CONICET | Buscador de Institutos y Recursos Humanos

The aims of this work were to investigate the synergistic antibacterial effect of phenolic compounds combinations against Listeria monocytogenes in BHI medium and, the anti-listeria effect of the best phenolic compounds combinations using commercial meat as model food. In BHI medium, the most effective combinations were gallic-caffeic acids, gallic-protocatechuic acids and rutin-quercetin. With 200 mg/L, the combinations of gallic-protocatechuic and gallic-caffeic acids and quercetin-rutin produced a cooperative synergistic effect with cell death. With the addition of 100 mg/L, only quercetin-rutin mixture produces the same effect. These combinations were selected to be probed in meat. At 20 °C, 100 mg/L of gallic-protocatechuic acids, gallic-caffeic acids and rutin-quercetin combinations decreased the growth of L. monocytogenes with respect to control meat. The addition of 200 mg/L, increased the inhibitory effect on the growth of gallic-protocatechuic acids combination at the end of incubation. In these conditions, gallic-caffeic acids and rutin-quercetin combinations produced cellular death. At 4 °C, treatment with 100 mg/L produced death of inoculated cells with all combinations. The addition of 200 mg/L of these combinations increased these lethal effects. Gallic-caffeic acids and rutin-quercetin were the most effective combinations since at 14 days incubations no viable cells were detected. The lowest decimal reduction times corresponding to 1.0 and 0.95 day were found for gallic-caffeic acids and rutin-quercetin combinations, respectively. These demonstrate that phenolic compound combinations were effectives to reduce the 90 % of the viable cells of L. monocytogenes in approximately 1 day. These results will permit to formulate new antimicrobial products such to be used as natural food preservatives or to be included in the human diet.