Recently, natural essential oils have been extensively studied for anti-bacterial application in foods due to their safety and high biological activity. Herein, Litsea cubeba essential oil (LC-EO) was applied as a natural anti-bacterial agent for exploring its anti-bacterial mechanism against Enterohemorrhagic Escherichia coli O157:H7 (EHEC O157:H7). The LC-EO could effectively inhibit the growth of EHEC O157:H7 and the minimal inhibitory concentration (MIC) was 0.5 mg/mL. In the study of anti-bacterial mechanism, the LC-EO was proved with good membrane penetration ability, which could destroy bacterial cell structure and disorder membrane permeability, thereby causing the leakage of intracellular organic matters. Furthermore, the inhibitory effects of LC-EO on physiological metabolism of EHEC O157:H7, including respiratory metabolism, enzyme activity, the replication of nucleic acid and the transcription level of main virulence genes (stx1, stx2, ehxA, eae), were also demonstrated in this study. Specially, the possible action mechanism of different components of LC-EO on bacterial genetic material was revealed deeply on molecular level by the molecular docking technology. Finally, the results of application evaluation indicated that the addition of LC-EO at MIC in different vegetable juices could maintain anti-bacterial rate above 99.9% for 4 days without remarkable influence on foods sensory quality. The information in this study provides the necessary theoretical foundation for extending the application of LC-EO in food preservation.

近年来，由于天然精油的安全性和高生物活性，已经广泛研究了其在食品中的抗菌应用。在此，Litsea cubeba精油（LC-EO）被用作天然抗菌剂，以探索其对肠出血性大肠杆菌的抗菌作用。O157：H7（EHEC O157：H7）。LC-EO可以有效抑制EHEC O157：H7的生长，最低抑菌浓度（MIC）为0.5 mg / mL。在抗菌机理研究中，LC-EO被证明具有良好的膜渗透能力，可破坏细菌细胞结构和紊乱的膜通透性，从而引起细胞内有机物的泄漏。此外，LC-EO对EHEC O157：H7生理代谢的抑制作用包括呼吸代谢，酶活性，核酸复制和主要毒力基因（stx1，stx2，ehxA，eae）的转录水平），也在本研究中得到了证明。特别地，通过分子对接技术在分子水平上深刻揭示了LC-EO不同组分对细菌遗传物质的可能作用机理。最后，应用评估结果表明，在不同蔬菜汁中的MIC中添加LC-EO可以使4天的抗菌率保持在99.9％以上，而对食品的感官质量没有显着影响。本研究中的信息为扩展LC-EO在食品保鲜中的应用提供了必要的理论基础。