• Journal of the Institute of Convergence Signal Processing
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• v.16 no.3
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• pp.108-114
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• 2015

Ballast water is carried by ships to ensure stability, trim and structural integrity. When a ship loads cargo, the ballast water is discharged. When foreign marine microorganisms are introduced into new marine environments, they pose a threat to the local marine ecological system. UV system is commonly used for the disinfection of waste and surface water. This method would not be as efficient because some species do survive to form viable populations, much of the sediment and organisms at the bottom of tanks, and may become serious pests. In this paper, we designed and implemented ballast water treatment system using fuzzy PID controller to prevent lamp damage, and to reduce the formation of the viable populations. The experiments were conducted with ballast water treatment system using fuzzy PID controller with short time exposure to the temperature above $40^{\circ}C$. This system was shown to be effective by significantly reducing bacterial population and lamp life extension through appropriate temperature of ballast water.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.4
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• pp.265-270
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• 2014

Protease producing microorganisms were isolated from many kinds of food waste and fermented foods, which contains high amount and variable kinds of degraded substances. Several microorganisms were identified by 16S rRNA full sequencing analysis methods. The activity of protease was analyzed and identified in variable conditions for the application. For industrial use for biowaste treatment some proteases were isolated, identified and selected from microbial cells. And the tests were carried for the further use. The protein degrading activity at low temperature is useful for the treatment of organic waste, which contains much proteins. By the protein degradation process the organic waste can be utilized in variable fields, for example from feedstuff supplement to fertilizer for agriculture. Bacterial cells with protease activity at low temperature were isolated and identified. The optimal conditions for microbial cultivation and protease production were studied.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.1
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• pp.103-108
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• 2023

In this study, basic research was conducted to secure microbial resources applicable to autonomous crack healing concrete. To this end, in this experiment, biomineral-forming microorganisms were separated from natural sources, and the ability of survival in cement and calcium carbonate precipitation were compared to secure suitable microbial resources. Bacillus-type bacteria forming endospores were isolated from the sample, and the amount of calcium carbonate produced by the six microorganisms identified by 16S rRNA sequencing was compared. Two types of microorganisms, Bacillus velezensis and Bacillus subtilis, with the highest calcium carbonate precipitation were selected, and the survival of the microorganisms was confirmed through phase contrast microscopy after being cured after being added to the mortar. In addition, it was confirmed that the autonomous crack healing capability by the crack healing material produced by microorganisms was confirmed by artificially generating cracks in the mortar.

• Korean Journal of Food Science and Technology
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• v.31 no.5
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• pp.1345-1348
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• 1999

The utility of a bioluminescence adenosine triphosphate(ATP) assay method for estimating bacterial levels in mackerel(Scomber japonicus) was investigated. Mackerel was stored at $1^{\circ}C$ throughout 10 days and its RLU(relative light unit) and APC(aerobic plate count) was determined. The ATP bioluminescence assay was validated during the storage of 32 samples, resulting in an agreement between the ATP assay and standard plate count methods of over 90% credibility. Therefore, ATP bioluminescence assay was considered as a rapid and near real-time means in estimating the microbial load on mackerel skin.

• The Korean Journal of Food And Nutrition
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• v.13 no.3
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• pp.213-220
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• 2000

본 연구는 찹쌀가루액에 효소처리 및 미생물 접종을 시킴으로써 유과의 제조시 수침과정을 거치지 않고도 유과를 만들수 있는 새로운 방법을 개발하기 위하여 시도되었다. 찹쌀 수침액에 분포된 미샐울은 Bacillus sp와 Lastobacillus spp.로 나타났다. 찹쌀 수침액에 인위적으로 상기 미생물을 배양하였을 대 유과를 제조하기 위한 최적 조건은 3$0^{\circ}C$에서 18시간 이었다. 이때 찹쌀수침액의 PH는 배양시간이 증가함에 따라 증가하였다. 이 찹쌀 수침액에서는 수침시간이 증가함에 따라 $\alpha$-amylase 활성이 증가하여 효소처리된 시료액의 효소 활성화 유사한 경향을 나타내었다. 유과의 팽화도는 효소처리시킨 혼합 접종처리 군을 제외한 모든 처리군에서 28일간 수침한것과 유사하게 나타났다. 경도와 peak수는 모든 처리순에서 28일간 수침시킨 대조군에 비해 유의적으로 더 낮게 나타났다.(P<0.05). 미세구조에서 기공수는 효소처리시킨 단독 접종군이 다른 모든 처리군에 비해 더 많은 기공수를 지니고 있었고 기공의 둘레 및 면적도 유의 적으로 낮은 수치를 나타내었다. .(P<0.05). 따라서, 수침공정을 대폭 단축할 수 있었으며, 향후 미생물 접종을 고려한 효소처리 조건을 정밀 분석한다면 수침공정이 없어도 유과의 품질특성을 나타내는것이 가능할 것으로 보인다.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.185.1-185
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• 2003

최근 세계적으로 편의식품의 소비가 증가하면서 과채류의 신선도를 유지시킴과 동시에 편리하게 조리에 이용할 수 있는 최소가공식품(minimally processed foods)의 시장이 확대되고 있다. 그러나, 기개발된 최소가공 과채류는 미생물학적 안전성 및 색 변화 등의 문제점을 수반하여 이 부분을 보완할 수 있는 기술개발이 시급한 실정이다. 따라서 본 연구는 감마선을 이용하여 미생물학적 안전성 및 저장성을 향상시킨 최소가공식품 개발의 일환으로, 김치를 모델식품으로 원료배추의 최소가공식품을 개발하기 위해 미생물학적, 이화학적 품질특성을 조사하였다. 절단한 배추의 염농도가 3%가 되도록 절임 및 함기포장 하고, 0~2 kGy의 선량으로 감마선 조사한 후 4$^{\circ}C$에서 3주 동안 저장, 분석하였다. 비조사구의 경우 총균수, coliform Salmonella spp., lactic acid bacteria 등이 모두 7 log cycle 수준을 보였으며, 감마선 조사시 2-5 log cycle 이상 감소하는 것으로 나타났다. 또한 색도, 물성 등은 감마선 조사에 의해 비조사구와의 유의적인 차이를 보이지 않았으며, 감마선 조사시 절임배추의 발효현상에 의해 나타나는 pH 저하를 억제할 수 있어 저장성을 향상시킬 수 있는 것으로 나타났다. 결론적으로 감마선 조사를 이용한 최소가공 절임배추의 개발시 미생물학적 안전성을 보장하면서, 이화학적 특성이 저하되지 않고 저장성을 향상시킨 최소가공식품을 개발할 수 있었다.

• Korean Journal of Microbiology
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• v.27 no.2
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• pp.130-138
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• 1989

Microbiological parameters such as bacterial biovolume and biomass in Soyang Reservoir was statistically analyzed with the physico-chemical enviromental factors. Analysis of correlation and multiple regression showed that temperature affects most of microbiological parameters. Variations of total bacterial number, total bacterial biovolume and saprophyte number were highly correlatd with the concentrations of chlorophyll a and pheophytin a. Bacterial production by the $^{3}H$-thymidine incorporation rate was largely affected by Seston. It suggests that microbiological factors such as bacterial biovolume and bacterial biomass were controled by the concentration of seston and distribution of phytoplankton which acts as carbon and energy source for the bacterial community in the water column of Soyang Reservoir.

• Korean Journal of Microbiology
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• v.37 no.2
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• pp.101-108
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• 2001

Risk assessment defines as the process of estimating both the probability that an event will occur and the probable magnitude of its adverse effects. Chemical or microbial risk assessment generally follows four basic steps, that is, hazard identification, exposure assessment, dose-response assessment, and risk characterization. Risk assessment provides an effective framework for determining the relative urgency of problems and the allocation of resources to reduce risks. Using the results of risk analyses, we can target prevention, reme-diation, or control effects towards areas, sources, or situations in which the greatest risk reductions can be achieved with resources available. Risk assessment is also used to explain chemical and microbial risks as well as ecosystem impacts. Moreover, this process, which allows the quantitation and comparison of diverse risks, lets risk managers utilize the maximum amount of complex information in the decision-making process. This information can also be used to weigh the cost and benefits of control options and to develop standards or treatment options.

• Journal of Food Hygiene and Safety
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• v.16 no.3
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• pp.221-226
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• 2001

Various sterilization methods were applied to the powder of ginseng for the improving hygienic quality. Ultra-violet (UV) and Infrared ray (IR) treatments could not inhibit highly growth of bacteria in ginseng powder. However, high hydrostatic pressure treatment showed high inhibition rate against bacterial growth in ginseng powder. Changes of viable cell count by the pressure showed positive relationship between growth inhibition rates and the pressures applied. When powder was treated with 2,000 kg/$\textrm{cm}^2$ for 10 min at $25^{\circ}C$, initial viable cell count of the powder, 2.0$\times$10$^4$CFU/g, was decreased to 1.0$\times$10$^4$CFU/g. When it treated with 3,000, 4,000 and 5,000 kg/$\textrm{cm}^2$ of pressures under the same condition, viable cell counts were 8.0$\times$10$^3$, 7.0$\times$10$^3$and 1.8$\times$ 10$^3$CFU/g, respectively. Ginseng saponins of the powders were all detected when analyzed by TLC chromatography after treatment with the Pressures. Therefore, it was considered that saponin of ginseng powder was stable under the condition of 5,000 kg/$\textrm{cm}^2$ of pressure, even though the treatment induced coagulation of the powder.

• Korean Journal of Food Science and Technology
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• v.41 no.4
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• pp.452-457
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• 2009

In order to secure microbiological safety and quality of commercial vegetable sprouts, buckwheat seeds and sprouts were investigated for their microbiological flora and for the effect of chlorine treatment on quality. Microbiological analyses showed that major inherent bacteria including Enterobacter, Sphingomonas, and Klebsiella were found in commercial buckwheat sprouts with a population size ranging from $10^5$ to $10^7$ CFU/g. In addition, buckwheat seeds had a similar microbial flora to sprouts. Foodborne pathogenic bacteria such as Escherichia coli O157:H7, Staphylococcus aureus, Salmonella Typhimurium, and Listeria monocytogenes were not detected in the sprout or in the seed samples. Chlorine treatment with 50-150 ppm sodium hypochlorite noticeably reduced viable bacteria cell counts of the sprouts by about 1 log. However, no significant difference was observed among the different chlorine concentrations. After storage for 7 days at $5^{\circ}C$, the sprouts treated with 100-150 ppm chlorine showed higher sensory scores in visual quality than the others (p<0.05). The results indicated that proper pretreatment, such as dipping in chlorinated water, could confer a beneficial effect on the microbiological safety and visual quality of buckwheat sprouts.