A research of starter properties of Lactobacillus bacteria isolated from traditional Turkish cheese samples

Lactic acid bacteria (LAB) are bacterias used in the production of food dairy products. LABS include large number of bacteria types such as Lactobacillus, Lactococcus, tetracoccus, Leuconostoc, and Bifidiobacteria.. One of the most important types of LAB is Lactobacillus. The micro-organisms in this type can be found in fermented foods other than the gastrointestinal system. Lactobacillis are associated with the formation of cheese ripening and flavor as starter and / or support culture or non-starter microflora. In this study, the starter features of 18 units of Lactobacillus bacteria which are previously isolated and identified by 16sRNA; its hydrogen peroxide, lipolytic, proteolytic activity levels and its antimicrobial activity on some pathogenic test bacteria (Esericiha e coli ATCC 35218, Staphylococcus aureus ATCC 25923, Bacillus cereus RSKK 863, Salmonella enteritidis ATCC 13076) are examined. Furthermore, its ability to produce hydrogen sulfide was detected. 6 of the 18 Lactobacillus species used in the study are Lb. Rhamnosus, 5units are Lb. Fermentum, 5 units are Lb. Brevis, one unit from Lb. helveticus ve Lb. Casei. The proteolytic activities of Lactobacillus strains were determined with MRS and disk diffusion method in 10% Skim Milk medium. While the Proteolytic activity zone diameters of these bacteria in MRS medium as 1.26 ? 2.09 cm, in Skim Milk they were determined as 1:09 to 1:33. Lipolytic activities of Lactobacillus strains were determined by YSB agar disc diffusion method in medium . In only 8 of the Lactobacillus strains proteolytic activity was observed. The proteolytic activities of these strains were found between 0.97 - 1.27 mm zone diameters, respectively. The proteolytic activities of these strains were found between 0.97 - 1.27 mm zone diameters, respectively. None of the Lactobacillus strains produced H2S in TSI medium. The antimicrobial activities of Lactobacillus strains were searched on pathogenic bacterias by diffusion agar method (Escherichia coi, Staphylococcus aureus, Bacillus subtilis, Salmonella enteritidis). It was determined that all Lactobacillus species other than Lb. brevis KIR3 has a general inhibition on pathogenic bacteria which were tested. The effect of inhibitor substances of Lb. fermentum BP5 strain was observed on E. coli ATCC 3528 except the lactic acid. No effect of other inhibitor substances of Lactobacillus strains was observed on all test bacteria tested except lactic acid.