Eighteen reference strains (Table 1) were included in the study. All working cultures were maintained in chalk litmus milk (Oxoid, Basingstoke, UK) at 4°C and sub-cultured in the same medium every 2 months.
Eighteen reference strains (Table 1) were included in the study. All workingcultures were maintained in chalk litmus milk (Oxoid, Basingstoke, UK) at 4°C andsub-cultured in the same medium every 2 months.