Probiotic bacteria encounter various stresses after inges- tion by the host, including exposure to a low pH in the stomach and contact with bile in the small intestine. L. reuteri I5007, initially known as Lactobacillus fermen- tum I5007, was selected from over 7,000 native Lactoba- cilli colonies according to criteria including resistance to heat, low pH, copper, and bile salts, as well as storage sta- bility and antagonism to pathogenic agents [16]. Other L. reuteri strains also show resistance to low pH and bile salts [12,17-19].