The starter bacteria have to remain viable at the time of consumption and capable of surviving in the intestinal tract to get maximum benefits from fermented milk. These bacteria should also be able to establish in the intestinal epithelium in sizable number by replacing resident harmful pathogens. The above said conditions can almost be met by Bifidobacteria when compared to other starter cultures.

It is a well known fact that the fermented milk products including bifidus milk are nutritionally superior and have improved digestibility and palatability when compared to plain milk but the therapeutic benefits of the concerned bacteria in the fermented milk products can be demonstrated in vivo only with viable biomass of starters of human origin viz. Lactobacillus and Bifidobacteria.

Among the genus Bifidobacterium, the commonly used species in the production of bifidus milk are Bifidobacterium bifidum, B.infantis, B.longum, B.adolenscentis and B.animalis.

Morphological features and growth characteristics of Bifidobacteria

The bifidobacteria are gram positive, rod shaped and anaerobic organisms. The morphology varies depending upon the strain and species. They are short, regular, thin cells with pointed ends or long cells with slight bend or protuberances. They may also be found as club shaped, or with spatulated extremities and also in star like arrangements.

The bifidobacterium is the normal inhabitant of the intestine of the infants fed with breast milk. Human milk proves to be a good substrate for the growth of bifidobacteria due to the presence of bifidus factor. Bifidobacteria of infant origin such as B.bifidum and B.infantis start growing and get implanted in the intestinal epithelium of infants if breast-fed.

As the infants grow and become child, the favourable bifidobacteria will be replaced by harmful bacteria. It can be inferred from the above statement that those infants fed with mother’s milk are more likely to have the benefits from the bifidobacteria than those who are bottle-fed. The other alternative is to prepare bifidus milk and supplement in the diet of infants and growing children.

Fermented products (bifidus milk products) from bifidobacteria