Challenge test

What is a challenge test?

The challenge test is a microbiological resistance test designed to evaluate the effectiveness of a preservative system or finished product when exposed to simulated contamination. It involves introducing a specific microbial strain (bacteria, yeasts, molds) into the sample and then measuring the reduction in population over time.

This test can be customized according to the sector of activity (cosmetics, food processing, pharmaceuticals, veterinary medicine) and applicable regulatory constraints. It is a key requirement in the processes of market launch or reformulation.

Why conduct a challenge test?

The challenge test allows you to:

• Verify the microbiological robustness of a product throughout its lifespan
• Validate the effectiveness of a preservative or antimicrobial system
• Meeting regulatory or normative requirements (e.g., ISO 11930, European Pharmacopoeia, USP, etc.)
• Optimize formulations containing natural or synthetic preservatives
• Documenting quality/safety/compliance records during registration or inspection

It is a fundamental element of the HACCP plan, the cosmetic regulatory file (PIF), or the safety assessment of care, nutritional or phytosanitary products.

Test methodology

The protocol can be adapted according to:

• Target microorganisms: Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, Aspergillus brasiliensis, Escherichia coli, etc
• Applicable regulations: ISO 11930 (cosmetics), USP <51>, food or veterinary standards
• The product tested: aqueous formula, emulsion, powder, plant extract, food supplement, etc.
• Internal objectives: in-house criteria, specific tolerances, testing under extreme conditions

Decay kinetics are measured at different times (e.g., 0h, 7d, 14d, 28d) and compared to acceptable thresholds defined by the reference standards.

Affected matrices

• Cosmetic products (creams, gels, lotions, oils)
• Liquid, powder or capsule food supplements
• Plant extracts and phytotechnical formulations
• Hygiene or care products for human or veterinary use
• Technical products sensitive to microbiological contamination

Standards and requirements covered

Our partner laboratories perform challenge tests according to the main international standards:

• ISO 11930 (preservation assessment in cosmetic products)
• USP <51> (Antimicrobial Effectiveness Testing)
• European Pharmacopoeia
• Internal client protocols (custom testing)

Why choose YesWeLab?

YesWeLab relies on a network of laboratories specializing in microbiology applied to the food, cosmetics, and healthcare sectors. Our partners are accredited to ISO 17025, COFRAC, or GLP standards, and adapt their methods to the specific needs of each project.

With our digital platform, you:

• Centralize your analysis requests
• Easily access quotes, track your samples, and reports
• Benefit from the expertise of our scientific team to adapt standards, microorganisms, or experimental conditions

Need a challenge test that complies with current standards?

Add this analysis to your quote request or contact our team directly for assistance in setting up the protocol adapted to your product.