# Lacticaseibacillus rhamnosus WH.FH-19: Probiotic Traits, Fermentation Performance, and Potential for Functional Fermented Milk Production

## TL;DR

A new probiotic strain, Lacticaseibacillus rhamnosus WH.FH-19, shows strong probiotic and fermentation properties for making functional dairy products.

## Contribution

L. rhamnosus WH.FH-19 demonstrates superior probiotic and technological performance compared to the widely used L. rhamnosus GG strain.

## Key findings

- L. rhamnosus WH.FH-19 shows enhanced epithelial adhesion, gastrointestinal tolerance, cholesterol assimilation, and antioxidant activity.
- The strain exhibits vigorous growth and rapid acidification in milk, with improved safety and sensory attributes in co-culture fermentations.
- Optimal synergy with L. bulgaricus and S. thermophilus improves fermentation kinetics and product quality without post-acidification.

## Abstract

Lacticaseibacillus rhamnosus WH.FH-19 exhibits robust probiotic and technological traits for fermented dairy applications. L. rhamnosus WH.FH-19 shows superior functional potential compared to the benchmark strain Lacticaseibacillus rhamnosus GG. Kinetic studies confirm L. rhamnosus WH.FH-19’s vigorous growth and rapid acidification kinetics in bovine milk. In vitro characterization reveals enhanced probiotic properties, including significantly greater epithelial adhesion, tolerance to gastrointestinal stresses, cholesterol assimilation capacity, and antioxidant activity. Comprehensive safety assessment demonstrated the absence of hemolysis, sensitivity to clinically relevant antibiotics, and negligible tyramine production. Optimal synergistic fermentation with L. bulgaricus CICC 6047 and S. thermophilus CICC 6038 was achieved using a defined inoculum ratio. Under these conditions, L. rhamnosus WH.FH-19 specifically potentiated the activity of the S. thermophilus strain, accelerating fermentation kinetics without subsequent post-acidification while improving product sensory attributes. These findings establish L. rhamnosus WH.FH-19 as a safe, functionally robust probiotic with significant technological benefit for commercial fermented dairy production.