ABSTRACT

Probiotics have been defined as “live microorganisms which, when administered in adequate amounts, confer a health benefi t on the host” (FAO/WHO), and prebiotics as “non viable components of foods whose intake confers benefi ts to the host because they are associated with the modulation of his microbiota” (FAO). The simultaneous administration of prebiotics and probiotics (named symbiotics) may synergistically improve their health-promoting effects in the organism. A great number of bacterial strains, mainly belonging to different species of the genera Lactobacillus and Bifi dobacterium, are currently considered as probiotics due to their ability to survive in the gastrointestinal tract and to exert, in a strain-specifi c manner, activities capable of inducing physiological responses and health-promoting effects in the consumer. Such probiotic activities have been widely described and some of these are listed in Table 1.