Artisanal Vlasina Raw Goat's Milk Cheese: Evaluation and Selection of Autochthonous Lactic Acid Bacteria as Starter Cultures

Abstract

The aim of this study is the isolation, characterization and identification of autochthonous lactic acid bacteria (LAB) from artisanal Vlasina raw goat's milk cheese for the selection of potential starter cultures. Soft white Vlasina cheese was manufactured at a household on the Stara Planina Mountain using traditional techniques without starter cultures. One hundred and forty nine LAB isolates were collected from two samples of Vlasina cheese, designated as BGVL2 (5 days old) and BGVL2a (15 days old). The population of LAB in the cheese samples was characterized by phenotype-based assays and presumptively identified using repetitive element palindromic polymerase chain reaction (rep-PCR) with the primer (GTG)5. Results were 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-day-old BGVL2a (93 isolates), Lactobacillus plantarum (33), Enterococcus durans (26) and Pediococcus pentosaceus (14) were predominant. Lc. lactis ssp. 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, which belonged to the species Ln. pseudomesenteroides, utilized citrate and produced diacetyl and acetoin. They appeared to be suitable candidates for inclusion in the starter culture. This study contributed to the understanding of the role of autochthonous LAB in the quality of artisanal cheese and the possibility of using the selected LAB as potential starter cultures for cheese making under controlled conditions.

Keywords

• artisanal Vlasina cheese
• lactic acid bacteria
• rep-PCR
• 16S rDNA sequencing
• starter cultures