Introduction: Fermentation is one of the oldest and most widely used food-processing technologies, transforming raw materials into safe, flavorful, and nutritionally enriched products. Fermented foods act as a natural source of diverse microorganisms, mainly lactic acid bacteria (LAB), yeasts, and molds, which contribute to the organoleptic, functional, and health-promoting qualities of these foods. Globally, the market value of fermented foods exceeds USD 600 billion, indicating their cultural and economic significance. In addition to improving shelf life through bio-preservation, fermentation enhances digestibility, reduces anti-nutritional factors, and generates bioactive compounds beneficial to human health.
Methods: This review is based on published literature retrieved from databases such as PubMed, Scopus, and Google Scholar using keywords including fermented foods, microbial diversity, probiotics, food safety, and health benefits. Additional insights were gathered from recent reports on microbial genomics and databases such as FermDB, which provide structured data on microbial species associated with traditional and industrial fermentations. Articles were selected based on relevance to microbial ecology, safety aspects, and functional health properties.
Results: Bacteria: LAB dominate most fermentations (Lactobacillus, Lactococcus, Leuconostoc, Streptococcus), while Bacillus species are common in alkaline fermentations. Other groups include Micrococcus, Staphylococcus, Bifidobacterium, Brevibacterium, and Propionibacterium. Opportunistic microbes like Enterobacter, Klebsiella, and Pseudomonas may appear if processing is inadequate.Yeasts and Molds: Saccharomyces, Candida, Debaryomyces, and molds (Aspergillus, Rhizopus, Penicillium, Monascus) are crucial for enzymatic degradation and flavor development.Production of bioactive metabolites such as short-chain fatty acids, bacteriocins, exopolysaccharides, and ACE-inhibitory peptides (VPP, IPP) supports gut health, immunity, and cardiovascular function.Postbiotics and paraprobiotics (cell components and metabolites) show emerging benefits like anti-inflammatory and antioxidant effects.Risk of contamination by pathogens (e.g., Listeria, Salmonella, Bacillus cereus) and toxin-producing molds necessitates proper starter culture selection and hygienic processing.
Conclusion: Fermented foods are a vital part of the human diet, offering unique flavors, extended shelf life, and a natural source of functional microbes and metabolites. Controlled fermentation not only improves food safety but also contributes to health through probiotics, postbiotics, and bioactive compounds. Future research should focus on omics-based characterization, novel starter cultures, and personalized nutrition applications to maximize the benefits while ensuring safety.