QCS-010 - Quality Operations Procedures for Pharmaceutical, API, and Biotechnology - page 44

SOP No. QCS-010.00 Effective date: mm/dd/yyyy
Approved by:
Subject: Microbiological Media Handling
10.1 PurPose
The purpose of this SOP is to outline a procedure to be used for handling of media in a microbiologi-
cal laboratory.
10.2 Procedure
Observe aseptic conditions throughout all handling steps of media in the laboratory.
1. Holding molten media:
a. Maximum holding time at 48°C is 4 h.
b. Media must be poured as soon as possible.
2. Remelting agar:
a. Most media will stand remelting once in a boiling water bath.
b. Never remelt agar more than once.
3. Medium dispensing:
a. Aseptically dispense the medium into sterile tubes, flasks, or plates as desired.
b. Immediately cover or recap the bottle to reduce the chance of contamination.
c. Tighten the caps of the tubes in which the media have been dispensed.
4. Pouring plates:
a. Media should be cooled to just less than 50°C before pouring either by using a water bath
at 48°C or cooling on the bench.
b. Immediately before pouring, the medium should be swirled gently to ensure thorough
mixing.
c. Aseptically dispense the media into sterile plates. Immediately cover or recap the bottle
to reduce the chance of contamination.
d. Plates should contain at least 5-mm depth of medium if they are to be stored before use
to minimize the effect of drying that will occur during storage. In this case, the amount
of medium will be more than that specified for the pour plate method.
5. Drying plates:
a. Carefully place the plate under laminar air flow (LAF) with the medium-containing side
up. Lift the base of the dish up and rest it on the lid.
b. This allows excess moisture to evaporate while minimizing the possibility of contami-
nating the agar.
6. Adding enrichments and supplements:
a. Heat-labile enrichments and supplements are added to media after sterilization to avoid
heat that led to deterioration of the substance.
b. Generally, cool sterile agar base media to approximately 45-50°C in a water bath.
Aseptically add the enrichment to the medium as directed on the media container label.
Swirl the flask to mix thoroughly; avoiding the formation of bubbles.
c. Sterile broth may be cooled to room temperature before adding enrichment.
d. Any antibiotic supplement reconstituted, but not used, should be discarded.
7. Storage of prepared media:
a. Prepared media must be used on the same day of preparation.
b. The storage period of prepared media is dependent upon the composition of the medium,
the form in which it is stored and the conditions of storage.