DMDC对假单胞菌浮游菌和被膜菌的杀菌效果及其应用

为探究二甲基二碳酸盐(DMDC)对食源性有害微生物的控制,本研究分析DMDC对生鲜食品特定腐败菌荧光假单胞菌和隆德假单胞菌的浮游菌和被膜菌的杀菌效果。通过API ZYM试剂盒、XTT检测试剂盒、共聚焦显微镜观察分析DMDC处理对假单胞菌存活性、胞内酶活、成熟生物被膜的影响,并评价该处理对生鲜蔬菜品质的影响。结果表明:与3种致病菌相比,DMDC对荧光假单胞菌和隆德假单胞菌杀菌效果显著,250 mg/L DMDC处理5 min能完全杀灭2种细菌,其与抑制白氨酸芳氨酶和萘酚-AS-BI-磷酸水解酶的活性有关。DMDC在250 mg/L质量浓度下能有效破坏荧光假单胞菌和隆德假单胞菌的成熟生物被膜,处理15 min内被膜菌数量分别降低4.60 lg(CFU/cm²)和4.15 lg(CFU/cm²),细胞活力也显著下降,被膜中死细菌显著增加,且厚度变薄。西红柿和生菜在250 mg/L DMDC处理下表面菌落总数、假单胞菌数及霉菌酵母数明显减少,其中菌落总数分别降低2.60 lg(CFU/cm²)和1.98 lg(CFU/cm²),假单胞菌数分别减少2.56 lg(CFU/cm²)和1.73 lg(CFU/cm²),未检测出霉菌和酵母,且不影响色泽等感官品质。可见,DMDC能有效杀灭食品腐败的假单胞菌浮游态和被膜态,对2种果蔬微生物控制的应用效果良好。

Bactericidal Effect and Application of DMDC on Pseudomonas Planktonic and Biofilm Bacteria

To explore the bactericidal effect of dimethyl dicarbonate(DMDC)on foodborne harmful microorganism,the bactericidal effect of DMDC on the planktonic and biofilm bacteria of Pseudomonas fluorescens and Pseudomonas lund of spoilage organism in fresh food were comparatively evaluated in the present study.Effects of DMDC on the bacterial activity,intracellular enzyme activity and mature biofilm of Pseudomonas were measured by using API ZYM kit,XTT kits and confocal microscope.Meanwhile,antibacterial activity of DMDC at different mass concentration in tomato and lettuce were performed.The results showed that DMDC had stronger bactericidal action against the two Pseudomonas compared with other three pathogens.The two Pseudomonas were inactivated by 250 mg/L DMDC treatment for 5 min,which was attributed to the decreasing activities of alanine araminase and naphthol-AS-BI-phosphohydrolas.In addition,mature biofilm of P.fluorescein and P.lund could be effectively destroyed.The population in biofilm cell decreased by 4.60 lg(CFU/cm²)and 4.15 lg(CFU/cm²),respectively,and the cell activity significantly dropped,resulting in the increase of dead cell and the thinner biofilm structure,when treated by 250 mg/L DMDC.Moreover,the aerobic plant count(APC),Pseudomonas number(PA),and mold and yeast count(MYC)of tomato and lettuce were significantly reduced by treatment of DMDC at 250 mg/L.The APC and PA in tomato was reduced by 2.60 lg(CFU/cm²)and 1.73 lg(CFU/cm²),and in lettuce was decreased by 2.56 lg(CFU/cm²)and 1.98 lg(CFU/cm²),respectively,for 15 min treatment,accompanied by no detection of mold and yeast after 5 min treatment.Sensory qualities were not affected.Thus,DMDC significantly killed the planktonic and mature biofilm of two Pseudomonas,and has a good bactericidal effects when applied to the surface of two kinds of fruits and vegetables,which is expected to become a new cleaning agent in fruit and vegetable.