A research about viable Lactobacillus bulgaricus and Streptococcus thermophilus numbers in the market yoghurts.

Abstract: The industrial production of yoghurt is increasingly developed in the world. Yoghurt is a fermented milk product obtained from fermentation of Lactobacillus bulgaricus and Streptococcus thermophilus strains. In Turkey, yoghurt is produced by the two ways; one of them is a traditional method without using starter culture in small dairy plants and the second production method by using industrial starter culture in modern plants. In this study yoghurt samples were collected from the local markets which were produced traditional process and produced in modern plants by addition of starter cultures, their viable L. bulgaricus and S. thermophilus bacteria numbers, coliform, Escherichia coli, yeast and mould counts, pH values were determined and compared each others. Yoghurts have pH values between 3.95-4.23, viable S. thermophilus and L. bulgaricus numbers were determined between 10-10 cfu/g for yoghurts producing with starter culture, 10-107 8 5 6 cfu/g and 10-10 cfu/g for yoghurts producing with traditional methods, respectively. Coliforms, E. coli, yeast6 7 and mould counts have at low numbers for all yoghurt samples. As the result, yoghurts which are produced by starter cultures have high numbers of yoghurt bacteria means that yoghurts produced by using starter cultures have higher therapeutic and/or antimicrobial properties beside of their organoleptic characteristics. Importance of yoghurt production by using starter cultures should be known and advantages of using starter cultures in fermentation products should be stated.