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Sang-do Ha - One of the best experts on this subject based on the ideXlab platform.
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Synergistic Effects of Combined Chlorine and Vitamin B1 on the Reduction of Murine Norovirus-1 on the Oyster (Crassostrea gigas) Surface
Food and Environmental Virology, 2019Co-Authors: Shin-young Park, Sang-do HaAbstract:This study investigated the synergistic effects of Combined Chlorine (200, 500, 700, and 1000 ppm) and vitamin B1 (1000, 2000, and 3000 ppm) on the murine norovirus-1 (MNV-1), a human norovirus (NoV) surrogate, on oyster surface. Vitamin B1 slightly reduced MNV-1 (0.04–0.3 log-reduction), whereas Chlorine significantly reduced MNV-1 (0.4–1.0 log-reduction). The Combined Chlorine and vitamin B1 resulted in a 0.52–1.97 log-reduction of MNV-1. The synergistic reduction in the MNV titer was not dependent on the concentrations of Chlorine and vitamin B1, and it ranged between 0.08 and 1.03 log10 PFU/mL. The largest synergistic reduction observed was for the Combined 700 ppm Chlorine and 1000 ppm vitamin B1. The pH and mechanical texture of the oysters were not significantly changed by the Combined 0–1000 ppm Chlorine and 3000 ppm vitamin B1. The overall sensory acceptability were significantly (P
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Synergistic Effects of Combined Chlorine and Vitamin B_1 on the Reduction of Murine Norovirus-1 on the Oyster (Crassostrea gigas) Surface
Food and Environmental Virology, 2019Co-Authors: Shin-young Park, Sang-do HaAbstract:This study investigated the synergistic effects of Combined Chlorine (200, 500, 700, and 1000 ppm) and vitamin B_1 (1000, 2000, and 3000 ppm) on the murine norovirus-1 (MNV-1), a human norovirus (NoV) surrogate, on oyster surface. Vitamin B_1 slightly reduced MNV-1 (0.04–0.3 log-reduction), whereas Chlorine significantly reduced MNV-1 (0.4–1.0 log-reduction). The Combined Chlorine and vitamin B_1 resulted in a 0.52–1.97 log-reduction of MNV-1. The synergistic reduction in the MNV titer was not dependent on the concentrations of Chlorine and vitamin B_1, and it ranged between 0.08 and 1.03 log_10 PFU/mL. The largest synergistic reduction observed was for the Combined 700 ppm Chlorine and 1000 ppm vitamin B_1. The pH and mechanical texture of the oysters were not significantly changed by the Combined 0–1000 ppm Chlorine and 3000 ppm vitamin B_1. The overall sensory acceptability were significantly ( P
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predictive modeling for the growth of salmonella enterica serovar typhimurium on lettuce washed with Combined Chlorine and ultrasound during storage
Journal of Food Hygiene and Safety, 2019Co-Authors: Shin-young Park, Cheng Yi Zhang, Sang-do HaAbstract:This study developed predictive growth models of Salmonella enterica Serovar Typhimurium on lettuce washed with Chlorine (100~300 ppm) and ultrasound (US, 37 kHz, 380 W) treatment and stored at different temperatures (10~25°C) using a polynomial equation. The primary model of specific growth rate (SGR) and lag time (LT) showed a good fit (R2≥0.92) with a Gompertz equation. A secondary model was obtained using a quadratic polynomial equation. The appropriateness of the secondary SGR and LT model was verified by coefficient of determination (R2=0.98~0.99 for internal validation, 0.97~0.98 for external validation), mean square error (MSE=- 0.0071~0.0057 for internal validation, -0.0118~0.0176 for external validation), bias factor (Bf=0.9918~1.0066 for internal validation, 0.9865~1.0205 for external validation), and accuracy factor (Af=0.9935~1.0082 for internal validation, 0.9799~1.0137 for external validation). The newly developed models for S. Typhimurium could be incorporated into a tertiary modeling program to predict the growth of S. Typhimurium as a function of Combined Chlorine and US during the storage. These new models may also be useful to predict potential S. Typhimurium growth on lettuce, which is important for food safety purposes during the overall supply chain of lettuce from farm to table. Finally, the models may offer reliable and useful information of growth kinetics for the quantification microbial risk assessment of S. Typhimurium on washed lettuce.
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synergistic effects of Combined Chlorine and vitamin b1 on the reduction of murine norovirus 1 on the oyster crassostrea gigas surface
Food and Environmental Virology, 2019Co-Authors: Shin-young Park, Sang-do HaAbstract:This study investigated the synergistic effects of Combined Chlorine (200, 500, 700, and 1000 ppm) and vitamin B1 (1000, 2000, and 3000 ppm) on the murine norovirus-1 (MNV-1), a human norovirus (NoV) surrogate, on oyster surface. Vitamin B1 slightly reduced MNV-1 (0.04–0.3 log-reduction), whereas Chlorine significantly reduced MNV-1 (0.4–1.0 log-reduction). The Combined Chlorine and vitamin B1 resulted in a 0.52–1.97 log-reduction of MNV-1. The synergistic reduction in the MNV titer was not dependent on the concentrations of Chlorine and vitamin B1, and it ranged between 0.08 and 1.03 log10 PFU/mL. The largest synergistic reduction observed was for the Combined 700 ppm Chlorine and 1000 ppm vitamin B1. The pH and mechanical texture of the oysters were not significantly changed by the Combined 0–1000 ppm Chlorine and 3000 ppm vitamin B1. The overall sensory acceptability were significantly (P < 0.05) reduced in oysters treated with 1000 ppm Chlorine and 3000 ppm vitamin B1 than in those treated with 0–700 ppm Chlorine and 3000 ppm vitamin B1. This study suggests that the Combined 700 ppm Chlorine and 3000 ppm vitamin B1 could potentially be used to reduce NoV on oyster surface without causing concomitant changes in the mechanical texture, pH, or sensory qualities of the oysters.
Shin-young Park - One of the best experts on this subject based on the ideXlab platform.
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Synergistic Effects of Combined Chlorine and Vitamin B1 on the Reduction of Murine Norovirus-1 on the Oyster (Crassostrea gigas) Surface
Food and Environmental Virology, 2019Co-Authors: Shin-young Park, Sang-do HaAbstract:This study investigated the synergistic effects of Combined Chlorine (200, 500, 700, and 1000 ppm) and vitamin B1 (1000, 2000, and 3000 ppm) on the murine norovirus-1 (MNV-1), a human norovirus (NoV) surrogate, on oyster surface. Vitamin B1 slightly reduced MNV-1 (0.04–0.3 log-reduction), whereas Chlorine significantly reduced MNV-1 (0.4–1.0 log-reduction). The Combined Chlorine and vitamin B1 resulted in a 0.52–1.97 log-reduction of MNV-1. The synergistic reduction in the MNV titer was not dependent on the concentrations of Chlorine and vitamin B1, and it ranged between 0.08 and 1.03 log10 PFU/mL. The largest synergistic reduction observed was for the Combined 700 ppm Chlorine and 1000 ppm vitamin B1. The pH and mechanical texture of the oysters were not significantly changed by the Combined 0–1000 ppm Chlorine and 3000 ppm vitamin B1. The overall sensory acceptability were significantly (P
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Synergistic Effects of Combined Chlorine and Vitamin B_1 on the Reduction of Murine Norovirus-1 on the Oyster (Crassostrea gigas) Surface
Food and Environmental Virology, 2019Co-Authors: Shin-young Park, Sang-do HaAbstract:This study investigated the synergistic effects of Combined Chlorine (200, 500, 700, and 1000 ppm) and vitamin B_1 (1000, 2000, and 3000 ppm) on the murine norovirus-1 (MNV-1), a human norovirus (NoV) surrogate, on oyster surface. Vitamin B_1 slightly reduced MNV-1 (0.04–0.3 log-reduction), whereas Chlorine significantly reduced MNV-1 (0.4–1.0 log-reduction). The Combined Chlorine and vitamin B_1 resulted in a 0.52–1.97 log-reduction of MNV-1. The synergistic reduction in the MNV titer was not dependent on the concentrations of Chlorine and vitamin B_1, and it ranged between 0.08 and 1.03 log_10 PFU/mL. The largest synergistic reduction observed was for the Combined 700 ppm Chlorine and 1000 ppm vitamin B_1. The pH and mechanical texture of the oysters were not significantly changed by the Combined 0–1000 ppm Chlorine and 3000 ppm vitamin B_1. The overall sensory acceptability were significantly ( P
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predictive modeling for the growth of salmonella enterica serovar typhimurium on lettuce washed with Combined Chlorine and ultrasound during storage
Journal of Food Hygiene and Safety, 2019Co-Authors: Shin-young Park, Cheng Yi Zhang, Sang-do HaAbstract:This study developed predictive growth models of Salmonella enterica Serovar Typhimurium on lettuce washed with Chlorine (100~300 ppm) and ultrasound (US, 37 kHz, 380 W) treatment and stored at different temperatures (10~25°C) using a polynomial equation. The primary model of specific growth rate (SGR) and lag time (LT) showed a good fit (R2≥0.92) with a Gompertz equation. A secondary model was obtained using a quadratic polynomial equation. The appropriateness of the secondary SGR and LT model was verified by coefficient of determination (R2=0.98~0.99 for internal validation, 0.97~0.98 for external validation), mean square error (MSE=- 0.0071~0.0057 for internal validation, -0.0118~0.0176 for external validation), bias factor (Bf=0.9918~1.0066 for internal validation, 0.9865~1.0205 for external validation), and accuracy factor (Af=0.9935~1.0082 for internal validation, 0.9799~1.0137 for external validation). The newly developed models for S. Typhimurium could be incorporated into a tertiary modeling program to predict the growth of S. Typhimurium as a function of Combined Chlorine and US during the storage. These new models may also be useful to predict potential S. Typhimurium growth on lettuce, which is important for food safety purposes during the overall supply chain of lettuce from farm to table. Finally, the models may offer reliable and useful information of growth kinetics for the quantification microbial risk assessment of S. Typhimurium on washed lettuce.
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synergistic effects of Combined Chlorine and vitamin b1 on the reduction of murine norovirus 1 on the oyster crassostrea gigas surface
Food and Environmental Virology, 2019Co-Authors: Shin-young Park, Sang-do HaAbstract:This study investigated the synergistic effects of Combined Chlorine (200, 500, 700, and 1000 ppm) and vitamin B1 (1000, 2000, and 3000 ppm) on the murine norovirus-1 (MNV-1), a human norovirus (NoV) surrogate, on oyster surface. Vitamin B1 slightly reduced MNV-1 (0.04–0.3 log-reduction), whereas Chlorine significantly reduced MNV-1 (0.4–1.0 log-reduction). The Combined Chlorine and vitamin B1 resulted in a 0.52–1.97 log-reduction of MNV-1. The synergistic reduction in the MNV titer was not dependent on the concentrations of Chlorine and vitamin B1, and it ranged between 0.08 and 1.03 log10 PFU/mL. The largest synergistic reduction observed was for the Combined 700 ppm Chlorine and 1000 ppm vitamin B1. The pH and mechanical texture of the oysters were not significantly changed by the Combined 0–1000 ppm Chlorine and 3000 ppm vitamin B1. The overall sensory acceptability were significantly (P < 0.05) reduced in oysters treated with 1000 ppm Chlorine and 3000 ppm vitamin B1 than in those treated with 0–700 ppm Chlorine and 3000 ppm vitamin B1. This study suggests that the Combined 700 ppm Chlorine and 3000 ppm vitamin B1 could potentially be used to reduce NoV on oyster surface without causing concomitant changes in the mechanical texture, pH, or sensory qualities of the oysters.
Henrik Rasmus Andersen - One of the best experts on this subject based on the ideXlab platform.
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Full scale test of UV-based water treatment technologies at Gladsaxe Sport Centre - with and without advanced oxidation mechanisms.
2020Co-Authors: Gert Holm Kristensen, Henrik Rasmus Andersen, Morten Møller Klausen, Lothar Erdinger, Frants Roager Lauritsen, Erik Arvin, Hans-jørgen Albrechtsen, Dtu EnvironmentAbstract:Synopsis A technology testing project is being undertaken for the Danish EPA with the objective to establish a solid knowledge basis regarding possibilities for improvement of pool water quality by application of four selected UV-based technologies. The tested technologies encompass: UV photolysis by low pressure UV and medium pressure UV - separately and in combination, low pressure UV in combination with a TiO2 covered surface, UV in combination with ozone, and high pressure UV. This paper includes results from the three first mentioned technologies. All technologies were tested in full scale as side-stream treatment of the recirculation flow of a 50 m 3 warm water pool at Gladsaxe Sport Centre in Denmark. The main objective of the project was to study the impact from the technologies on the disinfection by-products: Combined Chlorine and total THM (TTHM) and to establish information regarding costs for investment and operation of the technologies. Besides Combined Chlorine and TTHM, the monitoring programme included monitoring of NVOC, AOX, THM-Formation Potential, and AOX-Formation Potential. TTHM was monitored on-line by application of MIMS – Membrane Inlet Mass Spectrometry. The on-line TTHM monitoring revealed that TTHM was a highly dynamic water quality parameter with significant variations over the day and over the week depending on bather load, pool activity, etc. The MIMS-data also revealed that salt addition to enhance the in-line-based Chlorine electrolysis was followed by significant formation of brominated DBP’s slowly returning to the usual low level after a couple of days. Medium pressure UV photolysis showed efficient for control of Combined Chlorine while low pressure UV photolysis was less efficient. When comparing the TTHM levels in the pool water during periods with UV treatment with reference periods with no UV treatment, no difference in TTHM level could be observed. Advanced oxidation with UV in combination with ozone was able to lower significantly the NVOC level, however, no similar effect on the TTHM level and the AOX level could be observed. Background Recreational industry is growing rapidly and it is expected that swimming pools and water theme parks, etc. are going to experience increased load from the bathers and more stringent demands from the users as regard to documentation and securing a satisfactory water quality so that the bathers can rely confidently on the facilities. Historically, Chlorine has been the preferred disinfectant with reference to the protection of the hygienic water quality in swimming pools since the 20ies of last century. Chlorine has the advantage of being highly effective against most micro
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Photolytic removal of DBPs by medium pressure UV in swimming pool water
Science of the Total Environment, 2013Co-Authors: Kamilla M S Hansen, Raissa Zortea, Aurelia Piketty, Sergio Rodriguez Vega, Henrik Rasmus AndersenAbstract:Medium pressure UV is used for controlling the concentration of Combined Chlorine (chloramines) in many public swimming pools. Little is known about the fate of other disinfection by-products (DBPs) in UV treatment. Photolysis by medium pressure UV treatment was investigated for 12 DBPs reported to be found in swimming pool water: chloroform, bromodichloromethane, dibromochloromethane, bromoform, dichloroacetonitrile, bromochloroacetonitrile, dibromoacetronitrile, trichloroacetonitrile, trichloronitromethane, dichloropropanone, trichloropropanone, and chloral hydrate. First order photolysis constants ranged 26-fold from 0.020min-1for chloroform to 0.523min-1for trichloronitromethane. The rate constants generally increased with bromine substitution. Using the UV removal of Combined Chlorine as an actinometer, the rate constants were recalculated to actual treatment doses of UV applied in a swimming pool. In an investigated public pool the UV dose was equivalent to an applied electrical energy of 1.34kWhm-3d-1and the UV dose required to removed 90% of trichloronitromethane was 0.4kWhm-3d-1, while 2.6kWhm-3d-1was required for chloral hydrate and the bromine containing haloacetonitriles and trihalomethanes ranged from 0.6 to 3.1kWhm-3d-1. It was predicted thus that a beneficial side-effect of applying UV for removing Combined Chlorine from the pool water could be a significant removal of trichloronitromethane, chloral hydrate and the bromine containing haloacetonitriles and trihalomethanes. © 2012 Elsevier B.V.
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Photolytic removal of DBPs by medium pressure UV in swimming pool water
Science of The Total Environment, 2012Co-Authors: Kamilla M S Hansen, Raissa Zortea, Aurelia Piketty, Sergio Rodriguez Vega, Henrik Rasmus AndersenAbstract:Abstract Medium pressure UV is used for controlling the concentration of Combined Chlorine (chloramines) in many public swimming pools. Little is known about the fate of other disinfection by-products (DBPs) in UV treatment. Photolysis by medium pressure UV treatment was investigated for 12 DBPs reported to be found in swimming pool water: chloroform, bromodichloromethane, dibromochloromethane, bromoform, dichloroacetonitrile, bromochloroacetonitrile, dibromoacetronitrile, trichloroacetonitrile, trichloronitromethane, dichloropropanone, trichloropropanone, and chloral hydrate. First order photolysis constants ranged 26-fold from 0.020 min − 1 for chloroform to 0.523 min − 1 for trichloronitromethane. The rate constants generally increased with bromine substitution. Using the UV removal of Combined Chlorine as an actinometer, the rate constants were recalculated to actual treatment doses of UV applied in a swimming pool. In an investigated public pool the UV dose was equivalent to an applied electrical energy of 1.34 kWh m − 3 d − 1 and the UV dose required to removed 90% of trichloronitromethane was 0.4 kWh m − 3 d − 1 , while 2.6 kWh m − 3 d − 1 was required for chloral hydrate and the bromine containing haloacetonitriles and trihalomethanes ranged from 0.6 to 3.1 kWh m − 3 d − 1 . It was predicted thus that a beneficial side-effect of applying UV for removing Combined Chlorine from the pool water could be a significant removal of trichloronitromethane, chloral hydrate and the bromine containing haloacetonitriles and trihalomethanes.
Krishna K Verma - One of the best experts on this subject based on the ideXlab platform.
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solid phase extraction and spectrophotometric determination of Chlorine in air and residuals of free and Combined Chlorine in water utilizing azo dye formation
Analyst, 1998Co-Authors: Madhurima Pandey, Shefali Gosain, Bhushan Sahasrabuddhey, Krishna K VermaAbstract:Oxidation of phenylhydrazine-4-sulfonic acid to the 4-diazobenzenesulfonic acid cation and its electrophilic coupling with N-(1-naphthyl)ethylenediamine dihydrochloride to give an azo dye is a new reaction scheme that is proposed for the spectrophotometric determination (545 nm) of Chlorine in air and free and Combined Chlorine residuals in environmental waters. Masking of free Chlorine with acetone permitted the determination of Combined Chlorine residuals in water. The maximum molar absorptivity was found to be 1.46 × 106 l mol–1 cm–1. A rectilinear calibration graph was obtained for 2.5–100 µg l–1 Cl. The azo dye could also be preconcentrated by solid-phase extraction on a C18 sorbent, leading to an enrichment factor of at least 40-fold. The limit of detection (without enrichment) was 0.2 µg l–1 Cl. Up to 50 µg l–1 bromate, 10 mg l–1 chlorate, 40 µg l–1 copper(II) and 100 µg l–1 iron(III) did not interfere. Chlorine dioxide was removed by bubbling the water sample with nitrogen. A comparison of the proposed method with the standard 4-N,N-diethylaminoaniline procedure was made and advantages of the present method are noted.
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Flow-injection spectrophotometric determination of residual free Chlorine and chloramine
Fresenius' Journal of Analytical Chemistry, 1995Co-Authors: Anupama Chaurasia, Krishna K VermaAbstract:2,4-Dinitrophenylhydrazine has been suggested as a new reagent for the flow-injection spectrophotometric determination of residual Chlorine based on its oxidation to 2,4-dinitrophenyldiazonium ion. The measurement of the decrease in colour intensity under reversed flow-injection (reagent injection) conditions has been used for the determination of 0.1–10 mg/l Cl present as free or Combined Chlorine, and for its speciation. The limit of detection was 0.05 mg/l Cl. Copper (II), iron (III) and many other ions have been found not to vitiate the results.
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determination of free and Combined residual Chlorine by flow injection spectrophotometry
Analytica Chimica Acta, 1992Co-Authors: Krishna K Verma, Archana Jain, Alan TownshendAbstract:Abstract A new reaction scheme for the determination of free residual Chlorine in the presence of other Chlorine species, viz. chlorite, chlorate, Combined Chlorine and Chlorine dioxide, has been evaluated. It is based on the oxidation of 4-nitrophenylhydrazine by free Chlorine to the 4-nitrophenyldiazo cation and its electrophilic coupling with N-(1-naphthyl)ethylenediamine dihydrochloride to give an azo dye which absorbs maximally at 532 nm. Flow-injection systems are proposed for the determination of 0.05–10 μg ml−1 free Chlorine by the reagent-injection technique, and 1–40 μg ml−1 free Chlorine by sample injection. The limits of detection of free Chlorine and mean R.S.D. (range) were 0.03 μg ml−1 and 0.9% (0.6–1.2%), and 0.4 μg ml−1 and 0.6% (0.4–0.8%), respectively. Only Chlorine dioxide interferes. The results were in good agreement with those obtained by flow-injection N,N-diethyl-p-phenylenediamine spectrophotometric and classical iodimetric titration methods. Since chloramines do not interfere in free Chlorine determination, a method was developed for the determination of total Chlorine (and hence of Combined Chlorine by difference after determination of free Chlorine) utilizing a secondary reaction of both free and Combined Chlorine with bromide to yield bromine which then acts as oxidizing agent. The sample throughput was 110 h−1 in both methods.
Bo Karlberg - One of the best experts on this subject based on the ideXlab platform.
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the miniaturisation of the standard method based on the n n diethyl p phenylenediamine dpd reagent for the determination of free or Combined Chlorine
Water Research, 1999Co-Authors: Karin Carlsson, Ludvig Moberg, Bo KarlbergAbstract:Abstract A miniaturised continuous flow method for the determination of free or Combined Chlorine in purification plant water has been developed. The method is based on the standard batch procedure which uses a phosphate buffer for pH adjustment and N , N ′-diethyl- p -phenylenediamine (DPD) as a colorimetric reagent. The sample, the reagent and the buffer solutions are continuously pumped into a miniaturised flow system. The mixing, the thermostating and the chemical reaction take place in a manifold with an engraved zigzag flow channel. A flow through detector is positioned at the flow channel outlet. The flow channel volume is about 25 μ l and the detector volume is 0.25 μ l. An experimental design was performed revealing that the significant variables were the total flow rate and the length of the mixing channel. Based on the results from this experimental design a total flow rate of 90 μ l/min and a channel length of 60 mm were selected. The total consumption of sample and reagent is less than 3.9 l per month when the system is operated continuously. The response time is less than 2 min. When Combined Chlorine, in essence chloramine, is determined, potassium iodide is added to the buffer solution. The limit of detection is 3.2 μ M for free Chlorine and 1.9 μ M for monochloramine.
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The miniaturisation of the standard method based on the N,N′-diethyl-p-phenylenediamine (DPD) reagent for the determination of free or Combined Chlorine
Water Research, 1999Co-Authors: Karin Carlsson, Ludvig Moberg, Bo KarlbergAbstract:Abstract A miniaturised continuous flow method for the determination of free or Combined Chlorine in purification plant water has been developed. The method is based on the standard batch procedure which uses a phosphate buffer for pH adjustment and N , N ′-diethyl- p -phenylenediamine (DPD) as a colorimetric reagent. The sample, the reagent and the buffer solutions are continuously pumped into a miniaturised flow system. The mixing, the thermostating and the chemical reaction take place in a manifold with an engraved zigzag flow channel. A flow through detector is positioned at the flow channel outlet. The flow channel volume is about 25 μ l and the detector volume is 0.25 μ l. An experimental design was performed revealing that the significant variables were the total flow rate and the length of the mixing channel. Based on the results from this experimental design a total flow rate of 90 μ l/min and a channel length of 60 mm were selected. The total consumption of sample and reagent is less than 3.9 l per month when the system is operated continuously. The response time is less than 2 min. When Combined Chlorine, in essence chloramine, is determined, potassium iodide is added to the buffer solution. The limit of detection is 3.2 μ M for free Chlorine and 1.9 μ M for monochloramine.