Microbial production of bioactives: from fermented functional foods to probiotic mechanisms

Lactic acid bacteria (LAB) have been shown to produce a range of bioactive metabolites possessing numerous therapeutic properties which may well be responsible for the probiotic properties observed for many of these strains. Such microbially-produced compounds interact with 'intelligent communication' systems in the human body including those of the cardiovascular, immune, endocrine and neuronal systems and may play a major role in maintaining host health. This review focuses solely on three categories of microbially-produced bioactive compound: the bioactive peptides produced during milk fermentation; the fatty acid, conjugated linoleic acid (CLA); and the non-protein amino acid, gamma amino butyric acid (GABA). The ability to augment the concentration of any of these compounds through the addition of the compound itself, the producing bacteria, and/or the necessary substrate in fermented dairy products should provide an attractive means of increasing the functional properties of fermented food products.