Isolation and identification of the indigenous lactic acid bacteria from Lighvan cheese

Milk، curd، fresh (1-day old) and ripened (90-days old) Lighvan cheese (10 samples from each one) have been investigated for lactic flora as one the most well-known starter free sheep raw milk cheeses. MRS، MRS+vancomycin، M17 and KAA media were used for determining of Lactobacilli and Pediococci، Leuconostocs، Lactoccoci and Enterococci genera، respectively. Isolated strains were identified up to genus level with gram staining and catalase test، morphology، colony pigmentation،gas production from glucose،growth in 10°C and 45°C،salt tolerance،growth at pH9. 6، argenine hydrolysis and citrate utilization. Random colonies were selected from each medium and confirmatory tests showed Enterococcus (33. 68%)، Lactobacillus (33. 68%) and Lactococcus (26. 31%) as the most common genera during the all stages. Finally، these isolated colonies were subjected to carbohydrate fermentation with API 50 CH and API 20 STREP methods and were determined up to species and sub species level. Totally،95 strains were isolated and identified during all production stages. API system results showed the following species: Lactobacillus plantarum، Lb. brevis، Lb. paracasei ssp. paracasei، Lb. delbrueckii ssp. delbreuckii، Lb. fructivorans، Lac. lactis. ssp. lactis، Enterococcus. faecalis، Ent. faecium، Ent. durans، P. pentosaceus، Leu. lactis، Leu. mesenteroides. The lactic acid bacteria changes revealed the pattern that Lactococcus and Lactobacillus were predominant at the first stages and replaced by Enterococcus at the end of production and ripening stage. The most dominant species during all satages follows as: Lac. Lactis ssp. lactis (25. 26%)، Lb. plantarum (20%)، Ent. Faecalis (15. 78%)، Ent. faecium (15. 78%). Thus، we expect that these species may play an important role in ripening and production of Lighvan cheese and also have potential application in industrial scale.