Microbial Survival in Compressed Gases Under Fast Decompression to Normal Atmospheric Conditions

The FDA guideline for the manufacturing of sterile products using aseptic processes specifically mentions that a compressed gas should be of appropriate purity (e.g., free from oil) and its microbiological and particle quality after filtration should be equal to or better than that of the air in the environment into which the gas is introduced1 . Additional guidance on cleanroom or clean air monitoring and limits of particulate and microbial contaminants in the pharmaceutical industry is provided in EU GMP Annex 1 20082 , and the USP chapter 11163 . A more specific reference is ISO 8573, a group of international standards relating to the quality (or purity) of compressed air. The standard consists of nine separate parts, with part 1 specifying the quality requirements of the compressed air4 and parts 2 – 9 specifying the methods of testing for a range of contaminants. The test method for microbial monitoring of compressed gases is provided in ISO 8573-75 .