Testing program

In brief

Two kinds of test describe the microbiological quality of a cosmetic. Preservative efficacy testing shows how well a formula protects itself in use. Microbial limits testing describes the quality of a lot at release. Every carton carries its expiry date and lot number, which ties the product in hand to its batch record.

Preservative efficacy: ISO 11930

A preserved cosmetic has to stay within its microbiological limits while it is being used, as well as at release. ISO 11930 measures that. The finished product is inoculated with five defined organisms: Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli, the yeast Candida albicans, and the mold Aspergillus brasiliensis. Surviving counts are measured at set intervals over 28 days, and the reductions are compared with the standard's two sets of acceptance criteria, A and B.

The result shows whether the preservative system protects the formula against contamination introduced during use. For the sealed ampoule, it underpins the in-use period. After the first draw, refrigerate and use within 28 days.

Microbial limits: USP 61, USP 62 and ISO 17516

USP 61 counts the total aerobic microorganisms and the total yeasts and molds in a sample of the lot. USP 62 tests the sample for the absence of specified organisms. ISO 17516 sets the acceptance limits for cosmetics: a maximum count for the product's category, and the absence of Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans in the quantity tested.

The result describes the microbiological quality of that lot at release.

The lot record

Each lot has a batch record, and the lot number on the carton is the key to it. The batch record also holds the finished pH of each formula. The Brightening NanoSerum has a finished pH of 3.6.

How the tests connect to the formula

A preservation statement belongs to the formula tested, and a microbial quality statement belongs to the lot tested. The methods are described in plain terms on how we test. How evidence feeds the claims on each formula is set out in the dossiers, such as the Hyaluronic Skin Repair dossier, whose sealed ampoule is the Hyaluronic Skin Repair ampoule set.

Related

The manufacturing standard behind each lot is on manufacturing and GMP. The commitments these tests serve are in the quality charter. Professional accounts request documents through professional documentation. The other safety pages are listed on the science hub.