• 한국식품과학회지
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• 제36권6호
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• pp.1020-1025
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• 2004

생식제품 및 제조 공정 중 위해 미생물의 제어 및 저감화를 위하여 제조공정을 개선하고 전해수, 오존수 등 살균효과에 대하여 조사하였다. 7가지의 위해미생물 오염도가 높은 생식원료에 대한 전해수의 살균효과가 차아염소산소다수 또는 오존수에 비하여 전체적으로 강한 것으로 나타났으며 오존수의 살균효과는 차아염소산소다수와 비슷하거나 다소 강한 것으로 나타났다. 그러나 전해수나 오존수를 이용하여 생식원료를 세정, 살균하여도 원료의 종류에 따라 살균효과에 차이가 있으며, 비 가열가공이라는 생식의 특성상 원료에서 검출되는 위해미생물은 최종제품까지 생잔할 가능성이 높기 때문에, 각 원료에 따른 살균처리지침을 위한 database 축적이 요구된다. 한편 모델공장을 선택하여 공장위생, 종업원 개인위생 및 제조공정을 개선한 후 공정개선의 미생물학적 효과를 조사한 결과 공정개선 전에는 원료에서 보다 최종제품에서 위해미생물의 수가 증가하는 경향을 나타내었으나, 공정개선 후에는 원료의 균수를 그대로 유지하거나, 감소하였으며 외주 원료의 혼합으로 인하여 위해미생물의 균수가 증가하였다. 따라서 생식의 제조공정에서 위해미생물을 저감화를 위해서는 외주 원료의 철저한 위생관리가 요구되며, 전해수 오존수 등을 이용한 원료의 비가열 세정살균과 지속적이고 위생적인 공정관리가 이루어진다면 위해 미생물의 균수를 저감화할 수 있을 것으로 사료된다.

• Fisheries and Aquatic Sciences
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• 제25권1호
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• pp.40-48
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• 2022

Seahorses, which have been cultivated since the 2000s, are economically very important. Gas bubble disease (GBD) is a significant concern in the cultivation of seahorses; therefore, this study aimed to determine the cause of GBD-induced death in two species of Syngnathidae (Syngnathus schlegeli and Hippocampus haema). Rod-shaped bacteria were observed histopathologically and identified as Vibrio splendidus by conventional and real-time PCR analyses. The lethality of V. splendidus varies depending on the host's immune status, and the disease can be prevented through water quality management or improvement of the breeding environment. In this study, the GBD lesions (gas bubbles) were observed at 12℃, 8.0 mg/L of dissolved oxygen, 30 ppt of salinity, and pH 7.7. In addition, rod-shaped bacteria, infiltration of inflammatory cells, and extensive serous exudate were confirmed in the lesions where gas bubbles were found. PCR analysis was able to detect V. splendidus, possibly a secondary infection of the immunocompromised syngnathid fish. Understanding the risk of immunity control and the correlation between these lesions and causal agents will be of great help to the aquaculture industry and the ornamental fish market.

• 한국해양바이오학회지
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• 제13권1호
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• pp.10-19
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• 2021

This study investigated how ozone treatment can successfully inactivate pathogenic bacteria in both artificial seawater and effluents discharged from the fishery quarantine station in Pyeongtaek Port, Korea. Vibrio sp. and Streptococcus sp. were initially inoculated into the artificial seawater. All microbes were almost completely inactivated within 10 min and 30 min by injecting 6.4 mg/min and 2.0 mg/min of ozone, respectively. It was discovered that the water storing Pleuronichthys, Pelteobagrus, and Cyprinus imported from China contained the indicator bacteria, Vibrio sp., Enterococcus sp., total coliforms, and heterotrophic microorganisms. Compared to the control, three indicator bacteria were detected at two to six times higher concentrations. The water samples displayed a diverse microbial community, comprising the following four phyla: Bacteroidetes, Proteobacteria, Firmicutes, and Actinobacteria. Almost all indicator bacteria were inactivated in 5 min at 2.0 mg/min of ozonation; comparatively, 92.9%-98.2% of the less heterotrophic microorganisms were deactivated within the same time period. By increasing the dosage to 6.4 mg/min, 100% deactivation was achieved after 10 min. Despite the almost complete inactivation of most indicator bacteria at high doses after 10 min, several bacterial strains belonging to the Proteobacteria have still been found to be resistant under the given operational conditions.

• Fisheries and Aquatic Sciences
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• 제3권3_4호
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• pp.217-221
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• 2000

In previous study, marine actinomycetes producing the antibiotics were investigated to invent new antibiotics from east coast of Korea. The optimum growth conditions of Streptomyces sp. NS 13239 were $28^{\circ}C$, pH 7.0 and $3\%$ of NaCl concentration in various media. Streptomyces sp. NS 13239 showed strong antimicrobial activity against gram-positive bacteria, specially Methicillin resistant Staphylococcus aureus (MRSA), but just weak antimicrobial activity against yeasts and mold. On the other hand, it did not show antimicrobial activity against gram-negative bacteria. The optimum conditions for producing antibiotics were almost consistent with optimum growth conditions except carbon source and nitrogen source.

• 한국어업기술학회:학술대회논문집
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• 한국어업기술학회 2001년도 추계 수산관련학회 공동학술대회발표요지집
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• pp.147-148
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• 2001

Many people living in Asia countries, particularly Korea, Japan and China, have consumed very widely fresh seafood products, such as shrimps, oysters, mussels and other marine invertebrates and fishes, without any heating or cooking. A variety of Vibrio spp., including V. parahaemolyticus, V. cholera. V. vulnificus, and V. fluvialis, lives in these seafoods and cause great problems associated with human disease. A strong antimicrobial agent to effectively inhibit the growth of these pathogenic bacteria in in vivo or in vitro is urgently need for preventing fish and human diseases. (omitted)

• Nutrition Research and Practice
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• 제6권3호
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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.

• Ocean and Polar Research
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• 제39권4호
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• pp.245-255
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• 2017

There are a number of pieces of evidences that suggest a link between marine diatoms and microorganisms, but knowledge about related microbial communities is greatly lacking. The present study investigated the microbial community structures related to the growth of the marine diatom Cyclotella meneghiniana. We collected free-living bacteria (FLB) and particle-associated bacteria (PAB) at each growth stage (e.g., lag, exponential, stationary and death) of the diatom, and analyzed their bacterial 16S rDNA using pyrosequencing. Metagenomics analysis showed that community structures of FLB and PAB differed considerably with the progress of growth stages. FLB showed higher diversity than PAB, but variation in the different growth stages of C. meneghiniana was more evident in PAB. The proportion of the genus Hoeflea, belonging to the order Rhizobiales, was dominant in both FLB and PAB, and it gradually increased with the growth of C. meneghiniana. However, Enhydrobacter clade tended to considerably decrease in PAB. In addition, Marinobacter decreased steadily in FLB, but first increased and then decreased in PAB. These results suggest that Hoeflea, Enhydrobacter, and Marinobacter may be closely related to the growth of diatom C. meneghiniana.

• 한국수산과학회지
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• 제51권4호
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• pp.397-403
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• 2018

We determined the resistance rates of pathogenic bacteria isolated from cultured olive flounder Paralichthys olivaceus to erythromycin (Em), antibiotic typically used in aquaculture and analyzed the genotypes of resistant bacteria using polymerase chain reaction (PCR). We isolated and utilized 160 isolates of Streptococcus parauberis, 1 of S. iniae, 66 of Edwardsiella tarda, 56 of Vibrio sp. and 23 of unidentified bacteria from presumed infected olive flounder from Jeju Island from March 2016 to October 2017. Of the 306 isolated strains, Em-resistant strains included 33 of S. parauberis, 39 of E. tarda and 2 of Vibrio sp. We conducted PCR to assess the resistance determination of Em-resistant strains. Five different types of Em-resistance genes were detected in the 74 Em-resistant strains: erm (A), erm (B), erm (C), mef (A) and mef (E); erm (A) and erm (B) were detected in 1 (3%) and 24 (72.7%) S. parauberis isolates, respectively. In E. tarda, erm (B) was detected in five isolates (12.8 %) and no Em-resistance genes were detected in the two Vibrio sp. isolates.

• 한국수산과학회지
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• 제51권4호
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• pp.389-396
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• 2018

Marine pathogenic bacteria, such as Streptococcus parauberis, Edwardsiella tarda and Vibrio harveyi, can cause lethal infections in farmed fish, ozone and antibiotics, are employed to sterilize waters used for rearing fish to mitigate this threat. The most widely used method is treatment with sodium hypochlorite solution. However, the maintenance of a constant concentration of chlorine in rearing waters can be difficult. We investigated the potential of a mixed oxidant (MO) solution generated by electrolysis of sea water to improve water quality. We measured the survival rates of fish pathogenic bacteria exposed to different concentrations of MO (0.5, 1.0, 1.5 and 2.0 MO) and sodium hypochlorite (0.5, 1.0, 1.5 and 2.0 ppm) for various lengths of time (0, 5, 10, 15, 20, 25 and 30 min). We found a time-dependent decrease in the survival rates of the tested pathogenic microorganisms. The sterilization effect of the MO solution on pathogenic organisms was greater than that of sodium hypochlorite for gram-negative and gram-positive bacteria. We conclude that MO solution produced by electrolysis could be used to maintain a constant chlorine concentration in aquaculture systems.

• 미생물학회지
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• 제48권4호
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• pp.328-331
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• 2012

울릉도 연안의 심해(1500 m)에 서식하는 미생물의 다양성을 조사하였다. Ultramembrane filter를 사용하여 해양미생물을 여과한 다음 미생물군집 DNA를 정제하여 16S rDNA를 증폭하였다. Pyrosequencing 방법으로 염기서열을 분석한 결과 총 13,029 reads를 얻었으며, 이중에 54.1%가 uncultured bacteria, 23.4%가 alphaproteobacteria, 22.3%가 gammaproteobacteria이었고 flavobacteria, actinobacteria, epsilonproteobacteria 등이 0.2%이내에서 분포하고 있었다. 울릉도 지역의 해양심층수에서 배양이 가능한 것으로 알려진 미생물로서는 alphaproteobacteria의 Rhodobacteraceae과 (family), gammaproteobacteria의 Alteromonadaceae, Halomonadaceae, Piscirickettsiaceae과가 주로 분포하였다.