实时光电微生物法快速检测生鲜乳中的嗜冷菌

对50份生鲜牛乳样品中的嗜冷菌同时采用实时光电微生物快速检测方法和平板计数法进行检测,分析比较两种检测方法所得的嗜冷菌检测数据。结果表明:采用嗜冷菌检测标准曲线:Lg CFU/mL=-0.417*DT+7.91的实时光电微生物法检测的嗜冷菌含量在2.3~3.7×106CFU/mL,检出时间在3.2~18.1 h。采用平板计数法的检出结果范围在4.0~3.0×106CFU/mL。当实时光电微生物检测方法的检出时间大于18 h时,样品检测结果均为未检出,此时平板计数法的检测结果均为<1 CFU/mL。实时光电微生物法检测结果对数值与平板计数法检测结果对数值的差值范围在-0.9~0.8,两者差值的绝对值均<1。采用实时光电微生物法和平板计数法两种检测方法的检测结果相当吻合,实时光电微生物法检测生鲜牛乳中嗜冷菌具有良好的适用性,可大大缩短检测时间,且方法准确、简便易行。

Enumeration of Psychrophilic Bacteria in Raw Milk by Rapid Real-time Optoelectronic Microbiological Method

Psychrophilic bacteria from 50 raw milk samples were enumerated by rapid real-time optoelectronic microbiological method and aerobic plate counting method in the same time. Testing data of psychrophilic bacteria was assayed and compared deriving from the two detection methods. The results showed that counts of psychrophilic bacteria using standard curve: Lg CFU/mL= -0.417*DT+7.91 of rapid real-time optoelectronic microbiological method were 2.3~3.7×106 CFU/mL and the detection time was of 3.2 to 18.1 h. The result of aerobic plate counting was 2.3~3.7×106 CFU/mL. When the detection time of rapid real-time optoelectronic microbiological method was more than 18 h, the psychrophilic bacteria was not detected. Meanwhile the results of aerobic plate counting were <1 CFU/mL. The difference of logarithm of testing results between the two detection method was -0.9~0.8 with the absolute values of <1. The testing results from the two methods were quite consistent. These results indicated that using rapid real-time optoelectronic microbiological method to detect psychrophilic bacteria in raw milk had high applicability, greatly shorten the testing time, and the method was also accurate, simple and easy.