Isolation and characterization of autochthonous strains of lactic acid bacteria isolated from sjenica cheese

Abstract

Lactic acid bacteria strains isolated from autochtonous cheeses of Sjenica were researched. In those products, where starters were not added fermentation occurs as a result of natural flora present in the surrounding environment. Forty thermophilic, mesophilic and citrat+ LAB strains were isolated by selective mediums (MRS agar, LM17 agar and LDC agar) from 5 samples of Sjenica-cheese. These strains were exposed to the further analysis and indetification. After examination by Gram test and catalase test, 23 strains of LAB, were selected for further analysis. On the basis of lactose fermentation manner and acid production in 1% reconstituted skim milk, only 6 strains were selected. Determination of theese strains by API 50 CHL and Rapid ID 32 Strep tests, showed that 2 strains belong to the Lactococcus lactis ssp. lactis, 1 strain to the Lactococcus lactis ssp. cremoris, 1 strain to the Lactococcus lactis ssp. lactis bivar. diacetylactis and 2 strains to the Lactobacillus para. paracasei.

U radu su izolovani i karakterisani sojevi bakterija mlečne kiseline izdvojeni iz sjeničkog sira, proizvedenog autohtonom tehnologijom, bez dodavanja starter kultura. Iz pet uzoraka sjeničkog sira izvršena je izolacija 40 termofilnih, mezofilnih i citrat+ sojeva BMK na odgovarajućim selektivnim podlogama (MRS agar, LM17 agar i LDC agar). Ovi sojevi su dalje podvrgnuti ispitivanju na Gram reakciju i katalaza test, posle čega je izabrano 23 soja za dalja ispitivanja. Na osnovu načina fermentacije laktoze i acidogene sposonosti praćene u 1% rekonstituisanom obranom mleku selekcionisano je samo šest sojeva. Determinacijom ovih sojeva pomoću API CHL 50 i Rapid ID 32 Strep testa, pokazalo se da dva soja pripadaju Lactococcus lactis ssp. lactis, jedan soj Lactococcus lactis ssp. cremoris jedan soj Lactococcus lactis ssp. lactis bivar. diacetylactis i dva soja Lactobacillus para. paracasei vrsti.