A rapid spectrophotometric method for the quantitative and quantitativedetection of total coliforms

摘要

To develop a rapid, accurate and sensitive method for determining the number of total coliforms, a new approach was established based on the performance of triphenyltetrazolium chloride (TTC) medium combined with spectrophotometric detection. Bromocresol purple was used as the main indicator and the culture mixture was grown for 8 h at 36 °C. When the color of the culture reached stability, the intensity at 420 run indicated the total coliform numbers in samples. The results of the new method were correlated to the actual content of bacteria (correlation coefficient, R2 = 0.982). One-hundred and forty samples were tested by the new method and the traditional most probable number (MPN) method; the results of the two methods were compared. The new method was credible and accurate within the 95% confidence interval of the MPN method. Compared with the MPN method, the sensitivity of detection was increased. The TTC/spectrophotometric method saves testing time and produces results with a higher confidence level than the MPN method and may therefore be useful for the detection of total coliforms in many fields.