Abstract Title
Inactivation of feline calicivirus by a 255 nm ultraviolet light emitting diode system
Presenter
Doris D'Souza, University of TennesseeElena Jerkovic, University of TennesseeBrahmaiah Pendyala, Tennessee State UniversityAnkit Patras, Tennessee State University
Co-Author(s)
Elena Jerkovic, Brahmaiah Pendyala, Ankit Patras, Doris H. D'Souza, University of Tennessee, Knoxville, TN and Tennessee State University, Nashville, TN
Abstract Category
Food & Environmental Virology-I (Food)
Abstract
Feline calicivirus (FCV), a respiratory virus causing illness in cats, continues to be used as a cultivable surrogate for human norovirus research. Ultraviolet-light emitting diode (UV-C LED) systems at 255-nm are being explored as an alternate to traditional mercury-based UV-C lamp systems for microbial inactivation on surfaces. Polypropylene surfaces are widely found in food preparation environments. As surface properties can play a role in UV-C inactivation, the doses of 255-nm UV-C LED required to inactivate FCV on polypropylene surfaces need to be determined.
The research aim was to determine the 255-nm UV-C LED dose required for the inactivation of FCV on polypropylene discs.
FCV (50 μl of ~6.5-7 log PFU/mL) was air-dried at ambient temperature after surface spreading on sterile propylene discs. These inoculated discs were treated with 255-nm (dose up to 14.5 mJ/cm2) for up to 25 seconds. Viruses were recovered in cell-culture media and ten-fold serially diluted. Infectivity was determined using plaque assays of recovered counts of three replicate trials assayed in duplicate. These counts were statistically analyzed for significant differences (p≤0.05). The linear model dose (D10-value) required to decrease FCV infectivity by one-log was determined.
Treatments of FCV with 255-nm UV-C LED at a dose of 2.9 mJ/cm2 showed 0.88 ± 0.19 log reduction, while doses of 5.8 mJ /cm2, 8.7 mJ/cm2, 11.6 mJ/cm2 and 14. 5 mJ/cm2 showed log reductions of 1.83 ± 0.14, 2.55 ± 0.17, 3.12 ± 0.19, and 3.55 ± 0.53, respectively. This resulted in a calculated linear model dose (D-10 value) for FCV on polypropylene discs of 3.26 ± 0.24 mJ/cm2 and a D-value (time for 1 log reduction) of 5.61 ± 0.42 seconds using this 254-nm UV-C LED device.
These data show that the 254-nm UV-C LED system has the ability to inactivate FCV on polypropylene surfaces within a short contact time with potential for application in the food environment. This study provides the information needed to deliver the required 255-nm UV-C doses for FCV inactivation on polypropylene surfaces.
The research aim was to determine the 255-nm UV-C LED dose required for the inactivation of FCV on polypropylene discs.
FCV (50 μl of ~6.5-7 log PFU/mL) was air-dried at ambient temperature after surface spreading on sterile propylene discs. These inoculated discs were treated with 255-nm (dose up to 14.5 mJ/cm2) for up to 25 seconds. Viruses were recovered in cell-culture media and ten-fold serially diluted. Infectivity was determined using plaque assays of recovered counts of three replicate trials assayed in duplicate. These counts were statistically analyzed for significant differences (p≤0.05). The linear model dose (D10-value) required to decrease FCV infectivity by one-log was determined.
Treatments of FCV with 255-nm UV-C LED at a dose of 2.9 mJ/cm2 showed 0.88 ± 0.19 log reduction, while doses of 5.8 mJ /cm2, 8.7 mJ/cm2, 11.6 mJ/cm2 and 14. 5 mJ/cm2 showed log reductions of 1.83 ± 0.14, 2.55 ± 0.17, 3.12 ± 0.19, and 3.55 ± 0.53, respectively. This resulted in a calculated linear model dose (D-10 value) for FCV on polypropylene discs of 3.26 ± 0.24 mJ/cm2 and a D-value (time for 1 log reduction) of 5.61 ± 0.42 seconds using this 254-nm UV-C LED device.
These data show that the 254-nm UV-C LED system has the ability to inactivate FCV on polypropylene surfaces within a short contact time with potential for application in the food environment. This study provides the information needed to deliver the required 255-nm UV-C doses for FCV inactivation on polypropylene surfaces.