A probiotic composition comprising, as an active ingredient, viable biologically homogeneous and pure Escherichia coli strain BU-230-98, ATCC Deposit No. 202226 and DSM 12799, and a formulation comprising at least one volatile fraction (VF) of a plant extract, wherein said plant extract is obtained by water extraction and wherein said volatile fraction (VF) of a plant extract is obtained by steam distillation of said plant extract under a pressure lower than atmospheric pressure and at a bath temperature not exceeding 38° C. for maintaining viability of said Escherichia coli strain.