Consumer Perception, Sensory Acceptance, and Microbial Characterization of Artisanal Milk Kefir During Shelf Life

Milk kefir is a traditional fermented beverage with a complex microbiota of bacteria and yeasts that contributes to its distinctive sensory profile and functional properties. Artisanal kefir, in particular, preserves this natural microbial diversity but faces challenges related to sensory stability and limited shelf life. This study investigated the physicochemical, microbiological, metagenomic, and sensory characteristics, as well as gastrointestinal survival, of artisanal kefir samples stored for 0, 15, and 30 days. The physicochemical and microbiological parameters remained within the limits established by Brazilian legislation throughout storage. Metagenomic analysis revealed changes in microbial composition, with reductions in certain bacterial species and alterations in the relative abundance of fungal genera over time. Simulated gastrointestinal survival tests confirmed the stability of bacterial populations, indicating the maintenance of probiotic potential. Sensory analysis demonstrated general acceptance of the product, with significant differences detected mainly in texture. The analysis of social representations highlighted associations with health, naturalness, and positive consumer perceptions. Together, these findings show that artisanal kefir remains safe, microbiologically stable, and acceptable to consumers for at least 30 days, providing insights that can guide future standardization and commercial development strategies. Practical Applications Artisanal kefir showed physicochemical, microbiological, and sensory stability for up to 30 days, maintaining its probiotic potential and consumer acceptance. These findings contribute to strategies for standardization, increased shelf life, and strengthened commercial development of the product.