Patent ID: 9709516
Date: 2017-07-18
CPC Classifications: C12M,C12Q,G01N

Claim:
1. An impedance-based microbial growth detection method comprising the steps of: providing at least one vessel containing a liquid sample suspected of containing microorganisms disposed between and in contact with a first electrode and a second electrode; providing a time-varying electrical signal to the first electrode in contact with the liquid sample, wherein the second electrode is electrically connected to a phase-sensitive signal detector; and selecting a frequency of said time-varying electrical signal so that an out-of-phase signal amplitude measured by said phase-sensitive signal detector becomes equal to zero at the selected frequency; measuring the out-of-phase signal amplitude over time with the phase-sensitive signal detector at the selected frequency, wherein an increase in the signal amplitude over time at the selected frequency indicates microbial growth within the liquid sample; and after measuring, detecting the presence or absence of microbial growth.