Evaluación de la actividad inhibitoria in vitro de Lactobacillus spp. aislado de yogures comerciales expendidos en la ciudad de Cuenca frente a Staphylococcus aureus ATCC 29213 y Escherichia coli ATCC 25922

Abstract

Currently, the use of chemical preservatives in yoghurt raises questions about food safety. However, yoghurt consumption provides benefits due to its probiotics, with the Lactobacillus genus capable of producing postbiotics as a product of its metabolism. The aim of this work was to evaluate the in vitro antibacterial activity of Lactobacillus spp. isolated from commercial yoghurts (TN, NT, AP and PC) against Staphylococcus aureus ATCC 29213 and Escherichia coli ATCC 25922 by estimating the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) using the broth microdilution technique; the supernatant of the Lactobacillus culture was used as the antibacterial agent. The study demonstrated that the MIC of Lactobacillus spp. against Staphylococcus aureus ATCC 29213 of TN and PC was 12.5% and the MBC was 25%. The MIC of NT was 25% and the MBC was 50%. AP has MIC of 50% and MBC of over 50%. While against Escherichia coli ATCC 25922, the MIC was 12.5% and the MBC 25% for TN, NT and PC, for AP the MIC was 25% and the MBC 50%. It was concluded that the concentration of Lactobacillus in commercial yoghurts is not sufficient to exert an optimal biopreservative effect. However, postbiotics have a significant capacity to counteract several pathogenic bacteria and could therefore be a strategy to improve food safety and provide health benefits to the consumer.