Direct vat set (DVS) B. bifidum Bb-12 or L. casei-01 strains were
transferred at a rate of 2% (w/v) into MRS broth supplemented with
L-cysteine hydrochloride 0.05% (w/v) (MRS-C). Incubation was
aerobic for lactobacilli or anaerobic, using the anaerogen system, for
bifidobacteria at 37 C for 18 h. Cultures were then centrifuged at
3000 g for 5 min at 4 C, pellets were harvested, washed twice by
using normal saline and suspended in normal saline (1 g pellets in
9.0 mL saline) as mentioned by Mandal, Puniya, and Singh (2006).