Traditional and Emerging Strategies for Bread Preservation: A Sourdough-Centered Critical Review

Bread is highly susceptible to microbial spoilage and quality deterioration, creating a continued need for effective and consumer-acceptable preservation strategies. This critical review examines traditional and emerging approaches for bread preservation, including physical, chemical, and biological methods, with sourdough considered as the focal clean-label strategy. Physical approaches such as freezing and advanced packaging are effective for delaying spoilage, but their protection is often limited by cost, cold-chain dependence, or reduced post-opening efficacy. Chemical preservatives remain highly practical and effective, yet their use is increasingly challenged by clean-label expectations. Biological approaches offer a promising alternative, particularly through lactic acid bacteria and fermentation-derived metabolites. Among these strategies, sourdough stands out because it combines acidification, antifungal metabolites, and LAB-yeast interactions in a multi-hurdle system that can suppress spoilage while also contributing to bread texture, flavor, and staling control. However, its large-scale application remains constrained by microbiota variability, long fermentation times, activity loss in dried formats, and insufficient process standardization. Overall, sourdough represents one of the most promising clean-label tools for modern bread preservation, but its broader industrial adoption will depend on improved starter design, tighter process control, and integration with other preservation hurdles.