Survival of bifidobacteria ingested via fermented milk during their passage through the human small intestine: an in vivo study using intestinal perfusion.

The ability of a strain of Bifidobacterium sp to survive passage through the upper gastrointestinal tract when ingested in fermented milk was investigated in six fasting healthy adults by using in vivo ileal perfusion. After ingestion of 10.0 +/- 0.5 log10 bifidobacteria in 400 g fermented milk, ileal flow of bifidobacteria increased significantly and reached a maximum of 8.8 +/- 0.2 log10 bifidobacteria/h 1.7 +/- 0.4 h after ingestion of fermented milk. The average number of bifidobacteria recovered from the terminal ileum during the 8 h after fermented-milk ingestion was 9.0 +/- 0.1 log10 and constituted 23.5 +/- 10.4% of the number ingested. These results indicate that in healthy adults Bifidobacterium sp survive transit through the gastrointestinal tract when ingested in fermented milk. Further studies are needed to investigate the behavior of these exogenous bacteria in the colonic lumen and to explore their effects on the physiology of the human gastrointestinal tract.