In this article we will discuss about the process of inoculation in microorganisms.
Preparation of Agar Slant:
Agar slants are-prepared (Fig. 16.11) to inoculate microbial culture. To prepare agar slant a required number of culture tubes are taken and about 12 to 15 ml of liquified agar medium is poured in each of them. The tubes are now cotton-plugged and sterilized in an autoclave.
After the sterilization is over the tubes are taken out and are placed in slanting (sloping) position for sometimes; the tubes get cooled and the medium in them is solidified resulting in a slopy surface.
Procedure (Fig. 16.12):
I. The tube containing inoculum and the tube containing agar slant are held in the left hand and the inoculation loop/needle in the right hand. Tubes should almost be parallel to the ground to avoid contamination.
II. Both the tubes are opened by removing the cotton-plug with fingers of the right hand and the open mouth of the tubes is sterilized by passing through the flame twice.
III. Immediately after de-plugging and sterilizing the mouth of the tubes, the loop/needle is also flame- sterilized and is inserted within the agar surface of the inoculum containing tube to quench the heat, and a small bit of inoculum is taken on the loop/needle tip.
IV. The inoculum containing loop/needle is taken out and brought in within the agar slant containing tube where the inoculum is just rubbed on the surface of the agar slant.
V. All the steps starting from plug removal from the mouth of the tubes to the rubbing of the inoculum on the surface of the agar slant should be taken quickly to avoid contamination.
VI. When inoculation is complete, the open mouths of tubes and the cotton plugs are sterilized by flame and the cotton plugs are replaced.
VII. The inoculated tube is incubated under suitable temperature to favour rapid growth of microorganisms.