• Korean Journal of Human Ecology
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• v.5 no.1
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• pp.42-47
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• 2002

Antimicrobial activity of silk and cotton fabrics dyed with gromwell colorants was examined by shake flask method. The effects of bacterial reduction rate on dye uptake and mordanting were explored. The silk(K/S value 8) and cotton fabric (K/S value 4) dyed with gromwell colorants showed high bacterial reduction rate of 99 % and 88 %, respectively. Post-mordanted silk fabric increased at K/S value, also showed higher bacterial reduction rate than unmordanted. But the effects of antimicrobial activity on mordants showed respectively different results. Pre-mordanted cotton fabric except Sn mordant increased at K/S value, but it was not significant. Pre-mordanted cotton fabric showed significantly higher bacterial reduction rate than unmordanted. Therefore, it was considered that dye uptake of cotton fabric dyed with gromwell colorants and mordants were involved in the bacterial reduction rate. It was concluded that gromwell colorants had antimicrobial activity.

• Journal of the Korean Home Economics Association
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• v.42 no.3
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• pp.145-158
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• 2004

Experimental conditions for evaluating chitosan antibacterial activities were established. The chitosan antibacterial activities were measured against the Staphylococcus aureus and evaluated for their application to antibacterial textile finishing. The strain of Staphylococcus aureus used in this experiments was KCTC 1916. The chitosan antibacterial activities were estimated from the bacterial densities or ％reduction of bacteria in chitosan solutions and bacterial culture mixtures after incubation under specific conditions. Six parameters as follows were evaluated to optimize the experimental conditions for measuring antibacterial activities. The different combinations of mixtures according to the different ratios of chitosan solutions to the bacterial cultures showed different antibacterial activities. However, the chitosan antibacterial activities could be evaluated by comparing the data obtained from the same combinations of mixtures. The solvent influence on the chitosan solution antibacterial activities could be eliminated using control solution containing the same concentration of acetic acid. The initial pH of the chitosan -bacterial mixtures also affected the chitosan antibacterial activity; at a higher pH, higher activity in terms of ％reduction of bacteria was observed. In case of the bacterial solution without either the acetic acid or chitosan, the initial pH of the solution did not significantly affect bacterial growth. The ％ reduction of bacteria increased when contact times of bacteria with chitosan in the chitosan -bacterial mixture were expended upto 24 hours. However, the chitosan antibacterial activities could be successfully evaluated at contact time 0 where the chitosan-bacterial mixture was plated immediately after mixing and incubated to measure the bacterial number to 24 hours. Evaluating ％reduction of bacteria in the test mixtures after incubation were not changed when the inoculated bacterial concentrations were 2.3${\times}$10$\^$0/ml to 2.3${\times}$10$\^$6/ml. The optimal range of incubation time of the petri-Dish after plating the chitosan-bacterial mixture was 24 to 72 hours depending on the antibacterial activities of the test solutions.

• Food Science and Biotechnology
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• v.17 no.4
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• pp.842-845
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• 2008

This study was carried out to investigate the bactericidal efficacy of concentration (0.1, 0.2, and 0.4 ppm) and exposure time (10 and 30 min) of ozone on bacterial reduction rate of Salmonella typhimurium KCTC 2541 and Staphylococcus aureus ATCC 13515 in the distilled water (DW), and DW supplemented with 0.2% soluble starch (SS), and metal ion (MC) using argentums (Ag) and copper (Cu). The significant bactericidal differences of S. aureus were showed in the treatments of DW and SS, respectively, at the concentration of ozone above 0.1 ppm for 10 min, comparing the respective initial bacterial counts. The bacterial reduction of S. aureus was more sensitive than that of S. typhimurum at the same concentration of ozone. The bacterial reduction rate of SS treatment was slightly lower than that of DW treatment at the same concentration of ozone (p<0.05), however, the bacterial reduction rate of strains improved in the MC treatment compared to the DW treatment at the same concentration of ozone.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.31 no.2
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• pp.138-146
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• 2021

Objectives: This study aims to compare and evaluate the reduction efficiency of disinfectants used in the domestic meat processing industry to reduce bioaerosol exposure of meat industry workers and to use this as basic data for establishing work environment management measures. Methods: Thirteen disinfectants sold in South Korea were selected for evaluation and the bacterial reduction effect of the disinfectants was investigated. Bacterial suspension and surface disinfection tests were conducted to compare and analyze the antibacterial strength of the disinfectants. Pork carcasses, cutting boards, benches, and conveyor belts were selected for surface sterilization tests. Results: As a result of the bacterial suspension experiment test, all disinfectants had a bacterial reduction efficiency of more than 86%. Among them, the bacterial reduction efficiency of chlorine disinfectants was 99.93% on average. In the results of the pork carcass surface sterilization test, the rate of reduction of disinfectants made of quaternary ammonium compounds (QACs) was the highest. Tests of plastic cutting boards showed that chlorine disinfectants had the best sterilization effect. Experiments on stainless steel benches showed the best bacterial reduction efficiency for chlorine dioxide and QACs disinfectants. In the conveyor belt made of urethane, QACs disinfectants showed excellent sterilization effects. Conclusions: The study evaluated the disinfection power of disinfectants against bacteria occurring in domestic meat processing plants. All disinfectants were found to be effective in bacterial suspension experiments, and chlorine disinfectants were particularly effective. In surface sterilization experiments, sterilizing agents with QACs as the main ingredient were excellent.

• Korean Journal Plant Pathology
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• v.14 no.6
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• pp.744-746
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• 1998

Control effect of acidified nutrient solution on bacterial wilt of tomato plants was tested by examining the degree of bacterial growth inhibition and plant damage due to the acidity. Ralstonia solanacearum, the causal bacterium of bacterial wilt of tomato plants, showed 105 times population reduction when the bacterium was cultured in the acidified nutrient solution (pH 3.5∼4.0). However, fruit yields were decreased only fifteen to twenty percents. These results suggest that control of the bacterial wilt of tomato plants may be possible with supplying acidified nutrient solution.

• Journal of the Korean Society of Clothing and Textiles
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• v.28 no.6
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• pp.807-818
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• 2004

The antibacterial activities of several types of chitosan were measured against Staphylococcus aureus and evaluated for their application to antibacterial textile finishing. The ％ reduction of bacteria of the chitosans prepared in our laboratory were between 72 and 87%. The two water-soluble chitosans with molecular weights 1,000 and 3,000 did not show antibacterial activities. The deacetylation of chitosan was appeared to increase antibacterial activity. The ％ reduction in bacterial density of the 86％-deacetylated chitosan solution was 56% where that of the 76％-deacetylated chitosan solution was only 17％ at 0.1% chitosan concentration. Molecular weights of the chitosans seemed not to affect antibacterial activities of chitosans. The antibacterial activity of the acid-soluble, 86%-deacetylated chitosan with 4 cps showed 98% of the ％ reduction at the level of 0.2％ chitosan. The ％ reduction of bacteria of this chitosan was higher at the higher concentration of acetic acid in the chitosan-bacterial mixture. The antibacterial activity was increased with the pH change over the range of 4.0 to 6.5. The 100% of the ％ reduction of bacteria was achieved within 4 hour incubation of the chitosan-bacterial mixture. According to the data obtained from the above experiments, the four chitosans among the six prepared in our laboratory were proved to be valuable for antibacterial textile finishing.

• Korean Journal of Veterinary Research
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• v.12 no.1
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• pp.133-139
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• 1972

Estrous and non-estrous rabbits were inoculated with E. coli or Streptococcus pyogenes, and the mixture of the two organisms, and bacterial count and histopathological studies of uterine horns were made to observe the effects of estrogen on the resistance of the uterus to bacterial infection. The results obtained were summarized as followings; 1. Four hours after inoculation of bactoria into uterine horn, the number of organisms was significantly lower in estrous rabbits than in non-estrous regardless of the kind of organisms inoculated. 2. The highest reduction rate of the organisms among the three bacterial inoculation groups was found in estrous rabbits inoculated with E. coli, and the lowest reduction rate was with Streptococcus pyogenes. 3. Histopathological changes of uterine horns induced five days after bacterial inoculation were observed. In estrous rabbits, a mild inflammatory reaction was found in Streptococcus pyogenes group, but a slight inflammatory reaction and only a negligible inflammatory reaction were observed in mixed bacteria group, and in E. coli group respectively. In non-estrous group, however, a marked inflammatory reaction was observed in Streptococcus pyogenes group, a moderate inflammatory reaction and a slight inflammatory reaction were observed in the mixed bacterial group and E. coli group, respectively.

• Journal of Microbiology and Biotechnology
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• v.22 no.4
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• pp.547-554
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• 2012

Chromium is generated from several industrial processes. It occurs in different oxidation states, but Cr(III) and Cr(VI) are the most common ones. Cr(VI) is a toxic, soluble environmental contaminant. Some bacteria are able to reduce hexavalent chromium to the insoluble and less toxic Cr(III), and thus chromate bioremediation is of considerable interest. An indigenous chromium-reducing bacterial strain, Rb-2, isolated from a tannery water sample, was identified as Ochrobactrum intermedium, on the basis of 16S rRNA gene sequencing. The influence of factors like temperature of incubation, initial concentration of Cr, mobility of bacteria, and different carbon sources were studied to test the ability of the bacterium to reduce Cr(VI) under variable environmental conditions. The ability of the bacterial strain to reduce hexavalent chromium in artificial and industrial sewage water was evaluated. It was observed that the mechanism of resistance to metal was not due to the change in the permeability barrier of the cell membrane, and the enzyme activity was found to be inductive. Intracellular reduction of Cr(VI) was proven by reductase assay using cell-free extract. Scanning electron microscopy revealed chromium precipitates on bacterial cell surfaces, and transmission electron microscopy showed the outer as well as inner distribution of Cr(VI). This bacterial strain can be useful for Cr(VI) detoxification under a wide range of environmental conditions.

• Journal of Animal Science and Technology
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• v.44 no.4
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• pp.453-458
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• 2002

In order to search for reliable rapid methods of estimating bacterial counts in pork, this study was tried to measure resazurin reduction time which is simple in experimental method, low in analytical cost, able to estimate bacterial count within short time. The results were summarized as follows; Correlation coefficient between initial bacterial log count(25$^{\circ}C$/72hr, Y) and resazurin reduction time(X) from blue color to pink color during incubation at 25$^{\circ}C$ and 30$^{\circ}C$ was higher than other conditions as -0.95 and -0.94, respectively. Considering correlation coefficient and reduction time, incubation temperature was compatible at 30$^{\circ}C$, and regression equation(RE) was Y = -0.4386X + 7.7870. At a bacterial load of $10^2$cfu/$cm^2$, $10^3$cfu/$cm^2$ and $10^4$cfu/$cm^2$ in pork, reduction time was 13.2hr, 10.9hr and 8.6hr, respectively. Correlation coefficient between initial bacterial log count(30$^{\circ}C$/72hr, Y) and resazurin reduction time(X) from blue color to pink color during incubation at 30$^{\circ}C$ was highest among other conditions as -0.93, and RE was Y = -0.4171X + 7.5540. At a bacterial load of $10^2$cfu/$cm^2$, $10^3cfu/$cm^2$ and $10^4cfu/$cm^2$ in pork, reduction time was 13.3hr, 10.9hr and 8.5hr, respectively. Correlation coefficient between initial bacterial log count(35$^{\circ}C$/72hr, Y) and resazurin reduction time(X) from blue color to pink color during incubation at 30$^{\circ}C$ was highest among other conditions as -0.93, and RE was Y = -0.3514X + 6.7513. At a bacterial load of $10^2$cfu/$cm^2$, $10^3$cfu/$cm^2$ and $10^4$cfu/$cm^2$ in pork, reduction time was 13.5hr, 10.7hr and 7.8hr, respectively.

• Fisheries and Aquatic Sciences
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• v.19 no.6
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• pp.28.1-28.7
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• 2016

Background: Significant increases in the bacterial resistance to various antibiotics have been found in fish farms. Non-antibiotic therapies for infectious diseases in aquaculture are needed. In recent years, light-emitting diode technology has been applied to the inactivation of pathogens, especially those affecting humans. The purpose of this study was to assess the effect of blue light (wavelengths 405 and 465 nm) on seven major bacterial pathogens that affect fish and shellfish important in aquaculture. Results: We successfully demonstrate inactivation activity of a 405/465-nm LED on selected bacterial pathogens. Although some bacteria were not fully inactivated by the 465-nm light, the 405-nm light had a bactericidal effect against all seven pathogens, indicating that blue light can be effective without the addition of a photosensitizer. Photobacterium damselae, Vibrio anguillarum, and Edwardsiella tarda were the most susceptible to the 405-nm light (36.1, 41.2, and $68.4J\;cm^{-2}$, respectively, produced one log reduction in the bacterial populations), whereas Streptococcus parauberis was the least susceptible ($153.8J\;cm^{-2}$ per one log reduction). In general, optical density (OD) values indicated that higher bacterial densities were associated with lower inactivating efficacy, with the exception of P. damselae and Vibrio harveyi. In conclusion, growth of the bacterial fish and shellfish pathogens evaluated in this study was inactivated by exposure to either the 405- or 465-nm light. In addition, inactivation was dependent on exposure time. Conclusions: This study presents that blue LED has potentially alternative therapy for treating fish and shellfish bacterial pathogens. It has great advantages in aspect of eco-friendly treating methods differed from antimicrobial methods.