Evaluation Germicidal of Disinfectants on Staphylococcus aureus and Escherichia coli

Diana Hualpa and Fanny Ludeña

The germicide efficiency of nine common disinfectants used in the food industry was evaluated against Sthaphylococcus aureus (ATCC 6538) and Escherichia coli. (ATCC 8739). Quaternary ammonium, chlorine and peracetic acid combined with hydrogen peroxide were used for disinfection of inert surfaces in contact with the product. While for disinfection of living surfaces (hands), ethyl alcohol, surfactants and alcohols with quaternary ammonium compounds in its composition were considered and glutaric aldehyde, benzyl-C12-C16-alkyl-dimetitylammoniumchloride and phosphate for footbaths. The disinfectants were applied at different concentrations (0.3-3%) and time of contact; the germicide efficiency was evaluated for each disinfectant by the plate count of survivor microorganism’s method. A neutralizer solution was used to inactivate the disinfectant and to perform correctly the count. Results showed that in the case of inert contact surfaces there was not significant differences in the germicidal efficiency among disinfectants (p>0.05). In the case of living surfaces (hands) the best disinfectant (p<0.05) was alcohol including in its composition quaternary ammonium compound at 1.7% with an exposure time of 2 minutes. For footbaths the disinfection treatment corresponded to benzyl-C12-C16-alkyl-dimetitylammoniumchloride at 0.3% (p<0.05) with an exposure time of 15 minutes shown the best results. Disinfectants containing quaternary ammonium compounds are effective against bacteria of Staphylococcus aureus and Escherichia coli.