the 1960s, Bifidobacterium species were collectively referred to as " Lactobacillus bifidus ". 3) Bifidobacterium Longum is a genus of Gram-positive , non-motile, often branched anaerobic bacteria inhabiting the Gastrointestinal tract and Vagina [1] . Bifidobacteria are one of the major genera of bacteria that make up the gut flora ,