Methods of determining exposure to uv light

Abstract

Methods of determining the dose of UVC light delivered to a sample comprising a low optical transmission complex fluid are provided. Also provided are methods of inactivation of an organism, such as a spore, a bacteria or a virus, in a sample comprising dose of UVC light delivered to a sample comprising a low optical transmission complex fluid.

What is claimed is: 
     
         1 . A method of determining the dose of UVC light delivered to a sample comprising a low optical transmission complex fluid comprising:
 (a) measuring the fluence rate delivered by a UVC source;   (b) generating a standard curve by:
 (i) contacting a bleachable fluorescence emitter with a low optical transmission complex fluid to form a control mixture; 
 (ii) exposing the control mixture to UVC light for an initial residence time; 
 (iii) obtaining an aliquot from the control mixture; 
 (iv) measuring the fluorescence emitted by the aliquot of (iii); 
 (v) repeating (ii)-(iv) one or more times, wherein the control mixture is exposed to UVC light for a residence time that is longer than the initial residence time; 
 (vi) correlating the fluorescence emitted with the residence time; 
   (c) contacting a bleachable fluorescence emitter with a test fluid comprising a low optical transmission complex fluid to form a test mixture;   (d) exposing the text mixture to UVC light for a selected residence time;   (e) measuring the fluorescence emitted by the test mixture; and   (f) determining the dose delivered to the test mixture using the standard curve of (b).   
     
     
         2 . The method of  claim 1 , wherein the UVC light has a wavelength in the range of about 200 nm to about 280 nm. 
     
     
         3 . The method of  claim 2 , wherein the UVC light has a wavelength of 254 nm. 
     
     
         4 . The method of  claim 1 , wherein the low optical transmission complex fluid comprises cell culture media, serum, a mixture comprising a vitamin, a sugar and a pigment, and a solution containing amino acids, peptides or proteins. 
     
     
         5 . The method of  claim 1 , wherein the bleachable fluorescence emitter comprises a UV-sensitive fluorescent microsphere. 
     
     
         6 . The method of  claim 1 , wherein the UVC source is a NIST traceable UVC source. 
     
     
         7 . The method of  claim 1 , wherein the dose is provided as one of a dose distribution, a mean dose, a P10 dose, a P50 dose and a P90 dose. 
     
     
         8 . The method of  claim 1 , wherein the fluence rate delivered by the UVC source is measured using a NIST traceable UVC detector. 
     
     
         9 . A method of inactivating an organism in a sample comprising a low optical transmission complex fluid known or suspected to comprise an organism, the method comprising:
 (a) identifying a dose of UVC known or suspected to inactivate the virus; and   (b) exposing the sample to the inactivating dose of UVC light provided by a UVC source;   wherein the inactivating dose comprises a selected wavelength, a selected UVC reactor power and a selected residence time; and   wherein the power and irradiation time are determined using a standard curve generated by:
 (i) measuring the fluence rate delivered by the UVC source; 
 (ii) contacting a bleachable fluorescence emitter with a low optical transmission complex fluid to form a control mixture; 
 (iii) exposing the control mixture to UVC light for an initial residence time; 
 (iv) obtaining an aliquot from the control mixture; 
 (v) measuring the fluorescence emitted by the aliquot of (iii); 
 (vi) repeating (iii)-(v) one or more times, wherein the control mixture is exposed to UVC light for a residence time that is different than the initial residence time; and 
 (vii) correlating the fluorescence emitted with the exposure time. 
   
     
     
         10 . The method of  claim 9 , wherein the UVC light has a wavelength in the range of about 200 nm to about 280 nm. 
     
     
         11 . The method of  claim 10 , wherein the UVC light has a wavelength of 254 nm. 
     
     
         12 . The method of  claim 9 , wherein the low transmission fluid comprises cell culture media. 
     
     
         13 . The method of  claim 9 , wherein the fluorescence emitter comprises a UV-sensitive fluorescent microsphere. 
     
     
         14 . The method of  claim 9 , wherein the organism is a spore. 
     
     
         15 . The method of  claim 9 , wherein the organism is a virus. 
     
     
         16 . The method of  claim 9 , wherein the organism is a bacteria. 
     
     
         17 . The method of  claim 9 , wherein the virus comprises one or more of a dsDNA virus, a ssDNA virus, a dsRNA virus and a ssRNA virus. 
     
     
         18 . The method of  claim 17 , wherein the virus comprises a virus of one or more of the virus families adenoviridae, asfarviridae, herpesviridae, iridoviridae, papillomaviridae, polyomaviridae, poxviridae, circoviridae, hepadnaviridae, parvoviridae, birnaviridae, reoviridae, arenaviridae, vornaviridae, bunyaviridae, deltaviridae, Filoviridae, orthomyxoviridae, paramyxoviridae, rhabdoviridae, arterioviridae, astroviridae, caliciviridae, cornonavirdae, Flaviviridae, HEV-like viruses, nodaviridae, picornaviridae, togaviridae, and tertroviridae. 
     
     
         19 . The method of  claim 18 , wherein the virus is the parvovirus MVM, the retrovirus MuLV or the bunya virus CVV. 
     
     
         20 . The method of  claim 9 , wherein the method provides a viral log reduction value (LRV) of greater than or equal to about 0.5, about 1.0, about 1.5, about 2.0, about 2.5, about 3.0, about 3.5, about 4.0, about 4.5, about 5.0, about 5.5, about 6.0, about 6.5 or greater than about 6.5. 
     
     
         21 . The method of  claim 9 , further comprising the step of modifying one or both of (a) the initial power and (b) the initial period, such that the mean dose delivered by the UVC reactor is equal to the inactivating dose. 
     
     
         22 . The method of  claim 9 , wherein the UVC source is a NIST traceable UVC source. 
     
     
         23 . The method of  claim 9 , wherein the dose is one of a dose distribution, a mean dose, a P10 dose, a P50 dose and a P90 dose. 
     
     
         24 . The method of  claim 9 , wherein the fluence rate delivered by the UVC source is measured using a NIST traceable UVC detector.