USP provides risk-based guidelines for the use of adenosine triphosphate (ATP) bioluminescence methods for rapid detection of viable microorganisms for short-life products. ATP bioluminescence detects the presence of viable contamination in less than seven (7) days compared to the required 14-day compendial sterility test. Determining the generation time of the slowest growing microorganism spanning bacteria, yeast and filamentous fungi in the presence of a product helps establish the incubation time of microbial detection. As per USP , inoculum levels for all tested microorganisms were less than 10 CFU. Appropriate enrichment broth and incubation conditions were followed, and product matrices such as mammalian cells and DNA plasmids were evaluated. Samples were filtered with a hollow fiber sampling tip, which captures any bacterial, fungal and yeast cells while removing cellular debris and any non-microbial ATP from the sample being tested. Microbial cells are eluted off the filter and collected in a collection tube for testing with an ATP-bioluminescence method based on the luciferin-luciferase cascade emitting light that is measured with a luminometer. This study demonstrates practical ways of identifying the slowest growing organism, determining generating time, and calculating time to detection, which are all relatively novel concepts for QC Microbiology Testing.
Kahline et al. (Thu,) studied this question.