Probiotic potential, safety assessment, and functional properties of lactic acid bacteria from camel milk

Camel milk is one of the most valuable food sources in the Algerian desert. Furthermore, it is a strong candidate for use as a functional food because it contains beneficial microorganisms that promote health. The present study investigates 144 lactic acid bacteria isolated from camel milk, examining their probiotic, safety, technological, and antioxidant properties. Of these, 19 lactic acid bacteria showed very high tolerance to the simulated gastric environment and were selected for further analyses. According to the sequence analysis, 15 isolates were identified as Lactiplantibacillus plantarum, 3 as Lactobacillus gasseri, and 1 as Enterococcus faecium. The results indicated that all isolates demonstrated tolerance to bile salts, with levels ranging from 94.86 % to 102.81 %. It was established that none of the strains exhibited undesirable hemolysis, DNase and gelatinase activity, or transmissible antibiotic resistance. Furthermore, the absence of virulence or biogenic amine genes was confirmed. In particular, strain L. gasseri C1 showed remarkably high levels of auto-aggregation and hydrophobicity, which was also revealed in the principal component analysis. Furthermore, the strains exhibited potent antagonistic properties against various foodborne pathogens. Notably, several strains, including L. plantarum A5, A8, and BN2, and L. gasseri C1, showed specific antimicrobial activity against Listeria monocytogenes, potentially due to bacteriocin or other antimicrobial compounds production. Additionally, the majority of the isolates demonstrated bile salt hydrolysis activity, and all strains exhibited antioxidant activity by scavenging DPPH free radicals. Moreover, 11 L. plantarum isolates possessed the gad gene responsible for GABA production. These findings support the potential application of these isolates as probiotics in both food and therapeutic contexts.