Detection and quantification of Bifidobacterium lactis LAFTI®B94 in human faecal samples from a consumption trial

A method was developed to allow detection of the probiotic Bifidobacterium lactis LAFTI®B94 in human clinical samples. A new probe, Laf94p, was developed to accomplish colony hybridization of B. lactis B94. PCR detection of B94 was also achieved using the species-specific (B. lactis) primer pair. These tests and probes allowed detection and quantification of B94 in the human intestinal flora. The sensitivity of the probe was assessed by monitoring faecal levels of B94 in humans who were fed the culture. In this trial, five volunteers were fed with the probiotic. The presence of B94 was assessed daily. Viable B94 could be detected at high levels (as high as 1.8 × 109 cfu g−1 wet weight) during the feeding period. Four weeks after the feeding stopped, B94 could still be detected in one subject. These results indicate that B94 survives in the human gastrointestinal tract.