鼠伤寒沙门氏菌生物被膜的清除效果研究

目的:比较食品工业中常用的消毒剂、常用的防腐剂及几种天然成分对鼠伤寒沙门氏菌（Salmonella typhimurium）生物被膜的影响。方法:通过在培养过程中添加不同种类、不同浓度的清除剂，测定所选清除剂对生物被膜形成过程的影响；用所选的清除剂对成熟生物被膜进行浸泡处理，评估每种清除剂不同含量下的清除效果；利用噻唑蓝（Methylthiazolyldiphenyl-tetrazolium bromide，MTT）比色法测定经不同清除剂处理后生物被膜菌内细胞的代谢活性；采用稀释平板涂布法计算不同物质处理后生物被膜内细菌的存活数。结果:消毒剂乙醇（50%）、过氧化氢（1%）、苯扎氯铵（0.6%）、苯扎溴铵（0.6%），天然成分香芹酚、肉桂醛和百里香精油（1.0 μL/mL）在较低浓度下即可有效抑制S. typhimurium CDC3和S. typhimurium ST34生物被膜的产生；消毒剂洗洁精、过氧化氢和天然成分香芹酚、肉桂醛和百里香精油在清除成熟生物被膜方面表现出了一定的优势，其中清除效率最理想的是过氧化氢，最大可达90%左右，洗洁精最大清除率可至80%，香芹酚、肉桂醛和百里香精油可达70%左右；消毒剂乙醇、苯扎氯铵和苯扎溴铵，以及天然成分香芹酚、肉桂醛和百里香精油可以明显降低生物被膜菌的细胞代谢活性及活菌存活数，可将生物被膜内活菌数降低2~3个lg值。结论:对于成熟生物被膜的清除，在初始的培养中添加清除剂或是天然成分可以更加完全有效地控制生物被膜的产生。

Study on the Removal Effect of Salmonella typhimurium Biofilm

Objective: This research focused on the effects of different disinfectants, preservatives and natural ingredients commonly used in the food industry on the biofilm of Salmonella typhimurium. Methods: By adding different kinds and concentrations of scavengers during the culture process, the influence on the formation of biofilm was determined. The mature biofilm was soaked with various selected scavengers to evaluate the clearance effect under different concentrations of each substance. The metabolic activity of bacteria cells in the biofilm was determined by methylthiazolyldiphenyl-tetrazolium bromide(MTT) assay. And the number of viable bacteria was calculated by dilution plate coating method. Results: The disinfectant ethanol(50%), hydrogen peroxide(1%), benzalkonium chloride(0.6%), benzalkonium bromide(0.6%), and natural components carvol, cinnamaldehyde and thyme essential oil(1.0 μL/mL) could effectively inhibit the formation of S. typhimurium CDC3 and S. typhimurium ST34. Disinfectants detergent, hydrogen peroxide, natural ingredients(carvol, cinnamaldehyde and thyme essential oil) showed certain advantages in the removal of mature biofilm. Among them, the most ideal removal efficiency was hydrogen peroxide, which could reach about 90%, the maximum removal rate of detergent could reach 80%, and the essential oils of carvacrol, cinnamaldehyde and thyme could reach about 70%. The disinfectant ethanol, benzalkonium chloride and benzalkonium bromide, as well as the natural components carvol, cinnamaldehyde and thyme essential oil could significantly reduce the cell metabolic activity and the number of viable bacteria in biofilm, the number of viable bacteria in the biofilm could be reduced by 2 to 3 lg values. Conclusions: In contrast with the removal of mature biofilm, the addition of scavenging agent or natural ingredients at the early stage of cultivation made up for a more efficient control of the biofilm.