What Is Ultraviolet (UV) Light?
Ultraviolet (UV) light is a non-visible electromagnetic radiation commonly known as light from the sun or as a “black light” used to check currency. It has shorter wavelengths than visible light but longer wavelengths than X-ray radiation. UV light covers wavelengths from 100 to 400 nm and is divided into three subcategories:
Ultraviolet A UVA 400 – 315 nm
Ultraviolet B UVB 315 – 280 nm
Ultraviolet C UVC 280 – 100 nm
Both UVA and UVB radiation pass through the earth’s atmosphere, reaching the surface, but UVC radiation is mostly absorbed by the ozone layer, never completely reaching land.
The UVA wavelength is relatively long and is commonly referred to as a black light when providing artificial illuminatio. It is not absorbed by the ozone layer but accounts for almost 95% of the UV radiation that reaches the earth’s surface.
In lighting spectrums, a shorter wavelength means more energy. UVC has the shortest wavelength which allows it to be more energetic than visible light, and a more powerful tool for effective radiation. It is versatile and can be used for disinfecting water and destroying harmful micro-organisms in other liquids, on surfaces, food products and in ‘air’ organisms. UVC technology is an inexpensive, highly efficient and reliable way to destroy more than 99.999% of all pathogens within seconds without the additional use of chemicals or harmful side effects.
Ultraviolet A Light For Poultry
Poultry, unlike humans, have a fourth retinal cone that allows them to see in the UVA part of ultraviolet radiation.
The graph below shows the color sensitivity of a typical chicken eye. You can see there are 4 (four) distinct color peaks. The highest sensitivities are to green, blue and red light but you can see another one in the UV spectrum (far left peak on the curve).
Responses of poultry to ultraviolet radiation
Chickens use UVA for feeding and peer recognition, mate selection, breeding and various social encounters. Retinally perceived, UVA controls the release of melatonin in the pineal gland of dark-adapted birds. Because ultraviolet radiation has shorter wavelengths than visible light, it is unable to penetrate to the hypothalamus to induce a photosexual response. UVA also has anti-rachitic properties, which catalyse the synthesis of vitamin D3 from 7-dehydroxycholesterol in the skin of feet and legs, a function that prevents rickets, minimises the incidence of tibial dyschondroplasia, and normalises growth and bone ash in young birds fed diets deficient in vitamin D3.
LEWIS, P., & GOUS, R. (2009). Responses of poultry to ultraviolet radiation. World’s Poultry Science Journal, 65(3), 499-510. doi:10.1017/S0043933909000361
How Ultraviolet C (UVC) Light Sterilization Works
Bio-security protocols are only as good as their weakest link—meaning,there is proven evidence that shows the best ways to ensure policy compliance is through hard-wiring, forcing functions, constraints and automation. That’s where irradiation by germicidal UVC light comes in.
In many instances non-compliance with established policies tend to be low among employees. Many bio-secure facilities require individuals to shower in and out, which only limits cross-contamination on the person. They fail to limit or address the import of pathogens through everyday items, like cell phones, eye glasses and lunch boxes
The entire UVC range of ultraviolet radiation is germicidal and falls into a subset of light called Ultraviolet Germicidal Irradiation (UVGI). UVGI is an environmentally friendly way of disrupting, mutating and breaking apart the DNA and RNA of bacteria, viruses and a majority of fungal pathogens—consequently destroying their ability to multiply and cause disease. The two factors that directly influence how effective UV light sterilization is when using it as a bio-security tool are time of exposure and UV light intensity. The amount of time UVC is exposed to any given pathogen is proportional to the amount of killing or inactivation it does. The fluorescent-based light tubes in the BioShift® emit UVC light at 254 nm wavelength, which is in the range for optimal pathogen killing.