Neutralization of the activity of eight disinfectants by organic matter

Abstract

The effect of organic matter on the activity of 8 disinfectants was evaluated. Three types of interfering substrates (whole milk powder, dried beef blood and fish meal) were tested according to the method of Whitmore and Miner adapted to the AOAC [Association of Official Analytical Chemists] use-dilution method [test organism, Pseudomonas aeruginosa]. Glutaraldehdye and, to a certain extent, chlorhexidine acetate and the amphoteric surfactant kept their disinfecting activity after contact with high concentrations of organic matter. The quaternary ammonium compound and the quaternary ammonium-glutaraldehyde complex were more readily neutralized. Anionic acid, iodophore and sodium hypochlorite did not tolerate the presence of organic matter. The neutralizing activity of the organic substrates was correlated to their solubility and composition.