Puren Solutions UVC Light Products
UVC LIGHT
FOR MICROBIAL MANAGEMENT
CONTENT

WHAT IS UVC LIGHT AND WHAT DOES IT DO?

UVA and UVB are more commonly known bands of the ultraviolet spectrum. They are emitted by the sun and the reason we have sunscreen. These bands are also manufactured in man-made devices such as tanning beds, black lights, UV therapy lights, etc. The greatest concern surrounding UV wavelengths is damage to skin and eyes. This occurs through long-term, unprotected exposure. Ultraviolet-C, or UVC, is also emitted by the sun. However, it is not able to penetrate the ozone layer. As such, human exposure to UVC is always man-made (unless you are an astronaut). UVC irradiation refers to germicidal wavelengths of light in the 200-280 nm range.

UVC light works by deactivating and killing pathogens by damaging their DNA. The UVC spectrum, especially between 250-270 nm, is strongly absorbed by pathogens, making it the most lethal range for microorganisms. Not all UVC is equal in its germicidal capacity. UVC in the 222 nm range is indeed germicidal (and appealing due to it being considered safer for skin and eyes). However, the amount of time a pathogen needs to be exposed for deactivation and death is substantially greater than UVC in the 265 nm range. For industrial application, it is important to pay attention to UVC product specifications. This will ensure it can provide proper disinfection for the intended application.

IS UVC LIGHT SAFE?

As with many disinfection tools out there, UVC light can cause burns to skin and eyes if not used properly. It is not recommended to stare directly at the lights or hold them directly over your skin. Wearing safety glasses and clothing that covers your skin is recommended. Especially parts of the body that may have greater potential for exposure during use of UVC light devices.

A BRIEF HISTORY OF UVC

The germicidal effect of UV light has a long known history. It was first recognized for its germicidal effects in the late 1800s. Physiologist Arthur Downes and scientist Thomas P. Blunt first reported the inactivation of bacteria by sunlight. In 1893, Niels Finsen demonstrated that chemical rays (what we now call UV light) from sunlight or arc lamps had antibacterial effects. However, the exact mechanism for this effect was still speculatory. (Think of the open-air treatments in specially designed wards for patients battling the Spanish flu during the 1918-1919 pandemic.)

In 1903, J.E. Barnard and H. Morgan identified the UV spectrum around the 250 nm range as biocidal. Shortly thereafter, the study and publication of research around “ultraviolet radiation” grew rapidly. It was also during this time that the different categories of UV light were named – i.e. near UV, far UV, UVA, UVB, and UVC.

As research continued, major discoveries were made about its ability to destroy E. coli, tuberculosis, and measles. In the early 1990’s, UVC light became widely used – and still is today – in places like hospitals, schools, and airports.

UVC Light treatments by Finsen's UVC arc light

Niels Ryberg Finsen’s original UV arc light used to treat various skin conditions, including Lupus. Reprinted from DOI:10.2147/NDD.S26593

UVC FOR MICROBIAL MANAGEMENT

UVC light for microbial management offers a non-chemical approach to disinfection. Research has shown that UVC can effectively inactivate bacteria, viruses, fungus, and mold. There are many types of UVC light systems and equipment on the market. The use of lamps has a much longer history than that of LEDs. These lamp-based systems utilize UV lamps, fixtures, ballasts, and reflective surfaces. However, in recent years, LEDs have experienced rapid advancements in their technological development. This has opened the door for unlimited form factors and applications previously unavailable with lamps.

The most prominent applications of UVC light are in air, surface, and water disinfection. With advances in technology, more uses are being explored and implemented.

COMMON UVC AIR APPLICATIONS
  • In-duct
  • Recirculation units
  • Upper room systems
  • UV barrier systems
  • Overhead tank disinfection
COMMON UVC SURFACE APPLICATIONS
  • Equipment and packaging disinfection
  • Refrigeration and HVAC cooling coils
  • Lower room disinfection
  • Overhead surgical site disinfection
  • General area/room disinfection
  • Food surface disinfection
  • Mold remediation systems
COMMON UVC WATER APPLICATIONS
  • Wastewater disinfection
  • Reclaimed water disinfection
  • Drinking water, Ice making disinfection
  • Laundry water
  • Aquariums, hatcheries, and nurseries
  • Swimming pools/hot tubs

Research into UVC light treatment for wound care is promising. Aided by the development of technological advancements – such as UVC LEDs – new applications previously inaccessible to UVC lamp devices are now being explored.

UV light sunset, two farmers walking in field
UVC APPLICATIONS IN AGRICULTURE

Numerous crops are impacted by molds, mildew, and bacteria. One example is in California, where powdery mildew is estimated to account for nearly 75% of total pesticide application by grape growers. In cost, this equates to 3-7% of their total gross production value. Likewise, national losses in wheat yield due to powdery mildew have been estimated to be almost as much as half the total crop harvest. One of the biggest challenges in combating these pests is the increase of chemical resistance.

UVC light disinfects plants in two ways: germicidal effects and biological responses. Research cites the efficacy of UVC light in managing disease through direct germicidal activity as well as indirect ability to induce defense responses in plants.

Depending on the plant/species, UVC has also been shown to up-regulate plant metabolites (decreasing need for growth regulators ), resulting in:

  • Plants growing with increased fresh mass
  • Shorter height
  • Increased branching
  • Quicker to flower or delayed flowering
  • Increased flower and fruit production
  • Increased fruit weight at harvest
  • Reduced chemical use and residue

Research continues to build supporting UVC light as a powerful tool against prevalent agricultural woes. For example, multiple studies on multiple crop types revealed substantial decreases in plant and produce sensitivity to Botrytis and powdery mildew diseases. 

UVC Light and Agriculture research slide down, click to download.

Research also shows a significant decrease in already present Botrytis and powdery mildew counts on plants and plant products – both in the field and post-harvest. In multiple studies, nighttime applications of UVC provided suppression of disease severity statistically equivalent to chemical standards with no harm to plants or fruits and no chemical residue. Like the use of pesticides/fungicides, care should be taken to ensure the safety of personnel applying UVC.

From seed to harvest to storage/transport, UVC light is proving a powerful tool for bolstering plant resistance, mitigating pathogen outbreaks, and reducing chemical usage.

UVC APPLICATIONS IN FOOD PROCESSING

According to estimates by the Food and Agriculture Organization (FAO) of the United Nations, one-third of food produced globally is lost or wasted each year. This includes losses at the different stages of the food supply chain – including on-farm, harvest, processing, storage, and transportation.

For over 50 years, UVC has been used in food processing to disinfect water, air, and surfaces. The US FDA’s HACCP, Health Canada, and European Union have already approved the use of UV light for pathogenic control in many food industries. UVC light’s efficacy in managing disease/pathogen mitigation through direct germicidal activity and defense responses is bolstered by research showing it does not compromise quality in many plant and food materials. These defense responses are important in resistance to spoilage agents.

Conventional food safety technologies (thermal processing & pasteurization, cold plasma processing, radiofrequency heating, pulsed electric fields, etc.) have been studied extensively for application in the food industry. But they often alter physical and nutritional properties of food. UVC light – especially from LEDs – offers a strong tool free of the undesirable characteristics of traditional food safety approaches.

The FDA Food Safety Modernization Act (FSMA) requires facilities to have microbial control plans. Common pain points lie in cleanliness of suppliers, human related factors, and how process control is being addressed. These plans help address these issues through regular implementation of a multi-step process:

  • Risk Assessment
  • Sampling
  • Testing
  • Validation
  • Education and Training

Conditions commonly found in food processing facilities are excellent for microbial growth. Microorganisms have access to plenty of food, moisture, and ideal temperatures. Many studies have shown significant reduction of pathogens such as norovirus, E. coli, Salmonella, and Listeria on a range of food and food processing surfaces. For example, bacterial counts of listeria were significantly reduced (over 90% and up to 99% reduction) on multiple conveyor belt types using UVC light. Another study found up to 99.999% reduction of E. coli on four different conveyor belt materials (and egg surfaces) through the application of UVC light.

Studies also show the extension of shelf-life and successful control of post-harvest disease and decay in many food products. Primarily through the killing of spoilage organisms and up-regulation of plant/produce defense mechanisms. UVC also caused fewer changes (or no changes at all) in the nutritional and sensory properties of food compared to thermal processing.

Dosage, especially uniform dosing specific to the application, is a core component for successful UVC implementation. As UVC light technology continues to evolve and application research broadens, it is proving powerful potential for every step of control plans and for the food supply chain in general.

UVC light for food safety research resource, click to download
UVC APPLICATIONS IN HOSPITALITY

Hospitality is an industry that regularly interacts directly with customers, handles food, and has a wide range of shared spaces it must keep clean. From guest room disinfection to microbial mitigation of common touch points (doorknobs, keyboards, telephones, TV remotes, etc.) to laundry to food storage, preparation, and delivery, pathogen mitigation in hospitality is everywhere. The ramifications for failed sanitation protocols are great. They can lead to illness and death of customers, which lead to loss of trust and brand damage. All of which equate to financial losses.

Hospitality faces challenges with chemical exposures (think degreasers, oven cleaners, floor cleaners, a wide range of sanitizers, and even laundry soaps), property materials wear and tear, and food/food surface contamination. This is compounded by the tough and adaptable nature of bacteria, which increasingly develop resistance to chemical disinfection approaches.

Patrons are more aware and concerned with cleanliness than ever before. A 2020 study by the American Hotel & Lodging Association found cleanliness as guests top priority. Likewise, a study in 2018 found 81% of surfaces in hotels had some fecal bacteria present. These surfaces were not limited to bathrooms. Fecal bacteria was found on light switches, TV remotes, ice buckets, decorative bedding, and more.

For example, a study of bathroom counters in 4-star hotels were found to have an average of 2.5 million Colony Forming Units (CFU) per square inch. (For reference, the average home bathroom has 452 CFU per square inch.) Studies have also found that mops and cleaning cloths used by cleaning staff are often contaminated with germs while being used through a variety of spaces. One study planted a virus in a hotel room and was able to track its spread via hotel cleaning staff to three other rooms nearby. It can be expected, given the number of people moving through, that high levels of pathogens will be present in hospitality spaces. What is increasingly apparent is that current protocols are leaving far too many germs behind.

A study compared UVC light and alcohol wipes for routine once-daily disinfection of surfaces. It found that UVC reduced the number of housekeeping hours in half with similar pathogen reduction efficacy as the alcohol. Another study found a 94% reduction in pathogens when UVC light was added alongside the standard use of disinfectants.

Backed by extensive history and documentation of effectively killing microbes, UVC light offers powerful disinfection tools for just about any hospitality sanitation plan. Technological advancements are making it increasingly possible to deploy UVC in more settings than before with greater cost-effectiveness. It can easily be integrated into housekeeping processes, providing rapid sanitization of surfaces while reducing use of and exposure to chemicals. 

UVC for Norovirus research resource, click to download
UVC LIGHT SOURCES: LAMPS VS LEDS

Historically, a range of mercury (low-, medium-, and high-pressure), xenon, and excimer lamps have been the source of man-made UVC light.

This past decade has seen incredible advances in UVC LED technology. The novelty around home UVC LED devices is intriguing. But a majority of these devices lack the necessary power and durability for commercial applications. Industrial-strength UVC light is now possible for more applications with LED technology. It can readily be added to the arsenal of tools (even replacing or minimizing the use of some) available to cleaning and maintenance teams. It also offers a reliable addition for consistency in process control.

UVC LEDs have specific advantages over UV lamps:

LEDs offer a compact light source that does not require an electronic ballast for starting.
LEDs can be utilized where space does not allow regular UV lamps.
LEDs do not use the toxic heavy metals found in UV lamps.
LED efficacy is not affected by contact with oils from skin.
LEDs can be arranged in a variety of arrays and packaging for optimal use and disinfection.
LEDs provide directional light, reducing wasted energy seen with 360 degree emission of light by UV lamps.
LEDs can produce UVC at optimal wavelengths (265 nm) for germicidal effectiveness.
LEDs offer a lower maintenance solution to UV lamps.

One of the most exciting and important aspects of UVC LEDs is the potential for endless form factors and customizations. Since UVC light is only effective for pathogens directly in its path, a downfall of the technology (conventional or LED) in automated applications is “shadowing.” This is easily overcome by the packaging flexibility of UVC LEDs.

LEDs open the door for UVC application in conditions and spaces not safe, practical, or feasible for lamps. LED packaging can be configured to allow the delivery of UVC directly to surfaces, products, tools, and equipment. This allows for site-specific management of hygiene and microbial risk. It is now possible to integrate UVC into automated processing lines without safeguards for bulb breakage or special consideration for exposure to cleaning cycles.

IS UVC RIGHT FOR ME?

Facilities that properly implement UVC light in their systems and processes – regardless of industry – have seen direct correlations between the application of UVC and increased profits. In many situations, it can:

  • Improve systems efficiency and increase productivity
  • Extend equipment life
  • Help lower overall energy and maintenance costs
  • Combat human error factors and bolster process control
  • Provide safer working conditions
  • Extend product shelf life
  • Help achieve higher quality products
BROWSE UVC LIGHT PRODUCTS

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