How is the cosmetics challenge test performed?
CE.way checks the preservation system's effectiveness using the international cosmetics challenge test standard ISO 11930:2019 or the United States Pharmacopeia standard USP 51. The test is based on the monitoring of the presence of various pathogens in the cosmetic product when it is produced, followed by the intentional inoculation of a cosmetic product with five different strains of microorganisms:
Staphylococcus aureus (gram-positive bacterium)
Pseudomonas aeruginosa (gram-negative bacterium)
Candida albicans (fungus)
Escherichia coli (gram-negative bacterium)
Aspergillus brasiliensis (fungus)
The remaining concentration of these microorganisms is then determined after 7, 14 and 28 days. The product is considered to pass the preservative efficacy test if the concentrations of the fungi do not increase over the testing period and if the concentrations of the bacteria are reduced sufficiently by day 14 and do not increase from that time until the end of the test.