Evaluation of antimicrobial activity from native wine yeast against food industry pathogenic microorganisms

Currently, there is a worldwide trend toward the food consumption without the use of preservatives. For this reason, biocontrols have emerged as a natural option to replace preservatives. We identify and select native wine yeasts with antimicrobial activity (AA) that work against pathogenic bacteria of food importance. We evaluated the antimicrobial capacity of 103 yeast against Salmonella typhimurium, Listeria monocytogenes, and Escherichia coli, by measuring the growth inhibition. AA was qualitatively determined by measuring the inhibition zone diameter accompanied by death zone of target cells. Results revealed that nine yeast strains showed AA against the three pathogens, being mainly of the genera Pichia, Candida, and Saccharomyces. To determine the type of AA, the viability was assessed by the method of SYTOX Green (R). The results suggest that yeast exhibit AA bactericidal type. Thus, the use of yeasts arises as a natural and safe for the biocontrol of bacterial growth alternative. RESUMENActualmente existe una tendencia mundial por el consumo de alimentos sin el uso de preservantes. De esta forma, biocontroladores han emergido como una opcion natural para reemplazar preservantes. En este estudio se identificaron y seleccionaron levaduras vinicas con actividad antimicrobiana (AA) frente a bacterias patogenas. Evaluamos la capacidad antimicrobiana de 103 levaduras contra Salmonella Typhimurium, Listeria monocytogenes y Escherichia coli, determinando la inhibicion del crecimiento. La AA se determino cualitativamente midiendo el diametro de la zona de inhibicion acompanado de la zona de muerte de las celulas diana. Los resultados mostraron que 9 cepas de levadura mostraron AA frente a los tres patogenos, siendo principalmente de los generos Pichia, Candida, Saccharomyces y Metschnikowia. Para determinar el tipo de AA, se evaluo la viabilidad usando SYTOX Green (R). Los resultados sugieren que las levaduras presentan un tipo de AA bactericida. Asi, el uso de levaduras surge como una alternativa natural y segura para el control biologico del crecimiento bacteriano.