Postbiotics in food, feed, and culture media: mechanisms and applications of microbial metabolites in sustainable systems

Postbiotics, which are nonviable microbial cells, their components, and metabolites of fermentation products, are increasingly recognized as essential functional ingredients in food, feed, and biotechnology sectors because of their potential to improve health and sustainability. This review largely consolidates existing evidence on the components of postbiotics, which include short-chain fatty acids, bioactive peptides, exopolysaccharides, vitamins, and minerals, and describes their antimicrobial, antioxidant, immunomodulatory, and metabolic functions. The potential roles of these compounds in improving food safety, streamlining animal nutrition, and augmenting microbial bioprocesses in culture media are largely debated. Critical roadblocks, such as absence of harmonized terminology, variability in production protocols, and regulatory gaps, are examined to delineate the obstacles to their industrial exploitation. Postbiotics hold great promise for enhancing sustainable food systems, animal production, and biotechnology advances. Yet, stringent standardization of production processes and strict clinical trials need to be implemented to ascertain their effectiveness and safety, and thereby guarantee their potential to address global needs for resilient and health-enhancing food and feed alternatives.