Patra Jayanta Kumar, Baek Kwang-Hyun
Research Institute of Biotechnology and Medical Converged Science, Dongguk University, Ilsandong-gu, Gyeonggi-do, Republic of Korea.
Department of Biotechnology, Yeungnam University, Gyeongsan, Gyeongbuk, Republic of Korea.
Jundishapur J Microbiol. 2016 Jun 28;9(7):e31784. doi: 10.5812/jjm.31784. eCollection 2016 Jul.
Listeria monocytogenes is one of the most virulent types of bacteria and causes severe foodborne illness, such as listeriosis. Because this pathogen has become resistant to sanitizers and other disinfectants that are used to clean utensils and surfaces during food processing, it poses a serious threat to the food industry.
The study was conducted to determine the anti-listerial potential of essential oils extracted from four edible seaweeds against L. monocytogenes.
Essential oil was extracted from four edible seaweeds (Enteromorpha linza, Undaria pinnatifida, Laminaria japonica, and Porphyra tenera) against L. monocytogenes using the microwave hydrodistillation method. The anti-listerial activity of the essential oil was determined using the standard disc diffusion method.
Among the four essential oils, E. linza (ELEO) was most effective against all three strains of L. monocytogenes (11.3 - 16.0 mm). The other three essential oils were only effective against two strains, L. monocytogenes ATCC 19115 (10.0 - 10.5 mm) and L. monocytogenes ATCC 7644 (11.0 - 15.0 mm). The minimum inhibitory concentration and the minimum bactericidal concentration of all four essential oils varied from 12.5 - 25.0 mg/mL. Further, the mode of action of ELEO against L. monocytogenes was investigated by examining its effect on cell viability, the release of 260-nm absorbing materials, the number of K+ ions, the relative electrical conductivity, and the salt tolerance capacity. The results indicated that the essential oils exhibited strong anti-listerial activity against multiple strains of L. monocytogenes. It displayed potential inhibitory effects on the viability of bacterial cells and loss of integrity as indicated by an increase in the relative electrical conductivity, leakage of K+ ions and other 260-nm absorbing materials, and a loss of the salt tolerance capacity.
The results presented herein provided insight into a possible explanation for the modes of action of essential oils on L. monocytogenes. The outcome of the present study may aid the food industry in locating the most promising potential anti-listerial agents from edible seaweed sources to control L. monocytogenes and also in facilitating their application in food processing and preservation techniques in a nontoxic and environmental friendly manner.
单核细胞增生李斯特菌是毒性最强的细菌类型之一，可引发严重的食源性疾病，如李斯特菌病。由于这种病原体已对食品加工过程中用于清洁器具和表面的消毒剂及其他消毒剂产生耐药性，它对食品行业构成了严重威胁。
开展本研究以确定从四种可食用海藻中提取的精油对单核细胞增生李斯特菌的抗菌潜力。
采用微波水蒸馏法从四种可食用海藻（浒苔、裙带菜、海带和条斑紫菜）中提取针对单核细胞增生李斯特菌的精油。使用标准纸片扩散法测定精油的抗菌活性。
在这四种精油中，浒苔精油（ELEO）对所有三株单核细胞增生李斯特菌最为有效（抑菌圈直径为11.3 - 16.0毫米）。其他三种精油仅对两株菌有效，即单核细胞增生李斯特菌ATCC 19115（抑菌圈直径为10.0 - 10.5毫米）和单核细胞增生李斯特菌ATCC 7644（抑菌圈直径为11.0 - 15.0毫米）。所有四种精油的最低抑菌浓度和最低杀菌浓度在12.5 - 25.0毫克/毫升之间。此外，通过检测浒苔精油对细胞活力、260纳米吸光物质的释放、钾离子数量、相对电导率和耐盐能力的影响，研究了其对单核细胞增生李斯特菌的作用方式。结果表明，这些精油对多株单核细胞增生李斯特菌表现出强大的抗菌活性。它对细菌细胞活力显示出潜在抑制作用，且完整性丧失，表现为相对电导率增加、钾离子和其他260纳米吸光物质泄漏以及耐盐能力丧失。
本文给出的结果为精油对单核细胞增生李斯特菌的作用方式提供了一种可能的解释。本研究结果可能有助于食品行业从可食用海藻来源中找到最具潜力的抗李斯特菌剂来控制单核细胞增生李斯特菌，也有助于以无毒且环保的方式将其应用于食品加工和保存技术中。
