Screening of lactic acid bacteria isolated from locally fermented traditional foods for their probiotic potential.

Lactic acid bacteria (LAB) are key microorganisms responsible for the fermentation of traditional foods, they possess several functional traits that may qualify them as probiotics. The novelty of this study was achieved by a comparative probiotic screening across multiple food categories and different study sites using both molecular and cumulative scoring approaches. This study aimed to isolate, characterize, and assess the probiotic potential of new LAB strains obtained from commonly consumed Nigerian fermented foods. A total of 32 fermented food samples were collected from Southwestern Nigeria and analyzed using microbiological, biochemical, and molecular methods. 21 LAB isolates were obtained, and their safety, technological, and probiotic attributes were assessed through standard in vitro assays. Statistical analysis was performed using one-way ANOVA (SPSS 27.0). The five most promising isolates were identified molecularly using 16SrRNA gene sequencing. Five top-performing strains namely—Pediococcus pentosaceus (2 isolates), Enterococcus faecium (2 isolates), and Bacillus cereus (non-pathogenic strain) exhibited strong acid and bile tolerance, high auto-aggregation and hydrophobicity, and broad antimicrobial effects against enteric pathogens. Molecular sequencing confirmed ≥99% identity to reference probiotic strains. Indigenous Nigerian fermented foods harbor LAB with excellent probiotic properties and technological potentials. The isolates P. pentosaceus LoI52 and E. faecium NuE53 emerged as the most promising candidates for functional food development and probiotic applications. These findings suggest that traditional fermented foods are promising reservoirs of safe and effective probiotic LAB, which may serve as adjuncts in the therapy of gastrointestinal infections and form the basis for indigenous probiotic product development in Nigeria.