From Ancient Fermentations to Modern Biotechnology: Historical Evolution, Microbial Mechanisms, and the Role of Natural and Commercial Starter Cultures in Shaping Organic and Sustainable Food Systems.

From the first spontaneous fermentations of early civilizations to the precision of modern biotechnology, natural starter cultures have remained at the heart of fermented food and beverage production. Composed of complex microbial communities of lactic acid bacteria, yeasts, and filamentous fungi, these starters transform raw materials into products with distinctive sensory qualities, extended shelf life, and enhanced nutritional value. Their high microbial diversity underpins both their functional resilience and their cultural significance, yet also introduces variability and safety challenges. This review traces the historical development of natural starters, surveys their global applications across cereals, legumes, dairy, vegetables, beverages, seafood, and meats, and contrasts them with commercial starter cultures designed for consistency, scalability, and safety. Within the context of organic food production, natural starters offer opportunities to align fermentation with principles of sustainability, biodiversity conservation, and minimal processing, but regulatory frameworks-currently focused largely on yeasts-pose both challenges and opportunities for broader certification. Emerging innovations, including omics-driven strain selection, synthetic biology, valorization of agro-industrial byproducts, and automation, offer new pathways to improve safety, stability, and functionality without eroding the authenticity of natural starter cultures. By bridging traditional artisanal knowledge with advanced science and sustainable practices, natural starters can play a pivotal role in shaping the next generation of organic and eco-conscious fermented products.