Antilisterial potential of enterocin produced by Enterococcus faecium 3BWK isolated from Minas Frescal cheese

Abstract

Minas Frescal cheese is widely produced and consumed in Brazil, valued for its low cost, simple production process, and the diversity of lactic acid bacteria (LAB) it harbors. LAB have become highly relevant in food science and technology due to their role as starter cultures and their ability to produce antimicrobials, such as bacteriocins—ribosomally synthesized antimicrobial peptides. This study aimed to isolate LAB from artisanal Minas Frescal cheese and assess their potential to produce bacteriocins. LAB isolation was performed using ten cheese samples purchased from artisanal producers in Londrina, Paraná. A bacteriocin-producing strain was isolated and identified as Enterococcus faecium 3BWK based on partial 16S rRNA gene sequencing. To optimize bacteriocin production, a production curve was established, with maximal production observed at 24 h of fermentation. The antimicrobial activity of the bacteriocin was confirmed using well diffusion assays against Listeria species: L. monocytogenes Scott A, L. ivanovii CLIST 02057, L. innocua CLIST 02052, L. monocytogenes CLIST 02044 and the antibacterial activity remained stable at various temperatures, with optimal stability at −20 °C and 4 °C with a decrease from 60 °C. Additionally, retaining activity across a broad pH range, with maximal stability at pH 8. Thus, the peptide demonstrated significant activity against Listeria spp. and promising stability for application in ready-to-eat food products.