• Korean Journal of Food Science and Technology
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• v.37 no.3
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• pp.449-455
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• 2005

To reduce saft content of kochujang, various combinations of sub-materials such as ethanol mustard and chitosan were added to kochujang, and their effects on microbial characteristics, enzyme activities, and physicochemical characteristics of kochujang were investigated after 12 weeks of fermentation. Activities of ${\beta}$-amylase and pretense were low in ethanol-mustard-chitosan-added kochujang, whereas no significant difference was observed in ${\alpha$-amylase activity among all groups. Number of viable yeast cells decreased remarkably in mustard-added kochujang during late aging period, and anaerobic bacterial counts decreased in sub-material-added groups. Consistency of kochujang increased by addition of sub-materials, and oxidation-reduction potential was low in chitosan-added group. Mustard-chitosan-added kochujang showed lowest increase in total color difference(${\Dalta}E$) and decrease in water activity. PH of kochujang wns highest in mustard-chitosan-added kochujang, resulting in significantly increased titratable acidity. Addition of sub-material increased reducing sugar contents of kochujang, whereas ethanol production was significantly repressed in mustard-chitosan-added kochujang. Amino nitrogen content was Highest in mustard-chitosan-added kochujang during late aging period, whereas ammonia nitrogen content was lower in ethanol-mustard-added kochujang. Results of sensory evaluation indicated ethanol-mustard-added kochujang was more acceptable than other groups in taste and overall acceptability.

• Archives of Plastic Surgery
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• v.37 no.3
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• pp.227-232
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• 2010

Purpose: Continuous irrigation method is an important step in managing wound infection. V.A.C. devices have been used in intractable wounds for reducing discharge, improving local blood flow, and promoting healthy granulation tissue. We expect synergistic effects of reduced infection and more satisfactory, accelerated wound healing when using both methods simultaneously. This study evaluated continuous irrigation combined with V.A.C. appliance for treatment of infected chronic wounds. Methods: We reviewed data from 17 patients with infected intractable chronic wounds. V.A.C. device (Group A) was used in 9 patients, and V.A.C. with antibiotics irrigation (Group B) was used in 8 patients. We placed Mepitel$^{(R)}$ on the surface of wound and placed an irrigation and aspiration tube on each side. A sponge was placed on the Mepitel$^{(R)}$ and covered with film dressing. The wound was irrigated continuously with mixed antibiotics solution at the speed of 200 cc/hr and aspirated through the wall suction at the pressure of -125 mmHg. V.A.C. applied time, wound culture and wound size were compared between the two groups. Results: No complication were seen in two groups. Compared with Group A, in the Group B, V.A.C. applied time was shortened from 32.7 days to 25.6 days and showed efficacy in the reduction rate of wound size. No statistical differences were shown in bacterial reversion. Conclusion: V.A.C. appliance with continuous irrigation is an effective new method of managing infected chronic wounds and useful to reduce treatment duration and decrease wound size. Moreover it could be applied more widely to infected wound.

• Korean journal of food and cookery science
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• v.11 no.4
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• pp.379-385
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• 1995

The effect of low concentrations of ethanol (3-7％, v/v) in tryptic soy broth (TSB) as an antibacterial agent against Listeria monocytogenes was tested at -20, 5, 35, 45, 50 and 55$^{\circ}C$. Increasing concentrations of ethanol progressively inhibited initial growth of L. monocytogenes at 35$^{\circ}C$. Growth occured at 5％ ethanol, but only after a prolonged lag period. The number of viable cells of L. monocytogenes declined during incubation at 7％ ethanol. TSB containing 3-7％ ethanol was inoculated with 10$\^$5/-10$\^$6/ cells/$m\ell$ or L. monocytogenes and incubated at low temperatures (5$^{\circ}C$, -20$^{\circ}C$). In the presence of 3％ of ethanol at 5 or -20$^{\circ}C$, bacterial growth was inhibited more than 90％ of control cells. TSB containing 3-7％ ethanol was inoculated with 10$\^$6/-10$\^$7/ cells/$m\ell$ of L. monocytogenes and incubated at high temperatures (45$^{\circ}C$, 50$^{\circ}C$, 55$^{\circ}C$). Decrease in viability of the cells incubated at 45 or 50$^{\circ}C$ was slow and the survival of L. monocytogenes was not affected so much in the presence of 3％ of ethanol. The viability of L. monocytogenes was decreased with increasing concentration of ethanol and temperature. Decimal reduction times (D-values) based on tryptic soy agar plates at 55$^{\circ}C$ were 20.1, 12.6, 7.4 and 4.2 min in 0, 3, 5 and 7％ ethanol, respectively.

• Korean Journal of Environmental Biology
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• v.36 no.1
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• pp.90-97
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• 2018

This study assessed the effect of ozone to control pathogenic bacteria in inlet water flowing to flounder farms, establishing operational parameters of ozonation at seawater conditions. Hydraulic retention time in a reaction pipeline after ozonation was fixed at 3 minutes in a flow through system. Concentrations of total residual oxidant (TRO) by ozonation were measured according to different ozonation intensities. The oxidant reduction potential (ORP), which is indirect but enables real-time measurement, was measured in relation to TRO values. TRO values were $0.01{\pm}0.01mg\;L^{-1}$ at an ORP range of 320-410 mV, $0.07{\pm}0.02mg\;L^{-1}$ at 600 mV, and $0.16{\pm}0.03mg\;L^{-1}$ at 700 mV. A heterotrophic marine bacteria colony was reduced by 80.6-97.9%, showing the suppression effect of ozonation on total bacteria in inlet water. At an ORP range of 400-500 mV, colonies of heterotrophic marine bacteria, Vibrio spp., and gram negative bacteria were significantly reduced in outlet water from a culture tank with ongrowing flounder (230 g) at a stocking density of $8kg\;m^{-2}$. Especially, Vibrio spp. and gram negative bacteria were seldom found at 400-500 mV. The daily feeding rate was from over 0.7% to total body weight at 300-500 mV, showing better performance than that in the control. The pathogenic bacteria entering the flounder farm were effectively removed when the ORP range to 400 mV or less.

• The Korean Journal of Pesticide Science
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• v.18 no.4
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• pp.422-428
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• 2014

Endophytic bacterial strains from root tissue of strawberry were screened for their efficacy in growth improvement and control of Phytophthora blight disease of chili pepper plant under greenhouse condition. Plants treated with the strain EP103, identified as Pseudomonas fluorescens, showed growth improvement in terms of fresh weight and root length compared to the untreated control and other endophytic strains. When challenged with Phytophthora capsici, there was significant reduction of disease in EP103 treated plants with an efficacy of 78.7%. There was no direct inhibition of the target pathogen by EP103 when tested under in vitro antibiosis assay. Analysis of differential expression of selected marker genes for induced systemic resistance (ISR) in plants treated with EP103 and challenged with P. capsici showed up-regulation of PR1 and PR10 pathogenesis-related (PR) proteins. PCR analysis showed that EP103 produced secondary metabolites such as pyoluteorin, pyrrolnitrin, hydrogen cyanide and orfamide A. This study indicated the potential of endophytic P. fluorescens strain EP103 as an efficient biocontrol agent against P. capsici in chili pepper plant.

• Korean Journal of Food Science and Technology
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• v.41 no.5
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• pp.515-521
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• 2009

The DEFT (direct epifluorescent filter technique)/APC (aerobic plate count) test was utilized to screen powdered Ramen soup samples (RS-1, RS-2) whether or not they have been microbial-decontaminated. The initial microbial loads of commercially-packaged samples were log DEFT 6.46 (RS-1) and 7.05 (RS-2), but the viable bacterial counts were log APC 2.74 (RS-1) and 1.95 (RS-2), respectively; this finding showed that they have been already decontaminated by methods other than irradiation. The same samples were then subjected to gamma irradiation at 0, 5 and 10 kGy in order to evaluate the microbial and physicochemical changes during post-irradiation storage for 6 months under room conditions ($10{\pm}3^{\circ}C$). The DEFT count was constant in irradiated samples even at different doses, but APC decreased with dose increases; this implies that the log DEFT/APC increased in a linear fashion with dose. No coliforms, yeasts and molds were detected in any of the samples, whereas the initially detected aerobic bacteria ($5.49{\times}10^2CFU/g$) were inactivated by 5 kGy or more and no growth was observed during the subsequent storage period. The pH of RS-1 was reduced by irradiation (p<0.01), but increased (p<0.01) with increasing storage time. Irradiation induced a reduction in volatile basic nitrogen (VBN), whereas an increase in thiobarbituric acid (TBA) values was observed. The storage time proved more influential than irradiation up to 10 kGy in terms of changes in the VBN and Hunter’s color values of powdered Ramen soups.

• Journal of Microbiology and Biotechnology
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• v.17 no.3
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• pp.438-444
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• 2007

Bacillus licheniformis N1 is a biological control agent to control gray mold diseases caused by Botrytis cinerea. Various formulations of B. licheniformis N1 were generated and evaluated for the activity to control strawberry gray mold. The wettable powder type formulation N1E was selected in pot experiments with remarkable disease control activity on both strawberry leaves and flowers. The N1E formulation contained 400 g of com starch, 50 ml of olive oil, and 50 g of sucrose per a liter of bacterial fermentation culture. Optimum dilution of N1E to appropriately control the strawberry gray mold appeared to be 100-fold dilution in plastic house artificial infection experiments. The significant reduction of symptom development in the senescent leaves was apparent by the treatment of N1E at 100-fold dilution when N1E was applied before Bo. cinerea inoculation, but not after the inoculation. Both artificial infection experiments in a plastic house and natural infection experiments in the farm plastic house under production conditions revealed that the disease severity of gray mold on strawberry leaves and flowers was significantly reduced by N1E treatment. The disease control value of N1E on strawberry leaves was 81% under production conditions, as compared with the 61.5% conferred by a chemical fungicide, iprodione. This study suggests that our previously generated formulation of B. licheniformis N1 will be effective to control strawberry gray mold by its preventive activity.

• Journal of Microbiology and Biotechnology
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• v.30 no.4
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• pp.571-582
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• 2020

Quorum sensing (QS)-mediated infections cause severe diseases in human beings. The control of infectious diseases by inhibiting QS using antipathogenic drugs is a promising approach as antibiotics are proving inefficient in treating these diseases. Marine fungal (Pestalotiopsis sydowiana PPR) extract was found to possess effective antipathogenic characteristics. The minimum inhibitory concentration (MIC) of the fungal extract against test pathogen Pseudomonas aeruginosa PAO1 was 1,000 ㎍/ml. Sub-MIC concentrations (250 and 500 ㎍/ml) of fungal extract reduced QS-regulated virulence phenotypes such as the production of pyocyanin, chitinase, protease, elastase, and staphylolytic activity in P. aeruginosa PAO1 by 84.15%, 73.15%, 67.37%, 62.37%, and 33.65%, respectively. Moreover, it also reduced the production of exopolysaccharides (74.99%), rhamnolipids (68.01%), and alginate (54.98%), and inhibited the biofilm formation of the bacteria by 90.54%. In silico analysis revealed that the metabolite of P. sydowiana PPR binds to the bacterial QS receptor proteins (LasR and RhlR) similar to their respective natural signaling molecules. Cyclo(-Leu-Pro) (CLP) and 4-Hydroxyphenylacetamide (4-HPA) were identified as potent bioactive compounds among the metabolites of P. sydowiana PPR using in silico approaches. The MIC values of CLP and 4-HPA against P. aeruginosa PAO1 were determined as 250 and 125 ㎍/ml, respectively. All the antivirulence assays were conducted at sub-MIC concentrations of CLP (125 ㎍/ml) and 4-HPA (62.5 ㎍/ml), which resulted in marked reduction in all the investigated virulence factors. This was further supported by gene expression studies. The findings suggest that the metabolites of P. sydowiana PPR can be employed as promising QS inhibitors that target pathogenic bacteria.

• Applied Biological Chemistry
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• v.51 no.4
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• pp.281-287
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• 2008

Effect of combined use of anti-microbial materials, such as alcohol, mustard and chitosan, or pasteurization on the quality of low salted kochujang was investigated during storage at $30^{\circ}C$ for 12 weeks. Activity of amylase decreased during storage, with lower activity in pasteurized kochujang than the other groups. Acidic protease activity increased during storage, but neutral protease activity decreased after 4 weeks. Viable cells of yeast increased during storage, but bacterial counts decreased gradually and did not show any remarkable difference among the test groups. Hunter a-values decreased as storage time increased, whereas L- and b-values decreased after 4 weeks and the degree of increase in total color difference (${\Delta}E$) was low in the supplementary ingredients added kochujang. The moisture contents and water activities decreased during storage with being lower in supplementary ingredients added groups. Titratable acidity of kochujang was decreased after 4 weeks of storage with the highest in combination of the supplementary ingredients added group. Oxidation-reduction potential was low in the supplementary ingredients added kochujang. Total sugar and reducing sugar contents of kochujang decreased during storage, with the highest contents in the supplementary ingredients added group. Ethanol content of kochujang increased during storage, whereas ethanol production was reduced in ethanol added one. Amino-nitrogen and ammonia-nitrogen contents decreased during storage with being lower in kochujang prepared with supplementary ingredients. Therefore, supplementary ingredients added kochujang would be effective for extending shelf-life of kochujang.

• Environmental Engineering Research
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• v.10 no.5
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• pp.213-226
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• 2005

To treat wastewater efficiently by a one-step process of nitrogen removal, a new bacterial strain producing $N_2$ gas from ${NH_4}^+$ under an aerobic condition was isolated and identified. The cell was motile and a Gram-negative rod, and usually occurred in pairs. By 16S-rDNA analysis, the isolated strain was identified as Enterobacter asburiae with 96% similarity. The isolate showed that the capacity of $N_2$ production under an oxic condition was approximately three times higher than that under an anoxic condition. Thus, the consumption of ${NH_4}^+$ by the isolate was significantly different in the metabolism of $N_2$ production under the two different environmental conditions. The optimal conditions of the immobilized isolate for $N_2$ production were found to be pH 7.0, $30^{\circ}C$ and C/N ratio 5, respectively. Under all the optimum reaction conditions, $N_2$ production by the immobilized isolate resulted in reduction of ORP with both the consumption of DO and the drop of pH. The removal efficiencies of $COD_{Cr}$, and TN were 56.1 and 60.9%, respectively. The removal rates of $COD_{Cr}$, and TN were the highest for the first 2.5 hrs with the removal $COD_{Cr}/TN$ ratios of 32.1, and afterwards the rates decreased as reaction proceeded. For application of the immobilized isolate to a practical process of ammonium removal, a continuous operation was executed with a synthetic medium of a low C/N ratio. The continuous bioreactor system exhibited a satisfactory performance at 12.1 hrs of HRT, in which the effluent concentrations of ${NH_4}^+$-N was measured to be 15.4 mg/L with its removal efficiency of 56.0%. The maximum removal rate of ${NH_4}^+$-N reached 1.6 mg ${NH_4}^+$-N/L/hr at 12.1 hrs of HRT(with N loading rate of $0.08\;Kg-N/m^3$-carrier/d). As a result, the application of the immobilized isolate appears a viable alternative to the nitrification-denitrification processes.