ABSTRACT
Functional foods are foods going beyond providing simple nutrition and also having some bene cial effects on their host. Fermented products have been known for thousands of years, as already in the Bible, the term “acid milk” was rst used. Knowledge of the health bene ts of fermented dairy foods goes back to the 1900s, when Metchnikoff [1], in his Thesis entitled “The prolongation of life,” correlated the intake of large quantities of Bulgarian fermented milk with the longetivity of the Caucasian people. Moreover, Metchnikoff stated that the variety in the different micro ora pro le is a determinant for the well-being of the host and stressed the importance of interactions between the host and bacteria [1,2]. Escherich claimed that a global assessment of the intestinal micro ora was essential for solid knowledge of the host digestion mechanisms, but also for understanding the pathology and therapy of microbial intestinal diseases [3].
