AOAC 998.10 Efficacy of Preservation of Non-Eye Area Water-Miscible Cosmetic and Toiletry Formulations

AOAC 998.10 tests the preservation of cosmetic and toiletry formulations by introducing microbes into the product and measuring surviving organisms over time.

Preservation testing determines the resistance of the test sample to the growth of microorganisms and is an important part of product performance testing. Microbes may be contained during the production of a product, however, customer expectation drives demand for products to perform similarly while in use by the end-consumer.  Preservation testing is one component for testing how a product will perform during its expected use and how an antimicrobial preservative will perform over time.  Preservation testing is beneficial for a variety of industries, where testing provides valuable data on how a product will perform after a specific duration after opening and while in use.

In the AOAC 998.10 test method, bacteria, yeast, and mold are inoculated into the test product. The number of surviving organisms in the test product is measured over time using serial dilutions and plate counts. Products that meet the method- specified criteria are considered ‘adequately preserved’ for manufacture and consumer use.

Organisms that may be tested against in the AOAC 998.10 method:

  • Staphylococcus aureus
  • Staphylococcus epidermidis
  • Klebsiella pneumoniae
  • Escherichia coli
  • Enterobacter gergoviae
  • Pseudomonas aeruginosa
  • Burkholderia cepacia
  • Acinetobacter baumannii
  • Candida albicans
  • Aspergillus niger

For more information on AOAC test methods, please contact the lab at 847-483-9950 or