Microbiological suitability testing for bioburden: the foundation for reliable results

For accurate microbiological test results, the method must be verified for the specific product being tested. Microbiological suitability testing confirms that a method can detect viable microorganisms in a product sample, even when antimicrobial properties or complex product matrices might otherwise interfere.

ALS performs suitability testing in accordance with internationally recognised pharmacopoeia and quality standards, helping customers achieve consistent, reliable results aligned with regulatory requirements. 

Why suitability testing matters

Suitability testing reduces the risk of misleading microbiological results by demonstrating that the selected method is fit for purpose. It helps identify and control product-related interference so microbial recovery is reliable, and the resulting data can be trusted.

This is particularly important before routine bioburden testing, release testing and stability studies, where confidence in the method directly supports product quality and compliance.

What we test and how we handle challenging products

ALS performs microbiological suitability testing aligned with key pharmacopoeia requirements, including:

• Bioburden suitability: TAMC and TYMC

Performed in accordance with Ph. Eur. 2.6.12 and USP <61>, this testing confirms the suitability of the microbial counting method for the product.

• Suitability for specified microorganisms

Performed in accordance with Ph. Eur. 2.6.13 and USP <62>, this testing verifies the suitability of the test for specified microorganisms.

What is a suitability test?

A suitability test is a recovery study. It typically involves inoculating the product sample with up to five different microorganisms to evaluate whether the product inhibits or enhances microbial recovery.

Handling antimicrobial activity in samples

For products with antimicrobial properties, ALS applies appropriate mitigation strategies to support accurate microbial recovery, such as:

• Sample dilution
• Incorporation of neutralising agents
• Membrane filtration
• Other scientifically justified neutralisation approaches.

These measures help reduce antimicrobial effects and provide a more accurate representation of viable microorganisms in the sample.

How our expert team works with you

We approach suitability testing as a collaborative process, aligning with your product, timeline and regulatory expectations from the beginning.

Understanding your product

We start with a focused consultation to understand your product matrix, intended test method and potential antimicrobial risks.

Designing a tailored suitability plan

Based on your product, we define the microbiological testing strategy, challenge organisms, acceptance criteria and alignment with relevant pharmacopoeia and standards.

Laboratory execution

Testing is performed in our GMP-compliant laboratory in Sollentuna, Sweden. We communicate clearly on observations, recovery outcomes and any adjustments that may be needed.

Reporting and next steps

You receive a comprehensive, internally reviewed report with clear conclusions on method suitability. If optimisation is required, we work with you to identify the best path forward.

Quality, sustainability and a lifecycle mindset

ALS supports robust microbiological method performance from early suitability work through routine testing. We also aim to optimise laboratory resources wherever possible, helping customers reduce rework, lower risk and improve long-term testing readiness.

Partner with ALS

Whether you need suitability testing before routine bioburden analysis, support for pharmacopoeia-based microbiological methods, or help with challenging antimicrobial products, ALS provides regulatory-aligned, client-focused solutions with a strong focus on quality and reliability.

For support or project enquiries, contact sollentuna.lab@alsglobal.com.

Our experts are ready to help you move confidently from development to compliant routine microbiological testing.