吸光度法快速确定菌悬液浓度及其适用范围

摘要

The McFarland’s turbidimetry method was used to adjust the concentration of E. coli bacterial suspension to 8 × 108 cfu/ g,then diluted into several gradients to measure absorbance values by UV spectrophotometer at 600 nm wavelength,at the same time,tested the total numbers of colony of several gradients by plate count method. Took total numbers of colony as X-axis and absorbance values as Y-axis to draw a standard curve. The purpose was to determine rapidly the concentration of bacterial suspension and the scope of application with the absorbance method. The result showed that the eligible concentration of bacterial suspension was 105 ~ 108 cfu/ g with the absorbance method,which could not be used for bacterial suspension below 105 cfu/ g,and the data were more accurate than those of McFarland’ s turbidimetry.%采用麦氏比浊法，将大肠埃希菌的菌悬液浓度调整到约8×108 cfu/ g，再将其稀释成多个梯度，在600 nm 的波长下用紫外分光光度计测定吸光度值，同时将各个梯度的菌悬液分别做菌落总数试验，得到不同吸光度值对应的菌落总数，并制作标准曲线，通过测量菌悬液的吸光度值确定菌悬液浓度及其适用范围。试验证明，用此法确定菌悬液浓度时，其菌落总数宜在105~108 cfu/ g 之间，不适用于在105 cfu/ g 以下的菌悬液，所得结果比麦氏比浊法准确。