Probiotic properties and safety assessment of Enterococcus durans DMGUD5 and its suitability as a dairy starter culture to manufacture fermented dairy product

Abstract

This study aimed to isolate and characterize exopolysaccharide (EPS)-producing lactic acid bacteria (LAB) from goat milk and evaluate their probiotic potential and suitability as starter cultures for fermented dairy products. Of the 60 LAB isolates, 19 demonstrated EPS production ability, of which six strains exhibited the highest EPS production. These isolates were identified by 16S rDNA sequencing and assessed for their probiotic properties, including acid and bile tolerance, survivability in simulated gastric and pancreatic juices, autoaggregation, cell surface hydrophobicity, lysozyme and phenol tolerance, antibacterial and antifungal activities, antioxidative capacity, and safety tests. Enterococcus durans DMGUD5 exhibited the most promising probiotic characteristics and was used to prepare fermented curd. The curd was analyzed for its proximate composition and shelf life, considering its sensory attributes, pH, probiotic viability, and microbial safety. DMGUD5 demonstrated high EPS production, superior acid and bile tolerance, strong survival under simulated gastrointestinal conditions, and significant antibacterial, antifungal, and antioxidative activities. The curd prepared using DMGUD5 had acceptable sensory properties and maintained probiotic viability above 6 log₁₀ CFU/g for eight days under refrigerated storage (41C). E. durans DMGUD5, exhibits promising probiotic properties and can be used as a starter culture for the production of functional fermented dairy products.