Electronic measurement of bacterial growth

Abstract
The growth and multiplication of bacterial cells in a nutrient medium can be monitored by measuring changes in the AC conductivity at constant temperature produced by charged metabolites; the method is faster, more accurate and requires less labour than traditional viable counting. Two instruments are described; one presents conductance changes directly on a chart recorder; the other can handle up to 128 samples at a time, and normally feeds the data to a computer for processing. Methods of obtaining bacteriological parameters (mean generation time, lag time, inoculum number, etc.) from conductivity measurements are briefly described.