Synergistic antibacterial effects of ultrasound and thyme essential oils nanoemulsion against Escherichia coli O157:H7
Synergistic antibacterial effects of ultrasound and thyme essential oils nanoemulsion against Escherichia coli O157:H7
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DOI：
10.1016/j.ultsonch.2020.104988
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发表时间：
2020-09-01
影响因子：
8.4
通讯作者：
Liu, Donghong
中科院分区：
文献类型：
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作者：
Guo, Mingming;Zhang, Lianjiao;Liu, Donghong
精油纳米乳剂已被证明具有比单独的精油或粗乳剂更强的抗菌作用。声孔效应可能是一个有前途的候选人，触发协同效应与百里香精油纳米乳（TEON），并产生更有效的抗菌功效。因此，在这项研究中，超声波（US）与TEON处理结合对大肠杆菌（E。coli）O157：H7。在22 ℃条件下，超声（20 kHz，255 W/cm（2），9 min）和TEON（0.375 mg/mL）处理具有显著的协同效应，降低了E. coli O 157：H7细胞数增加7.42 ± 0.27 log CFU/mL。扫描电镜和透射电镜观察细胞形态学变化。结果表明，超声波和TEON协同作用改变了生物体细胞的形态和内部结构。激光扫描共聚焦显微镜（LSCM）图像显示，超声波和TEON联合处理改变了细胞膜的通透性，从而影响了E. coliO 157：H7细胞。这进一步表明，从这些细胞的处理后释放出大量的核酸和蛋白质。本研究的结果阐明了声致孔和TEON处理的协同效应的机制，并提供了有价值的信息，为他们在食品巴氏杀菌的潜力。
Essential oil nanoemulsions have been proven to have stronger antimicrobial effects compared to the essential oil alone or coarse emulsion. Sonoporation could be the promising candidate to trigger a synergistic effect with thyme essential oil nanoemulsion (TEON) and produce a more effective antibacterial efficacy. Therefore, in this study, the bactericidal effects of ultrasound (US) in combination with TEON treatments against Escherichia coli (E. coli) O157:H7 were investigated. The remarkable synergistic effects of US (20 kHz, 255 W/cm(2), 9 min) and TEON (0.375 mg/mL) treatments at 22 degrees C reduced E. coli O157:H7 populations by 7.42 +/- 0.27 log CFU/mL.The morphological changes of cells exposed to different treatments were observed by scanning electron microscopy and transmission electron microscopy. The results showed that the synergistic effects of the ultrasound and TEON treatments altered the morphology and interior microstructure of organism cells. Laser scanning confocal microscopy (LSCM) images revealed that the combination treatments of ultrasound and TEON altered the permeability of cell membranes, and this affected the integrity of E. coli O157:H7 cells. This was further indicated by the high amounts of nucleic acids and proteins released from these cells following treatment.The results from this study illustrated the mechanisms of the synergistic effects of sonoporation and TEON treatments and provided valuable information for their potential in food pasteurization.