• Journal of Microbiology and Biotechnology
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• v.23 no.6
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• pp.811-817
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• 2013

The present study dealt with the isolation, identification and enzyme characterization of potential luminous bacteria from water, sediment, squid, and cuttle fish samples of the Karaikal coast, Bay of Bengal, India during the study period September 2007 - August 2008. Bioluminescent strains were screened in SWC agar and identified using biochemical tests. As Shewanella henadai was found to be the most common and abundant species with maximum light emission [69,702,240 photons per second (pps)], the optimum ranges of various physicochemical parameters that enhance the luciferase activity in Shewanella hanedai were worked out. The maximum luciferase activity was observed at the temperature of $25^{\circ}C$ (69,674,387 pps), pH of 8.0 (70,523,671 pps), salinity of 20 ppt (71,674,387 pps), incubation period of 16 h (69,895,714 pps), 4% peptone (70,895,152 pps) as nitrogen source, 0.9% glycerol (71,625,196 pps), and the ionic supplements of 0.3% $CaCO_3$ (73,991,591 pps), 0.3% $K_2HPO_4$ (73,919,915 pps), and 0.2% $MgSO_4$ (72,161,155 pps). Shewanella hanedai was cultured at optimum ranges for luciferase enzyme characterization. From the centrifuged supernatant, the proteins were precipitated with 60% ammonium sulfate, dialyzed, and purified using anion-exchange chromatography, and then luciferase was eluted with 500 mM phosphate of pH 7.0. The purified luciferase enzyme was subjected to SDS-PAGE and the molecular mass was determined as 78 kDa.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.5
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• pp.518-523
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• 2018

This study analyzed the food safety in processing process of simple-processed fishery products. A total of 88 samples analyzed for the presence of pathogenic bacteria and physicochemical hazards. No major foodborne pathogenic bacteria, such as Salmonella sp., Listeria monocytogenes and Escherichia coli O157:H7, were detected in any of the samples. However, Bacillus cereus (12 samples, 13.6%) and Staphylococcus aureus (15 samples, 17.0%) were frequently detected in both the intermediate processing stages and the final products, although cell populations were not high. Very small amounts of heavy metals and histamine were detected in some samples, in quantities that did not exceed the safe guidelines according to Korean Government regulations. Similarly, no other physical hazards such as foreign material were observed in any of the samples. We concluded that there are no significant pathogenic bacteria or physicochemical food hazards in simply processed fish products from Korea. The present study strongly suggests that increased food sanitation measures should be implemented to decrease the prevalence of S. aureus in simple-processed fishery products.

• Journal of Applied Tourism Food and Beverage Management and Research
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• v.12 no.2
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• pp.1-41
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• 2001

The effect of smoking on the quality sausage Sausages were prepared from beef, port, chickens, games, fish and shellfish with polyphosphate salt and spices. Sausage history goes back to 3,000 years of age. The procedure of sausage 1) Meat Curing 2) Meat Control 3) Add Spices 4) Permissible Ingredients 5) Grinding 6) Mixing Emulsion 7) Stuffing 8) Showing 9) Smoking 10) Cooking 11) Drying 12) Packaging Sausage Product to get information on the effect of smoking onto the quality of meat produces. Sausage was smoked under a given conditions. Smoking was conducted as 35f$^{\circ}C$to 6$0^{\circ}C$ the related humidity of smokehouse was still at 60 to 70 percent. Results are as follows: 1. The Penetrated smoke in sausage was prolonged < p.<0.02 when sausage was smoked 2hours at 60~$65^{\circ}C$ the penetrated amount of free acetone in sausage was 0.5mg%. 2. Peroxide value of sausage as heating treatment both at 3$0^{\circ}C$ and at 5$0^{\circ}C$ was prolonged. 3. When sausage was heated at 3$0^{\circ}C$, bacteria of sausage increased In number while at 60~$65^{\circ}C$ bacteria of sausage increased In number fourteen hours. 4. When sausage was treated with smoking the distribution of free amino acids in sausage was changed markedly. 5. The longer smoking time of the products was the higher the content. 6. In case of oak wood smoke flavoring all of test samples. 7. Rapid decrease of does-response mutagenic curve of the smoke flavoring of oak wood and apple wood by in the peak of curve and phenol in the smoke flavoring. Continuous efforts are required to make sausages easily in the butcher shops and in the restaurants. 8. Sausage texture evaluation has 13 rules. It is Elasticity, Surface Moisture, Surface Smoothness, Center Hardness, Skin Toughness, Cohesiveness, Denseness, Moisture Release, Cohesiveness of Mass, Lumpiness, Graininess (of Contents), Skin separation, Oiliness and sensory 11 rules evaluation is color, texture, mold, flavor, sweet test, salty, sourness, bitter, and savory taste. 9. Smoked, component, peroxide value, bacteria, color, free amino acid, tenderness, flavor, shrinkage are important values.

• Journal of Applied Biological Chemistry
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• v.55 no.2
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• pp.135-140
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• 2012

To diversify usage of aquacultural red sea cucumber, new Kimchi containing red sea cucumber was developed and its quality and consumer preference were studied. The pH and total acidity, index of Kimchi ripening, decreased till 7 days of storage, then pH change became blunt and finally reached optimum pH 4-4.5. The amount of reducing sugar gradually decreased during storage period. The number of lactic acid bacteria increased in early fermentation period in both Kimchi containing boiled and fresh red sea cucumber, however, more lactic acid bacteria found in fresh red sea cucumber containing Kimchi. Preference of Kimchi containing boiled or fresh red sea cucumber compared to control Kimchi containing fermented salted fish was evaluated. The results revealed there were no differences in color, flavor, texture, taste, after taste and overall preference.

• Journal of fish pathology
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• v.24 no.3
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• pp.237-245
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• 2011

Disease survey was conducted to investigate the cause of high mortality in 23 farms of eel, Anguilla japonica, during the period from 2000 to 2010. Seven kinds of fish pathogens were confirmed in the tested fish, which included: Pseudodactylogyrus sp. (infection rate: 65.5%, 19/29 samples), aquabirnavirus (ABV, 62.5%, 15/24 samples), Edwardsiella sp. (44%, 11/25 samples), anguillid herpesvirus 1 (AngHV1, 16.7%, 2/12 samples), Heterosporis sp. (10.3%, 3/29 samples), Vibrio sp. (8%, 2/25 samples), Trichodina sp. (3.4%, 1/29 samples). The rate of single infection was 44.8% (13/29 samples), while 62.1% (18/29 samples) showed mixed type of infection with 2 to 5 different pathogens. The most predominant mixed infection were Pseudodactylogyrus sp.-Edwardsiella sp. (10.3%, 3/29 samples), Pseudodactylogyrus sp.-ABV (10.3%, 3/29 samples), Edwardsiella sp.-ABV (6.9%, 2/29 samples). Infection by the above infectious parasites, bacteria and virus was confirmed in tested eels of juvenile to adult sizes that were cultured at $25{\sim}30^{\circ}C$ in almost the examined farms.

• Journal of fish pathology
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• v.22 no.1
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• pp.9-14
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• 2009

Fifteen diseased rockfish (Sebastes schlegeli) were collected from 4 net-cage farms in Huksan island. Some round transparent nodules were observed on gill filaments in fish. Bacteriological and histopathological examinations on the diseased fish were performed. Any pathogenic bacteria could not be isolated from the internal tissues and histopathological alterations were not found in any of the tissues except the gills. Rock fish were infected with epitheliocystis, Microcotyle sebastes and unknown aetiology on the gills. Cysts of epitheliocystis measuring 44.1-68.9 $\mu{m}$ in diameter were mainly found in the distal portion of the gill filaments and sometimes in the middle portion. But host responses were moderate in spite of formation of the epithelial cysts. Some Microcotyle sebastes captured the secondary filaments with clamps on the opisthohaptor. Attachment of the parasites provoked epithelial proliferation and resulted in gill lamellar fusion.Cysts of unknown origins measuring 26-425 $\mu{m}$ in diameter were found in the cartilage of gill filaments. These cysts contained eosinophilic materials and proliferation of cartilage cells was confirmed around the cysts. But there was no significant pathological changes associated with the presence of the cysts except enlargement of the gill filament with the cysts.

• Korean Journal of Microbiology
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• v.54 no.1
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• pp.53-59
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• 2018

The objective of this study was to investigate the plasmid profiling of multi-drug resistant (MDR) Vibrio in influent (inflow) and effluent (discharged) water samples of fish farms in Jeju, South Korea. MDR isolates identified through disc diffusion susceptibility tests, were subjected to plasmid profiling. One hundred fifty Vibrio isolates were obtained from each influent and effluent water sample. All MDR isolates were subjected to plasmid profiling. Greater number of bacteria were enumerated from effluents (61%) comparing to influents (39%). High incidence of neomycin, sulfamethoxazole, amoxicillin and oxytetracycline resistance was observed among the isolates, which was higher in effluent samples. In contrast, Vibrio isolates were more susceptible to florfenicol, chloramphenicol, ciprofloxacin, and nalidixic acid. Among 99 (influent 39 and effluent 60) MDR isolates, a total of 58 (influent 38 and effluent 20) were found to bear plasmids ranging from 1.7 kb to >10 kb and showed 19 different antibiograms according to the size of plasmids. MDR isolates showed six and four distinct plasmid profiles in influent and effluent, respectively. Effluent samples contained more plasmid-carrying MDR Vibrio isolates with more diverse plasmid profiles and antibiograms, suggesting that fish farm tanks may serve as a reservoir of antibiotic resistance genes. The presence of plasmid-carrying MDR Vibrio isolates in fish farm effluent water may contribute to the dissemination of antibiotic resistance genes to the environments, which ultimately poses threat to human health.

• Journal of fish pathology
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• v.36 no.2
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• pp.277-286
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• 2023

Korean rockfish, Sebastes schlegelii, is a representative bony fish that belongs to the family Scorpaenidae and the order Scorpaeniformes. It has high ecological and economic value and is widely cultivated in many East Asian countries, including South Korea, Japan and China. One of streptococci, Streptococcus iniae, is Gram-positive cocci with a negative reaction for catalase and oxidase. The Korean rockfish shows clinical signs when infected with S. iniae, such as body darkening, bleeding, enlarged kidneys, blurred eyes, abdominal distension, etc., ultimately leading to death. The Korean rockfish causes significant economic losses every year in South Korea due to streptococcosis. In this study, we identified bacteria from the fish using polymerase chain reaction and conducted analyses of hemolytic activity and biochemical tests using API 20 STREP and API ZYM systems. Results of confirming the hemolytic activity (n=4) observed in alpha-type hemolysis (25%), beta-type hemol- ysis (50%), and gamma-type hemolysis (25%) of isolates. The biochemical test results exhibited sig- nificant variation among S. iniae. Additionally, we performed intraperitoneal injection with S. iniae in the fish and analyzed the phylogenetic tree using housekeeping genes of S. iniae, including cpsD, arcC, glnA, groEL, gyrB, mutS, pheT, prkC, rpoB, and tkt, via multilocus sequence typing (MLST). The lethal dose (LD₅₀) showed strong pathogenicity, such as 3.34 × 10 colony-forming unit (CFU)/ml for 23FBStr0601 strain and 7.16 × 10 CFU/ml for 23FBStr0602 strain. 23FBStr0603 strain showed relatively low pathogenicity at 1.73 × 10⁵ CFU/ml. The strains 23FBStr0601 and 23FBStr0602, which showed strong pathogenicity, clustered into one monophyletic group. The 23FBStr0603 strain showed weak pathogenicity and formed a monophyletic group with KCTC 3657.

• Journal of fish pathology
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• v.25 no.3
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• pp.263-270
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• 2012

This study surveyed for the prevalence of parasites, bacteria and viruses in four fish species, olive flounder (Paralichthys olivaceus), red sea bream (Pagrus major), black sea bream (Acathopagrus schlegeli) and black rockfish (Sebastes schlegeli) in 2010. The survey was aimed to compare the pathogens detected from wild and cultured fish for an epidemiological study. Anisakis sp. was predominantly detected from wild olive flounder and red sea bream (58.6% and 41.7% respectively), but not from the cultured fishes, suggesting anisakid infection is rare in cultured fish. The wild fish get in contact with the anisakids through their prey such as small fishes or crustaceans which carry the anisakids; whereas the cultured fish are fed with formulated feed, free of anisakids. Bacterial detection rates from the wild fishes examined in the study were lower than those of cultured fishes. Vibrio sp. dominated among detected bacterial population in cultured olive flounder (18%). Since vibriosis is known as a secondary infection caused by other stressful factors such as parasitic infections, handling and chemical treatment, it seems that cultured olive flounder are exposed to stressful environment. Viruses diagnosed in the study showed difference in distribution between wild and cultured fishes; hirame rhabdovirus (HRV) (0.1%) and lymphocystis disease virus (LCDV) (3.9%) were detected in the cultured olive flounder, but not in the wild fish, and marine birnavirus (MBV) (1.7%) and red sea bream iridovirus (RSIV) (3.2%) were detected from the wild and cultured red sea bream, respectively. From the survey conducted, it can be concluded that even though some pathogens (Trichodina sp., Microcotyle sp., etc.) are detected from both the wild and cultured fish, pathogens such as Anisakis sp., Vibrio sp. and LCDV showed difference in distribution in the wild and cultured host of same fish species and this can be attributed to their environmental condition and feeding.

• Journal of Microbiology and Biotechnology
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• v.19 no.12
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• pp.1656-1664
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• 2009

Bioaugmentation of bioreactors focuses on the removal of numerous organics, with little attention typically paid to the maintenance of high and stable nitrite accumulation in partial nitrification. In this study, a bioaugmented membrane bioreactor (MBR) inoculated with enriched ammonia-oxidizing bacteria (AOB) was developed, and the effects of dissolved oxygen (DO) and temperature on the stability of partial nitrification and microbial community structure, in particular on the nitrifying community, were evaluated. The results showed that DO and temperature played the most important roles in the stability of partial nitrification in the bioaugmented MBR. The optimal operation conditions were found at 2-3 mgDO/l and $30^{\circ}C$, achieving 95% ammonia oxidization efficiency and nitrite ratio ($NO_2^-/{NO_x}^-$) of 0.95. High DO (5-6 mg/l) and low temperature ($20^{\circ}C$) had negative impacts on nitrite accumulation, leading to nitrite ratio drop to 0.6. However, the nitrite ratio achieved in the bioaugmented MBR was higher than that in most previous literatures. Denaturing gradient gel electrophoresis (DGGE) and fluorescence in situ hybridization (FISH) were used to provide an insight into the microbial community. It showed that Nitrosomonas-like species as the only detected AOB remained predominant in the bioaugmented MBR all the time, and coexisted with numerous heterotrophic bacteria. The heterotrophic bacteria responsible for mineralizing soluble microbial products (SMP) produced by nitrifiers belonged to the Cytophaga-Flavobacterium-Bacteroides (CFB) group, and $\alpha$-, $\beta$-, and $\gamma$- Proteobacteria. The fraction of AOB ranging from 77% to 54% was much higher than that of nitrite-oxidizing bacteria (0.4-0.9%), which might be the primary cause for the high and stable nitrite accumulation in the bioaugmented MBR.