Standard operating procedures for monitoring sedimentation bacteria in clean areas

Purpose: To describe the method of checking dust and bacteria in clean area air in order to make a correct evaluation.

Scope: Clean areas of different levels

Responsibilities: Workshop director, quality supervisor, quality inspector.

Procedure:

1.Definition

The sedimentation bacteria are collected by exposure method and then cultured and counted. The sedimentation concentration is expressed in CFU/dish, min.

2.Instruments and equipment used

High pressure sterilizer, constant temperature incubator, p90mm culture dish and ordinary broth agar medium.

3.Test status

• During static test, the fan of the air purification and conditioning system in the clean area starts 30 minutes after the test. 

• Before the test, the clean room to be tested has been disinfected.

• The culture dishes for sedimentation bacteria determination should be arranged in representative places and places with the least air flow disturbance.

4.Test personnel

• Test personnel must wear work clothes that meet the environmental cleanliness level.

• During static test, there shall be no more than 2 test personnel in the room.

5.Number and arrangement of sampling points

a.Number of sampling points

b.While meeting the minimum number of measurement points, the minimum number of culture dishes must also be met, as shown in the following table. Regardless of the size of the area, as a measured object, it should meet this requirement.

6.Sampling method and culture

After placing the culture dish as required, open the lid of the culture dish, expose the surface of the culture dish to the air for 30 minutes, cover the culture dish, and place it upside down in a constant temperature incubator at 30-35℃. Count after 48 hours of culture. Three culture dishes can be selected for each batch for control culture

7.Result calculation

• Count directly with the naked eye or count on the colony counter.

• If there are 2 or more colonies overlapping on the culture dish, they are still counted as 2 or more colonies when they can be distinguished.

• Calculation formula

Where M is the average colony count (CFU)

Mi-represents the colony count of culture dish No. 1, 2, 3...…n: n-the total number of culture dishes.

8.Standard

9.The average colony count in the clean area must meet the standard.

If it exceeds the standard, the "Handling of deviations between the number of dust particles and the number of microorganisms in the clean area (SMP-QM-806-01)" shall be followed.