USP Challenge Test

USP 51 - Antimicrobial Effectiveness Test

This Preservative Efficacy Test (PET) or Cosmetic challenge test, is essential for assessing the safety of water based cosmetic products. It is most commonly used for products sold in the United States, but is recognised worldwide.

Which USP Test?

How Long?

Test Procedure

EP USP ISO
UK
EU
USA
World

EP, USP or ISO standard PET test?

EP USP ISO
Incubation (days) 28 28 28
Sample required (g) 250 250 250
Total Species 4/5 5 5
Staphylococcus aureus
Pseudomonas aeruginosa
Candida albicans
Aspergillus brasiliensis
Escherichia coli

PET test details

United States Pharmacopeia (USP)