食品科学

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酸适应海德尔堡沙门氏菌对环境胁迫耐受性分析

刘佳玫,栗军杰,陆兆新,别小妹*   

  1. 南京农业大学食品科技学院,江苏 南京 210095
  • 出版日期:2016-11-15 发布日期:2016-11-18

Tolerance of Acid-Adapted Salmonella heidelberg to Various Environmental Stresses

LIU Jiamei, LI Junjie, LU Zhaoxin, BIE Xiaomei*   

  1. College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
  • Online:2016-11-15 Published:2016-11-18

摘要:

目的:研究海德尔堡沙门氏菌(Salmonella heidelberg)低pH值酸适应性及酸适应对细胞其他胁迫环境耐受性的影响。方法:海德尔堡沙门氏菌在pH 5.5酸性培养基中生长2 h诱导酸适应性,以pH 3.0酸胁迫培养基及不同温度、NaCl、胆盐、消毒剂环境的存活率评价其耐受性。结果:pH 5.5酸适应2 h后,海德尔堡沙门氏菌在pH 3.0酸胁迫环境的存活率大幅提高。低pH值酸适应也使海德尔堡沙门氏菌在45、50 ℃高温条件下的存活率显著提高,对4 ℃冷藏环境的耐受性显著低于非酸处理菌株,但对-20 ℃冷冻环境的生存无影响。酸适应海德尔堡沙门氏菌对高渗、胆盐胁迫也表现良好的耐受性,5~10 g/100 mL NaCl溶液处理1 h,酸适应海德尔堡沙门氏菌的存活率大于60%,在1~10 g/100 mL胆盐溶液的存活率比对照组高3.8 倍。海德尔堡沙门氏菌酸适应性也使其对消毒剂的敏感性发生变化,酸适应性海德尔堡沙门氏菌在10~25 mmol/L H2O2溶液的存活率显著高于对照菌株,最高达3.1 倍;但对NaClO、乙醇消毒剂的耐受性显著降低,高质量浓度下二者无显著差异。结论:海德尔堡沙门氏菌在低pH值酸性条件生长一段时间会诱导产生酸适应性,还会协同提高其对高温、高渗、胆盐、H2O2胁迫环境的交叉抗性;但对4、-20 ℃低温、NaClO、乙醇等杀菌、保藏措施敏感性提高。

关键词: 海德尔堡沙门氏菌, 酸适应性, 环境胁迫

Abstract:

Purpose: To investigate the low pH acid adaptability of Salmonella heidelberg and the effect of acid adaptation
on its response to different environment stresses. Methods: S. heidelberg was exposed to TSB at pH 5.5 for 2 h for acid
adaptation. Comparison of the responses of acid adapted and unadapted cells to different temperature, high osmosis, bile
salt, and disinfectant stresses was conducted by calculating their survival rate. Results: pH 5.5 acid adaptation enabled
S. heidelberg to survive better in pH 3.0 acid challenge medium. Acid adaptation also provided S. heidelberg with increased
tolerance to thermal stress at 45 and 50 ℃, and made it more susceptable to 4 ℃ cold environment, but did not affect its
survival at −20 ℃. pH 5.5 acid adaptation also increased high osmotic and bile salt tolerance, and 60% of S. heidelberg
survived after 1 h treatment in 5?10 g/100 mL NaCl solution. It survival rate in 1?10 g/100 mL bile salt was 3.8 times higher
than that of the control group. Acid adaptation also changed S. heidelberg response to disinfectants, showing a significant
increase (3.1 times at most) in survival rate under H2O2 stress in the concentration range of 10?25 mmol/L when compared
to the control group. On the other hand, acid adapted Salmonella had enhanced sensitivity to NaClO and ethanol, with no
significant difference noted between the two disinfectants at high concentrations. Conclusion: Salmonella heidelberg could
develop acid tolerance response (ATR) after being inoculated in low pH medium. Low pH acid exposure induced crosstolerance
of S. heidelberg cells to thermal, high osmotic, bile salt and H2O2 stresses. However, the tolerance to 4 and −20 ℃
low temperatures, and NaClO and ethanol disinfectants was reduced due to acid adaptation.

Key words: Salmonella heidelberg, acid adaptation, environmental stresses

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