Inactivation of Aerosolized Hepatitis A Viral Droplets on Food Contact Surfaces by Ultraviolet-Light-Emitting Diodes at 255 nm and 279 nm

TL;DR

This study shows that 279 nm UV-C LEDs are more effective than 255 nm LEDs at inactivating hepatitis A virus on surfaces like stainless steel and glass.

Contribution

The study provides novel inactivation data for aerosolized hepatitis A virus using 255 nm and 279 nm UV-C LEDs on specific surfaces.

Findings

279 nm UV-C LED inactivates hepatitis A virus more efficiently than 255 nm UV-C LED.

Weibull models fit better than linear models when tailing is observed in virus inactivation.

Inactivation doses vary by surface material and UV wavelength.

Abstract

Hepatitis A viral outbreaks continue to occur. It can be transmitted through aerosolized droplets and thus can contaminate surfaces and the environment. Ultraviolet light emitting diode (UV-C LED) systems are used for inactivation of microbes, though research is needed to determine optimal doses for aerosolized HAV inactivation. This study evaluates the UV-C LED doses for the inactivation of aerosolized hepatitis A virus (HAV) deposited on stainless-steel and glass discs. HAV was aseptically deposited onto stainless-steel or glass discs (1.27 cm diameter) using a nebulizer within a chamber followed by treatments for up to 1.5 min with 255 nm (surface dose = 0–76.5 mJ/cm2) or 279 nm (surface dose = 0–8.1 mJ/cm2) UV-C LED. Plaque assays were used to enumerate infectious titers of recovered viruses and data from three replicates were statistically analyzed. The calculated linear D10-value (UV-C dose for a 1-log reduction in aerosolized deposits) for HAV by 255 nm UV-C LED was 47.39 ± 7.40 and 40.0 ± 2.94 mJ/cm2 (R2 = 0.94 and 0.91) and using 279 nm UV-C LED were 6.60 ± 0.27 and 5.57 ± 0.74 mJ/cm2 (R2 = 0.98 and 0.94) on stainless-steel and glass discs, respectively. The non-linear Weibull model showed δ (dose needed for a 1-log reduction in aerosolized HAV deposits) values for HAV of 29.69 ± 5.49 and 35.25 ± 15.01 mJ/cm2 by 255 nm UV-C LED (R2 = 0.99 and 0.92) and 6.67 ± 0.63 and 5.21 ± 1.25 mJ/cm2 by 279 nm UV-C LED (R2 = 0.98 and 0.95) on stainless-steel and glass discs, respectively. These data indicate that 279 nm UV-C LED showed higher efficiency for HAV inactivation than 255 nm UV-C LED, and that Weibull models were a better fit when tailing was observed. This study provides the inactivation data needed to aid in designing UV-C LED systems for delivering doses required to inactivate bio-aerosolized HAV deposits on stainless-steel and glass.

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