Selection and design of lactic acid bacteria probiotic cultures

Probiotics are defined as “live microorganisms that, when administered in adequate amounts, confer a health benefit on the host.” Probiotic‐containing foods can be categorized as functional foods and, along with prebiotics, represent the largest segment of the functional food market around the world. Fermented foods are the main vehicle of administration of probiotic organisms and, among them, dairy products are by far the most widely used. Many probiotic strains, which most often belong to the genera Lactobacillus and Bifidobacterium, are already applied in commercial probiotic fermented milks throughout the world. Nonetheless, the market of biofunctional dairy products, including probiotics, is continuously asking for diversifying the range of available products. To this regard, there is a growing need to identify new biofunctional strains, new strategies to assure survival of these cultures, and different sources from which to isolate strains. Before a probiotic can benefit human health, it must fulfill several criteria. Because the range of target functions and technological applications is wide, the selection and evaluation of potential probiotic candidates require a multistep approach. This review will give a general overview of main criteria and methods that have to be taken into consideration in the selection process of probiotic strains.