Technologies with free and immobilised cells for probiotic bifidobacteria production and protection

Interest in the incorporation of bifidobacteria into fermented products has developed considerably over recent years, with many studies reporting human health benefits associated with the consumption of these bacteria. Due to their slow growth in milk, bifidobacteria are generally propagated in pure cultures and eventually mixed thereafter with other lactic acid bacteria. Data on production of bifidobacteria with conventional free-cell cultures are reviewed, as well as new fermentation processes allowing cell productivity enhancement. Bifidobacteria are sensitive microorganisms with low survival to stresses occurring during their production, storage and consumption. Until now, little work has been published on improving the survival of bifidobacteria to these conditions, but new techniques, such as cell incubation under sublethal conditions and cell propagation in an immobilised biofilm state, are very promising. Combined with encapsulation, these techniques will allow better incorporation of bifidobacteria into established probiotic products, as well as the emergence of new applications. (c) 2005 Elsevier Ltd. All rights reserved.