ASTM F2638 - Standard Test Method for Using Aerosol Filtration for Measuring the Performance of Porous Packaging Materials as a Surrogate Microbial Barrier:
The ASTM F2638 Standard Test Method for Using Aerosol Filtration is a scientifically rigorous approach to evaluate the performance of porous packaging materials as microbial barriers. This method offers several advantages over traditional microbiological methods, including speed, convenience, and a quantitative measure of microbial barrier performance.
The test method uses a specific type of aerosol to assess the filtration efficiency of the material, employing single or dual particle counters to measure the results. It is specifically designed for porous materials used in the packaging of terminally sterilized medical devices.
A critical element of this test is determining the flow rate through the material at which maximum penetration occurs. This point of maximum penetration indicates the material's relative vulnerability to microbial contamination. Therefore, materials with a lower point of maximum penetration are considered more effective barriers against microbes than those with a higher point.
This test employs a physical testing methodology to provide a rapid determination of microbial barrier performance. It involves a challenge with 1.0 µm particles across a range of pressure differentials, from near zero to approximately 30 cm water column (WC) or 2942 Pa.
Implementing this method does not require specialized microbiological procedures, which expedites the testing process. Additionally, the output of this method is a typical filtration efficiency curve that measures the material's maximum penetration. Although dependent on individual material characteristics, this curve provides a fair basis for comparing the performance of different materials.