3.6. Resistance of S. cerevisiae LC3 to GI conditions
Stationary phase grown cells of S. cerevisiae LC3 were incubated at 37 C in the simulated gastric fluid at pH 2.0, 3.0 and 8.0. After 180 min of incubation in simulated gastric juice at pH 3.0 , S. cerevisiae LC3 did not show a significant (P ¼ 0.148) decrease in cell viability (Fig. 4). No decrease in survival was found at pH 8.0. The treatment at pH 2.0 for 180 min reduced cell viability of S. cerevisiae LC3 to 7.5 log CFU/mL. When wholemeal wheat bread was added to the juice at pH 2.0, S. cerevisiae LC3 resulted resistant. Probably, this was due to the increased value of pH (3.0) caused by the addition of bread or to the protective effect of the food matrix. After 180 min of treatment in simulated intestinal juice, only yeast cells, initially treated with gastric juice at pH 2, showed a final decrease of 2 log cycle.