• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.10a
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• pp.375-376
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• 2001

Many studies have been made on antimicrobial activity of Sawa-wasabi (Wasabia japonica). It has been reported that the essential oil of Sawa-wasabi has a particularly strong antimicrobial effect against Escherichia coli, Salmonella typhi, Pseudomonas aeruginosa and fish pathogenic bacteria such as Edwardtarda siella and Vibrio hollisae (Nishida, 1958; Inoue et al. 1983;).(omitted)

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.6
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• pp.910-916
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• 2022

The purpose of this study is to evaluate the effect of underwater non-thermal dielectric barrier discharge plasma (DBD plasma) on the sterilization of three types of pathogenic bacteria that cause diseases in freshwater fish and the reduction of a tetracycline antibiotics. This experiment was conducted in the DBD plasma generator, and the voltages used to generate plasma were 11.6 kV and 23.1 kV. The measurement intervals were 0, 1, 5, 10 and 15 min. As a result of DBD plasma treatment, Aeromonas hydrophila, Edwardsiella tarda and Pseudomonas fluorescens were removed 93-99% after 5 min at 23.1 kV, and the tetracycline antibiotics were reduced 70-95% after 15 min at 23.1 kV. In this study, as a result of treating the effluent with DBD plasma at a fish farm where the medicinal bath was conducted with oxytetracycline-HCl (OTC-HCl) products, OTC-HCl decreased by 62% after 10 min at 23.1 kV.

• Nutrition Research and Practice
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• v.6 no.3
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• pp.187-194
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• 2012

In this study, the antibacterial effect was evaluated to determine the benefits of high speed drying (HSD) and far-infrared radiation drying (FIR) compared to the freeze drying (FD) method. Citrus press-cakes (CPCs) are released as a by-product in the citrus processing industry. Previous studies have shown that the HSD and FIR drying methods are much more economical for drying time and mass drying than those of FD, even though FD is the most qualified drying method. The disk diffusion assay was conducted, and the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined with methanol extracts of the dried CPCs against 11 fish and five food-related pathogenic bacteria. The disk diffusion results indicated that the CPCs dried by HSD, FIR, and FD prevented growth of all tested bacteria almost identically. The MIC and MBC results showed a range from 0.5-8.0 mg/mL and 1.0-16.0 mg/mL respectively. Scanning electron microscopy indicated that the extracts changed the morphology of the bacteria cell wall, leading to destruction. These results suggest that CPCs dried by HSD and FIR showed strong antibacterial activity against pathogenic bacteria and are more useful drying methods than that of the classic FD method in CPCs utilization.

• Fisheries and Aquatic Sciences
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• v.22 no.7
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• pp.14.1-14.8
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• 2019

Olive flounder (Paralichthys olivaceus) is the major species developed for aquaculture in South Korea. Over the long history of olive flounder aquaculture, complex and diverse diseases have been a major problem, negatively impacting industrial production. Vibriosis is a prolific disease which continuously damages olive flounder aquaculture. A bacterial disease survey was performed from January to June 2017 on 20 olive flounder farms on Jeju Island. A total of 1710 fish were sampled, and bacteria from the external and internal organs of 560 fish were collected. Bacterial strains were identified using 16 s rRNA sequencing. Twenty-seven species and 184 strains of Vibrio were isolated during this survey, and phylogenetic analysis was performed. Bacterial isolates were investigated for the distribution of pathogenic and non-pathogenic species, as well as bacterial presence in tested organs was characterized. V. gigantis and V. scophthalmi were the dominant non-pathogenic and pathogenic strains isolated during this survey, respectively. This study provides data on specific Vibrio spp. isolated from cultured olive flounder in an effort to provide direction for future research and inform aquaculture management practices.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.38 no.6
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• pp.359-364
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• 2005

The distributions of sanitary indicative bacteria and pathogenic bacteria in seawater and four species of farmed fishes, including oliver flounder (Paralichthys olivaceus), black rock fish (Sebastes schlegeli), red sea bream (Pagrus major) and sea bass (Lateolabrax japonicus), collected at fish farms located in the southern coastal area of Korea were investigated from May to October in 2004. The detection rates of fecal coliform and Entirococcus spp. of sanitary indicative bacteria in all samples were $38.9\%$ and $23.8\%$, respectively. The occurrence of fecal coliform was highest of $58.3\%$ in Busan, Geoje and Wando area, followed Yeosu $33.3\%$, Jeju $12.5\%$, Tongyeong $11.1\%$. The occurrence of Enterococcus spp. was highest In Wando area ($45.8\%$), followed by Yeosu ($33.3\%$), Tongyeong ($22.2\%$), Busan ($16.7\%$), Geoje and Jeju ($12.5\%$). The detection rate of fecal coliform was higher than that of Enterococcus spp., except in the Tongyeong area. There was no difference in the detection rate of fecal coliform from May to October, but the detection rate of Enterococcus spp. increased with seasonal warming seawater temperature. Among the pathogenic bacteria, the detection rate of Vibrio alginolyticus ($49.2\%$) in all samples was highest, followed by V. parahaemolyticus ($36.5\%$), Staphylococcus aureus ($6.3\%$), Salmonella sp. ($2.4\%$). However, V cholerae, V. vulnificus and Shigella sp. were not detected in all tested samples. The detection rates of V. parahaemolyticus and V. alginolyticus increased with seasonal warming seawater temperature from May to August.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.10a
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• pp.145-146
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• 2001

Despite a variety of development in fish farming during the last decades, fish diseases by bacteria, virus, and parasites are still major problems in aquaculture. Aquaculture of Hounder fish is widely performed around Korea as well as Jeju island, due to relatively stable seed production, short farming period, and a higher value in market. However, intensive feeding and environmental pollution in aquacutural farm act as a great limiting factor in economic aspect. (omitted)

• Journal of fish pathology
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• v.13 no.1
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• pp.37-44
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• 2000

CT(Sodium N-chloro-para toluenesulfonamide, Chloramine-T) known to be a strong oxidative agent was investigated to use as a candidate of disinfectant in the marine aquaculture industry by the analysis of the bactericidal activity against different aquatic microorganisms. One hundred percent mortality appeared at and above 16 ppm CT in sea water in flounder, the predominant species in the marine aquaculture of Korea, when exposed for 48hr. However, bactericidal activity was appeared to be very effective, and all different species of the fish pathogenic bacteria exposed to CT of less than 2 ppm in sea water were dead within 15 min. It allowed us to confirm that CT could be a very effective disinfectant to protect the spread of fish pathogenic bacteria derived from diseased fish or sea water in marine aquaculture. High concentration(10 ppm) with longer exposing time(24 hrs) was required for the algicidal activity of CT, at which concentration might induce the acute toxicity against fish, however, restricted the expanded use of CT for the elimination of zooplanktons at phytoplanktons in marine farms. Moreover the bactericidal activity of CT inhibited almost completely in the present of more than 10 ppm of organic materials pointed out that quality of the culturing sea water should be considered carefully for the application CT to the aquatic farms as a therapeutic agent.

• Journal of Aquaculture
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• v.14 no.4
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• pp.221-226
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• 2001

The ethanol extract of root bark of Morus alba strongly inhibited the Gram positive bacteria like Streptococcus sp., Lactococcus garvieae and Staphylococcus sp., but weakly the Gram negative bacteria like Listonella anguillarm and Edwardsiella tarda. It was more effective in liquid medium than in solid medium. The minimum inhibition concentration (MIC) of the extract in liquid medium was 19.8 and 790~1185 $\mu\textrm{g}$/$m\ell$ for the Gram positive and Gram negative bacteria, respectively. The extract concentration, at which the growth was totally inhibited, was 67.2~403.0 $\mu\textrm{g}$/$m\ell$ for the Gram positive bacteria but it was as high as 1185 $\mu\textrm{g}$/$m\ell$ for L. anguillarum and almost ineffective against E. tarda. For diet supplementation of the extract, effective soaking duration was 3 minutes. The fish diet soaked in the extract inhibited the growth of all the tested Gram positive strains, but not the Gram negative strains. The relationship between the weight of fish diet and absorption of the extract by the fish diet was Y=7.5757X + 4.6962($R^2$ = 0.9998).

• Journal of Food Hygiene and Safety
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• v.19 no.2
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• pp.74-83
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• 2004

Raw-fish food contains a lot of moisture and is a high-protein food. It is a first-stage processed food taking a lot of manual work. Therefore, it is classified as a PHF food, very liable to cause a bacterial food-poisoning. But its manufacturers are usually small-sized and a systematic sanitation management is difficult to expect. But the manufacturer participating in this study produces chilled fresh raw-fish food. Fish are sliced into two fillets, which are packaged under vacuum, kept and distributed in refrigerators, and sold within a day. It is a newly-developed kind of raw-fish food, and a more improved kind of raw-fish food making possible a systematic sanitation management. The HACCP (Hazard Analysis and Critical Control Point) is a systematic and continuous process-control method which is very efficient for controling food sanitation and reducing the expenses. A new HACCP model has been developed to be applied to a large-sized chilled fresh raw-fish food manufacturer. To ascertain its efficiency, the baterial examination was done to its workplace and products. The significance test was done on its data by "SPSS 12.0 for Window" and "Mann-Whitney U Test". The numbers of bacteria on its final products were significantly different in flatfish and porgy. The number of bacteria tended to decrease in each time-differential sampling (P＜.00l). The final food products showed no food-poisoning bacteria in all the time-differential tests and in all the samplings, which proves that the CCP of the HACCP system is under control. After the SSOP program was applied, no pathogenic bacteria were found in the work-place, and the kinds and numbers of bacteria decreased. The numbers of general bacteria and colon bacilli also showed a significant difference from those before the SSOP program in the filleting board (P＜.05), in the skinning board (P＜.0l), in the neck-removing knife (P＜.05), and in the filleting knife (P＜.01). The working equipments, periodically disinfected, also showed a significant difference in sanitary conditions (in the dehydrator, P＜.05). The number of bacteria found on the food-touching surface was within the standard (below 500/l00 cm$^2$) After the SSOP program was applied, the general bacteria and colon bacilli were not found. The quality of water used in the food processing was also within the standard. The numbers of bacteria falling from the air in the work-place were negligible in all the samplings (＜30CFU/l000ι). The staphylococci and fungi were not found.

• Bulletin of the Korean Chemical Society
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• v.33 no.1
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• pp.115-122
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• 2012

Apidaecin Ib had strong antimicrobial activity against several tested Gram-negative bacteria including Escherichia coli, Enterobacter cloacae, and Shigella flexneri (MECs; $0.3-1.5{\mu}g/mL$), but showed no activity against all the tested Gram-positive bacteria including Bacillus subtilis, Micrococcus luteus, Staphylococcus aureus and one yeast, Candida albicans (MECs; > $125{\mu}g/mL$). Interestingly, this peptide showed potent antibacterial activity only against Edwardsiella species (MECs; $0.6-3.6{\mu}g/mL$) among the tested fish pathogenic bacteria through a bacteriostatic process and showed no significant hemolytic activity. Apidaecin Ib took an unordered structure in all environments and also had very weak membrane perturbation activity even at $25{\mu}M$. Anti-Edwardsiella activity of apidaecin Ib is stronger than those of other antimicrobial polypeptides or antibiotics, but its activity is salt-sensitive. These results suggest that apidaecin Ib has Edwardsiella speciesspecific antibacterial activity and could be applied as new preventive or control additives for Edwardsiella species infection in freshwater fish aquaculture.