Abstract: Postbiotics are inanimate microbial cells and/or their components as well as microecological preparations made from their metabolites, which are beneficial to the health of the host. Postbiotics can regulate intestinal microbial balance, enhance immunity, and have anti-inflammatory and antibacterial effects. Compared with probiotics, living bacterial cells, postbiotics are safer, and more stable, effective and convenient. This article summarizes the origin, microbial sources, preparation methods and advantages of postbiotics, and elucidates the mechanisms of action of postbiotics in comparison with those of probiotics. In addition, it introduces readers to the applications of postbiotics as functional food supplements, food quality improvers, food preservatives and detoxifying agents in foods. We believe that as the definition, classification, and functional components of postbiotics become clearer, they will be more widely used in the fields of foods, nutraceuticals, foods for special medical purpose, infant foods, and personal care products. The development of postbiotics will also promote the leapfrog development of basic and applied science.

Key words: postbiotics; heat-killed lactic acid bacteria; action mechanism; food; application