Inoculation was made through deep seeding 1 ml of each dilution
in DeMan-Rogosa-Sharpe agar (MRS agar Oxoid Ltd., Basingstoke,
UK) acidified to pH 5.4 with glacial acetic acid; plates were
anaerobically incubated (Anaerobic System Anaerogen, Oxoid) at
37 C for 72 h. After that, the colonies were counted and the result
swere expressed as log CFU/g.