Effect of weak acids on Listeria monocytogenes survival: Evidence for a viable but nonculturable state in response to low pH
Effect of weak acids on Listeria monocytogenes survival: Evidence for a viable but nonculturable state in response to low pH
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DOI：
10.1016/j.foodcont.2009.03.005
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发表时间：
2009-12-01
期刊：
影响因子：
6
通讯作者：
Oliver, James D.
中科院分区：
文献类型：
--
作者：
Cunningham, Eilis;O'Byrne, Conor;Oliver, James D.
单核细胞增生李斯特菌能够在通常对许多其他细菌致命的环境条件下生存，使这种病原体能够留在食物上，并最终在食用后感染。本研究调查了几种弱酸杀死单核细胞增生李斯特菌的程度，特别强调了常用的食品防腐剂。山梨酸钾发现山梨酸钾的作用高度依赖于pH值，仅在pH值为4.0时观察到显著的杀灭作用。在此pH下，测试的酸的有效性顺序为苯甲酸钠>丙酸钠>乙酸>山梨酸钾。温度对敏感性有显著影响，山梨酸钾在50 mM和升高的温度（37 ℃）下有效，但当细胞在4 ℃或21 ℃时不能影响存活。最后，我们发现，在pH 4.0的山梨酸钾存在下生长的细胞进入活的但不可培养（“VBNC”）状态，但到24小时变得不可活。相比之下，在这些条件下孵育的细胞在不存在山梨酸钾的情况下进入VBNC状态，并在整个24小时的研究期间保持活力。(c)2009爱思唯尔有限公司版权所有。
Listeria monocytogenes is capable of surviving environmental conditions that are normally fatal to many other bacteria, enabling this pathogen to remain on foods and eventually establish infection after consumption. This study investigated the extent to which L monocytogenes is killed by several weak acids, with particular emphasis on the commonly used food preservative. potassium sorbate. The effects of potassium sorbate were found to be highly pH dependant, with significant killing only observed at a pH of 4.0. At this pH, the order of effectiveness of the acids tested was Na benzoate > Na propionate > acetic acid > K sorbate. Temperature had a significant impact on sensitivity, with K sorbate being effective at 50 mM and elevated (37 degrees C) temperature, but failing to affect survival when cells were at 4 degrees C or 21 degrees C. Finally, we found that cells grown in the presence of K sorbate at pH 4.0 entered a viable but nonculturable ("VBNC") state, but became nonviable by 24 h. In contrast, cells incubated under these conditions in the absence of K sorbate entered the VBNC state and maintained viability throughout the 24 h study period. (c) 2009 Elsevier Ltd. All rights reserved.