低代谢活性。结晶紫染色和MTT反应表明CIT能够抑制生物膜形成并降低细菌细胞活性。此外，运动性评估试验显示，CIT抑制细菌聚集和游泳。扫描电子显微镜（SEM）和激光共聚焦显微镜（LSCM）观察表明，CIT对单核细胞增生李斯特菌的细胞结构和生物膜完整性有明显的不利影响。LSCM还观察到CIT治疗组中单核细胞增生李斯特菌的核酸受损，随着细菌细胞外核酸泄漏的增加。蛋白质组学结果还证实了CIT影响与代谢过程相关的蛋白质表达的能力，DNA复制和修复,单核细胞增生李斯特菌的转录和生物膜形成。与蛋白质组学结果一致的是，用不同浓度的CIT处理后，单核细胞增生李斯特菌的ATP酶活性和ATP含量显着降低。值得注意的是,CIT在4°C下通过熏蒸对奶酪上的单核细胞增生李斯特菌显示出良好的抑制活性。本研究为CIT在食品安全控制中的潜在应用奠定了基础。
