To Prepare Nutrient agar stab and slant

Aim – To prepare Nutrient agar stab and slant

Requirement – Test tube, Inoculation loop, cotton plugs, Nutrient agar media, Pipette, Water bath, Autoclave, Glass rod, Laminar air flow, Incubator

Theory – A test tube containing sterilised agar medium is heated and held in an inclined position with a slope of no more than 20 degrees. In order to create slants, the tubes are allowed to cool in that position. The organism that was injected has greater surface area to develop on thanks to the slanted surface. During each stab culture, a straight needle is utilised and poked down to the bottom of the agar medium known as “butt,” which is readily injected with a loop or needle.

Procedure –

Preparation of Agar Slant

1. Place the test tube in test tube racks.
2. Prepare Nutrient agar media and sterilize it.
3. Transfer about 5ml of molten agar medium into each test tube using a pipette.
4. Now place the cotton plugs to the agar tubes.
5. Sterilize the agar tubes using autoclave at 121°C for 15 minutes at 15 lbs pressure.
6. After sterilization remove the tubes from autoclave and place in a slanting position to a solid support to get sufficient surface area and allow the medium to solidify.
7. Incubate the tubes at 37°C for 24-48 hours to check for any contamination of the slants.
8. When no contamination is found the slants can be used.

Preparation of Agar Stabs

1. For the preparation of agar stabs, follow the same procedure as described for agar slants but instead of placing the agar tubes after sterilization in slanting position place it upright position and allow to solidify to get an agar stab.
2. Incubate the tubes at 37°C for 24-48 hours to check for any contamination of the slants.
3. When no contamination is found the slants can be used.

Result – The nutrient agar slab and slant has been prepared.