To 1 ml of the
washed cell suspension, 5 ml of simulated gastric juice and
1.5 ml NaCl (0.5 w/v) were added. Simulated gastric juice
was prepared freshly daily by suspending pepsin (3 g/L) in sterile
saline (0.5% w/v) and adjusting the pH to 2.0 with concentrated
HCl (Charteris et al., 1998).