Antimicrobial Preservative Effectiveness Testing Global Pharmacopoeia Standards for Topical Products
The following table is a summary of the different tests and specifications required by specific regions for Antimicrobial (Preservative) Effectiveness Testing (AET). The regions encompass Japan, Europe (including Great Britain), and the United States. In addition to the designated organisms, additional organisms can be used to challenge the product.
Important note: The Validation Test demonstrates the efficiency of the neutralizers used in the plate count method in inactivating the antimicrobial preservatives contained in the test sample. This is required by all compendial methods. Failure to properly neutralize the preservative system during testing can result in false negative results where lack of organism recovery may be due to inhibition of the organism.
 The PCPC test allows the microorganisms to be pooled into groups of bacteria, fungi and mold. Additional organisms are listed in the procedure. In addition, at least one rechallenge is recommended for an additional 28 days.
 The acceptance criteria listed above is only for topical products. The criteria will differ for other categories.
 The EP/BP A criteria express the recommended efficacy to be achieved. In justified cases where the A criteria cannot be attained, for example, for reasons of an increased risk of adverse reactions, the B criteria must be satisfied.