Enumeration of Microorganisms by Their Dynamic ac Conductance Patterns

Bacterial growth affects the ac conductance of a two-terminal measuring cell containing growth media. The dynamic characteristics of the recorded conductance provide quick information about the microorganisms´ initial concentration and their relative growth parameters. A simplified electrobacteriological model is described which explains the changes in the medium conductivity. The mathematical model was verified experimentally. This model establishes the use of conductance measurement as a rapid method to assess bacterial concentrations. High correlation existed between the conductance method and the conventional plate count method.