ABSTRACT
Research and commercial interest in the genus Bifidobacterium has flourished in recent
years, driven almost entirely by their potential health benefits in probiotic functional
foods. In 1990 there were approximately 30 publications in the international literature
focusing on bifidobacteria. In 2002 there were more than 10 times that number. The pre-
vious chapter by Jean Ballongue provides an historical perspective on the discovery of
bifidobacteria, their basic physiology, and an overview of the beginnings of a new wave
of interest in these organisms as probiotics. Since Ballongue’s chapter was published in
1998, there have been numerous changes within Bifidobacterium taxonomy and the
development of new applications and food technologies. A fundamental switch from cul-
ture-based, phenotypic examination of microbial diversity to the application of culture-
independent molecular techniques has provided new insights into the ecology of
bifidobacteria within the intestinal tract. Exciting advances have been made in demonstrat-
ing the efficacy of probiotic bifidobacteria in human health, including roles in the treat-
ment of allergy and the maintenance of remission in inflammatory bowel disease. New
therapeutic applications for bifidobacteria have emerged, such as their use to deliver tar-
geted gene therapy to hypoxic tumors. This chapter provides an update on our current
knowledge of bifidobacteria as probiotics. It focuses on recent advances in food technol-
ogy, our understanding of the ecology of bifidobacteria in the human intestinal tract, and
emerging evidence for clinical benefits and mechanisms of probiotic action.
