This study investigated physiological alterations involved in the inactivation of Levilactobacillus (L.) brevis and Leuconostoc (Lc.) mesenteroides in orange juice caused by Citrus lemon essential oil (CLEO) and C. reticulata essential oil (CREO) alone and combined with mild heat treatment (MHT). Damage in DNA, membrane integrity, membrane potential, metabolic and efflux activity of bacterial cells were measured after exposure (6 and 12 min) to CLEO or CREO (0.5 μL/mL) and/or MHT (54 °C) using flow cytometry. Limonene was the major constituent in CLEO (66.4%) and CREO (89.4%). The size of the damaged cell subpopulations increased (p < 0.05) after longer exposure time and varied with the tested essential oil and/or bacterial isolate. After exposure to CLEO and CREO alone, the cell subpopulations with damage in measured physiological functions were in a range of 19.6-66.8% and 23.8-75.9%, respectively. Exposure to CREO resulted in larger Lc. mesenteroides cell subpopulations (35.4-68.7%) with damaged DNA, permeabilized and depolarized membrane and compromised metabolic or efflux activity compared to L. brevis (23.8-58.0%). In contrast, exposure to CLEO led to higher damaged L. brevis cell subpopulations (35.1-77%) compared to Lc. mesenteroides (25.3-36.6%). Exposure to combined treatments (CLEO or CREO and MHT) affected the measured physiological functions in almost the entire L. brevis and Lc. mesenteroides cell population (up to 99%), although the damage extension on each isolate varied with tested essential oil. Results show that inactivation of L. brevis and Lc. mesenteroides cells caused by CLEO and CREO alone and combined with MHT in orange juice involves a multi-target action, which causes DNA damage, altered permeability and depolarization of membrane and compromised metabolic and efflux activities.

这项研究调查了柑桔柠檬精油（CLEO）和网状梭状芽胞杆菌引起的橙汁中短杆菌（Levilactobacillus（L.））和短杆菌（Leuconostoc（Lc。）mesenteroides灭活所涉及的生理变化精油（CREO）单独使用，并与温和的热处理（MHT）结合使用。使用流式细胞仪在CLEO或CREO（0.5μL/ mL）和/或MHT（54°C）中暴露（6和12分钟）后，测量细菌细胞的DNA损伤，膜完整性，膜电位，代谢和外排活性。柠檬烯是CLEO（66.4％）和CREO（89.4％）的主要成分。较长的暴露时间后，受损细胞亚群的大小增加（p <0.05），并且随所测试的精油和/或细菌分离株而变化。单独暴露于CLEO和CREO后，在测量的生理功能方面受损的细胞亚群的范围分别为19.6-66.8％和23.8-75.9％。暴露于CREO会导致更大的Lc。中肠膜与短乳杆菌（23.8-58.0％）相比，细胞亚群（35.4-68.7％）的DNA受损，膜的通透性和去极化以及代谢或外排活性降低。相反，与Lc相比，暴露于CLEO导致受损的短乳杆菌细胞亚群（35.1-77％）。mesenteroides（25.3-36.6％）。暴露于联合治疗（CLEO或CREO和MHT）几乎影响了整个短乳杆菌和Lc的生理功能。mesenteroides细胞群（高达99％），尽管每种分离物的损伤扩展随所测试的精油而异。结果表明，L。brevis和Lc的失活。中肠膜 单独由CLEO和CREO引起的细胞以及与橙汁中的MHT结合使用的多靶标作用导致DNA损伤，膜通透性和去极化改变以及代谢和外排活性受损。