• Food Science and Preservation
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• v.16 no.4
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• pp.573-578
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• 2009

Microbial contamination levels in a fresh-cut leafy vegetable processing plant were evaluated. Total plate counts of samples collected from the walls, equipment, and raw materials ranged from $10^1{\sim}10^2$ CFU/100 $cm^2$, $10^0{\sim}10^4$ CFU/100 $cm^2$, and $10^4{\sim}10^6$ CFU/g, respectively. No coliforms were detected on walls; however, equipment and raw materials contained coliforms in concentrations ranging from ND (not detected)to $10^2$ CFU/100 $cm^2$ and $10^4{\sim}10^5$ CFU/g, respectively. Additionally, total plate counts for falling and floating bacteria in the processing plant were $10^0{\sim}10^1$ CFU/plate and $10^1{\sim}10^3$ $CFU/m^3$, respectively. Pathogenic microorganisms such as Escherichia coli, Salmonella spp, Staphylococcus aureus, or Listeria monocytogenes were not detected on walls, equipment, or raw materials. Overall, the results of this study indicate that hygiene control in the fresh-cut processing plant should be improved.

• Food Science and Industry
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• v.50 no.2
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• pp.2-11
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• 2017

Packaging is the last defensive barrier that protects food products from insect infestation during storage. However, though packaging films are hermetically sealed, insects can still be attracted by strong olfactory cues and penetrate through packaging materials, resulting in contamination. Insect contamination may cause consumers to be repulsed by contaminated food products. Especially, it is well known that stored-product insects cause critical problems in the cereal industry by inducing quantitative and qualitative damages to the grain products. The contaminations are caused by insects' metabolic byproducts and body parts, consequentially caused customer repulsion. Therefore, it is necessary to repel and control insects. However, management systems for storage insects in food industry have been inadequate for many years. Synthetic pesticides has been widely used, but pesticides may accumulate in foods, causing acute and chronic symptoms in consumers. For this reason, there is a growing need for the development of natural insecticides that can replace synthetic pesticides. Thus, various reports about anti-insect packaging materials and strategies to repel insects were introduced in this study. Furthermore, we suggested new strategies to develop an insect-repelling active packaging materials which could be applied in the food packaging industry.

• Journal of Environmental Health Sciences
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• v.8 no.1
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• pp.25-30
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• 1982

The incidence of hospital infection has been seriously increased in the general hospital in recent years. This study was performed on hospital air and materials in a General Hospital in Seoul from June to December in 1980. The results were as follows: 1. Air sampling was done in multiple strategic areas by exposing standard petridishes for 5 minutes. There was a significant difference of airborne microbe between places. ($F._{99}$ = 3.2, p < 0.01). 2. The mean colony count was 8.6$\pm$6.2 colonies / plate / 5 minutes. 3. Gram stains of colony in air sampling were Gram (+) cocci 66.5%. Gram (+) rod 18.4%, Gram (-) cocci 1.3%, Gram (-) rod 8.7% Fungus 4.5%. 4. For the evaluation of sterilization of steam sterilizer and ethylene oxide gas sterilizer, biological monitoring were done by commercial spore strip. Positive culture was obtained in 2 out of 41 tests on 3 steam sterilizers, and in 3 out of 13 tests on ethylene oxide gas sterilizer. 5. Product sampling and culture were done for 2 kinds of disinfectants and 30 sets of various operation package or dressing materials. Positive culture was obtained in one disinfectants.

• Journal of Powder Materials
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• v.14 no.1 s.60
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• pp.32-37
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• 2007

Using spark plasma sintering process (SPS), Ti-6Al-4V alloy powders were successfully consolidated without any contamination happened due to reaction between the alloy powders and graphite mold. Variation of microstructure and mechanical properties were investigated as a function of SPS temperature and time. Compared with hot isostatic pressing (HIP), the sintering time and temperature could be lowered to be 10 min. and $900^{\circ}C$, respectively. At the SPS condition, UTS and elongation were about 890 MPa and 24%, respectively. Considering the density of 98.5% and elongation of 24%, further improving the tensile strength would obtain by increasing the SPS pressure.

• Journal of Soil and Groundwater Environment
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• v.16 no.6
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• pp.113-121
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• 2011

In this study, we suggested the management scheme of analyzing the national and oversea related policy against soil and groundwater contamination by radioactive materials due to nuclear accidents. In Korea, we need to remedy swiftly the contaminated land due to intensive land development demand. So, we need to develop more effective management scheme to recover actively the land contaminated by radioactive materials. We require to improve monitoring network, to expand media-specific monitoring system, to prepare management system for remediation of contaminated land, and to develop flow work for soil and groundwater remediation.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.11a
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• pp.165-170
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• 2009

Since artificial building materials and environmental contamination are getting worse recently, people has been interested in eco-friendly construction. In addition, the problems like Sick Building Syndrome are issued these days. In order to solve these problems, the reuse of building materials and the development of environment-friendly materials are urgently in demand. In this sense, Hwangtoh is in the limelight as the environment-friendly material, and broad studies on it have been in progress. However the reactivity of Hwangtoh is low, and without activation process it is very hard to use it as a building material. This study examined the usability of Hwangtoh as an environmental building material by experimenting the reactivity of inactivated Hwangtoh with Reaction Induction Material.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.422-423
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• 2006

Ultrasonic-milling of metal oxide nanopowders for the preparation of tungsten heavy alloys was investigated. Milling time was selected as a process variable. XRD results of metal oxide nanopowders ultrasonic-milled for 50 and 100h showed that mean crystallite size reduced with increasing milling time and there was no evidence of contamination or change of composition by impurities. It was found that nanocomposite powders reduced at $800^{\circ}C$ in $H_2$ atmosphere had a composition of 93.1W-4.9Ni-2.0Fe by EDX analysis. Hardness of sintered samples of 50 and 100h was 390 and 463 Hv, respectively, which corresponds to the hardness of commercial products.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.3
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• pp.189-192
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• 2009

Purpose: Autopipetting system is an efficient automated equipment pipetting patient samples and reagents for rapid and accurate test. However, it can cause carryover between high concentration sample and low concentration sample. We evaluated carryover contamination of TECAN freedom Evo 100 autopipetting system. Materials and Method: We studied carryover contamination of $\alpha$-fetoprotein (AFP) and carcinoembryonic antigen (CEA) test on TECAN freedom Evo 100 autopipetting system. Very low concentration control samples were pipetted for comparison to the contaminated very low concentration samples. Then, The contaminated very low concentration samples were pipetted following the high concentration samples were pipetted alternately. The difference of low concentration samples represents carryover. The target value to decide carryover was 1ppm (parts per million). Results: For AFP, the mean values of the uncontaminated control samples and the contaminated samples were less than 0.6 IU/mL (the l imit of detection (LoD)). Carryover did not occur even though the high concentration sample which value was 650000 IU/mL. For CEA, the values of the low concentration control samples and the contaminated samples were less than 0.2 ng/mL (LoD). Carryover did not occur even though the high concentration sample which value was 65,000 ng/mL. Conclusions: Sample carryover was not found on TECAN freedom Evo 100 autopipetting system for AFP, CEA. However, carryover is a potential problem with automated instruments and robotic pipetting systems. Therefore, Clinical laboratories must periodically verify carryover contamination for the accurate and confidential test results.

• Journal of Radiation Protection and Research
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• v.31 no.3
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• pp.141-148
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• 2006

Surveys of radioactive contamination were performed for imported foodstuffs in 2003. The following samples among imported foodstuffs were selected from markets and Korea Food and Drug Administration(KFDA); the imported samples from country associated with the Chernobyl nuclear accident, the samples produced around the nuclear power plants or nuclear tests, the foodstuffs reported as radioacitive contamination materials in foreign country. After pretreatments such as drying and homogenization, samples were analyzed. The $^{137}Cs$ radionuclide was only measured among the regulation radionuclides($^{137}Cs,\;^{134}Cs,\;^{131}I$) of food code. All foodstuffs except Inonotus Obliquus(Chaga mushooms) are less than 17.0 Bq/kg or below the minimum detectable activity(MDA). The activity concentrations of Chaga mushrooms from Russia ranged up to 131.25 Bq/ltg which is almost 35 % of the maximum permitted level of food code. The fraction of imported foodstuffs having meaningful radioactivity is small, however, the radioactive contamination survey of imported foodstuffs is still needed.

• Restorative Dentistry and Endodontics
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• v.27 no.1
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• pp.24-33
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• 2002

Leakage studies have been performed frequently, since a fluid-tight seal provided by various dental fill-ing materials has been considered clinically important. The leakage of the various root-end filling materials has been widely investigated mostly dye penetration method. These dye studies cannot offer any information about the quality of the seal of a test material over a long period of time The purpose of this study was to evaluate the microleakage of root end cavities in blood contamination filed amalgam, intermediate restorative material(IRM), light cured glass ionomer cement(GI) and mineral trioxide aggregate(MTA) by means of a modified fluid transport model. Fifty standard human root sections, each 5mm high and with a central pulp lumen of 3mm in diameter, were and filled with our commonly used or potential root end fill ing materials after they were contaminated with blood. At 24h. 72h, 1, 2, 4, 8, and 12 weeks after filling, leakage along these filling materials was determined under a low pressure of 10KPa(0.1atm) using a fluid transport model. The results were as follows : 1 MTA group showed a tendency of decreasing percent of gross leakage (20m1/day) in process of time, whereas the other materials showed a tendency of increasing in the process time. 2. At the all time interval, GI group leaked significantly less than amalgam group and IRM group (p＜0.05). 3. At the 4 weeks, the percentage of gross leakage in MTA group decreased to 0% thereafter, the low per-centage of gross leakage was maintained in MTA group until the end of the experiment, whereas the percentage in IRM group increased to 100% 4. At the 12 weeks, percentage of gross leakage was significantly low in MTA group(0%), comparison with GI group(40%), amalgam group(90%) and IRM group(100%), but there was no significant difference between latter two materials.