Functional Attributes of Gut Guardians: Probiotic Potential of Lactobacillus strains isolated from Traditional Nepalese Fermented Foods

The interplay between the gut microbiome and fermented foods has significant implications for human health and nutrition. Fermented foods, rich in beneficial microorganisms such as Lactic Acid Bacteria (LAB) including Lactobacillus spp., have attracted considerable research interest due to their potential probiotic effects. The six Nepalese fermented foods selected for this research—homemade yogurt, commercial yogurt, gundruk, tama, chhurpi, and achaar—are recognized for their diverse microbial profiles and purported health benefits, commonly consumed across various regions of Nepal. This study aims to elucidate their probiotic potential through tests such as acid and salt tolerance and their antimicrobial effects against five pathogens (Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, and Salmonella spp.). A total of 120 samples of these six different fermented foods were collected from households and local markets in Chitwan District. Among 120 fermented food samples, 103 samples (85.83%) were found to be LAB positive. Out of the total sample, 64 samples (53.30%) were found to be Lactobacillus spp. positive. These positive isolates were further tested for their pH tolerance, NaCl tolerance, and antibacterial potential. Upon research, 18 isolates were found to be tolerant at pH 2, and 21 isolates were found to be tolerant at 8% NaCl concentration. The highest antibacterial effect of Lactobacillus spp. was found against Staphylococcus aureus with ZOI 18 mm and lowest against Escherichia coli. The study here contributes to the importance of utilizing the microbial diversity present in fermented foods, along with providing valuable insights for developing novel probiotic interventions for enhancing gut and overall health. Moreover, the research highlights the potential of traditional fermented foods as a valuable source of probiotic strains, paving the way for innovative approaches to improve health through diet.