Artisanal vlasina raw goat's milk cheeses: Evaluation and selection of autochthonous lactic acid bacteria as starter cultures

Abstract

The aim of this study was the isolation, characterization and identification of autochthonous lactic acid bacteria (LAB) from artisanal Vlasina raw goat's milk cheeses for the selection of potential starter cultures. Soft white Vlasina cheeses were manufactured at a household on the Stara Planina Mountain without starter cultures using traditional techniques. One hundred and forty nine LAB isolates were collected from two samples of Vlasina cheeses, designated as BGVL2 (5 days old) and BGVL2a (15 days old). The population of LAB in cheeses has been characterized by phenotype-based assays and presumptively identified using repetitive element palindromic-polymerase chain reaction (rep-PCR) with the primer (GTG)5. Results have been confirmed by 16S rDNA sequencing. Among the BGVL2 isolates (56), the most numerous LAB species were Leuconostoc pseudomesenteroides (27) and Lactococcus lactis (26). In 15 d-old BGVL2a (93 isolates), Lactobacillus plantarum (33), Enterococcus durans (26) and Pediococcus pentosaceus (14) were predominant. Lc. lactis subsp. lactis BGVL2-8 showed good acidification ability and the ability to produce antimicrobial compounds, Lb. plantarum BGVL2a-18 had good proteolytic ability and produced exopolysaccharides while BGVL2-29 and BGVL2-63 that belonged to the species Ln. pseudomesenteroides utilized citrate and produced diacetyl and acetoin. They appeared to be suitable candidates for inclusion in a starter culture. This study contributed to the understanding of the role of autochthonous LAB on quality of artisanal cheeses and the possibility of using the selected LAB as potential starter cultures for cheese making under controlled conditions.