Autochthonous microflora of Sjenica cheese

Abstract

Autochthonous isolates of lactic acid bacteria and enterococci, from Sjenica cheese had been isolated and identified. From 10 samples of Sjenica cheese that were traditionally produced without starter cultures, 53 thermophile mesophile and citrate (+) isolates were isolated using selective media (MRS agar, M17 agar, LDCagar i LDV agar). According to Gram staining, cell morphology and catalase test, it was determined that all isolates were pure culture of G (+) and catalase (-) bacteria, 21 bacilli and 35 cocci. For the purpose of diferentiation enterococci and lactococci, growth of all cocci bacteria was examined on 6,5% NaCI, pH 9,6 and heat treatment 60°C 20 min. Out of 35 cocci isolates, 7 isolates were able to grow at these conditions. Identification by API CHL 50 test for lactobacilli and RAPID ID 32 Strep for cocci, showed that isolates were Lactococcus lactis ssp. lactis Lactobacillus paracasei ssp. paracasei, Lactobacillus plantarum, Lactococcus lactis ssp. lactis boiv. dicetylactis, Lactobacillus curvatus, Lactobacillus brevis, Leuconostoc sp. i Enterococcus sp. Dominant lactococci strain was Lactococcus lactis ssp. lactis (35,85%) and for lactobacilli Lactobacillus paracasei ssp. paracasei (18,86%). Strains from genus Enterococcus sp. had the rate of 13,20%.

U radu su izdvojeni i identifikovani izolati bakterija mlečne kiseline i enterokoka iz sjeničkog sira, proizvedenog na tradicionalan način, bez dodavanja starter kulture. Iz 10 uzoraka sjeničkog sira izdvojeno je 53 termofilna, mezofilna i citrat+ izolata na odgovarajućim selektivnim podlogama (MRS agar, M17 agar, LDCagar i LDV agar). Postupkom bojenja po Gramu, mikroskopskim pregledom i katalaza testom je utvrđeno da svi izolati predstavljaju čiste kulture Gram-pozitivnih i katalaza-negativnih bakterija pri čemu je utvrđeno da je 21 izolat štapićastog, a 35 okruglastog oblika. Radi razdvajanja enterokoka od laktokoka, za sve okruglaste forme je ispita-na sposobnost rasta pri 6,5% NaCI, pH 9,6 i nakon termičkog tretmana na 60°C 20 minuta je utvrđeno da od 35 izolata okruglastog oblika, 7 izolata podnosi navedene uslove. Determinacijom dobijenih izolata primenom API sistema i to za štapičaste oblike API CHL50testa, a za okruglaste oblike RAPID ID 32 Strep sistema, utvrđeno je da izolati pripadaju vrstama Lac-tococcus lactis ssp. lactis, Lactobacillus paracasei ssp. paracasei Lactobacillus plantarum, Lactococcus lactis ssp. lactis boiv. dicetylactis Lactobacillus curvatus, Lactobacillus brevis, Leuconostoc sp. i Enterococcus sp. Ubedljivo najveću zastupljenost je imala okruglasta vrsta Lactococcus lactis ssp. lactis (35,85%), a od štapićastih, vrsta Lactobacillus paracasei ssp. Paracasei (18,86%). Vrste roda Enterococcus sp. bile su zastupljene sa 13,20 %.