• Journal of Aquaculture
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• v.10 no.4
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• pp.435-438
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• 1997

Biological ammonia removal system have been used conventionally for the seawater fish farming. But this process requires long hydraulic retention times and large area. Also it has a trouble of NO3-N accumulation in the system. Therefore, this study was conducted to find out the feasibility of effective nitrogen removal efficiency in the sea water fish farming system by electolysis. As the result, electrolysis system showed a good ammonia and nitrate nitrogen removal and E. coli sterilization efficiencies. Because of the high salinities in the seawater for electron transfer, electrolysis is an effictive water treatment process for seawater fish farming. The relation among ammonia removal efficiency, hydraulic retention time (HRT) and electric wattage (watt) with 10 mm electrod distance isas follow ; log [$NH_4^$+-N(%)]=0.431log(HRT(sec)$\times$Watt)+0.88(r=0.950) And the relation between ammonia removal efficiency and residual chlorine concentration in the seawater is as follow; $$NH_4^+-N(%)=48\cdotlog[Residual\;chlorine(mg/\ell)+28(r=0.892)$$

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.18 no.1_2
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• pp.39-44
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• 2012

This study investigated the changes in the quality of minimally processed sliced Deodeok (Codonopsis lanceolata) during storage at $7^{\circ}C$ in relation to vacuum packing using PE film after the various surface washing treatments. The surface washing treatments resulted in approximately 1~2 log CFU/g reduction of microbial load in the early storage day. After 20 days, the weight loss rate, deterioration rate, hardness, color, total microorganism levels and the coliform count of deodeok washed by ultrasonic wave water was deteriorated rapidly like the control. When measured by the fresh-cut deodeok surface using the video microscope system, washing with chlorine water and electrolyzed water didn't seem to make perceivable quality deterioration during the 10 days at $7^{\circ}C$. The hardness and color maintenance of the product vacuum packaged using PE film after washing with electrolyzed water, was better than that of other treatments.

• Applied Biological Chemistry
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• v.44 no.3
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• pp.191-196
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• 2001

${\alpha},{\beta}$-Unsaturated carboxanilides 5 with trifluromethylated dihydro-1,4-oxathiins were synthesized for the development of new agrochemical fungicide. Chlorination of trifluoromethylated ${\beta}-keto$ ester 6 followed by the reaction with 1,2-mercaptoethanol gave intermediate 1,4-oxathiane 11. Without purification of 11, substitution of hydroxy group by chlorine, followed by dehydrochlorination of 10 in the presence of triethylamine afforded trifluoromethylated dihydro-1,4-oxathiin ethyl ester 9. Acylation of the hydroxy group of the carboxylic acid 12 followed by treatment of various amines gave the corresponding trifluoromethylated dihydro-1,4-oxathiin carboxamides 5. Antifungal screening (in vivo) of the synthesized compounds against typical plant diseases, which include rice blast, rice sheath blight, cucumber gray mold, tomato late blight, wheat leaf rust, and barley powdery mildew, was carried out. Where meta position of the phenyl group was substituted with isopropoxy or isopropyl group, excellent antifungal activities against rice sheath blight and wheat leaf rust were detected.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.8
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• pp.1227-1232
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• 2016

Electrolyzed activated water (EAW) has been reported to exhibit strong bactericidal effects on foodborne microorganisms. However, the disinfection efficacy of EAW is affected by factors such as water source and hardness. This study investigated bactericidal effects of EAW against three gram-positive (Bacillus cereus, Listeria monocytogenes, and Staphylococcus aureus) and three gram-negative (Cronobacter sakazakii, Escherichia coli O157:H7, and Salmonella Enteritidis) foodborne pathogens. Six strains were treated with EAW prepared at different water temperatures (4, 22, and $40^{\circ}C$) for 15 min, and D-values were generated. The results show that the lowest D-values for Lis. monocytogenes by EAW produced at $4^{\circ}C$ and $40^{\circ}C$ were 6.60 and 1.57 min, respectively. The lowest D-value for Sal. Enteritidis by EAW produced at $22^{\circ}C$ was 2.92 min. D-values of all strains treated by EAW produced at $40^{\circ}C$ decreased significantly compared to those treated by EAW produced at $4^{\circ}C$ (P<0.05). These results demonstrate that applying EAW produced at warm temperature is more effective for reducing foodborne pathogens for food safety.

• Journal of Wetlands Research
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• v.16 no.2
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• pp.269-274
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• 2014

The purpose of this study is to compare CT (disinfectant concentration * time) values in removing the antibiotic resistance bacteria, antibiotic resistance gene and transfer of antibiotic resistance genes. Different concentration of chlorine(C) and contact time(T) according to the removal of antibiotic resistance was calculated for each. As a result, for the 90% removal of antibiotic resistant bacteria, around 176~353 mg min/L CT values are needed. For the removal of the antibiotic resistance gene, 195~372 mg min/L CT values are required. For the 90% reduction of antibiotic resistance gene transfer by chlorine disinfection, 187~489 mg min/L CT values are needed. Based on our results, higher CT value was required for removing antibiotic resistant genes rather than antibiotic resistance bacteria.

• Korean Journal of Food Science and Technology
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• v.41 no.4
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• pp.452-457
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• 2009

In order to secure microbiological safety and quality of commercial vegetable sprouts, buckwheat seeds and sprouts were investigated for their microbiological flora and for the effect of chlorine treatment on quality. Microbiological analyses showed that major inherent bacteria including Enterobacter, Sphingomonas, and Klebsiella were found in commercial buckwheat sprouts with a population size ranging from $10^5$ to $10^7$ CFU/g. In addition, buckwheat seeds had a similar microbial flora to sprouts. Foodborne pathogenic bacteria such as Escherichia coli O157:H7, Staphylococcus aureus, Salmonella Typhimurium, and Listeria monocytogenes were not detected in the sprout or in the seed samples. Chlorine treatment with 50-150 ppm sodium hypochlorite noticeably reduced viable bacteria cell counts of the sprouts by about 1 log. However, no significant difference was observed among the different chlorine concentrations. After storage for 7 days at $5^{\circ}C$, the sprouts treated with 100-150 ppm chlorine showed higher sensory scores in visual quality than the others (p<0.05). The results indicated that proper pretreatment, such as dipping in chlorinated water, could confer a beneficial effect on the microbiological safety and visual quality of buckwheat sprouts.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.5
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• pp.595-602
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• 1996

The antimicrobial effects of two disinfectants commonly used in food industry on Listeria monocytogenes ATCC 15313 were studied. The two disinfectants tested were commercial benzalkonium chloride (BAC) and sodium hypochlorite (NaOCl). Their effects were studied on cells suspended in disinfectants (in vitro) and in the sponge model with the disinfectants (in vivo). When cells were exposed to $0\~0.1\%$ BAC and $0\~150\;ppm$ NaOCL for 20 minutes, BAC and NaOCl concentration more than $0.25\%$ and 100 ppm showed the antimicrobial effects respectively. This organism decreased rapidly during the first $0.5\~1$ minute followed by a slower decrease during the rest of the exposure time. Fifteen ml of cell solution $(about\;10^7\;CFU/ml\;in\;the\;TSB)$ was mixed with 15 ml of disinfectants in the sponge $(6.0{\times}4.0{\times}4.0cm)$, BAC and NaOCl concentration more than $0.1\%$ and 300 ppm showed the antimicrobial effects, and at $0.25\%$ and 800 ppm diminished in cell numbers 3-log cycles during the first 20 minutes. In the case of sponge model, 15 ml of cell solution and 15 ml of disinfectants $(0.25\%\;of\;BAC,\;800\;ppm\;of\;NaOCl)$ were suspended in the sponge during 20 minutes, washing with 200 ml of sterilized distilled water, and this sponge was transfered in the 100 ml TBS, and then incubated at various temperature. The cells were increased about 1-log cycle during 24 hrs at $5\~15^{\circ}C$. And the others temperature, the cells growth was in proporation to storage tepmerature and the cells were about $10^9\;CFU/ml$ after $1\~3$ days incubations.

• Journal of Food Hygiene and Safety
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• v.22 no.2
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• pp.127-131
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• 2007

This study evaluated the bactericidal effect of 10 sanitizers and disinfectants such as ethanol (75 and 95%), iodine (15 and 25 ppm), chlorine (100 and 200 ppm), quaternary ammonium, acid, hydrogen peroxide, and peroxide acetic acid against V. parahaemolyticus. Ten strains of V. parahaemolyticus isolated from Korean foods and 4 strains of standard V. parahaemolyticus were compared for efficacies of various sanitizers and disinfectants by EN 1276 method based on quantitative suspension test. Ethanol (75 and 95%), 25 ppm of iodine, 100 ppm of quaternary ammonium, 145 ppm of hydrogen peroxide and acid showed more than $5log_{10}CFU/mL$ reduction in both clean and dirty conditions. Tests result of chlorine (100 ppm) showed more than $5log_{10}CFU/mL$ reduction in clean condition. Iodine (15 ppm) showed more than $5log_{10}CFU/mL$ reduction except 4 isolated and 1 standard V. parahaemolyticus in clean condition. iodine (15 ppm) also showed under $5log_{10}CFU/mL$ reduction $(0.93{\sim}3.73log_{10}CFU/mL)$ in dirty condition. Eleven hundred ppm of hydrogen peroxide was evaluated as weak sanitizer and disinfectant due to their $0.99{\sim}4.79log_{10}CFU/mL$ reduction on both clean and dirty conditions. Consequently, ethanol, iodine (25 ppm), chlorine (200 ppm), quaternary ammonium, acid and peroxide acetic acid were thought to be effective sanitizer and disinfectant against V. parahaemolyticus.

• Korean Chemical Engineering Research
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• v.50 no.1
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• pp.173-176
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• 2012

Chlorine dioxide has an excellent ability to sterilize and deodorize and is harmless to humans. However, it is very unstable and explosive as it is highly concentrated, thus its use in the air clean filed has been limited. Therefore, there is a demand to develop the system to produce a low concentration of chlorine dioxide sustainedly. Here, for a first step in the development of the system on the sustained production of chlorine dioxide, the use of polymer hydrogels was investigated. P(MMA-co-HEMA) hydrogel particles were prepared via dispersion photopolymerization and sodium chlorite and citric acid were loaded respectively in the hydrogel particles. When sodium chlorite and citric acid were reacted with not loaded in the hydrogels, rapid production of chlorine dioxide occurred and the concentration of chlorine dioxide decreased over time. However, when sodium chlorite and citric acid were loaded respectively in the hydrogel particles and reacted, chlorine dioxide was produced slowly and sustainedly because the release of sodium chlorite and citric acid from the hydrogels delayed the reaction between them. The result shows that the use of P(MMA-co HEMA) hydrogels has the potential to develop the system on the sustained production of chlorine dioxide.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.29 no.1
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• pp.1-7
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• 2023

Chlorine dioxide (ClO₂) is widely used for post-harvest sterilization treatment. However, there are limitations in the retail application of ClO₂ due to difficulties in handling, expensive facilities, and safety concerns. Therefore, it is necessary to develop a ClO₂ technology that can be easily applied and continuously released for a long period. In this study, a series of ClO₂ self-releasing sachets were developed. First, poly(ether-block-amide) (PEBAX) and polyethylene-glycol (PEG) composite films containing different ratios of citric acid (CA) were prepared using the solution casting method. The as-prepared PEBAX/PEG-CA composite films were evaluated using FT-IR, DSC, and TGA to confirm chemical structure and thermal properties. Subsequently, PEBAX/PEG-CA composite films were designed in the form of a sachet and NaClO₂ powder was transferred into the sachet to achieve a ClO₂ self-releasing system. The ClO₂-releasing behavior of the sachet was investigated by measuring the release amount of the gas using UV-vis. The release amount of ClO₂ increased with increasing CA contents owing to the existence of higher protons (trigger) in the polymer matrix. Further, ClO₂ gas was released for a longer time. Therefore, the as-prepared smart sachet can be tuned according to applications and packaging sizes to serve an optimal sterilization effect.