Propionibacterium freudenreichii ssp. Shermanii is a probiotic bacterium traditionally used in cheese making, particularly Swiss-type cheeses. In recent years, scientific interest has increased regarding its immunomodulatory properties, including effects on the gut-associated lymphoid tissue (GALT), which encompasses Peyer’s patches. Peyer’s patches are important for the generation of mucosal immune responses. Several in vitro and animal studies have demonstrated that P. freudenreichii strains can modulate immune responses by interacting with intestinal epithelial cells and dendritic cells, influencing cytokine production, and enhancing the development of regulatory T cells within the GALT. Notably, research published in journals such as Applied and Environmental Microbiology and Frontiers in Immunology has shown that metabolites produced by this bacterium, especially short-chain fatty acids like propionate, can positively influence the health and function of Peyer’s patches by promoting anti-inflammatory pathways and supporting mucosal immunity.

However, while there is increasing experimental evidence from animal and in vitro studies suggesting a supportive effect on Peyer’s patches, robust human clinical trials are limited. Thus, the scientific evidence supporting the use of P. freudenreichii ssp. Shermanii specifically for Peyer’s patch support is promising but not yet definitive, warranting a moderate evidence rating.