次氯酸钠诱导肠炎沙门氏菌活的非可培养状态形成及复苏过程研究

Formation and resuscitation process of viable but non-culturable state of foodborne pathogen Salmonella enteritidis induced by sodium hypochlorite

中文关键词:  次氯酸钠  肠炎沙门氏菌  活的非可培养状态  复苏

英文关键词:sodium hypochlorite  Salmonella enteritidis  viable but non-culturable state  resuscitation

中文摘要:

      目的 研究不同有效氯浓度次氯酸钠溶液诱导肠炎沙门氏菌进入活的非可培养状态(viable but non-culturable state, VBNC)及复苏条件。方法 以不同有效氯浓度次氯酸钠处理肠炎沙门氏菌, 分析肠炎沙门氏菌活的非可培养状态菌数及VBNC发生率的变化, 结合扫描电镜观察肠炎沙门氏菌VBNC态细胞与正常细胞的形态差异, 而后比较不同复苏条件的复苏效果, 同时对复苏后的细胞生理活性进行评价。结果 40 mg/L有效氯浓度处理20 min可使活菌全部进入VBNC状态, 细胞表面出现褶皱塌陷; 高于60 mg/L有效氯浓度可全部杀灭, 细胞出现断裂、破损; 进入VBNC态的肠炎沙门氏菌在5种复苏处理下, 均可恢复可培养性; 在20 mmol/L丙酮酸钠×热激条件下恢复效果较好。细胞内pH (pHi)和胞内腺苷三磷酸(adenosine triphosphate, ATP)显示复苏后细胞活性较正常细胞有所降低。结论 在食品生产、环境清洁中应注意次氯酸钠使用浓度, 否则极易造成肠炎沙门氏菌VBNC态的形成和复苏, 导致食品污染, 从而增加食品安全风险。

英文摘要:

      Objective To study the induction of Salmonella enteritidis into a viable but non-culturable state (VBNC) by sodium hypochlorite solution with different available chlorine concentrations and the resuscitation conditions. Methods The Salmonella enteritidis was treated with sodium hypochlorite with different concentrations of available chlorine to analyze the changes of the viable non-culturable state bacteria count and the incidence of VBNC of Salmonella enteritidis, and the morphological differences between VBNC state cells was observed and normal cells of Salmonella enteritidis combined with the scanning electron microscope, and then the resuscitation effects of different resuscitation conditions were compared, and the physiological activity of the cells after resuscitation was evaluated. Results After treatment with 40 mg/L available chlorine for 20 min, all the viable bacteria entered the VBNC state and the cell surface became wrinkled and collapsed, more than 60 mg/L effective chlorine concentration could kill all, cell fractured damaged. Salmonella enteritidis entering the VBNC state could be cultured under 5 kinds of resuscitation treatments. The recovery was better under the condition of 20 mmol/L sodium pyruvate×heat shock. PHi and intracellular ATP showed a decrease in cell activity compared with normal cells after resuscitation. Conclusion In food production and environmental cleaning, attention should be paid to the concentration of sodium hypochlorite, otherwise it is easy to cause the formation and recovery of VBNC state of Salmonella enteritidis, leading to food contamination and thereby increasing food safety risks.