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
to intestinal juice, in accordance with Bao et al. (2010), 0.1 g of
trypsin (Sigma-Aldrich) and 1.8 g of bile salts were added to a
sterile solution of 1.1 g of sodium bicarbonate and 0.2 g of sodium
chloride in 100 mL distilled water. The pH of the solution was
adjusted to 8.0 with 0.5 M sodium hydroxide and sterilised by
filtering through a 0.45 mm membrane.