In the bile
tolerance test, the medium was MRS broth supplemented with 2.0%
bovine bile (Sigma-Aldrich). For the pancreatic fluid tolerance test,
150 mM NaHCO3, 1.9 mg/mL pancreatin (Sigma-Aldrich) and pH 8
were used, as suggested by Ronk € a et al. (2003) € . To test the tolerance