Preservative Efficacy (Challenge) Test

The Preservative Efficacy Test (Challenge Test) is performed to evaluate the effectiveness of preservatives used in cosmetic products, personal care products, household care products, and raw materials in maintaining microbiological stability before opening and throughout normal consumer use. This test assesses whether the preservative system is capable of protecting the product against microbiological contamination and deterioration before the original packaging is opened and during its intended period of use.

The Challenge Test is based on the artificial contamination of the product under laboratory conditions and the evaluation of the resulting microbiological data.

The test result is determined by the logarithmic evaluation of the microbial counts in the artificially contaminated product at specified time intervals, such as Day 2, Day 7, Day 14, and Day 28.

The test is initiated by inoculating the product under laboratory conditions with reference strains of the following microorganisms in accordance with the applicable reference methods:

• Pseudomonas aeruginosa ATCC® 9027
• Staphylococcus aureus ATCC® 6538
• Escherichia coli ATCC® 8739
• Candida albicans ATCC® 10231
• Aspergillus brasiliensis ATCC® 16404

The test duration is 28 days. In our laboratory, all procedures and test parameters are performed in accordance with the ISO/IEC 17025 standard.