Establishment and application of a novel fluorescence-based analytical method for rapid detection of viable bacteria in different samples

The present study described a rapid method for readily detecting the total numbers of viable bacteria cells in various samples (including surface water, solid inoculants and soil samples) using an newly developed hand-held fluorometer and a fluorescent dye Calcein UltraGreenTM AM. The traditional plate counting method requires 48 hours of cultivation, while the newly established method does not require any incubation time, making the detection method faster and more convenient. The portable rapid detection fluorometer has a wide dyanamic range of the values of relative fluorescence intensity are from 45 to 30133. It can detect bacterial concentration ranging from 105 to1010 cells/mL. This newly established method has a good applicability for accurately and quickly detecting the cell number of viable bacteria in various samples. These results of the fluorescence-based method were compared with that those of the traditional plate counting method, the relative standard deviation was less than 6%. This new rapid measurement system provides a robust method for the rapid detection of viable bacteria on site.