ASTM F1608 Standard Test Method for
Microbial Ranking of Porous Packaging
Materials ( Exposure Chamber Method).
Agenda
• Basic overview of the test method
• Proposed changes for the future.
Microbial Ranking Test - ASTM F1608
Copyright Nelson Laboratories 2014 3
Determines the Log Reduction Value (LRV) of porous material
Sample size must be a minimum of 47mm
in width
Packages placed into a chamber and
exposed to a specific organism (Bacillus)
Filters are blended and plated to
determine titer values
How it works..
Microbial Ranking Test
Copyright Nelson Laboratories 2012 9
Supplies • 55 Soybean Casein Digest Agar Plates • 500 mL Soybean Casein Digest Broth • 1000 mL Sterile Water • 7 (0.45 um) Nitrocellulose filters • Plating equipment
3 key proposed changes
1) Equipment availability
2) Chamber evacuation process.
3) Titration methods
1) Standard equipment issue…
• DeVilbiss #40 Nebulizer no longer available.
2) Exposure chamber evacuation “After exposure, turn off the vacuum, and the fan. Evacuate the chamber for 15 min by connecting the vacuum source to the chamber through a microbial filter assembly”
3) Titration methods
Tyvek 0.6 Weight Meltblown
Reference Material 0.45µm Pre-sterilized
Filters
Extraction Method Blended Vortex (10-1
Only) Vortex including
Direct Plating Blended Vortex Blended Vortex
Standard Deviation 0.8 0.6 0.6 0.2 0.2 0.2 0.1
Reproducibility 2.2 1.8 1.6 0.7 0.6 0.5 0.4
Thank you