Abstract This study evaluated the antimicrobial activities of combined use of essential oil (EO) compounds against E. coli O157:H7, using the Fractional Inhibitory Concentration (FIC) index and time-kill assay. The mechanisms of enhanced antimicrobial efficacies in EO combinations were evaluated using flow cytometry, and their application potentials as decontamination rinse were assessed using fresh-cut lettuce. Thymol (Thy), carvacrol (Car), trans-cinnamaldehyde (TC), eugenol (Eug) and vanillin (Van) displayed minimum inhibitory concentrations (MICs) in a range of 0.63–2.5 mg/mL, whereas citral (Cit) and linalool (Lin) were ineffective (MIC > 10 mg/mL). FIC indices (1.00–2.00) suggested additive interactions of all EO combinations, and time kill assay showed enhanced bactericidal activities in Thy/Eug, Car/Eug and TC/Eug combinations. The stronger antimicrobial efficacy in EO combination was attributed to increased membrane damages. Application of Thy/Eug and Car/Eug on fresh-cut lettuce as decontamination rinse caused a significant (P

中文翻译：

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精油化合物对大肠杆菌O157:H7的复合抗菌活性及其在鲜切生菜上的应用潜力

摘要 本研究使用分数抑制浓度 (FIC) 指数和时间杀灭试验评估了精油 (EO) 化合物联合使用对大肠杆菌 O157:H7 的抗菌活性。使用流式细胞术评估了 EO 组合中增强抗菌功效的机制，并使用鲜切生菜评估了它们作为去污冲洗的应用潜力。百里酚 (Thy)、香芹酚 (Car)、反式肉桂醛 (TC)、丁香酚 (Eug) 和香兰素 (Van) 显示的最小抑制浓度 (MIC) 范围为 0.63–2.5 mg/mL，而柠檬醛 (Cit) 和芳樟醇 (Lin) 无效（MIC > 10 mg/mL）。FIC 指数 (1.00–2.00) 表明所有 EO 组合的添加剂相互作用，时间杀灭试验显示 Thy/Eug、Car/Eug 和 TC/Eug 组合的杀菌活性增强。EO 组合中更强的抗菌功效归因于膜损伤增加。在鲜切生菜上使用 Thy/Eug 和 Car/Eug 作为去污漂洗导致显着（P