title: Enterococcus populations in artisanal Manchego cheese: biodiversity, technological and safety aspects.
abstract: Enterococci represent a considerable proportion of the microbiota in Manchego cheeses. In this study, a total of 132 enterococci isolated from good quality Manchego cheeses from two dairies at different ripening times were genotypically characterized and identified using molecular techniques. Representative isolates from the clusters obtained after genotyping were assayed for some enzymatic activities considered to have a potential role in cheese ripening, and for 2,3-butanedione and acetoin production, evaluation of odor intensity and appearance in milk and safety evaluation. Enterococcus faecalis was the predominant specie, accounting for 81.8% of the total isolates, while Enterococcus faecium, Enterococcus hirae and Enterococcus avium were present in low proportions. The number of genotypes involved at each ripening time varied both between dairies and with the ripening times; genotype E. faecalis Q1 being present in almost all the samples from both dairies. Eight isolates showed a higher proteolytic activity and 3 isolates produced high quantities of acetoin-diacetyl, for which reason they are interesting from a technological standpoint. A low antibiotic resistance was found and almost all the strains were susceptible to clinically important antibiotics. On the contrary, only four isolates (E. faecalis C4W1 and N0W5, and E. faecium N32W1 and C16W2) did not harbor some of the virulence genes assayed.
authors.affiliation: Departamento de Química Analítica y Tecnología de Alimentos, Facultad de Químicas, Universidad de Castilla-La Mancha, Avda. Camilo José Cela s/n, 13071 Ciudad Real, Spain.
authors.forename: Pedro
authors.initials: P
authors.lastname: Nieto-Arribas
authors.forename: Susana
authors.initials: S
authors.lastname: Seseña
authors.forename: Justa M
authors.initials: JM
authors.lastname: Poveda
authors.forename: Rosa
authors.initials: R
authors.lastname: Chicón
authors.forename: Lourdes
authors.initials: L
authors.lastname: Cabezas
authors.forename: Llanos
authors.initials: L
authors.lastname: Palop
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics; D044822:Biodiversity; D002611:Cheese / Q000382:microbiology*; D003931:Diacetyl / Q000378:metabolism; D016983:Enterococcus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology; D059022:Food Safety; D008969:Molecular Sequence Data; D010802:Phylogeny
chemical_list: D001426:Bacterial Proteins; D003931:Diacetyl