Isolation, Characterization and Development of Starter Culture from Traditional Djibna baida Cheese

Aims: To characterize the technological capabilities of lactic acid bacteria isolated from traditional cheeses coagulated by Jibben with a view to optimizing their use as starters in the manufacture of local cheeses. Study Design: Descriptive study based on analyses, property tests and interpretations of results. Place and Duration of Study: The study was carried out in the city of N'Djamena at the food microbiology laboratory of the Institute for Research in Livestock for Development (IRED), between January, 2023 to June, 2024. Methodology: Lactic acid bacteria were isolated from 9 samples of artisanal cheeses produced from cow's milk coagulated by Jibben (Solanum dubium). The identification of lactic acid bacteria isolates were carried out using classical microbiological techniques, such as evaluating their morphological, physiological and biochemical characteristics. Technological capabilities and interactions studies were carried out, followed by fermentation profiling. Results: The results showed that the microbial population of selected cheese is dominated by Lactococcus (32.06%), mesophilic Lactobacillus (26.77%), and Leuconostoc (16.03%) bacteria. The study revealed the ability of some of the selected strains to rapidly produce lactic acid and cause a drop in pH. The interaction studies between the previously identified strains reflect to compose two mesophilic ferments FI and FII. The FI ferment is composed of four strains of the genus Lactococcus (Lc7, Lc8, Lc11 and Lc12) and one belonging to that of Leuconostoc (Leuc4). The second FII ferment contains two strains of Lactococcus (Lc15 and Lc16) and two others belonging respectively to the genus Leuconostoc (Leuc6) and mesophilic Lactobacillus (LbI1). The interaction between the strains was positive through the technological evaluation. The acidification and proteolysis rates as well as the lipolysis and texturizing power also gave interesting results. Conclusion: The study highlighted the satisfactory technological characteristics of ferment I consisting of lactic acid bacteria isolates. These strains, after further characterization and investigation, could be used as starter cultures to improve the traditional cheese-making process.