Weissella confusa in fermented foods and beyond: A comprehensive review of probiotic functions, metabolite biosynthesis, stress adaptation, and application prospects.

Weissella confusa, a heterofermentative lactic acid bacterium widely distributed in fermented foods, plant surfaces, animal habitats, and the human gut, has emerged as a focal point of microbiological research becaues of its diverse metabolic functions, environmental resilience, and the potential probiotic traits exhibited by certain strains. This review summarizes current research on W. confusa from four dimensions: its probiotic-related functions and health-promoting mechanisms, key metabolites and biosynthetic pathways, stress resistance mechanisms, and potential applications. Specifically, we highlight strain-level evidence for reinforcing intestinal-barrier integrity, modulating immune responses, exerting antioxidant and antimicrobial activities, and showing antitumor effects in preclinical studies, primarily from in vitro and animal studies Biosynthesis and regulatory networks of exopolysaccharides, bacteriocins, organic acids, and other bioactive molecules are discussed, along with omics-based insights into adaptation to gastrointestinal (acid, bile) and industrial (osmotic, heat, oxidative) stresses. A central emphasis is the gap between preclinical findings and clinical application. Since safety is strain-specific and cannot be generalized, rigorous strain-level assessment is essential. Key research priorities include establishing strain-specific safety frameworks, conducting human trials, and clarifying molecular determinants that distinguish beneficial from pathogenic strains. This review aims to provide a theoretical basis for the application of W. confusa in health, food, and biotechnology that ensures its safety while fully realizing its potential value.