Preservative efficacy and microbiological stability testing are regulatory requirements and key components of any cosmetic product development.
EU No1223/2009 states that a cosmetic product safety report should demonstrate a preservation efficacy. The preservative system used in cosmetic formulations must ensure product robustness and consumer safety throughout product life cycles.
Preservative Efficacy Testing (PET) also known as Challenge Testing is the appropriate tool to substantiate antimicrobial preservation efficacy against microbial contamination.
Several challenge test protocols can be applied. Methodology may follow the pharmacopoeias, international standards, industry or in house developed protocols.
QACS, The Challenge Test Laboratory, is proposing a number of standard and customised protocols to support the cosmetic industry. To evaluate the preservation system of personal care products we offer:
EP or USP 51
Inoculates 5 microorganisms (Pseudomonas aeruginosa, Staphylococcus aureus, E. coli, Candida albicans, Aspergilus brasiliensi). We store the inoculated preparation at prescribed temperature, then withdraw samples from the container at specified time intervals and count the organisms. Results are available within 35 days. Minimum sample quantity 100g.
ISO 11930
ISO 11930, a reference method to evaluate the preservation of a cosmetic formulation inoculates 5 microorganisms (Pseudomonas aeruginosa, Staphylococcus aureus, E. coli, Candida albicans, Aspergilus brasiliensi). Remaining surviving micro-organisms are measured at defined time intervals during a period of 28 days. Results are available within 35 days. Minimum sample quantity 100g.
Re-inoculation protocol
The re-inoculation protocol is similar to the EP reference standard. Samples are re-inoculated on the 7th day. Observations are repeated after the times prescribed. The test is prolonged by 7 days. Results are available within 42 days. Minimum sample quantity 100g.
Mixed Culture
The multi strain in-house mixed culture test is designed to simulate single inoculation followed by a storage period. We divide several standard strains in categories of bacteria, yeasts and moulds and challenge the preparation with a mixture of strains. Readings are reported per strain. Results are available within 42 days. Minimum sample quantity 100g.
Wipe Protocol
Cosmetic challenge testing involves separately contaminating wet-wipe sub-samples with each one of 5 reconstituted strains. Then we proceed to test individual sub-samples for microbial count at every interval (0 time, 2 days, 7 days, 14 days, 28 days) and assess log-reduction.
The rest of the test complies with the EP reference standard. Results are available within 35 days. Minimum sample quantity 100g.
QACS, Cosmetic Challenge Testing services assists cosmetic RnD decisions with competitive market prices and real-time reporting. Intermediate results at specific time intervals, option for urgent delivery reporting at 14 days. EU carriage policy, 24 hour courier service for sample collection.
For challenge testing solutions contact QACS Lab at info@qacslab.com
