Nisin和柠檬酸对纯培养及鲜切黄瓜中单增李斯特菌的杀菌效果
The disinfection effect of nisin and citric acid against Listeria monocytogenes in pure culture and on fresh-cut cucumbers
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摘要: 本文研究了不同浓度的乳酸链球菌素(nisin)、柠檬酸及二者复配对纯培养和人工接种到鲜切黄瓜上的单增李斯特菌(LM)处理不同时间后的杀菌效果。结果显示nisin和柠檬酸对纯培养及鲜切黄瓜上的LM均具有一定的杀菌效果,其杀菌能力随着nisin和柠檬酸浓度的增加和处理时间的延长而增强。当nisin浓度为100μg/mL时,作用5min可使纯培养体系中的LM低于检测限,使鲜切黄瓜中的LM低于检测限需要15min,当柠檬酸浓度为0.5%时,分别作用10min和15min可以使纯培养和鲜切黄瓜中的LM低于检测限。nisin和柠檬酸复配的杀菌效果要优于二者单独使用,当二者复配浓度为50μg/mL+0.3%(m/v)时,处理20min可以使纯培养体系中的LM降低到检测限以下,而使鲜切黄瓜中的LM低于检测限则需15min。结果表明nisin和柠檬酸复配可以用于控制鲜切黄瓜中单增李斯特菌的污染。Abstract: The disinfection effect of nisin and citric acid separately and in combination at different concentration for inactivation of Listeria monocytogenes ( LM) in pure culture and on fresh- cut cucumbers was investigated. The results showed that both nisin and citric acid possessed considerable disinfection effect against LM in pure culture and on fresh-cut cucumbers, respectively, and the anti-listerial activity increased with the increasing concentration and treatment time.LM in pure culture was under the limit of detection within 5min by 100μg /mL nisin, while it need15min to reduce to that lever on fresh-cut cucumbers.LM was reduce to the lever that under the limit of detection by 0.5% citric acid within 10min in pure culture and within 15min on fresh-cut cucumbers.The anti-listerial activity of the combination of nisin with citric acid was stronger than that of their alone.Combination of 50μg /mL nisin with0.3% citric acid reduced LM to the lever that under the limit of detection in pure culture within 20min and on freshcut cucumbers within 15min. In a conclusion, washing with nisin and citric acid might be applied as an effective preservative to control the growth of Listria monocytogene on fresh-cut cucumbers.