Probiotic properties and safety aspect of three antifungal lactic acid bacteria strains isolated from wheat and camel milk

Demand for probiotics has increased significantly in recent years due to the growing consumer awareness of their benefits and advantages. In this study, we investigated the probiotic potential use of three antifungal lactic acid bacteria (LAB) strains namely Lactiplantibacillus pentosus 22B, Lactiplantibacillus plantarum 21B and Enterococcus faecium LC2V5 isolated from wheat and camel milk. A series of in vitro probiotic tests were performed to evaluate their functional and safety properties. Results indicated that consumption of these three strains does not present any health risk, as they showed no undesirable virulence factors (hemolysins and DNAse) or transmissible antibiotic resistance. All strains exhibited high tolerance to simulated oro-gastro-intestinal tract conditions since the number of viable cells was 109 CFU/mL after exposure to these digestive stress environments. Evaluation of cell surface characteristics revealed that the three strains showed high degrees of auto-aggregation, hydrophobicity and co-aggregation with pathogens. Moreover, the strains demonstrated strong antagonistic activity against all tested pathogenic bacteria (Salmonella typhimurium, Listeria monocytogenes, Klebsiella pneumoniae, Escherichia coli, Acinetobacter baumannii and Pseudomonas aeruginosa). Furthermore, they were able to produce exopolysaccharides and ferment lactose. The studied strains showed also antioxidant activity by scavenging 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radicals. In conclusion, the probiotic features demonstrated by the studied LAB strains suggest their suitability for potential use as probiotics.