For detection of Beta-Galactosidase activity.
Directions :
1. Place one disc into a sterile tube.
2. Add 0.1 ml of sterile 0.85% sodium chloride solution (physiological saline).
3. Pick the colony under test with a sterile loop and emulsify it in the tube containing the disc and physiological saline.
4. Incubate at 35°C-37°C.
5. Examine at hourly intervals for up to 6 hours to detect active lactose fermenters.
6. Organisms that are negative after 6 hours should be incubated for up to 24 hours to detect the late lactose fermenters.
Appearance: Filter paper discs of 6mm diameter with printed 'ON' on each side of the disc.
