Probiotic, technological and health-related characteristics of lactobacilli isolated from breast milk.

Abstract

Isolation and characterisation of lactobacilli from human milk and determination of their probiotic, technological and in vitro health-promoting properties with a view to their potential use in food fermentation. Seven lactobacilli isolates were obtained from human milk and identified as Lacticaseibacillus paracasei (isolates BM1-BM6) and Lactobacillus gasseri (BM7). The isolates were examined in vitro for their technological, probiotic and health-promoting potential. Overall, all isolates showed important technological properties based on the ability to grow in milk whey, a high to moderate acidification capacity and the absence of undesirable enzymatic activities. L. gasseri (BM7) differed from the L. paracasei isolates by the absence of several glycosidases and the inability to ferment lactose. Isolates L. paracasei BM3 and BM5 produced exopolysaccharides (EPS) from lactose. All isolates showed probiotic potential as they were tolerant to simulated gastrointestinal conditions, had high cell surface hydrophobicity, had not acquired resistance to relevant antibiotics and had no virulence characteristics. All L. paracasei showed high antimicrobial activity against various pathogenic bacteria and fungi, while L. gasseri showed a narrower spectrum of antimicrobial activity. All isolates showed health-promoting potential in vitro, as evidenced by high cholesterol-lowering activity, high ACE inhibitory activity and marked antioxidant activity. All strains showed excellent probiotic and technological properties for use in lactic ferments. Lactobacilli are an important part of the microbial population in human milk. A more detailed characterisation of these bacteria can contribute to the understanding of their functional and health importance for infants and to the selection of new probiotic strains for the dairy industry.