RAPID DETECTION OF ESCHERICHIA-COLI USING A SEPARATED ELECTRODE PIEZOELECTRIC CRYSTAL SENSOR

A separated electrode piezoelectric crystal sensor was used to determine Escherichia coli bacteria. This method is based on the fact that the resonant frequency shifts with the culture time in a culture medium where E. coli is inoculated, and the frequency detection time (FDT) is linearly related to the initial number of E. coli in the range 10-10(6) cells ml(-1). Factors that affect the determination are discussed. E. coli determination in pure culture was tested by the FDT method and compared with the most probable number technique and standard plate counts method. A correlation coefficient of 0.96 was obtained between the FDT and the decadic logarithm of initial concentration of bacteria. The proposed piezoelectric method is much more rapid and sensitive for determining microorganisms than the traditional methods.