SCREENING, ISOLATION, AND PROBIOTIC POTENTIAL OF LACTIC ACID BACTERIA FROM EGYPTIAN HUMAN AND COW MILKS

Abstract

Human and cow milk are recognized as rich sources of beneficial microorganisms that contribute to the development of infant gut microbiota. This study aimed to isolate, identify, and evaluate novel lactic acid bacterial (LAB) strains from human and cow milk for their probiotic and technological potential. A total of fourteen LAB isolates were identified using 16S rRNA gene sequencing. All isolates exhibited high survival rates under simulated gastrointestinal conditions, showed resistance to lysozyme, and demonstrated cholesterol assimilation capacities ranging from 21.35% to 38.50%. Antagonistic activity assays confirmed that all isolates exhibited moderate inhibitory effects against pathogenic bacteria, indicating significant antimicrobial potential. Overall, Enterococcus faecium C₁, Lacticaseibacillus rhamnosus C₈, Enterococcus mundtii H₂, and Enterococcus hirae H₁₀ possesses desirable probiotic characteristics, including gastrointestinal resilience and pathogen inhibition. These findings highlight their potential application as novel starter or co-cultures in functional dairy products. This study provides a basis for future investigations into LAB strains as probiotic candidates for improving the safety, quality, and health benefits of functional dairy foods.