Bifidobacterium longum is a Gram-positive, catalase-negative, rod-shaped bacterium present in the human gastrointestinal tract and one of the 32 species that belong to the genus Bifidobacterium.[2][3] It is a microaerotolerant anaerobe and considered to be one of the earliest colonizers of the gastrointestinal tract of infants.[2] When grown on general anaerobic medium, B. longum forms white, glossy colonies with a convex shape.[4]B. longum is one of the most common bifidobacteria present in the gastrointestinal tracts of both children and adults.[5]B. longum is non-pathogenic, is often added to food products,[2][6] and its production of lactic acid is believed to prevent growth of pathogenic organisms.[7]
^Yazawa, Kazuyuki; Fujimori, Minoru; Amano, Jun; Kano, Yasunobu; Taniguchi, Shun'ichiro (February 2000). "Bifidobacterium longum as a delivery system for cancer gene therapy: Selective localization and growth in hypoxic tumors". Cancer Gene Therapy. 7 (2): 269–274. doi:10.1038/sj.cgt.7700122. PMID10770636. S2CID7375660.