STANDARD OPERATING PROCEDURE Title: Preparation of Petri-dishes for Microbial Testing

Purpose:
To describe the method of preparing Petri-dishes for carrying out different microbiological tests

2. Scope:


3. Responsibilities:

1. Microbiologist
2. Lab Assistant

4. Procedure:

1. Transfer all the required materials to LFC bench taking all necessary microbiological precautions.
2. Remove plates from SS box on to the bench and let them cool.
3. After cooling of the plates obtain Media (TSA) from water bath and mop outer surface with duster wet with disinfectant.
4. Now carefully take one plate and half open it by one hand and pour approximately 20 ml of agar media and close the plate. Care should be taken that do not lean over the open plate or media nor take your hand or arm over opened plate.
5. Similarly pour all the plates as soon as possible as agar media starts solidifying. Plates are spreaded on the bench to ease the solidification.
6. Pour media in such a way to inhibit the bubble formation in the agar media.
7. Let plates as such for at least 20 minutes for solidification.
8. After solidification label each plate with abbreviation of media name, date of preparation.
9. Gather all the plates and transfer in a container into the appropriate incubator for pre-incubation in inverted position for at least 24-48 hours.
10. Before conducting any test observe the plates carefully for the evidence of any growth.

5. Precautions

1. Store the plate in refrigerator if testing is delayed.
2. Plates should be used as early as possible as de-moisturing starts.
3. See that media is not overheated.
4. Check that the sterilization cycles are satisfactory..
5. Check the expiry date of dehydrated media.
6. Check the washing process of the glassware.