Isolation, identification and characterization of indigenous lactic acid bacteria for flavour improvement

The presence of lactic acid bacteria (LAB) in fermented foods improves the health safety of food. Flavour development in dairy fermentations rises from a series of biochemical processes, and to restore the unique characteristics of traditional dairy varieties is to evaluate new wild LAB strains being isolated from good quality raw-milk. In order to study LAB biodiversity and to evaluate their potential use, bovine milk samples were collected from different regions of Iran. A total of 26 LAB were isolated from the milk samples. The bacterial isolates were evaluated for autolysis, proteolysis, acidification and diacetyl production. Six LAB isolates were found to bear the best characteristics. These were applied to produce types of curds. The curds were tested for aroma and the best curd samples were identified by molecular techniques. Finally two new Enterococcus faecium subspecies were registered at GenBank data library of National Center for Biotechnology Information (NCBI). Rich biodiversity of natural environments can be considered as good sources of new LAB species or strains. The different combinations of strains LAB in cheese manufacturing can influence dairy products flavour, and acid production, autolysis, proteolysis and production of diacetyl can be considered for their use as starters or adjuncts.