Challenge test or preservative efficacy test (PET) is one of the parts of the Product Information File and of the Cosmetic Product Safety Report (CPSR). According to ISO 29621 every cosmetic manufacturer has to ensure that the product, as purchased, is free from the numbers and types of microorganisms that could affect product quality and consumer health, as well as to ensure that microorganisms introduced during normal product use will not adversely affect the quality or safety of the product. The latter can be ensured by performing the challenge test. Basically challenge test checks how effective your preservative system is.
CE.way checks the preservation system effectiveness using the standard ISO 11930:2012. The test is based on the inoculation of a cosmetic product with 5 different strains of microorganisms: Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, Escherichia coli, Aspergillus brasiliensis. The remaining concentration of these microorganisms is then determined after 7, 14 and 28 days.
Challenge test is not required for certain products, such as products that don’t contain water, products that contain more than 20% alcohol, have pH below 3 or above 10, where containers are filled at more than 65 degrees celsius, products that contain certain raw materials that create a hostile environment, or for products packaged in aerosols, pump dispensers or single dose units. Any lack of challenge test however must be duly justified.