An ultraviolet photocatalytic oxidation device includes at least one first ultraviolet light source and at least one second ultraviolet light source. The ultraviolet light sources are all switched off when a fan for the HVAC system is switched off. In another feature of the present invention, while the evaporator coil is on, all of the ultraviolet light sources are turned on. Because the ultraviolet light sources are more effective when the evaporator coil is off, some of the ultraviolet light sources are turned off while the evaporator coil is off. While the evaporator coil is off, the ultraviolet light sources may be switched on alternately, such that they are on each on a substantially equal portion of the time that the evaporator coil is off.

Techniques for sterilizing a fomite are disclosed. A UV sterilization apparatus includes a housing for enveloping a fomite inside the housing. The housing is composed of a material that prevents transmission of electromagnetic radiation in the ultraviolet range. Attached to the housing is a closure element, and the closure element is also composed of a material that prevents transmission of electromagnetic radiation in the UV range but allows transmission of electromagnetic radiation in the visual range. An ultraviolet light source is attached to an internal surface of the housing or an internal surface of the closure element, and the light source sterilizes the fomite enclosed inside the housing by transmitting ultraviolet electromagnetic radiation towards the fomite.

A process for the destruction of microorganisms on a product using ultrasonic energy is disclosed. The process comprises contacting a product with an ultrasonic horn assembly and generating ultrasonic energy sufficient to result in a microorganism destruction rate of at least a 1-log kill.

A method and apparatus is described for neutralizing airborne pathogens in ventilated air, and in heating or air conditioning systems. The pathogen neutralization system is effective against a wide spectrum of pathogens, it incorporates commercially available components, and it can be readily integrated into commercial HVAC systems where it neutralizes airborne pathogens in large volumes of ventilated air in real time without any chemical reagents. Typically, the system has a flow-through reaction chamber that contains a UV light source that emits short intense flashes of broad-spectrum UV light, a source of water vapor or spray, and an ozone generator. The system generates highly reactive ozone intermediates by irradiating ozone gas with UV light in the presence of water droplets or water vapor. The pathogens that can be neutralized by this system include bacteria, viruses, spores, fungi and parasites.

A system and method of maintaining the integrity of freshly harvested, or freshly cut fruits and vegetables. Specifically, the invention focuses on a distinct series of processes which confer a lower total microbial count, delay browning, improve general organoleptic properties, and decrease the amount of chemical contaminants on the exposed surfaces without the use of preservatives. Examples of such process may be applying a first produce integrity maintenance process, a second produce integrity maintenance process, application of an antibrowning agent to the produce by a produce antibrown agent applicator, exposing the produce to ultraviolet light by an ultraviolet light system, and applying an ozone treatment by an ozone treatment system.