• Environmental Engineering Research
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• v.21 no.1
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• pp.52-57
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• 2016

Sediment is a useful natural source but deteriorated continually by anthropogenic and industrial sources. Therefore, it is imperative to search a suitable method for improving or restoring sediment quality. Sediment has been tested to identify the effects of some external agents on a polluted area for 28 days. Chemical analysis and total viable counts (TVC) test have been conducted for 4 days interval to assess their performance. The analyses of chemical oxygen demand (COD), acid volatile sulfide (AVS), total phosphorous (T-P), total nitrogen (T-N) indicate that the chemical agents was more efficient to improve sediment quality whereas the microbial agent was more efficient for nutrient releasing from sediment. Oxygen releasing property of the chemical agent was thought to be providing with more congenial environment for the higher growth of the bacterial community than the direct application of microbial agents.

• Journal of Korean Society on Water Environment
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• v.29 no.6
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• pp.808-812
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• 2013

A new type of microbial fuel cell (MFC) with anaerobic membrane filter was designed to produce bioelectricity and to treat domestic sewage at relatively high organic loading rate (OLR) of $6.25kgCOD/m^3/day$ and short hydraulic retention time (HRT) of 1.9 h. A following aeration system was applied to ensure effluent water quality in continuous operation. Glucose was supplemented to increase the influent concentration of domestic sewage. Influent substrate of 95% was removed via the MFC and following aeration system and the corresponding maximum power density was $25.6mW/m^3$. External resistor of $200{\Omega}$ and air-cathode system contributed better MFC performance comparing to $2000{\Omega}$ and dissolved oxygen as a catholyte.

• Korean journal of food and cookery science
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• v.22 no.4 s.94
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• pp.504-513
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• 2006

This study was performed to provide basic data for the operation of a safer cook-chill system by comparing and evaluating the quality of food prepared using the sous vide cook-chill(SVCC) and cook-chill(CC) systems, according to the preparation methods and storage temperature. When the effects of preparation methods and storage temperatures on the physicochemical and microbial qualities were analyzed, the following results were obtained. Firstly, the microbial risk was reduced and the food was raised when danhopark tzeam were prepared with SVCC compared with CC in which changes in pH and Aw and moisture content loss were less than with SVCC. Secondly, the storage period tested in this study was limited to only 10 days, which prevented any significant difference from being seen at 3$^{\circ}$C and 10$^{\circ}$C in the degradation of food quality when SVCC and CC were compared. However, the overall quality and safety as indicated by the physicochemical and microbial qualities at 10$^{\circ}$C were relatively low for and with CC, suggesting that SVCC is a more effective method, probably because vacuum packing eliminates oxygen in the food, thereby inhibiting bacterial growth.

• Food Science and Preservation
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• v.11 no.1
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• pp.7-11
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• 2004

To examine the effect of storage condition on the quality and microbiological change of strawberry “Minyubong”, the rate of weight loss, decay rate, pH and titratable acidity, and microbial (total bacterial count, mold and yeast) changes were determined during storage. Strawberry fruits were packaged with low-density polyethylene (LDPE). Strawberries were then stored at 4$^{\circ}C$ and 20$^{\circ}C$, respectively. LDPE package was effective on the decrease of decay rate of strawberry as well as the rate of weight loss, compared with the non-packaged. Microbial changes of strawberry stored at 4$^{\circ}C$ and 20$^{\circ}C$ were monitored during storage. Packaging affected the microbial change, resulting in retarding the growth of total bacteria as well as mold and yeast, compared with the non-packaged, regardless of storage temperature. These results indicate that storage of strawberry fruits wrapped with LDPE at 4'C should be recommended in terms of quality as well as its shelf-life.

• Food Science of Animal Resources
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• v.44 no.2
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• pp.372-389
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• 2024

This study investigated the efficacy of ultraviolet-C (UV-C) irradiation in enhancing the quality of raw bovine milk by targeting microbial populations and lipid peroxidation, both of which are key factors in milk spoilage. We categorized the raw milk samples into three groups based on initial bacterial load: low (<3 Log 10 CFU/mL), medium (3-4 Log 10 CFU/mL), and high (>4 Log 10 CFU/mL). Using a 144 W thin-film UV-C reactor, we treated the milk with a flow rate of 3 L/min. We measured the bacterial count including standard plate count, coliform count, coagulase-negative staphylococci count, and lactic acid bacteria count and lipid peroxidation (via thiobarbituric acid reactive substances assay) pre- and post-treatment. Our results show that UV-C treatment significantly reduced bacterial counts, with the most notable reductions observed in high and medium initial load samples (>4 and 3-4 Log 10 CFU/mL, respectively). The treatment was particularly effective against coliforms, showing higher reduction efficiency compared to coagulase-negative staphylococci and lactic acid bacteria. Notably, lipid peroxidation in UV-C treated milk was significantly lower than in pasteurized or untreated milk, even after 72 hours. These findings demonstrate the potential of UV-C irradiation as a pre-treatment method for raw milk, offering substantial reduction in microbial content and prevention of lipid peroxidation, thereby enhancing milk quality.

• BMB Reports
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• v.45 no.7
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• pp.377-389
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• 2012

Food fermentations have enhanced human health since the dawn of time and remain a prevalent means of food processing and preservation. Due to their cultural and nutritional importance, many of these foods have been studied in detail using molecular tools, leading to enhancements in quality and safety. Furthermore, recent advances in high-throughput sequencing technology are revolutionizing the study of food microbial ecology, deepening insight into complex fermentation systems. This review provides insight into novel applications of select molecular techniques, particularly next-generation sequencing technology, for analysis of microbial communities in fermented foods. We present a guideline for integrated molecular analysis of food microbial ecology and a starting point for implementing next-generation analysis of food systems.

• Korean Journal of Poultry Science
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• v.27 no.1
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• pp.25-30
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• 2000

Present study was conducted to investigate effects of microbial phytase in laying hen diets on utilization of non-phytate phosphorus(NPP) whose levels were adjusted to be adequate or lower than that of NRC requirements. Birds of control roup were fed a diet containing 0.275% NPP and 3.4% Ca, satisfying the NRC(1994) feeding standard. bird on T1, T2 and T3 were allowed to eat diets containing NPP at 100, 80 and 60%, respectively, of Control group, and 4.0% Ca level along with a microbial phytase added at a level of 300 DPU. Three hundred and sixty, ISA Brown layers, 23-week-old, divided into four treatment groups with three replications per treatment and 30 layers per replication were fed the diets for 12 weeks. Levels of feed intake were not different among the groups, The egg mass/feed intake ratio appeared better in T2 group by about 8%, though without a statistical significance, compared to that of control. Egg production fate tended to be improved over the control group by feeding the 100%(T1) and 80%(T2) NPP diets added with phytase, with a significant difference for T2(p<0.05). Mean egg weight and egg shell quality, measured by breaking strength and thickness of the egg shell, of the T2 group tended to show numerically better, without a significance than those of control. Furthermore, birds of the T2 group showed higher calcium and phosphorus contents in tibia by about 9%(p<0.05) than the control. Overall performances of birds in T1 appeared better than those of control, but tended to be lower than those of the T2. The birds in T3 performed similar to the those of the other dietary groups except the relatively low tibia calcium level. In conclusion, the results of this study suggest that supplementation of microbial phytase at a level of 300 DPU was effective to spare about 20% of NPP in laying hen diets without any adverse effects on production performances and bone quality.

• Preventive Nutrition and Food Science
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• v.13 no.4
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• pp.348-353
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• 2008

Aerobic bacterial growth on Korean pan.fried meat patties as a primary quality deterioration factor was modeled as a function of temperature to estimate microbial spoilage on a real.time basis under dynamic storage conditions. Bacteria counts in the stretch.wrapped foods held at constant temperatures of 0, 5, 10 and $15^{\circ}C$ were measured throughout storage. The bootstrapping method was applied to generate many resampled data sets of mean microbial counts, which were then used to estimate the parameters of the microbial growth model of Baranyi & Roberts in the form of differential equations. The temperature functions of the primary model parameters were set up with confidence limits. Incorporating the temperature dependent parameters into the differential equations of bacterial growth could produce predictions closely representing the experimental data under constant and fluctuating temperature conditions.

• Journal of Environmental Health Sciences
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• v.27 no.2
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• pp.1-9
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• 2001

This study was carried out to investigate the microbial characteristics of the urban air pollution in the subway stations, streets, department stores, wholesale markets, underground shopping centers, buildings, parks, houses and apartments in the Seoul and the suburbs area. Total cell count, total mold count and the presence of opportunistic pathogens(Streptococcus pneumoniae, Klebsiella pneumoniae, Aspergillus spp., Penicillium spp.) were evaluated determine the microbial air quality. Total cell count and mold count of indoor air in the houses and apartments were 2.9$\times$10$^2$-6.3$\times$10$^2$cfu/㎥ and 60-1.8$\times$10$^2$cfu/㎥, respectively, and the department stores and wholesale markets had much lower cell count than the houses and apartments. Ground level of commercial stations were 2.6 fold higher than the general subway stations, and Apergillus spp. and Penicillium spp. which could cause the bronchus and lung diseases were detected 17 sampling site out of 45. Dust were collected from the commercial facilities and houses, and total cell and mold count of the dust were 4.3$\times$10$^3$-1.7$\times$10$^{6}$ cfu/g and 2.3$\times$10$^3$-6.5 $\times$10$^4$cfu/g, respectively. Therefore the dust might be one of the main reservoir of microorganims.

• Preventive Nutrition and Food Science
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• v.17 no.2
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• pp.172-176
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• 2012

Doenjang is a traditional Korean fermented soybean product that provides a major source of protein. In this study, a total of 18 different home-made doenjang samples were examined for the presence of foodborne pathogens and the total aflatoxin levels. Using an enzyme-linked immunosorbent assay to assess microbial quality and potential public health risk, we showed that total coliform levels in the doenjang samples ranged from 0 to $4.43{\pm}2.32{\times}10^6\;CFU/g$, and the maximum limit of Bacillus cereus was $4.67{\pm}2.0{\times}10^5\;CFU/g$. However, other foodborne pathogens, such as Staphylococcus aureus, Escherichia coli O157:H7 and Salmonella spp., were not detected among the tested samples. One of the samples (S3) showed a maximum limit of $42.2{\pm}9.1\;{\mu}g/kg$ for aflatoxin levels, which was above the safety limit allowed by the Codex Alimentarius Commission (CAC) regulatory agency. Further research is necessary to determine whether and how doenjang safety can be improved via elimination/reduction of microbial contamination during fermentation and storage or using microbial starter cultures for its fermentation.