Lactic acid bacteria: an essential probiotic and starter culture for the production of yoghurt

Lactic acid bacteria (LAB) are ubiquitous and integral members of the heterogeneous class of bacteria employed for fermented food and dairy applications such as yoghurt products. LAB are gram-positive, non-spore-forming, non-respiring but aerotolerant microorganisms that are generally characterised by the production of lactic acid as a key fermentation product. LAB, specifically Lb. bulgaricus, are essential dairy starter cultures for the manufacture of several fermented dairy products such as yoghurt and cheese. In this review, we discuss the importance of LAB as starter cultures and a probiotic for yoghurt production, its mode of metabolism, acidification characteristic, synthesis of lactase (beta-galactosidase) and a perspective on LAB's growth medium for dairy fermentations.