Incorporation of Propionibacteria in Fermented Milks as a Probiotic.

Propionibacteria are mainly found in dairy products and fermented milks but are found in other foods as well. Dairy propionibacteria have recently shown to exert potential probiotic activities such as production of propionic acid, vitamins, bacteriocins, essential enzymes, and other vital metabolites. Furthermore, stimulating the immune system and lowering the blood cholesterol level are some of their favorable effects. They have a wide spectrum of antimicrobial activities, inhibiting the growth of gram-positive and some gram-negative bacteria, as well as some yeasts and molds. At industrial scale, they are used in cheese making, especially Swiss (hard) cheeses, as dominant starter cultures. There is a rising trend to use propionibacteria in fermented milks as probiotic. The current paper reviews the characteristics of propionibacteria related to their use in fermented milks either as starter culture or probiotic, methods for the enumeration of propionibacteria, and their functional (in vivo) efficiency.