• Title/Summary/Keyword: microbial model

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Effects of Combined Treatment of Aqueous Chlorine Dioxide and Fumaric Acid on the Microbial Growth in Fresh-cut Paprika (Capsicum annuum L.) (신선편이 파프리카의 미생물 생장에 있어서 이산화염소수와 푸마르산 병합처리의 효과)

  • Jung, Seung-Hun;Park, Seung-Jong;Chun, Ho-Hyun;Song, Kyung Bin
    • Journal of Applied Biological Chemistry
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    • v.57 no.1
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    • pp.83-87
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    • 2014
  • The effects of combined treatment of aqueous chlorine dioxide ($ClO_2$) and fumaric acid on the microbial growth in fresh-cut paprika were investigated. After the combined treatment, the populations of total aerobic bacteria and inoculated Listeria monocytogenes in the paprika sample were reduced by 0.82 and 1.21 log CFU/g, respectively, compared to those of the control. In addition, after 10 d of storage at $10^{\circ}C$, the populations were decreased by 1.21 and 2.10 log CFU/g, respectively. The predictive model for the populations of total aerobic bacteria and L. monocytogenes in the paprika was applied during storage. The prediction equation using Gompertz model was appropriate, based on the statistical analysis such as accuracy factor and bias factor. These results suggest that the combined treatment of aqueous $ClO_2$ and fumaric acid can be an effective technology for microbial decontamination and it can improve microbial safety by decreasing maximum growth rate and increasing lag time of bacteria in the fresh-cut paprika.

Microbial Risk Assessment of Non-Enterohemorrhagic Escherichia coli in Natural and Processed Cheeses in Korea

  • Kim, Kyungmi;Lee, Heeyoung;Lee, Soomin;Kim, Sejeong;Lee, Jeeyeon;Ha, Jimyeong;Yoon, Yohan
    • Food Science of Animal Resources
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    • v.37 no.4
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    • pp.579-592
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    • 2017
  • This study assessed the quantitative microbial risk of non-enterohemorrhagic Escherichia coli (EHEC). For hazard identification, hazards of non-EHEC E. coli in natural and processed cheeses were identified by research papers. Regarding exposure assessment, non-EHEC E. coli cell counts in cheese were enumerated, and the developed predictive models were used to describe the fates of non-EHEC E. coli strains in cheese during distribution and storage. In addition, data on the amounts and frequency of cheese consumption were collected from the research report of the Ministry of Food and Drug Safety. For hazard characterization, a doseresponse model for non-EHEC E. coli was used. Using the collected data, simulation models were constructed, using software @RISK to calculate the risk of illness per person per day. Non-EHEC E. coli cells in natural- (n=90) and processed-cheese samples (n=308) from factories and markets were not detected. Thus, we estimated the initial levels of contamination by Uniform distribution ${\times}$ Beta distribution, and the levels were -2.35 and -2.73 Log CFU/g for natural and processed cheese, respectively. The proposed predictive models described properly the fates of non-EHEC E. coli during distribution and storage of cheese. For hazard characterization, we used the Beta-Poisson model (${\alpha}=2.21{\times}10^{-1}$, $N_{50}=6.85{\times}10^7$). The results of risk characterization for non-EHEC E. coli in natural and processed cheese were $1.36{\times}10^{-7}$ and $2.12{\times}10^{-10}$ (the mean probability of illness per person per day), respectively. These results indicate that the risk of non-EHEC E. coli foodborne illness can be considered low in present conditions.

Immunostimulatory Effects of Blueberry Yeast Fermented Powder Against Cyclophosphamide-induced Immunosuppressed Model (Cyclophosphamide에 의한 면역저하 동물모델에서 블루베리 효모 발효 분말의 면역증강 효과)

  • Jeong, Do Youn;Yang, Hee Jong;Jeong, Su Ji;Kim, Min Guk;Yun, Chi Young;Lee, Hak Yong;Lee, Yang Hee;Shin, Dong Yeop;Yang, Yea gin;Lee, Hae Seong;Park, Young Mi
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.33 no.1
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    • pp.48-55
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    • 2019
  • Current studies have been reported that fruits such as berries may contain both antioxidant and antitumor polyphenols that may be important in this regard. We investigated the immunostimulatory effect of fermented blueberry (Vaccinium corymbosum L.) on cyclophosphamide-induced immunosuppression in animal model. Rats were administered blueberry yeast fermented powder (BYFP) at doses 30, 100, and 300 mg/kg for 4 weeks after cyclophosphamide (Cy) treatment, respectively. The immunomodulatory effect of BYFP were measured both in vitro and in vivo, and the changes of blood components were also analyzed. We found that BYFP recovered immunosuppression-mediated decreased liver, spleen, and thymus weights as well as up regulation of white blood cell, lymphocyte, and neutrophil in blood. Moreover, BYFP up-regulated IL-2, TNF-${\alpha}$, and IFN-${\gamma}$ pro-inflammatory cytokine production compared to immune suppressed control group, respectively. According to histological studies, BYFP regenerated significantly on Cy-mediated injured spleen at the high doses (BYFP 300) comparison with Cy-treated groups (immunosuppression). Collectively, these findings suggest that BYFP may have the potential as a dietary immunostimulatory agent.

Effect of Faba Bean Isolate and Microbial Transglutaminase on Rheological Properties of Pork Myofibrillar Protein Gel and Physicochemical and Textural Properties of Reduced-Salt, Low-Fat Pork Model Sausages

  • Geon Ho Kim;Koo Bok Chin
    • Food Science of Animal Resources
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    • v.44 no.3
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    • pp.586-606
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    • 2024
  • The study was performed to determine the effect of faba bean protein isolate (FBPI) alone or in combination with microbial transglutaminase (MTG) on the rheological properties of pork myofibrillar protein gel (MPG), and physiochemical and textural properties of reduced-salt, low-fat pork model sausages (LFMSs). The cooking yields of MPGs with MTG or FBPI alone decreased and increased, respectively. However, the combination of FBPI and MTG was similar to the control (CTL) without FBPI or MTG. Gel strength values of MPG added with both FBPI and MTG were higher than treatments with FBPI or MTG alone. The hydrophobicity values of CTL were lower than those of MPG with FBPI alone, whereas the addition of MTG decreased the hydrophobicity of MPGs. The incorporation of FBPI alone or in combination with MTG decreased sulfhydryl groups (p<0.05). Shear stress values of MPGs with MTG tended to be higher than those of non-MTG treatments at all shear rates, and the addition of FBPI into MPGs increased shear stress values. Reduced-salt (1.0%) LFMSs with FBPI alone or combined with MTG had both lower cooking loss and expressible moisture values than those of CTL and similar values to the reference sample (REF, 1.5% salt). Textural properties of reduced-salt LFMSs with FBPI or MTG were similar to those of REF. These results demonstrated that the combination of FBPI and MTG could improve the water binding capacity and textural properties of pork MPGs and LFMSs and might be suitable for application in the development of healthier meat products.

Quantitative Microbial Risk Assessment for Campylobacter jejuni in Ground Meat Products in Korea

  • Lee, Jeeyeon;Lee, Heeyoung;Lee, Soomin;Kim, Sejeong;Ha, Jimyeong;Choi, Yukyung;Oh, Hyemin;Kim, Yujin;Lee, Yewon;Yoon, Ki-Sun;Seo, Kunho;Yoon, Yohan
    • Food Science of Animal Resources
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    • v.39 no.4
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    • pp.565-575
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    • 2019
  • This study evaluated Campylobacter jejuni risk in ground meat products. The C. jejuni prevalence in ground meat products was investigated. To develop the predictive model, survival data of C. jejuni were collected at $4^{\circ}C-30^{\circ}C$ during storage, and the data were fitted using the Weibull model. In addition, the storage temperature and time of ground meat products were investigated during distribution. The consumption amount and frequency of ground meat products were investigated by interviewing 1,500 adults. The prevalence, temperature, time, and consumption data were analyzed by @RISK to generate probabilistic distributions. In 224 samples of ground meat products, there were no C. jejuni-contaminated samples. A scenario with a series of probabilistic distributions, a predictive model and a dose-response model was prepared to calculate the probability of illness, and it showed that the probability of foodborne illness caused by C. jejuni per person per day from ground meat products was $5.68{\times}10^{-10}$, which can be considered low risk.

가스상 TCE 처리를 위한 추출막 생물반응기의 수학적 모사

  • Kim, Ji-Seok;Kim, Gwan-Su;Jang, Deok-Jin
    • 한국생물공학회:학술대회논문집
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    • 2000.04a
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    • pp.370-373
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    • 2000
  • In this work, an extractive membrane bioreactor containing coulture broth of Burkholderia cepacia G4 PR1 constitutively expressing the TCE-degrading enzyme, tolune-ortho-monooxygenase(TOM), was used for the degradation of TCE. The membrane bioreactor operates by seperating the TCE-containing waste gas from the aerated biomedium, by which the air-stripping of TCE without degradation was overcome that could occur in conventional aerobic biological treatments of TCE-contaminated waste gases. This was achieved by a silicone rubber membrane which was coiled around a perspex draft tube. TCE from the gas phase diffuses across the silicone rubber membrane into microbial culture broth that was continuously fed from a separate aerobic CSTR. Therefore, TCE degradation occured without the TCE being directly exposed to the aerating gas stream. Of the TCE supplied to the membrane bioreactor, 72.6% was biodegraded during the operation of this system. To construct a mathematical model for this system, parameters describing microbial growth kinetics on TCE were determined using a CSTR bioreactor. Else parameters used for numerical simulation were determined from either indepedent experiments or values reported in the literature. The model was compared with the experimental data, and there was a good agreement between the predicted and the measured TCE concentrations in the system. To achieve a higher treatment efficiency, various operating conditions were simulated as well.

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Applications of Metabolic Modeling to Drive Bioprocess Development for the Production of Value-added Chemicals

  • Mahadevan, Radhakrishnan;Burgard, Anthony P.;Famili, Iman;Dien, Steve Van;Schilling, Christophe H.
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.10 no.5
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    • pp.408-417
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    • 2005
  • Increasing numbers of value added chemicals are being produced using microbial fermentation strategies. Computational modeling and simulation of microbial metabolism is rapidly becoming an enabling technology that is driving a new paradigm to accelerate the bioprocess development cycle. In particular, constraint-based modeling and the development of genome-scale models of industrial microbes are finding increasing utility across many phases of the bioprocess development workflow. Herein, we review and discuss the requirements and trends in the industrial application of this technology as we build toward integrated computational/experimental platforms for bioprocess engineering. Specifically we cover the following topics: (1) genome-scale models as genetically and biochemically consistent representations of metabolic networks; (2) the ability of these models to predict, assess, and interpret metabolic physiology and flux states of metabolism; (3) the model-guided integrative analysis of high throughput 'omics' data; (4) the reconciliation and analysis of on- and off-line fermentation data as well as flux tracing data; (5) model-aided strain design strategies and the integration of calculated biotransformation routes; and (6) control and optimization of the fermentation processes. Collectively, constraint-based modeling strategies are impacting the iterative characterization of metabolic flux states throughout the bioprocess development cycle, while also driving metabolic engineering strategies and fermentation optimization.

Estimating variation in the microbiological quality of seasoned soybean sprouts using probability model (확률 모형을 이용한 콩나물 무침의 미생물적 품질 변화 예측)

  • Park, Jin-Pyo
    • Journal of the Korean Data and Information Science Society
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    • v.21 no.5
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    • pp.909-916
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    • 2010
  • This study aims to establish storage stability conditions for cook-chilled korean ethenic foods. In order to achieve this aims, we establish a probability model of microbial counts of cook-chilled korean side dishes product-seasoned soybean sprouts. And seasoned soybean sprouts were stored during 1 to 5 days under constant temperature conditions at 0, 5, 10 and $15^{\circ}C$. Next we find confidence intervals for variation in the microbiological quality of seasoned soybean sprouts.

The Recovery of Heavy Metals Using Encapsulated Microbial Cells

  • Park, Joong-Kon;Jin, Yong-Biao;Park, Hyung-Woo
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.2 no.2
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    • pp.132-135
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    • 1997
  • We prepared capsules containing Saccharomyces cerevisiae and Zoogloea ramigera cells for the removal of lead(II) and cadmium ions. Microbial cells were encapsulated and cultured in the growth medium. The S.cerevisiae cells grown in the capule did not leak through the capsule membrane. The dried cell density reached to 250 g/l on the basis of the inner volume of the 2.0 mm diameter capsule after 36 hour cultivation. The dry whole cell expolymer density of encapsulated Z.ramigera reached to 200 g/L. The capsule was crosslinked with triethylene tetramine and glutaric dialdehyde solutions. The cadmium uptake of encapsulated whole cell expolymer of Z.ramigera was 55mg Cd/g biosorbent. The adsorption line followed well Langmuir isotherm. The lead uptake of the encapsulated S. cerevisiae was about 30 mg Pb/g biomass. The optimum pH of the lead uptake using encapsulated S. cerevisiae was found to be 6. Freundlich model showed a little better fit to the adsorption data than Langmuir model 95 percent of the lead adsorbed on the encapsulated biosorbents was desorbed by the 1 M HCl solution. The capsule was reused 50 batches without loosing the metal uptake capacity. And the mechanical strength of the crosslinked capsule was retained after 50 trials.

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Simulation for the Flowing Water Purification with Spring Shape Inside Chamber (챔버 내측에 스프링형상을 갖는 유수형 자외선 살균장치 시뮬레이션)

  • Jung, Byung-Gyeon;Jeong, Byeong-Ho;Lee, Jin-Jong;Jung, Byeong-Soo
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.59 no.4
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    • pp.411-416
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    • 2010
  • Interest in application of ultraviolet light technology for primary disinfection of potable water in drinking water treatment plants has increased significantly in recent years. The efficacy of disinfection processes in water purification systems is governed by several key factors, including reactor hydraulics, disinfectant chemistry, and microbial inactivation kinetics. The objective of this work was to develop a computational fluid dynamics(CFD) model to predict velocity fields, mass transport, chlorine decay, and microbial inactivation in a continuous flow reactor. In this paper, It describe the how to design optimal UV disinfection device for ground water, BWT and rainwater. Spring shape instrument silver coated located in inner side of disinfection chamber. It make lead the active flowing movement target water and maximize disinfection performance. To search the optimal design method, it was performed computer simulation with 3D-CFD discrete ordinates model and manufactured prototype. Using proposed design method, performed simulation and proved satisfied performance.