肉桂精油对食源性肠炎沙门氏菌和单增李斯特菌的抑菌作用

Antibacterial activity of cinnamon essential oil against foodborne Salmonella enteritidis and Listeria monocytogenes

为探究肉桂精油对肠炎沙门氏菌(Salmonella enteritidis)和单增李斯特菌(Listeria monocytogenes)的抑制效果,通过平板计数、电导率、核酸和蛋白质泄漏、显微镜观察和呋喃硼酸二酯类(autoinducer-2,AI-2)活性等分析肉桂精油对2种致病菌的最小抑菌浓度(minimum inhibitory concentration,MIC)、细胞膜损伤、黏附性及其群体感应的影响,并评价其对牛肉汁抑菌效果和品质的影响。结果显示,肉桂精油对肠炎沙门氏菌和单增李斯特菌的MIC分别为0.1和0.2 mg/mL,抑菌活性呈现浓度依赖性。处理时间越长,2种致病菌电导率上升越高,蛋白质和核酸泄露与肉桂精油浓度呈正相关,其中沙门氏菌高于单增李斯特菌。亚抑菌浓度肉桂精油还能有效减少沙门氏菌和单增李斯特的黏附和AI-2活性,在1/2 MIC作用下AI-2信号分别减少42.8%和37.6%。用0.8 mg/mL肉桂精油处理72 h后,菌落总数、肠炎沙门氏菌和单增李斯特菌分别降低2.38、3.56和2.97 lgCFU/mL。综上表明,肉桂精油对肠炎沙门氏菌和单增李斯特菌表现出良好的抑菌和杀菌活性,其中肠炎沙门氏菌更敏感,亚抑菌浓度下还干扰AI-2活性,减少生物被膜形成。该研究为植物精油在肉类保鲜中的应用提供了实验数据支撑。

The effect of cinnamon essential oil(EO)on Salmonella enteritidis and Listeria monocytogenes were studied.The minimum inhibitory concentration(MIC)and the AI-2 activity were investigated.The effect of cinnamon EO on quality in beef juice and antibacterial activity against two pathogens were further evaluated.The results indicated that the MIC against S.enteritidis and L.monocytogenes were 0.1 and 0.2 mg/mL,respectively.The conductivity of S.enteritidis and L.monocytogenes increased with time,the leahage of cell inner components were correlated with cinnamon EO.S.enteritidis had higher leakage of cell inner components than that of L.monocytogenes.Sub-MIC of cinnamon EO effectively reduced the adhesion and AI-2 signaling of two pathogens,in which dropped by 42.8%and 37.6%with 1/2 MIC,respectively.The inhibition of cinnamon EO at 0.1-0.8 mg/mL in chilled beef juice at 10℃was weaker than that of TSB medium.The total number of colonies,S.enteritidis and L.monocytogenes were decreased by 2.38,3.56 and 2.97 lg CFU/mL in beef juice treated with 0.8 mg/mL cinnamon EO for 3 days at 10℃.Thus,cinnamon EO showed good antibacterial and bactericidal activity against S.enteritidis and L.monocytogenes.Additionally,S.enteritidis was more sensitive to cinnamon EO than L.monocytogenes,and sub-MIC cinnamon EO decreased the biofilm formation by interfering with AI-2 activity.The research will provide a theoretical basis for the preservation application of plant EO in meat industry.