Action spectra for validation of pathogen disinfection in medium-pressure ultraviolet (UV) systems

Beck, Sara E.; Wright, Harold; Hargy, Thomas M.; Larason, Thomas C.; Linden, Karl G.

doi:10.1016/j.watres.2014.11.028

Cited by 136 publications

(103 citation statements)

References 27 publications

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“…However, a tunable laser at 270 nm has yielded 1.5 and at least 3 Log 10 -reductions of MS2 with doses of 20-30 mWs/cm 2 and 60 mWs/cm 2 , respectively [33,34]. The tunable laser at a lower wavelength of 253.7 nm yielded approximately 3.5 Log 10 -reduction of MS2 with a dose of 70 mWs/cm 2 [33], which corresponds to our result.…”

Section: Discussionsupporting

confidence: 87%

“…Doses from 41 to 60 mWs/cm 2 were needed to reach 2-3 Log 10 -reductions of MS2 at wavelengths of 255-280 nm (excluding 270 nm) [13,18,24], while approximately 110 mWs/cm 2 was needed at 285 nm to reach 3 Log 10 -reduction [21]. However, a tunable laser at 270 nm has yielded 1.5 and at least 3 Log 10 -reductions of MS2 with doses of 20-30 mWs/cm 2 and 60 mWs/cm 2 , respectively [33,34]. The tunable laser at a lower wavelength of 253.7 nm yielded approximately 3.5 Log 10 -reduction of MS2 with a dose of 70 mWs/cm 2 [33], which corresponds to our result.…”

Section: Discussionmentioning

confidence: 99%

“…Nucleotides have UV absorbance peaks between 240 and 280 nm and absorption maximum of DNA is considered to be near 260 nm [36]. UV-absorption of proteins generally peaks at 280 nm [37] although proteins of some viruses may efficiently be affected by wavelengths below 240 nm [33,34]. In addition, wavelengths on UVA region (above 315 nm) may produce reactive intermediates and oxidative damage to DNA and other components of the bacterial cell [38,39].…”

Section: Discussionmentioning

confidence: 99%

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UV-LEDs Efficiently Inactivate DNA and RNA Coliphages

Zyara

Heinonen‐Tanski

Veijalainen

et al. 2017

Water

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UV-LEDs are a new method of disinfecting drinking water. Some viruses are very resistant to UV and the efficiency of UV-LEDs to disinfect them needs to be studied. Drinking water was disinfected with UV-LEDs after spiking the water with MS2 and four UV-and/or Cl-resistant coliphages belonging to RNA or DNA coliphages isolated from municipal wastewater. UV-LEDs operating at a wavelength of 270 nm for 2 min with 120 mW of irradiation caused 0.93-2.73 Log 10 -reductions of coliphages tested in a reactor of a 5.2 L volume. Irradiation time of 10 min in the same system increased the Log 10 -reductions to 4.30-5.16. Traditional mercury UV (Hg-UV) lamp at a 254 nm wavelength caused 0.67-4.08 Log 10 -reductions in 2 min and 4.56-7.21 Log 10 -reductions in 10 min in 10 mL of water. All coliphages tested except MS2 achieved 4 Log 10 -reductions with UV-LEDs at a dose that corresponded to 70 mWs/cm 2 using Hg-UV. Thus, UV-LEDs are a promising method of disinfecting UV-and/or Cl-resistant viruses.

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Section: Discussionsupporting

confidence: 87%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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UV-LEDs Efficiently Inactivate DNA and RNA Coliphages

Zyara

Heinonen‐Tanski

Veijalainen

et al. 2017

Water

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“…For initial experiments, the lower operational limit of the laser emission was 212 nm; these data are combined with the results at 210 nm. The results shown represent damage to the full genome, from the log reduction of the RT-qPCR signal measured by using two different fragments, compared with the log reduction of MS2 viral infectivity, reported previously (28). The results indicate that across the germicidal UV spectrum from 210 nm to 290 nm, the rate of damage to the MS2 genome observed closely mirrored the loss of viral infectivity.…”

Section: Resultsmentioning

confidence: 53%

“…1. The inactivation rate was 0.050 (P ϭ 3.6 ϫ 10 Ϫ7 ) as measured by plaque assay infectivity (28). For the RT-qPCR data points at 253.7 nm calibrated to these infectivity data, the inactivation rates, representing log reductions of qPCR signals, were 0.046 (P ϭ 6.2 ϫ 10 Ϫ4 ) for data collected with the 1,185-base region and 0.058 (P ϭ 1.7 ϫ 10 Ϫ3 ) for data for the 2,169-base region.…”

Section: Resultsmentioning

confidence: 99%

Comparison of UV-Induced Inactivation and RNA Damage in MS2 Phage across the Germicidal UV Spectrum

Beck

Rodríguez

Hawkins

et al. 2016

Appl Environ Microbiol

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146

123

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c Polychromatic UV irradiation is a common method of pathogen inactivation in the water treatment industry. To improve its disinfection efficacy, more information on the mechanisms of UV inactivation on microorganisms at wavelengths throughout the germicidal UV spectrum, particularly at below 240 nm, is necessary. This work examined UV inactivation of bacteriophage MS2, a common surrogate for enteric pathogens, as a function of wavelength. The bacteriophage was exposed to monochromatic UV irradiation from a tunable laser at wavelengths of between 210 nm and 290 nm. To evaluate the mechanisms of UV inactivation throughout this wavelength range, RT-qPCR (reverse transcription-quantitative PCR) was performed to measure genomic damage for comparison with genomic damage at 253.7 nm. The results indicate that the rates of RNA damage closely mirror the loss of viral infectivity across the germicidal UV spectrum. This demonstrates that genomic damage is the dominant cause of MS2 inactivation from exposure to germicidal UV irradiation. These findings contrast those for adenovirus, for which MS2 is used as a viral surrogate for validating polychromatic UV reactors. UV irradiation is a common method of disinfection in the water treatment industry. UV light induces damage to the genomes of bacteria, protozoa, and viruses, breaking bonds and forming photodimeric lesions in nucleic acids, DNA, and RNA (1, 2). These lesions prevent both transcription and replication and ultimately lead to inactivation of the microorganisms (3, 4). Direct UV damage to nucleic acids occurs at the wavelengths absorbed by DNA and RNA, in the germicidal UV region between 200 and 300 nm (5, 6). In this wavelength range, however, UV light also damages other cellular and viral components, causing, for example, photochemical reactions in proteins and enzymes (7,8). For this reason, UV sources that emit polychromatic light, across the germicidal UV spectrum, are considered more effective at inactivating certain pathogens than sources that emit monochromatic light at 253.7 nm (9-12). As polychromatic sources become more common, more research is being undertaken to understand the mechanisms of inactivation occurring in pathogens exposed to polychromatic UV irradiation.Male-specific (MS2) coliphage is a single-stranded RNA virus. It infects strains of Escherichia coli that produce F ϩ pili, which serve as viral receptors. The virion consists of a short singlestranded RNA genome (3,569 bases) surrounded by an icosahedral protein capsid, 27 nm in diameter (13). MS2 is commonly used in the water treatment industry as a surrogate for enteroviruses because of its similar size, shape, and genome composition (9,14). It serves as a biodosimeter for UV disinfection studies (15) and for UV reactor validation in North America (14, 16). For reactor validation, MS2 is also used as a surrogate for Cryptosporidium and adenovirus, despite the differences in UV sensitivity and spectral sensitivity between these microorganisms. Recent interest has grown regarding microbial ...

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Evaluation of water‐assisted UV‐C light and its additive effect with peracetic acid for the inactivation of Listeria monocytogenes, Salmonella enterica and murine norovirus on whole and fresh‐cut strawberries during shelf‐life

et al. 2022

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BACKGROUND:The purpose of the present study was to examine the inactivation of Salmonella enterica (50 ∼L; 10 9 CFU g −1 ), Listeria monocytogenes (50 ∼L; 10 9 CFU g −1 ), and murine norovirus (MNV-1; 50 ∼L; 10 7 50% tissue culture infectious dose (TCID 50 ) mL −1 ) on whole and fresh-cut strawberries after 2 min disinfection treatments (water (H 2 O), chlorine 200 mg L −1 (NaClO), water-assisted ultraviolet-C (UV-C) (WUV), and the combination WUV and 40 mg L −1 of PA (WUV + PA)) in a water tank (15 L) equipped with 4 UV-C lamps (17.2 W each), and after 7 days of cold storage (4 and 10 °C). For MNV-1, dry UV-C treatment (DUV) was also tested. For all UV-C treatments, an irradiation dose of 1.3 kJ m −2 was used.RESULTS: When strawberries were washed with WUV, L. monocytogenes and S. enterica were reduced by 2.8 and 2.2 log CFU g −1 , respectively. The addition of 40 mg L −1 of PA to WUV (WUV + PA) increased the reduction range of L. monocytogenes and S. enterica by 1.9 and 0.8 log, respectively. Regarding the wash water, no pathogens were recovered after the WUV + PA treatment (detection limit 50 CFU mL −1 ). Depending on storage conditions (7 days at 4 or 10 °C), reductions observed were 0.5 to 2.0 log for S. enterica and 0.5 to 3.0 log for L. monocytogenes. The reductions in MNV-1 titer after disinfection treatments ranged from 1.3 to 1.7 log. No significant differences between storage conditions were observed for MNV-1: titers did not decline or were reduced up to 0.3 log after 7 days of cold storage.CONCLUSION: The three-way action for disinfecting strawberries by UV-C irradiation and PA, plus the physical removal of the microorganisms by agitated water, are effective against foodborne pathogens on strawberries and water wash. During storage, WUV had a larger impact on the inactivation kinetics of S. enterica. Storage had little impact on MNV-1 inactivation.

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Action spectra for validation of pathogen disinfection in medium-pressure ultraviolet (UV) systems

Cited by 136 publications

References 27 publications

UV-LEDs Efficiently Inactivate DNA and RNA Coliphages

UV-LEDs Efficiently Inactivate DNA and RNA Coliphages

Comparison of UV-Induced Inactivation and RNA Damage in MS2 Phage across the Germicidal UV Spectrum

Evaluation of water‐assisted UV‐C light and its additive effect with peracetic acid for the inactivation of Listeria monocytogenes, Salmonella enterica and murine norovirus on whole and fresh‐cut strawberries during shelf‐life

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