Author(s)

Victor J. Law^*, Denis P. Dowling

School of Mechanical and Materials Engineering, University College Dublin, Dublin, Ireland.

This paper describes the use of log-linear energy phase-space projections to analyze microwave-assisted inactivation of bacteria and viruses under different fomite conditions within multimode microwave ovens. The ovens are operated at a cavity-magnetron frequency of 2.45 ± 01 GHz. Porous fomites (moist face towels, cotton swabs, kitchen sponges, and scrubbing pads, cigarette filters and N95-like respirators); along with non-porous hard surface syringe fomites are studied. The fomites are classed as dielectric; and absorb microwave energy to varying degrees depending on their complex dielectric permittivity. Microorganism resilience to microwave stress (defined as ≥4 log₁₀ reduction in inactivation) when mapped using iso-volume trend-lines in energy phase-space reveals the persistence imparted by the fomite, and can be mapped between different microwave ovens. Microorganism resilience to thermal microwave-assisted treatment increases from vegetative Gram-negative to vegetative Gram-positive and on to Gram-positive spores. Bacteriophage MS2 and influenza viruses have an intermediate resilience dependency. It is shown that linear-scaled fomite temperature against process time graphs can differentiate between non-thermal and thermal micro-wave-assisted treatment of microorganisms.

Bacteria, MS2, Hepatitis C Virus, Human Immunodeficiency Virus, Influenza Virus, Disruption, Inactivation, Microwave Oven, Data Analysis

Law, V. and Dowling, D. (2022) Microwave-Assisted Inactivation of Fomite-Microorganism Systems: Energy Phase-Space Projection. American Journal of Analytical Chemistry, 13, 255-276. doi: 10.4236/ajac.2022.137018.