• Journal of the Korean Society of Food Culture
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• v.10 no.1
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• pp.67-74
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• 1995

This study researched microbial change of quality according to the various phases of product flow of cooked pea and rice, cold cucumber and seaweed soup, soybean sprouts japchae feeding urban type of a commissary school and a satellite school in Daejeon area, also it suggested the possibility that the central commissary foodservice system can be established and utilized more developmental to identify its food of variation of temperature and state of safety unitl 3 hours after cooking for the case of delay of distribution and holding because of the satellite school of geographical location and traffic problem. The critical Control Points identified for each category of menu items were: Boiled pea and rice: inadequate distribution, holding and storing before assembly; Cold cucumber and seaweed soup: pre-preparation and post-preparation after cooking; Soybean sprouts japchae: Pre-preparation, post-preparation and storing. As the result of observation of the variation of temperature and microbial safety according to the delay of distribution and holding for each food, all of them were relatively safe until 3 hours after cooking, but cold cucumber and seaweed soup being stored for 3 hours, the value of E. coli is $10^3$ CFU/g. The variation of temperature was more extreme in soybean sprouts japchae than cooked pea and rice and cold cucumber and seaweed soup. It was proved that the stainless container was excellent and that adequate holding container should be used.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.5
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• pp.314-324
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• 2011

Algal biomass cultivated by wastewater is potentially useful resource for biodiesel production. However, little is known about algal nutrient metabolism and microbial interaction with bacteria under real municipal wastewater condition. In this work, we characterized nitrogen and phosphorus removals of municipal wastewater by a representative wastewater-growing algal population. Ankistrodesmus gracilis SAG 278-2, and analyzed its ecological interaction with wastewater bacterial communities. Compared to wastewater sludge itself, algal-bacterial co-culture improved nutrient removal. According to bacterial community analysis with 16S rRNA genes, a selective and dominant growth of a Unclassified Alcaligenaceae population resulted from algal growth in the algal-bacterial co-culture. The selectively stimulated bacterial population is phylogenetically close to Alcaligenes faecalis subsp. 5659-H, which is known to be co-present interact with algae in aquatic environment. These findings suggest that algal growth/metabolism may have effects on selection of a specific bacterial population in algal-bacterial co-cultures that can efficiently remove nutrients from municipal wastewater.

• Journal of Microbiology
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• v.44 no.4
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• pp.439-446
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• 2006

In this study, the growth kinetics of Lactobacillus rhamnosus and lactic acid production in continuous culture were assessed at a range of dilution rates $(0.05 h^{-1}\;to\;0.40h^{-1})$ using a 2L stirred tank fermenter with a working volume of 600ml. Unstructured models, predicated on the Monod and Luedeking-Piret equations, were employed to simulate the growth of the bacterium, glucose consumption, and lactic acid production at different dilution rates in continuous cultures. The maximum specific growth rate of L. rhamnosus, ${\mu}_{max}$, was estimated at $0.40h^{-1}$I, and the Monod cell growth saturation constant, Ks, at approximately 0.25g/L. Maximum cell viability $(1.3{\times}10^{10}CFU/ml)$ was achieved in the dilution rate range of $D=0.28h^{-1}\;to\;0.35h^{-1}$. Both maximum viable cell yield and productivity were achieved at $D=0.35h^{-1}$. The continuous cultivation of L. rhamnosus at $D=0.35h^{-1}$ resulted in substantial improvements in cell productivity, of 267% (viable cell count) that achieved via batch cultivation.

• Journal of Life Science
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• v.17 no.6 s.86
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• pp.798-804
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• 2007

A Actinomycetes F-97 producing tyrosinase inhibitor was isolated from soil samples. The optimum culture condition for 쇼rosinase inhibitor production was investigated and the results were as follows. The best carbon source for tyrosinase inhibitor production was shown as soluble starch, the optimum concentration was 3.0%. The best nitrogen source for tyrosinase inhibitor production was shown as peptone, the optimum concentration was 0.36%. As effect of metal ions on the production of tyrosinase inhibitor, K$_2$HPO$_4$ was shown the best and the optimum concentration was 0.1 mM. The optimum pH and temperature was shown 7.0 and 30${\circ}$C, respectively. And the highest tyrosinase inhibitor production was observed at 70hr cultivation under optimum conditions in jar fermentor scale.

• The Plant Pathology Journal
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• v.36 no.6
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• pp.579-590
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• 2020

Botrytis cinerea, which causes gray mold disease in more than 200 plant species, is an economically important pathogen that is mainly controlled by synthetic fungicides. Synergistic fungicide mixtures can help reduce fungicide residues in the environment and mitigate the development of fungicide-resistant strains. In this study, we screened microbial culture extracts on Botrytis cinerea to identify an antifungal synergist for tebuconazole. Among the 4,006 microbial extracts screened in this study, the culture extract from Schizophyllum commune displayed the most enhanced activity with a sub-lethal dosage of tebuconazole, and the active ingredient was identified as schizostatin. In combination with 5 ㎍/ml tebuconazole, schizostatin (1 ㎍/ml) showed disease control efficacy against gray mold on tomato leaf similar to that achieved with 20 ㎍/ml tebuconazole treatment alone. Interestingly, schizostatin showed demethylation inhibitor (DMI)-specific synergistic interactions in the crossed-paper strip assay using commercial fungicides. In a checkerboard assay with schizostatin and DMIs, the fractional inhibitory concentration values were 0.0938-0.375. To assess the molecular mechanisms underlying this synergism, the transcription levels of the ergosterol biosynthetic genes were observed in response to DMIs, schizostatin, and their mixtures. Treatment with DMIs increased the erg11 (the target gene of DMI fungicides) expression level 15.4-56.6-fold. However, treatment with a mixture of schizostatin and DMIs evidently reverted erg11 transcription levels to the pre-DMI treatment levels. These results show the potential of schizostatin as a natural antifungal synergist that can reduce the dose of DMIs applied in the field without compromising the disease control efficacy of the fungicides.

• Korean Journal of Organic Agriculture
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• v.19 no.spc
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• pp.190-193
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• 2011

Organic and chemical fertilizer amendments are an important agricultural practice for increasing crop yields. In order to maintain the soil sustainability, it is important to monitor the effects of fertilizer applications on the shift of soil microorganism, which control the cycling of many nutrients in the soils. Here, culture-dependent and culture-independent approaches were used to analyze the soil microorganism and community structure under six fertilization treatments, including green manure, rice straw compost, rapeseed cake, pig mature compost, NPK +pig mature compost, NPK and control. Both organic and chemical fertilizers caused a shift of the cultural microorganism CFUs after treatments. Bacterial CFUs of the organic fertilization treatments were significantly higher than that of chemical fertilization treatments. The DGGE profiles of the bacterial communities of the samples showed that the green manure treatment was a distinct difference in bacterial community, with a greater complexity of the band pattern than other treatments. Cluster analyses based on the DGGE profile showed that rice straw compost and pig mature compost had a similar banding pattern and clustered together firstly. Rapeseed cake, NPK, NPK +pig manure compost and control clustered together in other sub-cluster and clearly distinguished from green manure.

• Journal of the Korean Society of Food Culture
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• v.11 no.4
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• pp.465-473
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• 1996

The purpose of this study was to evaluate microbiological hazards in the steps of production, transportation and selling of hamburger and sandwich that were marketed in CVS, then to identify methods of control. The reasults are as follows: As the reasult of operation surroundings of manufacturerand reserch of circulation, $4{\sim}6$ hours are needed from manufacturer to CVS. Also transportation car mean temperature was $10^{\circ}C$ which exceeds the standard of $7^{\circ}C$ or below. Hamburger: Critical control points identified were purchasing, cooking, post-preparation, transportation and holding at CVS. As the reasult of microbial analysis following the case of holding methods and reheating at CVS, microbes of cold holding and reheat after cold holding was within standard value. But in the case of room temperature microbes exceeded standard value. Sandwich: Critical control points identified were purchasing, cooking, post-preparation, transportation and holding at CVS. As the reasult of microbial analysis following the case of holding methods and reheating at CVS, total plate counts of cold holding and reheat after cold holding was within standard value. But in the case of room temperature holding after 24 hours total plate counts exceeded standard value. In the case of room temperature holding the number of microbes increased according to the passage of time. As a reasult of food poisoning bacteria, it was negative in every test in sample against V. parahaemolyticus, Salmonella, S. aureus.

• Animal Bioscience
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• v.34 no.4
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• pp.584-593
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• 2021

Objective: The objective of this study was to compare fenugreek (FG) with alfalfa (Alf) in ruminal fermentation and methane (CH4) production in vitro. Methods: Whole-plant FG harvested at 11- and 15-wk and Alf harvested at early and mid-bloom maturities, alone or as 50:50 mixture of FG and Alf at the respective maturity, were assessed in a series of 48-h in vitro batch culture incubations. Total fermentation gas and methane gas production, dry matter (DM) disappearance, volatile fatty acids, microbial protein and 16S RNA gene copy numbers of total bacteria and methanogens were determined. Results: Compared to early bloom Alf, FG harvested at 11-wk exhibited higher (p<0.05) in vitro DM and neutral detergent fibre disappearance, but this difference was not observed between the mid-bloom Alf and 15-wk FG. Regardless plant maturity, in vitro ruminal fermentation of FG produced less (p<0.001) CH4 either on DM incubated or on DM disappeared basis than that of Alf during 48-h incubation. In vitro ruminal fermentation of FG yielded similar amount of total volatile fatty acids with higher (p<0.05) propionate percentage as compared to fermentation of Alf irrespective of plant maturity. Microbial protein synthesis was greater (p<0.001) with 11-wk FG than early bloom Alf as substrate and 16S RNA gene copies of total bacteria was higher (p<0.01) with 15-wk FG than mid-bloom Alf as substrate. Compared to mid-bloom Alf, 15-wk FG had lower (p<0.05 to 0.001) amount of 16S RNA methanogen gene copies in the whole culture during 48-h incubation. Conclusion: In comparison to Alf, FG emerges as a high quality forage that can not only improve rumen fermentation in vitro, but can also remarkably mitigate CH4 emissions likely due to being rich in saponins.

• Journal of Korean Biological Nursing Science
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• v.23 no.4
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• pp.339-346
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• 2021

Purpose: To determine the extent of environmental contamination and the effect of disinfection around patients with carbapenem-resistant Enterobacteriaceae (CRE) using adenosine triphosphate (ATP) measurements and microbial culture tests. Methods: The subjects of this study were 10 patients hospitalized in a single room due to CRE from April 13 to 21, 2021. One hundred and sixty samples were collected using cotton swabs from the patients' environment including the surface and drain of sinks and toilet seats before and after disinfection of the room after discharge. Twenty-one samples were collected from the nurses' personal digital assistants (PDAs), keyboards, and computer mice before disinfection. The relative light units (RLUs) and CRE colony-forming units (CFU) of 181 samples were measured using ATP test equipment and chrome agar plates, respectively. Results: The highest RLUs were measured at the sink drains before and after disinfection. Four CRE samples from the sink drains (2), sink surface (1), and toilet bowl (1) before disinfection were cultured. Based on the failure criteria (≥ 250 RLU/cm² and ≥ 1 CFU/100 cm²), 90 % and 50 % of the samples from the drain exceeded the failure criteria before and after disinfection, respectively. In the culture tests, CRE was not detected after disinfection. Conclusion: According to the RLU and CFU measurements of drain samples, disinfection was not effective. Thus, improvements in the disinfection methods of drains, as well as more efficient and systematic environmental decontamination and disinfection evaluation tools, are needed to accurately evaluate the effectiveness of disinfection in various places.

• Journal of the Korean Society of Food Culture
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• v.39 no.2
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• pp.119-126
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• 2024

This study was conducted to examine the microbiological quality indicators (total bacterial count and coliform count) and physicochemical quality indicators (pH, redness, volatile basic nitrogen [VBN] content) of meat according to various storage temperatures (-20~15℃) and packaging methods (wrap, vacuum). Based on these results, we proposed a safe consumption period. Redness, pH, and VBN content were not considered appropriate for setting the expiration date, as the redness and pH of the meat after spoilage were better than the standard values for both vacuum and wrap packaging (p<0.05). Additionally, the VBN content at 2 and 4℃ increased slightly (fresh level) until the initial time of spoilage (1.0×10⁶ colony-forming unit [CFU]/cm²) and then increased rapidly thereafter. Therefore, the results were not consistent with microbial spoilage. When the decay point was evaluated based on the presence of microorganisms, vacuum packaging extended the storage period approximately 2.5-fold when compared with wrap packaging, and the meat could be stored at 2 or 4℃ for 40 or 23 days, respectively. Therefore, to evaluate meat quality, microbial indicators should be considered first. The microbiological standards proposed in this study can be used for safety management during the distribution of meat. However, to ensure meat safety, additional investigations of appropriate indicators of freshness must be conducted.