Postbiotics -- when simplification fails to clarify

Disagreement with the proposed new definition of postbiotic: the ISAPP consensus statement1 proposes a common term to simultaneously indicate inactivated microorganisms and their specific products or components, which, in our opinion, generates confusion as well-defined molecular factors cannot be distinguished from complex (undefined) matrices derived from microbial cells. • Review of the available scientific literature: the nomenclature adopted by the scientific literature in the past 10 years concerning inactivated microorganisms and their molecules and/or factors has been, in our opinion, mostly overlooked or misinterpreted. In particular, we believe the meaning most commonly attributed to the word ‘postbiotic’in scientific literature has been ignored.• Stability of products including inactivated microorganisms: the ISAPP’s document stated that “products with a long shelf life can be readily achieved for …