Validating a filter for microbiology
The specific conditions of the test, including buffers used, water, light conditions, and temperature, must be reproduced in the validation study.All test conditions also should be standardized and performed in the validation study exactly as performed in the test.Filtration through a low-binding filter material, such as polyvinylidene difluoride, helps to minimize this growth inhibition.Additionally, the preservative may be diluted or flushed from the filter by rinsing with a benign fluid, such as diluting A validated method for neutralizing the antimicrobial properties of a product must meet two criteria: neutralizer efficacy and neutralizer toxicity.However, despite potential toxicity, the convenience and quick action of chemical inhibitors encourage their use.Chemical inhibition of bactericides is the preferred method for the antimicrobial efficacy test.
The data generated from these studies are less variable if the cell populations are homogeneous.
Liquid cultures or confluent growths on solid medium are best suited for reproducible culture preparation.
The conditions of organism preparation and storage must be standardized for the neutralizer evaluation and should reflect the conditions of the antimicrobial assay.
This chapter provides guidelines for the validation of methods for the estimation of the number of viable microorganisms, for the detection of indicators or objectionable microorganisms, for the validation of microbiological methods used in antimicrobial effectiveness testing, and for the sterility testing of Pharmacopeial articles.
It is generally understood that if a product possesses antimicrobial properties because of the presence of a specific preservative or because of its formulation, this antimicrobial property must be neutralized to recover viable microorganisms.