In order to carry out an optimum microbial air sampling, it is critical to know all the legislation and procedures described in air sampling. Only in this way it is possible to protocolize the best microbial air sampling ever.

Although it is true that sometimes FDA and EU GMP regulations can present contradictions in cleanroom standards, the user holds the responsibility to develop and implement step-by-step a facility’s standard operating procedure (SOP) with the sampling locations, procedures, frequencies, and size/volume of the samples.

We have analysed all the above legislations to find the most essential aspects that someone should take into account to write and run an outstanding microbial air sampling protocol.


Timing and locations

Volumetric active air sampling requires the utilization of an impaction device in each classified area during dynamic operating conditions at least every six months. However, in prolonged break of activity, change in the ventilation or disinfection procedures occasions modifications of this plan occur.


Number of samplings, volume, and positions

These factors depend on the type of rooms that we are analyzing. Nevertheless, it is not common to establish the ideal number of sampling locations to be tested. The m² of the area to sampling determines the number of samples performed. A.1 table of ISO 14644-1:2015 establishes the quantity of sampling to carry out and the sampling location should represent the section.  


Sampling method: a good microbial air sampler

The core of the air sampling procedure is to utilize a good microbial air sampler with the following features:

  • Speed of the air impact which hits the culture medium it is a commitment between:

– Being high enough to allow catching the viable particles greater than 1 um.

– Being low enough to assure the life of viable particles, avoiding mechanic damages or the destruction of aggregates of bacteria.

  • The volume of sampling is a commitment between being able to detect low biocontamination levels and being small enough to avoid physical or chemical degradation of the medium.

Microbial air contamination monitoring is a fundamental process in facilities with special air cleanliness needs. IUL’s Spin Air samplers grant users a compact, portable, simple solution to air sampling. Accuracy and precision-enhancing Spin technology enable Spin Air samplers to outperform the accuracy of other air sampling systems.


Appropriate media and incubation conditions

In general terms, a microbiological growth media that supports the evolution of bacteria and fungi is essential. The USP chapter <797> states the uses of tryptic soy agar with polysorbate and lecithin for bacteria and malt extract agar for fungi isolation. However, the Controlled Environment Testing Association (CETA) accepts the utilization of a single non-selective media, but in both cases the legislation highlights the importance of monitoring incubation conditions.


Room’s class to analyse and the number of particles

The classification of air cleanliness by particle concentration of the rooms of your facility is vital for their airborne monitoring. ISO 14644-1 and GMP state classes of air cleanliness in terms of the number of particles expressed as a concentration in air volume. Cleanrooms and associated controlled environments provide for the control of contamination of air for accomplishing the appropriate activities.

If an out-of-specification count found at a location is attributed, you should document the cause, remedial action taken, and retesting performed of the failed sampling location, the immediate surrounding locations, and any other locations affected.


Registration of the results 

One of the most imperative steps in an air sampling procedure is to achieve a good traceability of the sampling to guarantee good practice and identify the critical points… The documentation should include all the actions made to prevent contamination or the ones that will be necessary to carry out if contamination happens.

microbial air sampling