In vivo safety assessment of two Bifidobacterium longum strains

Bifidobacteria are important members of the intestinal microbiota and are considered to contribute to maintaining health. However, the level of bifidobacteria colonising the intestine of elderly subjects tends to be lower than in younger adults. Therefore, two Bifidobacterium longum strains, isolated from healthy elderly, were chosen for supplementation of the endogenous Bifidobacterium microbiota in the elderly. Bifidobacteria are generally regarded safe for human consumption. However, since the strains are intended for consumption by the elderly, whom may be more prone to disease, it is important to ascertain their safety. For this purpose, the strains were given to healthy adult volunteers. No side effects were reported and no undesirable changes observed in the immune parameters measured. Based on this study it appears that the two strains are well tolerated by human subjects and there are no reservations about their food use.