Understanding the Non-Equivalency of Bio-Fluorescent Particle Counts versus the Colony Forming Unit

PDA J Pharm Sci Technol. 2023 Jul 14:pdajpst.2022.012790. doi: 10.5731/pdajpst.2022.012790. Online ahead of print.


Adopting emerging microbiological methods is often desirable because it enables more advantageous, real time monitoring practices. However, when the newer method measures contamination based on a different detection principle and provides results that are based on different units of measure, a paradigm shift is necessary. That shift can be one of the most difficult challenges in any such project and requires careful consideration. In this paper, we explore the challenges presented by the Bio-Fluorescent Particle Counting (BFPC) technology, when considering that the traditional Colony Forming Unit (CFU) is the gold standard which any change is measured against. We examine why attempts to correlate newer units of measure used by Bio-Fluorescent Particle Counters, namely the Auto-Fluorescent Units (AFUs), to the traditional CFUs are not necessarily appropriate. The paper explores in depth why there is no consistent correlation factor between the two units of measure, and why that should not be a barrier to fully leveraging, implementing, and using such modern technologies in routine monitoring.

Keywords: Alternative and Rapid Microbial Methods; Auto-Fluorescent Units; Bio-fluorescent Particle Counters.