SOP For passive air sampling (settle plate method) for viable count is described in this post which you can follow in the section of the microbiological lab. 

Objective:

This procedure has been established for passive air sampling by settle plate method to check the viable growth in the clean room/sterile manufacturing and testing area i.e. (Microbiology Lab)

Scope:      

This procedure is applicable to sterile manufacturing and testing area i.e. (Microbiology Lab)

Responsibility:                               

Microbiologist.

production pharmacist.

Accountability:

Quality Control Manager. 

Procedure:

For regular monitoring of sterile area by plate exposure by settle plate method always use media plates of nutrient agar that are pre-incubated at least for 24-48hrs at a temperature of 32oC±2.5oC.

Mark each media plate with location name, date of exposure, observation date, and plate number for that typical location.

Mark the plates as per location chart map and wrap them properly in aluminum foil and place in a stainless steel closed container and transfer them under UV-light of pass through window atleast 2hrs before moving to the sterile area to avoid contamination.  

Before settling the plate for exposure ensure proper airflow in the area.

Expose atleast two plates for each single location by opening the lid and setting it aside and settle the plate to take the air sample for atleast 2.5hrs-4hrs.

At the end of 4hrs of exposure put the lid back to the plate and collect all plates from each location repack them in aluminum foil and place in stainless steel container and transfer back the container in the pass through window.

After exposure move the plates to incubation room of the microbiology lab and incubate the plates at 22oC±2.5oC for 3-5days for yeast mold count followed by  32oC±2.5oC for 2-3 days for bacterial count.

At the end of incubation period observe the plates and count the number of colony forming units and record in the respective reports.

Always perform atleast 3 consecutive plates exposure runs before allowing the aseptic injection filling (Either powder/Liquid)  and average result of these three runs will decide either the area is ready for aseptic filling activity or not.

Suggested Initial Contamination Recovery Rates

 In Aseptic Environment

ISO Class

U.S FS 209E Class

Grade

Settle plate (90mm)

ISO5

100

A

<1cfu

ISO6

1000

B

<3cfu

ISO7

10,000

C

<5cfu

ISO8

100,000

D

<10cfu

Reference: USP40, Volume 1, Pg.# 684








Incase of massive growth change the disinfectant solution, frequency, concentration or method and repeat the procedure.

Sampling Frequency:

Suggested Frequency of Air sampling For Aseptic Processing Area

ISO Class

U.S FS 209E Class

Grade

Frequency of Sampling

ISO5

100

A

Each Operating Shift

ISO6

1000

B

Each Operating Shift

ISO7

10,000

C

Once a week

ISO8

100,000

D

Twice a week