A Swine Health Information Center (SHIC)-funded working group report on ultraviolet light (UVC), a type of electromagnetic energy, provides guidance on how it can be used on farms to exclude pathogens from being introduced into a herd -- a process known as bio-exclusion, according to information SHIC posted on the American Association of Swine Veterinarians website.

When utilized and maintained properly, UVC light germicidal chambers can be an effective component of comprehensive biosecurity programs, SHIC said. However, proper construction and use of the chambers is necessary to obtain the full benefit of UVC bio-exclusion. Ensure that UVC lights are working properly to provide the intensity of light exposure or dose necessary to inactivate the microorganism, SHIC said. Place items for maximum exposure in the chamber and time in a way that the light can have an impact on all surfaces of the items. In addition, safety should be a top priority when utilizing UVC chambers.

The working group involved in this project examined UVC properties, related equipment, practices and pathogens resulting in best practices for UVC use for bio-exclusion on the farm.

Chambers, which may be commercial or homemade, are usually constructed so items to be disinfected are passed through from the dirty side (entry/hallway) to the clean side (office/breakroom). UVC germicidal chambers are mostly used for small to medium-sized items like lunchboxes, cell phones, small tools and medications, SHIC said. Food and semen bags can also be passed through the chamber without negative effects. Repeated exposure of plastics to UVC light may lead to a change in the color or smell of the object. Paper and cardboard cannot be disinfected in a UVC germicidal chamber. Larger UVC chambers, or UVC rooms, can be built for larger items.

SHIC said the full report contains detailed information on the physics of UVC, including wavelength details and how it inactivates pathogens. Information on dose calculations is incorporated, along with specifics on measuring UVC with a UV meter, factors influencing effectiveness, light system components and a discussion of different light bulbs. In addition, detailed maintenance and safety requirements are included for optimum results using UVC in germicidal chambers. The report concludes with a section on best practices in the field as well as extensive tables and resources on inactivation results. A fact sheet on UVC use has been developed as well.

As the world deals with the COVID-19 pandemic, SHIC continues to focus efforts on prevention, preparedness and response to novel and emerging swine disease for the benefit of U.S. swine health. As a conduit of information and research, SHIC encourages the sharing of its publications and research, which may be forwarded, reprinted and quoted freely. SHIC is funded by America's pork producers to fulfill its mission to protect and enhance the health of the U.S. swine herd. For more information, visit www.swinehealth.org.