Studies on the sensor for the determination of total viable counts.

目的1)制备用于测定总活菌细胞数的传感器。2)建立所提出传感器的最佳使用条件。3)该传感器在测定鱼肉中活细胞总数中的应用。方法用膜滤器过滤每ml的菌悬液。过滤器固定在氧电极的尖端，并覆盖有透析膜。测定了传感器对磷酸盐缓冲液和含氧饱和培养基的输出电流。在半对数图上绘制了两种电流衰减差的总活菌计数。结果1)分别从腐臭杆菌、大肠杆菌、干酪乳杆菌、葡萄球菌、荧光假单胞菌和除干酪乳杆菌外的混合菌中制备了总活菌计数传感器和氧电极。2)建立各传感器的最优条件如下；A.腐殖质：pH 7.2, 25‰；大肠杆菌：pH 7.2, 25 C；干酪乳杆菌：pH 6.8, 30 C；葡萄球菌：pH 7.2, 25 C；P. fluorescens: pH 7.2, 25 C；混合菌（干酪乳杆菌除外）：pH 7.2, 25‰。3)在10^6 ~ 10^8/ml范围内，纯细菌的总活菌数与传感器的电流衰减有良好的关系。4)腐臭芽孢杆菌的总活菌数与混合菌制得的传感器输出电流有良好的关系。5)以腐臭芽孢杆菌为指标，测定了蓝鳍金枪鱼和鲭鱼肉在5℃温度下3 d的总活菌数/g。腐坏芽孢杆菌和荧光芽孢杆菌在数量上优于其他细菌，目前正在研究它们对传感器输出电流的影响。

Objectives 1) Preparation of the sensor for the determination of total viable bacterial cell counts. 2) Establishment of the optimum conditions for Using the proposed sensor. 3) Application of the proposed sensor to the determination of total viable cell counts in fish meat.Methods Each one ml of bacteria suspensions was filtered through a membrane filter. The filter was fixed at the tip of an oxygen electrode and covered with a dialysis membrane. The output currents of the sensor for phosphate buffer and culture medium saturated with oxygen were determined, respectively. The total viable counts against the difference between both current decreases were plotted on the semi-logarithmic graph.Results 1) Sensors for the determination of total viable counts were prepared from A. putrefaciens, E. coli, L. casei, Staphylococcus, P. fluorescens, and the mixed bacteria except for L. casei, respectively, and oxygen electrode.2) The optimum conditions for each sensor were established as follows; A. putrefaciens: pH 7.2, 25ﾟC; E.coli: pH 7.2, 25ﾟC: L. casei: pH 6.8, 30ﾟC, Staphylococcus: pH 7.2, 25ﾟC; P. fluorescens: pH 7.2, 25ﾟC; mixed bacteria (except L. casei): pH 7.2, 25ﾟC. 3) Good relationships were obtained between total viable counts of pure bacteria and the current decreases of the sensors at the range of about 10^6 to 10^8/ml. 4) Good relationship was obtained between total viable counts in terms of A. putrefaciens and the output current of the sensor prepared from the mixed bacteria. 5) The total viable counts/g of bluefin tuna and mackerel meats at 5ﾟC for 3 days were determined in terms of A. putrefaciens. The influence of A. putrefaciens and P. fliuorescens on the output current of the sensor is under investigation now when they are superior in number to the other bacteria.