Abstract: A real-time (RT) optoelectronic microbiological assay for rapid detection of moulds and yeasts in yogurt was reported and validated by comparing its results with those obtained by applying the Chinese national standard method plate counting. Rapid detection of moulds and yeasts in commercialized yoghurt and spiked positive samples was successfully achieved by a semi-quantitative analytical procedure using the method, which makes it possible to pre-alert their presence or absence. The RT microbiological assay allowed detection of 10–3.5×105 CFU/mL of moulds and yeasts in 1.8–33 h. The time spent in this method for detecting microbial numbers below 10 CFU/mL as determined by conventional plate counting was over 33 h, without pre-alert during 48 h running. In addition, the results obtained closely agreed with those obtained by the plate counting method. The proposed method in this study provided a sensitive, simple and convenient approach for rapid screening of moulds and yeasts in yogurt in factories and laboratories and hence monitoring of critical control points.

Key words: mould；yeast；real-time optoelectronic microbiological assay；hazard analysis and critical control point (HACCP)

摘要： 对酸奶中的霉菌酵母菌同时采用实时光电微生物检测系统与国标法进行检测,分析比较两种检测方法所得的检测数据.本实验利用实时光电微生物检测系统的霉菌酵母检测试剂瓶对市售酸奶及阳性添加样品采用半定量的检测方法进行快速检测,能快速地检测到目标菌存在,继而给系统提前预警.结果表明,当霉菌酵母菌含量在10～3.5×105CFU/mL时,实时光电微生物检测方法在1.8～33h内预警.当平板计数法的检测结果小于10CFU/mL时,实时光电微生物检测方法的检测时间均大于33h,在仪器设置运行48h内未出现预警现象.实时光电微生物检测技术与国标平板法两种检测方法的检测结果相当吻合.应用实时光电微生物检测技术能快速便捷,对酸奶产品中霉菌酵母菌进行监测,其检测速度和灵敏度均能满足工厂实验室的快速筛选检测,还利于产品的关键控制点的监测.

关键词: 霉菌；酵母菌；实时光电微生物检测技术；危害分析关键控制点