EN 17141:2021 – Impact on microbiological sampler requirements

EN 17141:2021, introduced in April 2021, defines the new standard for microbiological contamination control in cleanroom and controlled environments, introducing minimum physical and biological efficiency specifications for microbiological air samplers in order to properly perform microbiological sampling.

We talked about this important topic with Emanuele Cartabia, Division Manager of Hyclas products.

“The new standard EN 17141:2021 replaced both ISO 14698-1:2003 and ISO 14698-2:2003 and aims to establish the requirements, recommendations and methodology for the control of microbiological contamination in clean rooms and how this control is demonstrated.

As the new standard is not an international ISO applying only in Europe, it could be confusing for those working internationally. In any case, the ISO committee will revise 14698 Parts 1 and 2 to align them with the new CEN standard. That process has already begun, and the new ISO standard is under discussion.

The new EN17141 document definitely has more content (51 pages) and includes sections on potential contamination sources, risk assessment, plan definition, interpretation of results and data integrity.

There is also a section (Annex E) on microbiological measurement methods, covering: method choice, air samplers, soil, and incubation.

EN 17141 also has informative annexes related to the life-science and pharmaceutical industries, medical devices, health care, and food; as well as guidance on media-based methods and new rapid methods. Within these sections, there are references to a number of other industry guidelines, such as GMP and Pharmacopoeia.

The new standard covers many areas and topics that were included in the old 14698 standard, but in greater detail. Section 4 now focuses more on microbiological control, not “biocontamination.” It includes parts that describe system attributes; potential sources that may pose a risk of contamination; risk assessment approach; and the development of an effective EM plan. There is also a greater emphasis on data (not just logging, alerting and action limits), the need of data trend and data integrity.

As mentioned, Annex E describes the verification of measurement methods based on culture media and air samplers. Specifically, there are now sections describing the required characteristics for air samplers defining validation process and efficiency values.

To comply with the new standard, an air sampler must undergo specific performance tests:

    • physical sampling efficiency
    • microbiological sampling efficiency

Physical sampling efficiency

Physical sampling efficiency is the cut-off size (parameter d50) that defines the equivalent aerodynamic particle diameter for which the sampler captures 50 percent of the particles in air.
The standard defines how measuring this value and the acceptable value.
Active air samplers are considered compliant if they have a d50 value of less than 2µm.
Given the complexity of physics related to particle capture, it is very reductive and superficial to calculate this value with simple mathematical formulas. In any case, the value must be validated by a laboratory with tools and expertise to perform the measurement.

Microbiological sampling efficiency

Biological sampling efficiency represents the ability of a sampler to capture microbe-carrying particles and includes losses caused by both physical efficiency and impact velocity.

EN17141 also establishes the measurement method and acceptability criteria for this value.

Active air samplers are considered appropriate only if they have a biological efficiency value of 100±50% relative to a reference sample.

The test must be performed according to defined protocols and requires the use of specific instrumentation and qualified personnel.

Hyclas samplers compliance

Hyclas air samplers have been validated according to EN17141 by an independent external laboratory, ensuring the outcome from an extensive validation work and not from a simply self-declaration.

Unlike many manufacturers, all Hyclas model configurations have been validated, so all conformities are based on actual experimental data and are not made “by analogy.

The validation report is available upon request.”

If you would like more information about microbiological sampling systems and UNI EN 17141:2021, please fill in the contact form: our experts are at your disposal.