Abstract
We compared the survival of three bifidobacterial strains in yogurt products accessible in Japanese market using two methods; a static in vitro digestion model and a human-validated in vitro gastrointestinal model TIM-1. The strains tested were B. animalis subsp. lactis strain A and two B. longum strains (respectively coded as B. longum strain B and B. longum strain C). For the static in vitro digestion model, the survival of bifidobacteria in the yogurt matrix was measured after exposing them for 1 hour to artificial gastric fluid or 5 hours to artificial intestinal fluid. While B. animalis subsp. lactis strain A showed a survival of 68% and 79% against gastric and intestinal fluids respectively, survival of B. longum strain B was 1% and 11%, and survival of B. longum strain C was 1% and 16%, respectively for gastric and intestinal fluids. Using TIM-1, we measured the survival of bifidobacteria for each yogurt product (in triplicate) mimicking the average physiological gastrointestinal conditions of an adult fed with yogurt. B. animalis subsp. lactis strain A showed an average survival of 22.9% (8.9×109 cfu). The survival of B. longum strain B and B. longum strain C were not measureable due to the low survival (i.e. below detection limit of 400 cfu).
In conclusion, both of our in vitro experiments demonstrated higher survival capacity for B. animalis subsp. lactis strain A compared to both B. longum strains.
