China Blue Lactose Agar is recommended for differentiation and enumeration of bacteria in milk. The medium does not contain any inhibitory substances therefore all the organisms present in milk sample grow luxuriantly on this medium. Lactose is the fermentable sugar. China blue is the pH indicator that changes from colorless to blue due to degradation of lactose to acid, thus differentiating lactose-fermenters from non-fermenters.
- Appearance: Light yellow to greenish yellow homogeneous free flowing powder
- Gelling: Firm, comparable with 1.5% Agar gel
- Color and Clarity of prepared medium: Light blue colored, clear to slightly opalescent gel forms in Petri plates
- Reaction of 3.83% w/v aqueous solution at 25°C. pH : 7.0±0.2
- Cultural characteristics observed after an incubation at 35-37°C for 22-24 hours