Identification and characterization of lactic acid bacteria isolated from traditional yoghurts collected from Gaziantep province' s villages

Yoghurt is a dairy product obtained by bacterial fermentation of milk. Commercial yoghurts are produced using standard starters while, in the production of traditional yoghurt, the microbiota is quite different since yoghurts are used as starter for years. To determine the final characteristics of the fermented product it is necessary to know the biochemical properties of the starter cultures, such as acidity, aroma and flavor. This can only be achieved by identifying and characterizing the bacteria in starter cultures. In our study, 208 traditional yoghurt samples were collected from 9 different locations in Gaziantep. Their pH and lactic acid bacteria profiles were analyzed. Isolated bacteria were identified by MALDI-TOF (matrix assisted laser desorption-ionization time-of-flight) mass spectrometry, which is a fast and reliable method for identification of bacterial isolates compared to classical laboratory methods. In this study, 41% of the isolates were identified by using this method, which is 99.9% and 34.0% confidence. The isolates contained two genera (Enterococcus and Lactobacillus) and four species. Afterwards, the four lactic acid bacteria were characterized physiologically and biochemically and we found that they differed from lactic acid bacteria used in commercial yoghurt production.