Abstract Consumption of contaminated food appears to be the main route of acquiring listeriosis and has been estimated as the source of L. monocytogenes infection for up to 99% of cases. The interest in and combined use of natural food preservatives to control Listeria contamination of food products has dramatically increased in recent years. The aim of this study was to investigate the effect of carvacrol, a major component of oregano essential oil, against L. monocytogenes. Changes in membrane permeability, membrane depolarization, respiratory activity and membrane structure were determined to elucidate possible mechanisms of action. Carvacrol had potent antibacterial activity against all strains studied, including 10403S and food isolates, with a MIC of 250 μg/ml and MBC ranging from 250 to 500 μg/ml. Bacterial cells exposed to carvacrol showed increased membrane permeability and depolarization, and changes in respiratory activity. Transmission electron microscopic analysis showed degenerative changes of cell wall and cytoplasmic membrane, and structural disruption to L. monocytogenes cells treated with carvacrol. These results indicated that carvacrol inactivates the bacterium through a multi-target action that disrupts cell membranes leading to cell lysis, as well as inhibits the respiratory activity. The synergistic interaction of carvacrol and nisin against L. monocytogenes 10403S and three food isolates (CM2, CM8 and CM11) was shown in vitro by checkerboard assay with FICI values ranging from 0.375 to 0.500. The synergic effect of carvacrol and nisin on the survival of L. monocytogenes 10403S was examined during 4 °C storage of sliced bologna sausages. For up to seven days, the presence of carvacrol combined with nisin resulted in significant growth rate reductions compared to those of controls (p

中文翻译：

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香芹酚的作用机制及其与乳酸链球菌素对切片博洛尼亚香肠的单核细胞增生李斯特菌的协同作用

摘要 食用受污染的食物似乎是感染李斯特菌病的主要途径，据估计，高达 99% 的病例是单核细胞增生李斯特菌感染的来源。近年来，人们对天然食品防腐剂控制食品中李斯特菌污染的兴趣和组合使用急剧增加。本研究的目的是研究香芹酚（牛至精油的主要成分）对单核细胞增生李斯特菌的影响。确定膜通透性、膜去极化、呼吸活动和膜结构的变化以阐明可能的作用机制。香芹酚对所有研究的菌株（包括 10403S 和食品分离株）均具有强效抗菌活性，MIC 为 250 μg/ml，MBC 范围为 250 至 500 μg/ml。暴露于香芹酚的细菌细胞显示出膜通透性和去极化增加，以及呼吸活动的变化。透射电子显微镜分析显示细胞壁和细胞质膜的退行性变化以及用香芹酚处理的单核细胞增生李斯特菌细胞的结构破坏。这些结果表明香芹酚通过多靶点作用使细菌失活，破坏细胞膜导致细胞裂解，并抑制呼吸活动。香芹酚和乳链菌肽对单核细胞增生李斯特菌 10403S 和三种食物分离物（CM2、CM8 和 CM11）的协同相互作用在体外通过棋盘试验显示，FICI 值范围为 0.375 至 0.500。香芹酚和乳酸链球菌素对乳杆菌存活的协同作用。在切片的博洛尼亚香肠 4 °C 储存期间检测了单核细胞增生李斯特菌 10403S。长达 7 天，香芹酚与乳酸链球菌素的存在导致与对照组相比显着降低生长速度（p