Question

Which of the following technique has been demonstrated in the image given above?

• A. Spread plate method
• B. Pour plate method
• C. Serial dilution
• D. Both A and B

Answer 1

The correct option is D Both A and B

In spread plate technique, the sample is appropriately diluted and a small aliquot is transferred to an agar plate. Then, bacteria is distributed evenly over the surface by a special streaking technique. After colonies are seen, they are counted and the number of bacteria in the original sample calculated.

In a pour plate, a small amount of inoculum from a broth culture is added by pipette to the center of a Petri dish. Molten but cooled agar medium in a test tube or bottle is then poured into the Petri dish. The dish is then rotated gently to ensure that the culture and medium are thoroughly mixed and the medium covers the plate evenly.

This method allows micro-organisms to grow both on the surface and within the medium i.e subsurface. These plates are then used to test the anti-microbial effects of various substances.

Thus the correct answer is option D