流式细胞技术检测酸性饮料中菌落总数的研究

张兰; 徐红; 翁文川; 凌莉; 冼钰茵; 杨铭燕; 潘斯威; 黄焯枝

流式细胞技术检测酸性饮料中菌落总数的研究

Study on total plate count detection in acid beverage by flow cytometry

摘要

摘要: 利用流式细胞技术(Flow Cytometry,FCM)检测酸性饮料(pH<4.6)中的菌落总数并与平板法和滤膜法进行比较分析,建立FCM快速检测酸性饮料中菌落总数的方法。选择13种常见实验菌株,通过人工加菌实验进行验证。结果表明,基质和含菌量对FCM法的检测结果影响较大,酸性饮料中的部分菌株难以直接被FCM法检出,需经过滤富集菌于中性TSB肉汤中36 ℃培养22 h排除基质和含菌量低的影响,培养后的菌溶液经FCM法与平板法检测结果均在一个数量级。运用AOAC官方分析方法对酸性饮料中不同浓度13种实验菌株滤膜法和增菌22 h后FCM法的定性检测结果进行统计学分析,卡方值X²<3.84,同时假阴性率=1.9%<2%,假阳性率=4.2%<9.6%,说明FCM法可替代滤膜法进行酸性饮料中菌落总数的定性检测,用于产品的快速放行。

Abstract: Compared and analyzed with pour plate method and membrane filtration method,flow cytometer(FCM)was used to determine total plate count(TPC)for establishing a FCM method in rapid detection of TPC in acid beverage(pH＜4.6). 13 strains were selected to conduct artificial add experiment. The results showed that substrate and concentration had great influence on FCM method,some bacteria in acid beverage could not be detected by FCM method directly,which need to be filtrated on membrane and pre-enriched in neutral TSB broth at 36 ℃ for 22 h,then detected by FCM and pour plate method,results were at the same order of magnitude. The official AOAC analysis method was used to do the statistics analysis on qualitative result of 13 strains in acid beverage with different concentration detected by membrane filtration method and FCM method after pre-enrichment for 22 h,X²<3.84 and false negative rate was 1.9%<2%,false positive rate was 4.2%<9.6%,which showed that membrane filtration method could be replaced by FCM method for TPC qualitative detection in acid beverage,then used for products quick release.