Contamination by Listeria monocytogenes is a particularly challenging problem in the food industry due to the ability of the bacterium to develop under conditions normally used for food preservation. Here, we show that the gaseous phase of Citrus limon var pompia leaf essential oil (hereafter PLEO) exerts specific anti-Listeria activity on ricotta salata cheese stored at 5 °C. The synergic effect of gaseous PLEO treatment and refrigeration was first confirmed in vitro on L. monocytogenes strains treated for 3 h with gaseous PLEO and then stored at 5 °C. Ricotta cheese was then inoculated with L. monocytogenes strains and subjected to hurdle technology with different concentrations of gaseous PLEO. Cell counts revealed gaseous PLEO to exert a bactericidal effect on L. monocytogenes 20600 DSMZ and a bacteriostatic effect on a mix of L. monocytogenes strains. Scanning and transmission electron microscopy analyses of L. monocytogenes cells suggested that gaseous PLEO targets the bacterial cell wall and plasma membrane. Chemical analyses of the liquid and vapor phases of PLEO indicated linalyl acetate to be the predominant compound, followed by limonene and the two isomers of citral, whereas EO composition analysis, although generally in line with previous findings, showed the presence of linalyl acetate for the first time. Solid-phase microextraction coupled with gas chromatography confirmed the presence of all crude oil components in the headspace of the box.

中文翻译：

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气态柑橘柠檬蓬蓬叶精油对意大利乳清干酪奶酪上单核细胞增生李斯特氏菌的抗菌活性。

由于细菌在通常用于食品保存的条件下发展的能力，单核细胞增生李斯特氏菌的污染在食品工业中是一个特别具有挑战性的问题。在这里，我们显示了柑橘柠檬蓬皮叶精油（以下称PLEO）的气相对储存在5°C的意大利乳清干酪具有特定的抗李斯特菌活性。首先在体外确认气态PLEO处理和冷藏的协同作用对用气态PLEO处理3 h​​的单核细胞增生李斯特氏菌菌株，然后在5°C下保存。然后用单核细胞增生李斯特氏菌菌株接种乳清干酪，并用不同浓度的气态PLEO进行跨栏技术。细胞计数显示，气态的PLEO对单核细胞增生李斯特菌20600 DSMZ具有杀菌作用，对L.的混合物具有抑菌作用。单核细胞增生菌株。单核细胞增生李斯特氏菌细胞的扫描和透射电镜分析表明，气态PLEO靶向细菌细胞壁和质膜。对PLEO液相和气相的化学分析表明，乙酸芳樟酯是主要的化合物，其次是柠檬烯和柠檬醛的两个异构体，而EO组成分析虽然与以前的发现大体一致，但表明乙酸芳樟酯的存在第一次。固相微萃取结合气相色谱法确证了该箱顶部空间中所有原油成分的存在。对PLEO液相和气相的化学分析表明，乙酸芳樟酯是主要的化合物，其次是柠檬烯和柠檬醛的两个异构体，而EO组成分析虽然与以前的发现大体一致，但表明乙酸芳樟酯的存在第一次。固相微萃取结合气相色谱法确证了该箱顶部空间中所有原油成分的存在。对PLEO液相和气相的化学分析表明，乙酸芳樟酯是主要化合物，其次是柠檬烯和柠檬醛的两个异构体，而EO组成分析虽然与以前的发现基本一致，但表明乙酸芳樟酯的存在第一次。固相微萃取结合气相色谱法确证了该箱顶部空间中所有原油成分的存在。