Impedimetric determination of activity of disinfectants and detergents on Listeria: preliminary study

The efficiency of several disinfectants or detergents against three strains of Listeria monocytogenes, one strain of Listeria innocua and two strains of Streptococcus group D was tested in water as well as in the presence of milk, whey and salt by an impedimetric method using a Bactometer M120. Certain synergistic effects between active agents and matrix could be observed. Differences in sensitivities were noticed amongst the tested strains. Products containing iodine, peroxide or quaternary ammonium as active agents were shown to be efficient, even at relatively low concentrations.