RAPISARDA Viviana Andrea
congresos y reuniones científicas
Effect of oxidative treatments on bacterial biofilms of potential foodborne pathogens
OLMEDO, G. M.; GRILLO-PUERTAS, M.; CERIONI, L.; RAPISARDA, V. A.; VOLENTINI, S. I.
Congreso; IX Congreso SAMIGE 2013; 2013
In food industry, contamination with pathogen bacteria can occur during growing, harvesting, processing, storing, and shipping of fresh or minimally processed products. Thus, the study of disinfectants to eliminate undesirable microorganisms is relevant. Oxidizing biocides such as hypochlorite and peroxides are widely used in sanitization of food and contact surfaces, because of their antimicrobial effects, availability and low cost. In our laboratory, a sequential oxidative treatment (SOT) has been previously standardized for the elimination of fungal phytopathogens and Xanthomonas citri subsp. citri, consisting in two sequential incubations, first with NaClO, and then with H2O2 in presence of Cu2SO4. These compounds generated a synergistic effect. Here, we tested the capacity of the oxidizing compounds to inhibit and remove bacterial biofilms. Assays were carried out on polystyrene surfaces, using Escherichia coli C, Klebsiella pneumoniae and Salmonella enterica serovar Typhimurium as pathogenic and surrogate foodborne bacteria. As a preventive treatment for biofilm formation, an optimal combination of NaClO, H2O2 and Cu2SO4 was established for each strain. E. coli and K. pneumoniae biofilm formation was inhibited by the application during 2 min of 5 ppm NaClO, 0.1 mM CuSO4 and 100 mM H2O2, whereas S. Typhimurium biofilm was inhibited applying 5 ppm NaClO, 0.1 mM CuSO4 and 200 mM H2O2. Compounds were also combined to evaluate their disinfectant action in biofilm remotion. With a time of contact of 5 min, the effective treatments were: 5 ppm NaClO, 0.1 mM CuSO4 and 100 mM H2O2 for E. coli; 12 ppm NaClO, 0.1 mM CuSO4 and 250 mM H2O2 for K. pneumoniae; 10 ppm NaClO, 0.1 mM CuSO4 and 200 mM H2O2 for S. Typhimurium. Oxidative treatment represents a simple technique that involves short times of contact between the compounds and bacteria. Thus, we propose it as a disinfection strategy to prevent and eradicate bacterial biofilms from food contact surfaces.