With most technologies (not PureFize®), germs can repair themselves after having been irradiated. It means that they return to a state where they can start multiplying again. This process is called photoreactivation and may greatly reduce the efficacy of UV disinfection.
Germ regrowth poses a serious risk. For example, E. coli can repair itself within two hours after irradiance thus starting to multiply again after only 17 minutes in 37°C. The same applies to all germs but with various repair and regrowth times. In applications where constant irradiation is not possible, permanent inactivation is therefore a must. Different UV technologies can inactivate germs to different degrees, some only temporarily and some permanently.
A number of studies have been performed to investigate this subject and researchers have found that using UV light at a broad range of wavelengths hinders subsequent photoreactivation (1). PureFize, with its broad wavelength spectrum, is designed to deliver enough UV dose to prevent any germ reactivation and regrowth.
(1) For example: Oguma K, Katayama H, Ohgaki S. Photoreactivation of Escherichia coli after low- or medium-pressure UV disinfection determined by an endonuclease sensitive site assay. Appl Environ Microbiol. 2002;68(12):6029-6035.
If you have any questions or would like more information about UV technology in general or PureFize® in particular, please contact us.