SOP for sterility testing of compressed air, carbon dioxide and nitrogen gas  is described in this post which you can follow in the section of microbiological lab.

Objective:

This procedure has been established for providing the guidelines for sterility testing of compressed air, carbon dioxide and nitrogen gas.

Scope:   

This procedure is applicable to microbiology lab.

Responsibility:                          

Microbiologist.                             

Accountability:

Quality Control Manager.            

Procedure:

prepare 100ml of buffered peptone water solution (PW), FTM (fluid Thioglycolate media) and TSB (Tryptic Soy broth ) and autoclave as per SOP

After autoclavation pre-incubate the medias atleast 24-48hrs before use and transfer the materials through pass through box into sterile area.

Move the air sampler apparatus at sampling site and assemble air sampling apparatus and start taking sample(in a pre-sterilized media bottle) atleast for 10minutes. Take atleast 100ml sample of the compressed air nitrogen gas etc.

At the end of sampling immediately close the valves and wrap the properly with aluminum foil and repeat the same sampling procedure for Nitrogen and Carbon dioxide. 

Move the sample through pass through box to sterility room and perform the test through membrane filtration method and for 14 days incubate FTM at 32oC±2.5oC

and TSB at 22oC±2.5oC and visually inspect the medias on daily basis.

If no turbidity or growth observed during incubation period in the sample media the test complies with specifications

If turbidity or growth observed during incubation period in the sample media then test does not comply with specifications 

incase of failure investigate the cause of failure of sterility test.

For each single lot of sterility testing always perform negative control test as well as positive control