Reliable air sampling forms a critical part of monitoring for the presence of microbes in cleanrooms. In the most recent update of EU GMP Annex 1 there has been an increased focus on the way microbiological environmental monitoring in cleanrooms is carried out to ensure compliance. So, what are the practical considerations when thinking about environmental monitoring using portable microbial air samplers for cleanroom integrity?
Keeping a close eye on microbe levels in cleanrooms improves productivity and product quality in different ways. First of all, it can help ensure product safety by preventing contamination during manufacturing. Monitoring also helps detect deviations in microbe levels, enabling early intervention and root cause analysis before an elevated microbe level becomes a significant issue.
Regulatory bodies such as the FDA, EMA and ISO also require routine environmental monitoring (EM) to ensure that cleanroom conditions meet stringent guidelines. Failure to meet these can lead to warnings, product recalls or even facility shutdowns. In Europe, the update to “EU GMP Annex 1: Manufacture of Sterile Medicinal Products”, which came into effect in 2023, calls for continuous and risk-based monitoring – and requires a comprehensive contamination control strategy (CCS), with EM as a core component.
Portable microbial air samplers play a key role in meeting these requirements (Figure 1). They provide quantifiable data on the presence of viable particles and can be used rapidly and flexibly within a controlled environment. Here, we take a closer look at portable active air samplers – what they are, why they’re essential for cleanroom productivity, and what to consider in order to maximise their effectiveness in ensuring cleanroom compliance.
Active air sampling is a microbiological EM method used to detect viable microorganisms in the air
Why active air sampling?
Active air sampling is a microbiological EM method used to detect viable microorganisms in the air of controlled environments like cleanrooms. It works by actively pulling a known volume of air through a device that collects airborne microorganisms onto a nutrient medium. After sample collection, the medium is incubated to allow any collected microbes to grow into colonies for counting. The measurement result will typically be the number of these ‘colony-forming units’ per cubic metre of air sampled (CFU/m3).
Active sampling offers increased sensitivity compared to passive methods such as settle plates. It also offers more precise control of sampling conditions, such as sampling time and volume of air collected. Fixing these parameters enables reliable quantification of data, whereas passive sampling is usually limited to more qualitative data. In addition, although cost-effective, settle plates can be vulnerable to interference and contamination from non-airborne sources. Furthermore, as passive air sampling relies on sedimentation, it can be biased towards larger microorganisms that settle more quickly.
When it comes to applying active air sampling in the cleanroom, the use of portable equipment offers several important benefits. Portable samplers provide flexibility for use within different areas of a controlled environment and can support interventions or out-of-spec investigations. They can also be used alongside fixed systems to ensure a highly robust system that combines continuous monitoring with fast, versatile sampling. Portable active air samplers can also support programmable, extended sampling intervals to simulate monitoring over a defined period.
Figure 1: Portable handheld air sampler for environmental monitoring - SAS microbial air sampler range
Best practices for sampling
The action points at the bottom of this article give a guide to selecting the right solution for your application. Having selected the most suitable portable samplers, it’s time to think about
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