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SOP for Storage and Preparation of Media and Culture

1.0 Objective: Media is the main source of growth of the microbial. To detect the microbes in the test samples we can follow some guidelines for the preparation of the Media.

2.0 Scope: This procedure is applicable to Microbiology Department.

3.0 Responsibility:
The microbiology officer is responsible to implements this SOP.
Head Department is responsible for overall compliance with SOP.

4.0 Procedure for Media preparation:
4.1 Ensure that the media bottles are in the refrigerator.

4.2 Weigh the required media carefully on the balance and transfer it into the conical flask.

4.3 Add quantitated (using a Measuring cylinder) distilled water into the media.

4.4 Shake well the conical flask for a complete mix-up of the media.

4.5 Place the cotton plug in the conical flask, wrap the plug with aluminum paper, and put it in a rubber band.

4.6 Load the conical flask in the autoclave for sterilization of the media.

4.7 Kept the media bottle in the refrigerator.

5.0 Procedure for Media Storage

Objective: The testing chemicals/media is effectively acting when the specified storage conditions. For accurate/ reliable results the media must be stored in the specified storage conditions. Otherwise, the media is not working as a nutrient for microbial growth.

5.1 After inoculation of the samples if the sterilized media is remain in excess in the conical flask.

5.2 Keep the cotton plug and rubber band in the conical flask.

5.3 Write the date of the preparation and the name of the media on the conical flask.

5.4 Place the conical flask in the refrigerator.

5.6 Sterilize the media before the addition of another day.
5.7 The prepared media is useful within the week.

6.0 Procedure for Cultures Storage.

Objective: To determine the micro results, the positive controls also should be compared with the testing samples. For positive controls, we can add known culture in the Agar/Media to determine the organisms in the samples.

6.1 Cultures are considered as two types one is Mother Culture and the other is Sub Culture.

6.2 Prepare the Nutrient Agar media solution, transfer about 5 ml of the media into the 10 ml
test tube and Sterilize in the autoclave.
6.3 Remove the test tube from the autoclave and kept on the LAF working bench in a slanty position
and cool for solidification.
6.4 Take one loop full culture from the mother culture and streak on the Agar of the test tube. 6.5 Place the test tube in the Incubator for 24 hours at about 35 °C
6.6 After 24 hours the culture is considered a fresh culture and should be useful for the culture of the
sample and stored in a refrigerator.
6.7 The old mother culture is autoclaved and discarded.
6.8 The fresh culture is considered for the mother culture for one month.
6.9 The procedure is repeated once a month for the survival of the cultures.


SOP: Standard Operating Procedure

LAF: Laminar Air Flow

°C: Degree Celcius

ml: Mili Liter

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