An investigation of indirect conductimetry for detection of some food-borne bacteria

Indirect conductimetry using a rapid automated bacterial impedance technique was investigated. Strains of Staphylococcus aureus, Listeria monocytogenes, Enterococcus faecalis, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, Aeromonas hydrophila and Salmonella spp. grown in Whitley Impedance broth all elicited indirect conductimetric changes. These indirect conductance responses were improved by the addition of 2 g/l glucose to the medium and resulted in maximum changes of 2340-4300 microS with associated maximum rates of change of 520-1210 microS/h. Furthermore, the indirect conductimetric assay detected growth of staphylococci, listeria and salmonella in media containing high concentrations of salts used as selective agents in culture media for the isolation of these organisms.