# Autochthonous Human Milk Lactobacillus Strains as Potential Probiotic Starter Cultures

## TL;DR

This study identifies beneficial bacteria from human milk that could be used as probiotic starter cultures in dairy products.

## Contribution

The study isolates and evaluates novel lactobacilli strains from human milk for use as functional starter cultures.

## Key findings

- Three strains showed high casein degradation, antimicrobial activity, and antioxidant properties.
- The selected strains survived well during freeze-drying, a key technological requirement.
- Human milk is highlighted as a valuable source of lactic acid bacteria with functional potential.

## Abstract

Human milk is rich in bioactive molecules and beneficial bacteria that contribute to shaping the newborn's microbiota. In this study, we aim to evaluate lactic acid bacteria strains isolated from human milk of healthy Croatian women as potential functional starter cultures.

In order to define novel potential probiotics for use in dairy products, eight strains of lactobacilli were analysed for their proteolytic, antimicrobial and antioxidant activity as well as their survival rate during freeze-drying.

Based on the results obtained, the exopolysaccharide-producing Limosilactobacillus fermentum MC1, the surface (S)-layer-producing Levilactobacillus brevis MB2 and the plantaricin-producing Lactiplantibacillus plantarum MB18 strains are candidates for the production of fermented dairy products with potential functional and nutritional relevance for the host. The selected strains exerted high casein degradation capacity, a broad spectrum of antimicrobial activity and a promising 2,2-diphenyl-1-picrylhydrazyl hydrate radical scavenging activity. They also fulfilled the primary technological criterion by having a high survival rate during freeze-drying.

The data presented emphasise the importance of human milk as a valuable source of lactic acid bacteria with unique technological and functional properties, which are important both as a basis for scientific research and for the development of novel starter cultures for functional products.