Title : Probiotic potential and safety analysis of lactic acid bacteria isolated from Ethiopian traditional fermented foods and beverages
Abstract:
Probiotics are live microorganisms that effectively combat foodborne pathogens, promoting intestinal health when consumed in sufficient amounts. This study evaluated the probiotic potential and safety analysis of lactic acid bacteria from Ethiopian traditional fermented foods and beverages, including Kotcho, Bulla, Ergo, Cabbage-Shamita, Borde, and Bukuri. The bacteria were characterized through morphological, physiological, biochemical, and MALDI ToF/Mass analysis. To assess their probiotic activity, the tolerance and survival rate of LAB to a variety of stress conditions, including low pH, intestinal inhibitor substances, salt concentration, bile salt, stimulated gastric/intestinal juice, and low pH, were studied. LAB isolates were also tested for antagonistic activity against common bacterial pathogens such as S. aureus, S.Thyphimurium, E. coli, P. aurugionsa, K. pnemonia, and C. albacans. Furthermore, the safety analysis (auto-aggregation, co-aggregation, cell source hydrophobicity, hemolytic activity, DNase and antibiotic susceptibility) were evaluated to determine the safety issue of LAB isolates. About 125 probiotic lactic acid bacteria were identified in this study. Out of 125 isolates, 54 LAB isolates survived low pH (2, 2.5, and 3), bile salt (0.3%), intestinal inhibitor chemicals (phenol, bile, low acidity, pepsin, and pancreas), and stimulated gastro-intestinal settings with a near 60–94% survival rate. The isolates' ability to withstand acids, intestinal inhibitor chemicals, stimulated intestinal circumstances, and bile salt tolerance, as well as effective antagonistic activities, contributes to good and more effective antagonistic activity against all selected foodborne pathogens. All 54 LAB isolates were resistant to Amplicin, Vancomycin, Gentamycin, Kanamycin, Clindamycin, and Chloramphenicol, while they were susceptible to Streptomycin and Tetracycline. The seventeen efficiency probiotic LAB isolates were identified using MALDI TOF Mass spectrometry as belonging to Pediococcus, Enterococcus, and Lactococcus species, including P.pentosasceus, E.faecium, L.lactis, and P.acidilactic. Hence, all 54 LAB strains were found to be the most potentially lactic acid bacteria, and they were selected as potential probiotic LAB that can be applied as the best starter culture and bio-preservative for the enhancement of food shelf life. This study established the groundwork for the selection of excellent probiotic candidates, as well as the development and application of LAB for possible antibacterial action, starter culture production, and preservation activities.
Keywords: Antimicrobial activity, Ethiopian, Lactic acid bacteria, Probiotic potential, Traditional fermented products
