Rationale | Probiotic formulation defining the intervention class | Example | Comment |
---|---|---|---|
Common identity | Single strain of one specific genus and specie | L. acidophilus strain A | All studies include the same strain; may include studies conducted in different food matrices |
Common identity | Single defined blend of multiple strains (strains A + B + C) | L. acidophilus strain A and L. casei strain B and B. lactis strain C | Strains must be maintained in equivalent relative doses in all studies |
Common taxonomy | Studies used different strains of same species or subspecies? | L. acidophilus strain A, L. acidophilus strain B, or L. acidophilus strain C | Different studies using different strains included |
Common structural or secreted product (e.g., beta-glycosidases, exopolysaccharides) | Different strains from a defined taxonomic group that may include different species or genera | All strains of L. bulgaricus and S. thermophilus | Different studies using different strains included |
Common mechanism of action known to be necessary and sufficient for the effect (e.g., production of a specific bacteriocin or range of bacteriocins known to be active against a specific pathogen, or induction of immune mechanisms needed for the effect) | Different strains from a defined taxonomic group that may include different species or genera | L. salivarius strain A | Different studies using different strains included |
L. salivarius strain B | |||
Common physiological effect previously proven by at least one human study of quality | Different strains from a defined taxonomic group that may include different species or genera | All strains | Different studies using different strains included |