OBJECTIVE :- The purpose of this procedure is to describe the method for sampling a measured quantity of air so that viable particles ( cfu ) are impinged upon an agar surface
to allow subsequent culture and quantitification

UNIT OF RESPONSIBILITY : QA Executive and trwained QA Assistants


1 Air Sampler

2 Sterile soyabean casien digest agar strips

Note :- The media preparation batch no is given to prepared media


1 It is not advisable to expose the Agar strips beyond 7 minutes as the medium gets

2 The coated surface of the Agar strips should face down during incubation or while
storing in order to avoid water of condensation

3 The instrument can be operated either on battery (6 dry cell batteries of 105 Volts)
or with battery eliminator of 9 volts & 1500 m amp

4 Ensure that the air flow rate is calibrated and certified


1 Prepare the Soyabean casien digest agar media as per media preparation SOP

2 Autoclave the media at 121 deg C for 20 minutes

3 After completion of autoclaving transfer the media to the microbiology room

4 Prepare the strips by pouring the sterilized Soyabean casien digest agar medium

aseptically taking care to avoid contamination from the person preparing them. Cool the strips

5 The prepared strips are labelled and incubated for 24 hours at 35 to 37 degree C

6 Sterilize the drum, impeller blade, timer box, cylinder the use of 70 % IPA and fumigation


7 Tear open the plastic tubing covering Agar strip

8 Slide back the sliding cover filted on the outer socket Remove the agar strip with the

medium filled side facing downwards & insert into the slot in the side of the drum of

the Air Sampler

9 Care must be taken that the medium does not touch the impeller and the end strip

produces enough for it to be pulled out of the instrument again after the sampling

10. To avoid contamination do not touch the layer of culture medium in the agar strips

before and after measuring process

11 Bring the Air Sampler to the required position Set up the running time and

switch on

12 The sampling time may be set as per the following table


1 ON 1 Min = 40 lts

2 ON 2 Min = 80 lts

4 ON 4 Min = 160 lts

All Switches On 7 minutes = 280 lts

13 Remove and incubate the agar strip for 72 hours at 35 to 37 deg C

15 After incubation count the cfu on the agar strip , and identify the growth observed on the

agar strip their gram character by Gram staining refer sop

14 For immediate second sampling using same drum & impeller blade, 70 % IPA may be

used for sterilization

15 Record the observation in the attachment 1



Total no of colonies observed on the strip be counted with the help of colony counter or

directly by holding the strip against light The total microbial load may be arrived by using

the following formula –

Total no. of colonies on agar strip
c.f.u./litre of air = ———————————————————–
Volume of air sucked in X time of exposure
Total no. of colonies
c.f.u/ m /min = —————————————— X 25
Time of exposure in minutes
1) Manufacturing area : : NMT 10 cfu
2) Storage Area : : NMT 10 cfu
3) Filling area : : NMT 05 cfu
Standard operating procedure SOP for microbiology and aseptic techniques for manufacturing of sterile dosage forms injections

This Website is a Guide for Pharmaceutical Manufacturing Pharmacy Students Pharmacy Colleges and Pharmacists pharmaceutical companies in health care

Following are some of articles which will be useful for you in further understanding of aspects of sterile dosage form manufacturing

Pharmaceutical Validation

Cleen Room Classification

Pharmaceutical Industry

Pharmaceutical Manufacturing

Clinical Trials

Media fill

Pharmaceutical companies

Regulatory Affairs in Pharmaceutical Industry

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