Isolation, Cultivation, and Storage of Bifidobacteria

Since their first discovery in breast-fed infant feces by Tissier, bifidobacterial occurrence and species distribution have been now extensively documented in various ecological niches: gut of humans and other mammals, human vagina, human and animal oral cavity, hindguts of honeybees and bumblebees, fermented and unfermented foods, and sewage. Moreover, in these habitats bifidobacteria do not always constitute a major part of the microbiota, therefore their isolation or enumeration is difficult. Nowadays, there is no standard medium for the isolation of bifidobacteria with respect to their source (with the only exception being milk products) and more than 20 media for their differential enumeration have been developed (medium with elective carbohydrate, medium with antibiotics, medium with propionate, and medium with elective substance and/or low pH). However, it is only through the isolation of species in pure culture that they can be fully characterized for their physiological and potential probiotic properties (growth rates, growth yields, substrate uptake rates and affinities, beneficial health effects). For this reason, isolation, still today, is a fundamental step both for the general and deeper knowledge of bifidobacteria. The present chapter is an overview of culture media (basal, elective, differential, and selective) and culture conditions for detection of bifidobacteria in different environments, their cultivation, and their storage.