NOAA Publication: HPUV Proposed Studies by Kurt Garrett

HIGH PERFORMANCE UV (HPUV) INACTIVATION OF E. COLI. Kurt A. Garrett, Cheryl M. Davis and De Lois M. Powell, Department of Natural and Physical Sciences, Shaw University, Raleigh, NC

The use of ultraviolet light for inactivation of microorganisms is well documented in the literature. Ultraviolet light used for inactivation is sometimes called germicidal UV or UV254 (the specific wavelength known to have the most lethal effect on bacteria, fungi and viruses).

While this band of invisible light is part of the sun’s spectral energy, artificial sources of germicidal UV come from manufacturers such as Sylvania and General Electric. The greatest users of germicidal UV lamps are wastewater treatment facilities seeking alternative methods of disinfection that reduce the need for chlorine and chlorine derivatives. The disinfection mechanism generally points to the disruption of the microorganism’s DNA. In turn, the disruption of microbial DNA prevents replication and can cause ‘death’. Early UV light inactivation research was set back when conventional ultraviolet lamps performed below expectation. This failure was traced to lamp design. While researchers sought intense high-energy germicidal UV light, manufacturers designed low-energy UV lamps, primarily used for wastewater disinfection. In research typical inactivation times, using conventional germicidal UV lamps, range from 20 minutes to several days for virus and similar times for bacteria.

Recently, we tested a new lamp system, High Performance Ultraviolet Light (HPUV; CSMO, Inc.) and found it to reduce 106 colonies of herpes simplex virus (HSV) in three seconds. We are proposing use of the HPUV for inactivation of E. coli. Our studies will measure inactivation initiation, inactivation optimum and hyper-inactivation. HPUV is expected to result in quicker inactivation times for E. coli than conventional UV lamps. This data will allow us to construct a response curve for E. coli when using HPUV inactivation. Future research will use these data to determine inactivation conditions that preserve important protein triggers of the cellular immune response.