From UVC to Far-UV: Comparing the Efficacy, Safety, and Cost of UV Technologies for Pathogen Control

By James Rush

The food processing industry has long used ultraviolet (UV) light as an effective mechanism for pathogen deactivation. Ultraviolet-C (UVC), also known as Germicidal UV, has been used for pathogen deactivation for well over a century, weaving through scientific discoveries and evolving technologies.

In the 1940s and 1950s, UVC was widely adopted for water disinfection and air purification in hospitals and healthcare facilities, and for food processing. A few decades later, concerns about potential harm to skin and eyes from UVC exposure led to stricter safety regulations and the development of shielded systems. These concerns, understandably, slowed the adoption of this technology as shielding mechanisms added significantly to the cost.

Far UV-C is renowned for its highly efficient decontamination of air and surfaces from deadly pathogens.

In the 1990s, research and applications of Pulsed UV emerged. Pulsed UV is a highly intense form of UV with a range of wavelengths. It could do in seconds what it might have taken continuous UV minutes or longer to do. This shorter exposure time was intended to deal with the safety issues, but safety concerns still were manifest.

More recently, we have seen the development and use of Far UV. This shorter wavelength light has solved the safety issues. At this wavelength, the light cannot penetrate skin or eyes and therefore does not pose a health risk, but they lacked the intensity to deactivate pathogens in seconds, particularly on surfaces.

“Far UV-C, characterized by its emerging status and possessing the shortest wavelengths among UV-C lights, is renowned for its highly efficient decontamination of air and surfaces from deadly pathogens,” said Dr. Sun-Jin Park, Co-Founder and CTO of Eden Park Illuminations and Adjunct Professor of Engineering, University of Illinois. “Recent scientific studies have confirmed its enhanced safety for skin and eyes when exposed to the light, making it a transformative tool for application in occupied spaces. Ongoing research and development efforts are underway to explore safer and more efficient uses of this light, offering increased flexibility in its practical applications, particularly within the food industry.”

Choosing Among UV Alternatives for Deactivation

UV light, regardless of form, has many advantages over other forms of sanitation. It is dry, chemical-free, and relatively easy to maintain.

But ultimately, the decision among alternative forms of UV light, as it would be with any solution, comes down to efficacy and cost. Does it work, and relative to alternate solutions, is it cost-effective?

Efficacy

All three wavelengths of ultraviolet (UV) light mentioned have the potential to disinfect surfaces and air by inactivating pathogens like bacteria, viruses, and fungi. However, each has situations in which it is the preferred alternative.

The efficacy of UV light is a function of the time of exposure, distance from the light to the surface being treated, and the bulb’s intensity. The priority among these variables determines choice among these alternative forms.

A few examples:

• When the surface to be disinfected is stationary and humans are present, Far UV is preferred. Such is the case with Clean Beam’s footwear sanitizer, where a user stands on glass through which Far UV light passes. In 8 seconds of exposure, a 4+ log reduction in bacterial count is evident. This solution is safe as it is.
• When the contact surface is moving and can’t be made to slow down or even stop, Pulsed UV is preferred. The high intensity of these lamps deactivates pathogens within one second of exposure at a 1-inch distance.
• In the case of water treatment, where time is less of an issue and no humans are around, continuous UV is preferred.

Choosing between UVC, pulsed UV, and far-UVC depends on specific needs and priorities. UVC is a well-established and cost-effective option but requires careful safety measures. Pulsed UV offers great efficacy in a very short time frame but at a higher cost, while far-UVC is the answer for stationary surfaces where humans are present.

About the author
James Rush, Ph.D., is VP of Marketing at Clean Beam in St Charles, IL. Clean Beam designs, manufactures, and installs sanitation solutions for food processing, food preparation, and healthcare facilities – anywhere product safety is compromised by harmful pathogens. Every patented solution produced is powered by DryZAP!, an intense and broadband form of Pulsed Ultraviolet Light. Our solutions protect the perimeter (footwear, fork truck wheels, pallet jack wheels, and pallets), food contact surfaces (conveyors), and the product itself. Our solutions are proven most effective and are dry, safe, chemical-free, and easy to maintain.