N.14 – Standard Operative Procedure for Microbial Air Sampling in Clean Room


It is important to organize a correct and clear sampling plan when several clean rooms or controlled contamination areas are to be monitored at the same time for microbial bioburden.

To reach this goal it is necessary to have a suitable set of air samplers and a specific SOP that gives to the operators all the information to avoid mistakes and / or misunderstanding.

The reported Standard Operating Procedure (SOP) can be used as a guide to be adopted to each individual case.



Microbial air sampling of multi Clean Room premises


To obtain reliable and consistent microbial air monitoring of the Clean Room


Clean Room Manager in close co-operation with Microbiology Laboratory Manager


Agar, Air Sampler, Aseptic, Bioaerosol, Bioburden, Clean Room, Contact Plate, Contamination, Delay Time, Disinfection, Incubation Time, Incubation Temperature, Interval time, Irradiation, Microbiology Medium, Micro-organisms Captured by impact, Numbers of run, Poured Contact Plates, Sampling Site, Single Run Volume, Sterilization.


Microbiology air sampler

Battery charger  

Clean Room transfer case

Tripod for air sampler

Poured Contact Plates (Plate Count Agar) tripled bagged and irradiated

Disinfectant spray (70% ethanol) tripled bagged, filtered and irradiated


Introduction of the air sampler into the Clean Room

Follow the Good Aseptic Practice

Introduction of poured Contact Plates into the Clean Room

Use the irradiated triple bagged Contact Plates

Introduction of disinfectant spray into the Clean Room

Use the irradiated triple bagged disinfectant spray

Identification of Contact Plates

Each plate must be identified by sampling site (XXXX), date (XX / XX / XX), hour (XX.XX).

Disinfection of air sampler

Follow the Good Disinfection Practice

Use of air sampler

Follow the instruction manual.

Air sampler positioning inside the Clean Room

The microbiology air sampler can be positioned:

a) directly on the surface, close to the considered most critical area

b) fixed on tripod, at the height considered most critical

c) fixed on the wall, using the wall arm

Air sampler programming

The volume of air to be sampled and the sampling program are a choice of the Clean Room Manager. The suggested amount of air per each plate in a Clean Room should be 1000 / 1800 litres of air.

Sampling data downloading

Each sampler should be connected to the printer for sampling data downloading (date, operator identification, sampler identification, sampling site, volume of air).

Transfer of Contact Plate to incubation

At the end of sampling operation, each identified Contact Plate must be protected by its sterile bag and sent to the lab for incubation. 


Contaminated Contact Plates Do not use them
Expired Contact Plates Do not use them
Torn plastic bag Do not use them
Low Battery warning signal Charge the air sampler