The International Scientific Association for Probiotics and Prebiotics (ISAPP) published a consensus statement on May 4 providing clarity on the definition for “postbiotic” and its scope.  The statement proposed to define a postbiotic as a “preparation of inanimate microorganisms and/or their components that confers a health benefit on the host.” The statement clarifies that postbiotics are deliberately inactivated microbial cells that contribute to demonstrated health benefits, but that purified microbial metabolites and vaccines are not postbiotics. It also provides details on important processing factors in creating postbiotics, their proper characterization, and information on how postbiotics improve intestinal and systemic health.

ISAPP has previously published consensus statements on the definitions and scopes of the terms probiotics, prebiotics, synbiotics, and fermented foods as follows:

• Probiotics: “live microorganisms that, when administered in adequate amounts, confer a health benefit on the host.”
• Prebiotics: “substrate[s] that [are] selectively utilized by host microorganisms conferring a health benefit.”
• Synbiotics: “mixture[s] comprising live microorganisms and substrate(s) selectively utilized by host microorganisms that confer a health benefit on the host.”
• Fermented Foods: “foods made through desired microbial growth and enzymatic conversions of food components.”

Taken together, the consensus statements aim to provide stakeholders with a common understanding of these terms and avoid confusion between similar terms. For instance, its consensus statement on fermented foods aims to draw a line between fermented foods and probiotics by clarifying that fermented food products should only be labelled as “containing probiotics” when there is evidence that their live microbial components provide health benefits and the precise microbiological content is defined.

ISAPP underscores in each statement that implicit in each definition is the requirement that the subject be safe for its intended use and that any claims related to health benefits must be substantiated in the target host.