• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.1084-1087
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• 2002

The guard-ring type 3-terminal parallel plate electrodes proposed by ASTM D 150-81 and IEC 250 have been widely used for measurement of dielectric constants of solid dielectrics. However the method using this electrodes causes many uncertainty associated with the measurement errors of the diameter of the guarded electrode. the gap between guarded and guard-ring electrode. the distance of two active electrodes(the thickness of specimen), the roughness and contamination of surface of electrode and specimen. close adherence grade of electrode and specimen. In this paper. a new electrode system of cross capacitance type based on Thompson-Lampard theorem is designed and is employed for the measurement of dielectric constant. The results of simulation of guard-ring electrode and cross capacitance electrode using FEM program show that distance measurement between two electrodes in guard-ring electrode produces large uncertainty. on the other hand this effect in cross capacitance electrode is negligible. Furthermore. the air gap effects in the cross capacitance electrode is 5.6 times less sensitive than that in guard-ring electrode by assuming air gap of $50{\mu}m$.

• Journal of Food Hygiene and Safety
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• v.11 no.3
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• pp.177-187
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• 1996

Time-temperature relationship and microbiological quality were assessed and critical control points were identified through hazard analysis during the phases of production in two different packaged meals (Dosirak) manufacturing establishments (A, B:Kim Pab). Microbiological tests on foods, equipments and utensils were done according to standard procedures and included total plate count, coliforms and fecal coliforms. The results of the study are summarized as follows : time-temperature control management was needed because time-temperature abuse more than 8 hours at dangerous temperature zone (5-6$0^{\circ}C$) was observed from pre-preperation to distribution phase; Poor sanitary practices of employees were observed in hand washing and using disposable gloves; Microbiological analysis results of equirpments and utensils showed possible cross-contamination risks when foods were contacted with them; Kim Pab needed thorough quality control because it included various mixed ingredients of cooked and uncooked and had many apportunities of cross-contamination either by equipments or hands through whole production processes.

• Journal of the East Asian Society of Dietary Life
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• v.19 no.2
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• pp.256-264
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• 2009

This study investigated the status of foodservice operations and perceived performance of management for school dietitians in the Kyunggi area. According to the results, the perceived performance of dietitians for cooking management presented an overall average of $3.90{\pm}0.61$, and carrying out examination and preservation of food was the highest among all sectors with $4.83{\pm}0.49$. The area of cross contamination marked a total average of $4.15{\pm}0.67$, and the perceived performance of serving management was lower than the sanitary management of cooking and cross contamination with $3.64{\pm}0.75$. The most recognized cause on foodborne illness was food materials (44.6%). Sanitary level, the temperature of most foods, and the personal hygiene of workers were also important causes of foodborne illness.

• Journal of Nutrition and Health
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• v.37 no.8
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• pp.722-731
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• 2004

The objective of this study was to evaluate the microbiological quality of non-heat-processed foods for implementation of a HACCP (Hazard Analysis and Critical Control Point) system in day-care center foodservice operations. The evaluating points were microbial assessment of foods, utensils, and employee's hands during preparation, cooking, and serving. The temperature of non-heated food being served was also measured. Microbiological quality was assessed using 3 M Petrifilm/syp TM/ to measure total plate count and coliforms for food and utensils and Staphylococcus aureus for hands in five Gumi day-care centers. Results showed low microbiological quality of non-heated foods. This was probably due to contaminated raw ingredients and cross-contamination that occurred during preparation and cooking (e.g., unsatisfactory washing and disinfection of raw materials and utensils). These results suggest that it is essential to educate employees on good personal hygiene (hand washing) , prevention of cross-contamination through use of properly washed and sanitized utensils, and proper washing and disinfection of raw vegetables. Establishing Sanitation Standard Operating Procedures (SSOPs) are an essential part of any RACCP system in day-care center foodservice operations.

• Food Engineering Progress
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• v.22 no.4
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• pp.283-294
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• 2018

Food allergy is a chronic disease that is increasing all over the world, and it can even lead to a loss of life. To prevent any incidents resulting from food allergies, most countries keep strengthening their food allergen labeling requirements domestically and internationally, with a constant monitoring system against undeclared allergens and recall of offending products. In order to avoid economic losses to industry and damages to international relations from undeclared allergens, it is necessary to confirm each country's regulatory policy on food allergen labeling prior to exportation. Another required action is to try for a reduction of the cross-contamination risk of the allergens during manufacturing and storage, which should be verified by using an accurate and reliable analysis of food allergens. This paper is intended to provide an introduction to the regulation of food allergen labeling by country, allergen management methods to avoid cross-contamination, and allergen detection methods using ELISA, PCR, and LC/MS. Changes of allergenicity during thermal or nonthermal processing also will be investigated in our review. This review will be helpful for the food industry to better understand patients suffering from food allergies and to manage food allergens in food manufacturing.

• Food Science of Animal Resources
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• v.41 no.1
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• pp.135-144
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• 2021

This study determined the antibiotic resistance patterns of Escherichia coli and Staphylococcus aureus from the raw meat and feces of three game species from three different farms across South Africa. The Kirby-Bauer disk diffusion method was used according to the Clinical and Laboratory Standards Institute 2018 guidelines. E. coli was tested against ampicillin, ceftazidime, chloramphenicol, streptomycin, sulphafurazole and tetracycline. S. aureus was tested against tetracycline, erthromycin, vancomycin, penicillin, oxacillin and cefoxitin. There were no significant differences in the E. coli antibiotic resistance profiles between the meat and fecal samples (except towards ceftazidime where 5% of the meat isolates were resistant and 0% of the fecal isolates). The S. aureus meat isolates showed high (75%) resistance towards penicillin and on average, 13% were resistant to oxacillin/ cefoxitin, indicating methicillin resistance. The results from this study indicate that there is incidence of antibiotic resistant bacteria from the feces and meat of wildlife species across South Africa, suggesting that cross contamination of the meat occurred during slaughter by antibiotic resistant bacteria from the abattoir personnel or equipment and or from carcass fecal matter. In addition, the results highlight the importance of food safety and hygiene procedures during slaughter to prevent cross-contamination of antibiotic resistant bacteria, as well as pathogens, onto raw meat.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.230-230
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• 2013

In amorphous or microcrystalline thin-film silicon solar cells, p-i-n structure is used instead of p/n junction structure as in wafer-based Si solar cells. Hence, these p-i-n structured solar cells inevitably consist of many interfaces and the cell efficiency critically depends on the effective control of these interfaces. In this study, in-situ plasma treatment process of the interfaces was developed to improve the efficiency of a-Si:H solar cell. The p-i-n cell was deposited using a single-chamber VHF-PECVD system, which was driven by a pulsed-RF generator at 80 MHz. In order to solve the cross-contamination problem of p-i layer, high RF power was applied without supplying SiH4 gas after p-layer deposition, which effectively cleaned B contamination inside chamber wall from p-layer deposition. In addition to the p-i interface control, various interface control techniques such as thin layer of TiO2 deposition to prevent H2 plasma reduction of FTO layer, multiple applications of thin i-layer deposition and H2 plasma treatment, H2 plasma treatment of i-layer prior to n-layer deposition, etc. were developed. In order to reduce the reflection at the air-glass interface, anti-reflective SiO2 coating was also adopted. The initial solar cell efficiency over 11% could be achieved for test cell area of 0.2 $cm^2$.

• The Korean Journal of Food & Health Convergence
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• v.5 no.3
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• pp.35-40
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• 2019

In this study, general bacterial counts and coliform counts, which are hygienic indicator microorganisms, were tested for candy, chocolate, and jelly which are easily available and enjoyed around. After dropping each sample on the desk, indoors, and outdoors, it is immediately collected, or washed and collected to confirm the myth of the 3-second rule. Immediately after removing the wrapping paper, each sample was dropped on the desk, indoors, and outdoors, and after 3 seconds from the moment of contact with the surface, and then collected in a sample bag using sterilized sanitary gloves. After the same operation, each sample was rinsed for 5 seconds using sterilized sanitary gloves and sterilized distilled water, and then collected in a sample bag. The number of bacteria detected in non-washing candies was 41 CFU/g at outdoor and the number of bacteria detected in non-washing chocolate was 76 CFU/g at outdoor. The number of bacteria detected in non-washing jellies was 79 CFU/g at outdoor. Coliform group was not detected in all samples. This showed good results at the level of m = 10,000 or less, which is an allowable value suggested in the Food Code. Also, effect of washing on contaminated food was confirmed. This result is remarkably low compared with the microorganism specimens shown in Food Code, and it is confirmed that contamination occurs but not high value. Therefore, the myth of the 3-second rule is true compared to the figures based on Food Code. However, it showed the characteristics of bacteria that could survive and cross-contaminate on dry food surfaces and emphasized the importance of hygiene through food contact to unsanitary surfaces to minimize the risk of food poisoning.

• Journal of dental hygiene science
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• v.23 no.4
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• pp.343-350
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• 2023

Background: Digital panoramic dental X-ray equipment (PDX) is frequently used by patients and dental workers for diagnosis and examination in dental institutions; however, infection control has not been properly implemented. Therefore, in this study, we aimed to systematically review the potential risk of cross-infection in the dental environment by investigating the contamination level of general aerobic bacteria and Staphylococcus aureus, which are important in hospital infections, in PDX areas that people mainly contact. Methods: This survey was conducted from March to May 2023 and covered one general hospital, three dental hospitals, and nine dental clinics equipped with PDX. Bacteria samples were collected from the left-handle, right-handle, forehead support, and head side support as the patient's contact areas, as well as the X-ray exposure switch and left-click mouse button as the dental hygienist's contact areas of the PDX. The collected bacteria were spread on Petrifilm, and colonies formed after 48 hours of culture were counted. Results: General aerobic bacteria and S. aureus were detected in all areas investigated. Significant differences in bacterial counts between different regions of the PDX were observed in both groups (p<0.001). The detection rates of general aerobic bacteria (p<0.001) and S. aureus (p<0.001) were significantly higher in the contact areas of patients than those of dental hygienists. A positive correlation was observed between the forehead and the temple region in terms of general aerobic bacteria and S. aureus detection (r=1) (p<0.01). Conclusion: Taken together, the presence of many bacteria, including S. aureus, detected in PDX indicates that PDX has a potential cross-infection risk. Our results therefore highlight the need for the development of appropriate disinfection protocols for reusable medical devices such as PDX and periodic infection prevention training for hospital-related workers, including dental hygienists.

• Journal of The Korea Institute of Healthcare Architecture
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• v.24 no.1
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• pp.51-58
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• 2018

Purpose: In this study, through the comparison of the pressure fluctuation and air exchange volume in negative isolation room according to the type of the door and door opening/closing speeds, which is one of the main factors causing the cross contamination of the negative pressure isolation room, establishes standard operating procedures to prevent cross contamination in high risk infectious diseases and isolation room design. Methods: In this study, the air flow each of the room is analyzed using ANASYS CFX CODE for flow analysis. In addition, the grid configuration of the door is constructed by applying Immersed Solid Methods. Results: The pressure fluctuation due to the opening and closing of the hinged door was very large when the moment of the hinged door opened and closed. Especially, at the moment when the door is closed, a pressure reversal phenomenon occurs in which the pressure in the isolation room is larger than the pressure in the anteroom. On the other hand, the pressure fluctuation due to the opening and closing of the sliding door appeared only when the door was closed, but the pressure reversal phenomenon not occurred at the moment when the sliding door was closed, unlike the hinged door. As the opening and closing speed of the hinged door increases, the air exchange volume is increased. However, as the opening and closing speed of the sliding door is decreased, the air exchange volume is increased. Implications: According to the results of this study, it can be concluded that the pressure fluctuation due to the opening and closing of the hinged door is greater than the pressure fluctuation due to the opening and closing of the sliding door. In addition, it can be confirmed that the pressure reversal phenomenon, which may cause to reduce the containment effect in negative pressure isolation room, is caused by the closing of the hinged door. Therefore, it is recommended to install a sliding door to maintain a stable differential pressure in the negative isolation room. Also, as the opening and closing speed of the hinged door is slower and the opening and closing speed of the sliding door is faster, the possibility of cross contamination of the room can be reduced. It is therefore necessary to establish standard operating procedures for negative isolation room for door opening and closing speeds.