Isolation and characterization of potential probiotic enterococci strains from soft cheese flora

Abstract

This study was conducted to determine the in-vitro probiotic properties of Enterococcus faecium strains isolated from soft cheese. To evaluate the safety of Enterococcus strains, we compared the pathogenic genes, antimicrobial susceptibility of the probiotic strains to those of clinical isolates, and their antimicrobial activity against food-borne pathogenic and spoilage bacteria. Enterococcus strains were identified and evaluated in vitro for biochemistry methods acid, bile salts, lysozyme and pancreatin tolerance. One hundred and three strains were identified as E. faecium, and none of them were no vancomycin-resistant, and no pathogenic genessuch as cylA, asa1, gelE, ace and cpdwere found. The isolates showed good viability at 120 and 240 min of incubation with pH 3.0, and were able to resist 0.3% and 0.1 g/ml of bile salts and pancreatic enzyme, respectively. One observed strong autoaggregation phenotype, and the isolates demonstrated high activity against L. innocua, L. monocytogenes, E. faecalis S. aureus, Salmonella Enteritidis and Salmonella Typhimurium. The results instigate the continuity of studies of E. faecium isolates in order to obtain a known probiotic strain.

SELECCIÓN Y CARACTERIZACIÓN DE CEPAS NATIVAS DE Enterococcus CON POTENCIALIDAD ANTIMICROBIANA AISLADAS DE QUESOS DE ELABORACIÓN ARTESANAL

“…Las cepas Enterococcus faecium QPa.1 y Enterococcus faecium QPa.2, aisladas de quesos de elaboración artesanal de la región de Puno, mostraron una actividad inhibitoria efectiva contra E. faecium QPe.1 y Listeria monocytogenes (Tablas 4 y 6, Figura 2). Diversos autores también reportaron que ciertas cepas de E. faecium asociados a leche de vaca (Banwo et al, 2013), quesos Koopeh de Iran (Hassanzadazar et al, 2014), quesos Coalho de Brasil (Freitas et al, 2013;Dos Santos et al, 2014) y quesos de cabra de Francia (Hammi et al, 2018), produjeron un efecto inhibitorio contra Listeria monocytogenes, con probabilidades de ser utilizados como probióticos y/o cultivos iniciadores (Banwo et al, 2013;Hassanzadazar et al, 2014;Furlaneto-Maia et al, 2017). La actividad antimicrobiana del sobrenadante neutralizado libre de células de la cepa seleccionada E. faecium QPa.1 fue completamente inactivada después de ser tratada con las enzimas proteolíticas tripsina y αquimotripsina, indicando que el compuesto inhibitorio es de naturaleza proteica (Tabla 5).…”

Aksaray İli̇nde Satişa Sunulan Tulum Peyni̇rleri̇nden İzole Edi̇len Enterokoklarin Anti̇bi̇yoti̇k Di̇rençli̇li̇kleri̇ İle Hemoli̇ti̇k Akti̇vi̇teleri̇ni̇n Beli̇rlenmesi̇

“…Their high ability to resist adverse environmental conditions, such as low pH and high salt concentrations, enables them to survive through cheese-making and ripening processes (Giraffa, 2003). Although many reports have been published regarding their positive contributions to cheese making technology in point of view of aroma production (Martino et al, 2016) and inhibition of several foodborne pathogens (Maia et al, 2017), they are not recognized as safe, unlike other LAB. Thus, the use as a starter or probiotic is still under debate, and they arenot listed in the QPS (qualified presumption of safety) approaches declared by the European Food Safety Authority (EFSA, 2013).…”