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The Effect of UV Light & Bacteria Growth in Food Shops & Hospitals

Many hospitals and food shops employ the use of UV (ultraviolet) light to aid in killing microorganisms, specifically bacteria and mold. Preventing infection and the spread of airborne diseases is the goal of hospitals. Food shops aim to keep their food products and preparation surfaces free of bacteria and mold spores. UV light can also be used to purify water.

  1. How UV Light Works

    • “UV is artificially produced by mercury vapor low and medium pressure lamps,” according to American Air and Water. Most of the radiant energy released by low-pressure lamps is in the UVC part of the spectrum, which is known as the germicidal spectrum. UVC from mercury lamps is often called UVGI (ultraviolet germicidal irradiation). UV Comparision’s article "The Science of UV Light" notes that “the UVC spectrum is the most lethal range of wavelengths for microorganisms.” It is lethal to microorganisms because it damages its DNA, which disrupts cellular processes, resulting in the cell’s inability to function normally. Therefore, the cell will be unable to reproduce or cause disease and, if damaged enough, the cell will die.

    History

    • UVGI has been used for more than 100 years. It was first shown to disinfect water in 1877. Since then, various doctors have carried out research on UV light in noting its effect in, for example, treating smallpox and lupus, controlling the spread of airborne diseases, reducing surgical wound infections and reducing infection in classrooms. The results of these studies offered hope that UVGI would be able to help prevent the spread of disease.

    Use in Food Shops

    • Food shops employ UVC to help keep the work areas disinfected. In areas where food is processed or prepared, UV lights aid in killing bacteria and preventing mold or mold growth. However, the University of Rochester cautions that "the germicidal properties of ultraviolet light are used in addition to routine chemical disinfection and must not be relied on as the sole method of disinfection."

    Use in Hospital Operating Rooms

    • In hospitals, UV lights are often used in operating rooms to help prevent infection. The Journal of Bone and Joint Surgery's article "Ultraviolet Lighting During Orthopaedic Surgery and the Rate of Infection" explains that, previously, laminar airflow had been used to help stop infections during operations. The article also claims that since changing to UV lights, one surgeon has seen a significant drop in infection occurring in his patients. His records show that infection was 1.43 to 4.4 times more likely to happen when laminar airflow was used in the operating room as opposed to UV lights.

    UV Lights Used in HVAC

    • The use of UV lights in HVAC (heating, ventilating and air conditioning) systems has increased in recent years. Utilizing UV lights in this manner helps prevent mold in HVAC systems and also generates a healthier quality of indoor air. This application is advantageous in many public buildings, including hospitals. In fact, according to the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE), “The U.S. General Services Administration requires that UVC be included in cooling coil air-handling units for all new facilities and alteration projects to maintain coil cleanliness and improve air quality.”

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