Continuous UV-C Treatment for Safe Disposal of Pathogen Waste in Flow Cytometry

The application of flow cytometry for sorting and analyzing pathogenic organisms poses significant challenges, not only due to the difficulty of maintaining a sterile environment but, more critically, because of improper handling and disposal of pathogen-containing waste. If viable pathogens remain in the waste stream, they can present serious environmental risks. Conventional practice typically relies on adding chemical disinfectants, which in turn creates complications for subsequent autoclaving. In this work, we demonstrate an alternative approach using UV-C light for bacterial disinfection prior to waste collection. A UV-C device was integrated just before the flow cytometer’s waste chamber, ensuring that liquid waste flowing through the flow cytometry waste tubing was continuously exposed to UV-C irradiation. To validate this approach, we analyzed three bacterial species: Escherichia coli, Salmonella sp., and Klebsiella sp. to determine the efficacy of using such a device in a flow cytometer. Samples from the waste stream were collected both before and after UV-C exposure and plated on agar overnight. Our results showed complete inactivation (100% kill rate) of two bacterial species (E.coli and Klebsiella sp.) and near- complete inactivation of Salmonella sp. following UV-C treatment. This method provides a simple, chemical-free, and effective approach to enhance biosafety and ensure safe waste disposal in laboratories performing flow cytometry with pathogenic organisms.