热辅助超声波处理中VBNC态鼠伤寒沙门氏菌产生及其机制

Occurance of Viable But Non-culturable State in Salmonella enterica Serovar Typhimurium during Thermosonication and Its Mechanism

为了研究热辅助超声波(TS)处理中鼠伤寒沙门氏菌进入活的非可培养态(VBNC)的情况及可能机制,本文采用RT-qPCR与平板计数法检测其VBNC态发生情况,采用ESR方法定性、定量检测TS处理中产生自由基并用数学模型分析其与VBNC态发生率指数之间的关系。结果表明:TS处理强度与VBNC态鼠伤寒沙门氏菌产生及自由基强度有重要影响。经TS处理,在BPY培养基中主要产生3种自由基,包括以碳为中心自由基、羟基自由基与氢质子自由基。自由基强度与VBNC态发生率指数之间高度相关,可用Boltzmann模型进行拟合和验证。以丙酮酸钠作为自由基清除剂,验证了自由基对鼠伤寒沙门氏菌进入VBNC态具有重要作用。本研究结果对于TS处理技术的应用具有指导意义。

To investigate the generation and occurrence mechanism of viable but non-culturable(VBNC)in Salmonella enterica serovar Typhimurium artificially inoculated in BPY broth during thermosonication(TS),RT-qPCR and plate counting methods were used to detect the viable and VBNC state S.Typhimurium,ESR was used to detect free radicals generation.The relationship between free radicals generation and VBNC state incidence index was analyzed.Generally,higher intensity of TS treatment promoted S.Typhimurium into VBNC state and produced more free radicals.Three kinds of free radicals were detected,including C-centered radicals,hydroxyl radicals and hydrogen radicals.There was a correlation between the intensity of free radicals and the VBNC state incidence index during TS treatment,which can be fitted and validated using the Boltzmann model.Sodium pyruvate,as a free radical scavenger,was used to confirm that free radicals play an key role in inducting VBNC state microbial cells.These obtained results may help to facilitate application of TS processing.