Considerations for the Validation of Non-CFU Based Bio-Fluorescent Particle Counting Technologies

The use of Bio-Fluorescent Particle Counting technologies as a rapid, alternative method to monitor microbial contamination in water and cleanroom air samples has been of interest to the pharmaceutical industry for several years. These technologies are a non-growth-based method that use the detection of particle scatter and intrinsic fluorescence to categorize detected particles as biologic or non-biologic. As a result, the systems report in a unit of measure not equivalent to the colony forming unit. Although guidance on the validation of alternative microbial methods is available, significant challenges can exist when validating non-growth based alternative methods compared to the growth-based compendial method. Collaborators in the Modern Microbial Methods (M³) industry working group provide thoughts and recommendations on a method validation pathway for the non-growth-based bio-fluorescent particle counting technology. Technology specific recommendations on the primary and secondary validation are provided with considerations on the applicability of individual validation parameters and associated acceptance criteria for this emerging technology that does not rely on the colony-forming unit.