Question

When performing a Mulitple Tube Fermentation Technique, what does a positive Confirmed test include?

1. dark red to black colonies (with a sheen ) on LES endo plate

2. A Gram stain showing gram-negative, none - spore- forming rods

3. Turbidity and gas in brilliant green lactose bile broth

4. Turbidity and gas in lauryl lactose trytose broth

please i need the answer with in 1 hrs

Answer 1

Answer =

When performing a Mulitple Tube Fermentation Technique, a positive Confirmed test include

3. Turbidity and gas in brilliant green lactose bile broth

Explanation = Mulitple Tube Fermentation Technique,test for coliforms as a most probable number.

This technique is completed in three stages:

1.Presumptive stage

2.Confirmed stage

3.Completed stage

In confirmed stage brilliant green lactose bile broth fermentation tubes are used.after the presumptive stage if there is any growth, gas formation then these tubes are carry forward for confirmed test.

In this stage a loopful of culture is transferred to the tubes containing the brilliant green lactose bile broth.

Then incubate these tubes at 350C.if there is formation of any amount of gas takes place in the inverted vial within 48 hours it shows a positive confirmed test.