Microbial retention is the single most important performance attribute of sterilizing-grade air and gas filters. In the food and beverage industry, the sterility of air or gas is crucial to the success of filtration processes to ensure the end product is contaminant-free.
Understanding how sterilizing-grade cartridge air filters are validated for microbial removal from air or gas assists the end user in effective filter selection. According to guidance from the FDA, the validation work carried out by filter manufacturers demonstrates the microbial retention and removal efficiency of hydrophobic sterilizing-grade cartridge air filters when challenged with a defined minimum concentration of model microorganisms. In addition to these basic bacterial challenge tests, filter manufacturers may do more validation work demonstrating filter retention of bacterial spores, long-term aerosol bacterial challenges, and aerosol bacteriophage removal, to illustrate the filters’ fit for purpose in various applications.
Pall leverages three ways to validate the microbial retention performance of filters. Below are three methods used by filter manufacturers to validate microbial retention performance.