was monitored until the exponential
growth phase was reached. Cells were harvested by centrifugation
(3,000 g, 5 min at 4°C), washed in 10 mmol/L
phosphate-buffered saline (PBS) (pH 7.4), and resuspended
in MH broth to an approximate cell density of 1.0 ×
105 CFU/ml. The final cells concentration was confirmed
by viable counts.