• Korean Journal of Microbiology
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• v.45 no.4
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• pp.346-353
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• 2009

Viral, bacterial, and fungal infection can be transmitted from donor to recipient via transplantation of human amniotic membrane. Therefore human amniotic membrane for transplantation should be disinfected and sterilized before use. The purpose of this study was to examine the efficacy of the disinfection process and sterilization processes used at human tissue bank in the inactivation of viruses, bacteria, and fungi. A variety of experimental model viruses, bacteria, and fungus for human pathogens, including the human immunodeficiency virus type 1 (HIV-1), bovine herpes virus (BHV), bovine viral diarrhoea virus (BVDV), hepatitis A virus (HAV), porcine parvovirus (PPV), Escherichia coli, Bacillus subtilis, and Candida albicans were all selected for this study. Enveloped viruses such as HIV-1, BHV, and BVDV were effectively inactivated to undetectable levels by 70% ethanol treatment, gamma irradiation process, and ethylene oxide (EO) gas sterilization process. Also non-enveloped viruses such as HAV and PPV were effectively inactivated to undetectable levels by gamma irradiation and EO gas treatment. However HAV and PPV showed high resistance to 70% ethanol treatment. E. coli and C. albicans were effectively inactivated to undetectable levels by 70% ethanol treatment, gamma irradiation process, and EO gas treatment. Also B. subtilis was effectively inactivated to undetectable levels by gamma irradiation process and EO gas treatment. However it showed high resistance to 70% ethanol treatment.

• 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.

• Toxicological Research
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• v.17 no.1
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• pp.17-25
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• 2001

Korean ginseng products have been fumigated with ethylene oxide (EO) for sterilization and prolongation of storage periods. However, there had been controversies indicating that consumption of EO treated foods might cause harmful effects in human. In Korea, the use EO gas for sterilization of food was banned in 1991. Since then, irradiation technique has been developed as an alternative. This study was carried out to evaluate the safety of irradiated ginseng on peri- and postnatal developmental toxicity in rats. Either EO gas fumigated or gamma-irradiated ginseng was administered to pregnant Wistar rats by oral gavage from gestational day 16 to postnatal day 21. The amount of irradiation used in this study was 5, 10 and 30 kGy, respectively. There were no treatment related changes of dams in deaths, clinical signs, and parturition. No treatment related changes in food consumption, body/organ weight and lactation of dams were observed. Also, no F1 fetuses in external abnormality, physical development, reflex/sensory junctions and behavioral development were found. The results of this study showed that gamma-irradiated ginseng, up to 30 kGy, has no adverse effects on the peri- and postnatal development of rats.

• Analytical Science and Technology
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• v.25 no.6
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• pp.382-387
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• 2012

Ethylene oxide ($C_2H_4O$, EtO) is used as a raw material for the production of ethylene glycol and other industrially important material such as ethanolamines and also used as a disinfecting agent. It is applied for gas-phase sterilization of thermally sensitive medical equipment, and for processing of storage facilities as a mixture with fluorinated hydrocarbon. In this perspective, accurate determination of the mole fractions of components in the liquefied gas mixture is required for the quality control and safety of production and use. Each component of the liquefied gas mixture has different chemical and physical properties such as vapor pressure and boiling point. Therefore, we can suppose that analytical results can be different according to the introduction method for the gas phase of upper layer, or for the liquid phase of lower layer in gas cylinder. In this study, we designed a new on-line sample injection device for the liquefied gas mixture in liquid or gas state, and applied to the analysis of liquefied gas mixture of ethylene oxide and fluorinated hydrocarbons by GC/AED (gas chromatograph-atomic emission detector). We studied performance of AED, and effect of sample introduction and selected wavelength to the accuracy and repeatability of analytical results.

• International Journal of Industrial Entomology and Biomaterials
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• v.34 no.2
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• pp.32-37
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• 2017

The purpose of this study was (1) to demonstrate the anti-microbial properties of 4-hexylresorcinol (4HR) loaded silk mat and (2) comparison of bone formation between 4HR incorporated silk mat and collagen membrane. Anti-microbial properties of 4HR incorporated silk mat was done after sterilization of silk mat (autoclaving and ethylene oxide gas). For the evaluation of bone formation, bilateral bony defects (size: 8 mm) were prepared in the parietal bone of the rabbits (n=10). 4HR incorporated silk mat (size: $10{\times}10mm$) was applied on the right defect. For the comparative purpose, the same size of commercial collagen membrane was applied on the left defect. The anti-microbial properties of 4HR incorporated silk mat were maintained after sterilization process. When compared bone mineral density and bone volume, there was no statistically significant difference between groups at 4 weeks and 8 weeks after operation (p>0.05). In conclusion, 4HR incorporated silk mat could be autoclaved without concern of anti-microbial properties loss. In addition, 4HR incorporated silk mat showed similar bone regeneration to collagen membrane. Therefore, 4HR incorporated silk mat might be considered for the application of open membrane technique.

• Toxicological Research
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• v.17 no.2
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• pp.97-106
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• 2001

Korean ginseng products have been fumigated with ethylene oxide (EO) for sterilization and prolongation of storage periods. However, there had been controversies indicating that the consumption of food treated with EO might cause harmful effects in human. Since, in Korea the use of EO gas for food treatment was banned in 1991. Since then, irradiation technique has been developed as an alternative. This study was carried out to investigate the effects of irradiated ginseng on fertility, and reproductive and developmental toxicity. Either EO gas fumigated or gamma-irradiated ginseng was administered to male rats by oral gavage for 63 days during the premating period. Female rats were administered from 14 days before mating to day 20 of gestation or to day 21 of lactation. The exposure amount of irradiation used was 5, 10 and 30 kGy, respectively. There were no treatment related changes of darns in clinical signs, and parturition. No treatment related changes in food consumption, body/organ weights, male/female reproductive and fertility performances were observed. F1 fetuses showed no external abnormality. Reflex/sensory junctions, physical/behavioral development, and reproductive performance of F1 rats were not adversary affected. The results of this study show that gamma-irradiated ginseng, up to 30 kGy, has no adverse effects on the fertility, reproduction and development in Wistar rats.

• Toxicological Research
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• v.17 no.1
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• pp.27-32
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• 2001

Korean ginseng products have been fumigated with ethylene oxide (EO) for sterilization and prolongation of storage periods. However, there had been controversies indicating that consumption of EO treated foods might cause harmful effects in human. In Korea, the use EO gas for food treatment was banned in 1991. Since then, irradiation technique has been developed as an alternative. This study was carried out to evaluate the safety of irradiated ginseng on embryo and fetal developmental toxicity effects in rats. Either EO gas fumigated or $\gamma$-irradiated ginseng was administered to pregnant Wistar rats by oral gavage from gestational day 7 to 17. The amount of irradiation used in this study was 5, 10 and 30 kGy, respectively. There were no treatment related changes of dams in deaths, clinical signs, food consumption and body/organ weight. No treatment related changes in implantation ratio, litter size, sex ratio and body/organ weight of fetuses were observed. Also, no F1fetuses with external, visceral, head and skeletal mal-formation were observed. The results of this study showed that $\gamma$-irradiated ginseng, up to 30 kGy, has no adverse effects on fetal development of rats.

• Korean Journal of Food Science and Technology
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• v.18 no.4
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• pp.283-287
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• 1986

E.O. and gamma irradiation treatment on the sterilization of ground samples of 5 different types of spices(red and black pepper, onion, garlic and ginger) were investigated. Populations of mesophilic bacteria, mesophilic spores, acid tolerant bacteria and fungi in various samples were $10^4-10^6/g,\;10^3-10^5/g,\;10^3-10^5/g\;and\;10^3-10^4/g$, respectively. Coliforms and osmophilic molds were found only in red and black pepper as $10^3-10^4/g$. A radiation dose of 5 to 7 kGy proved sufficient to redure the viable cell count of the total bacteria and fungi to the level of $10^3/g$ and they were sterilized completely by radiation dose of 10 kGy or more. Coliforms, mesophilic spores and acid tolerant bacteria were sterilized at 5,7 and 10 kGy, respectively. In the mean time $D_{10}$ values of each spices ranged from 1.38 to 2.88 kGy. Comparison of E.O. and gamma irradiation treatment showed that E.O. treatment was less effective than radiation in controlling microbial contamination in spices.

• Microbiology and Biotechnology Letters
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• v.38 no.2
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• pp.168-176
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• 2010

Acellular dermal matrix (ADM), produced by decellularization from human cadaveric skin, has been used for various biomedical applications. A manufacturing process for ADM ($SureDerm^{TM}$) using tri-n-butyl phospahate (TnBP) and deoxycholic acids as the decellularization solution has been developed. The manufacturing process for $SureDerm^{TM}$ has 70% ethanol treatment and ethylene oxide gas sterilization for inactivating infectious microorganisms. The purpose of this study was to examine the efficacy of the 70% ethanol treatment, decellularization process using 0.1% TnBP and 2% deoxycholic acids, and EO gas sterilization process in the inactivation of viruses. A variety of experimental model viruses for human pathogens, including the human immunodeficiency virus type 1 (HIV-1), bovine herpes virus (BHV), bovine viral diarrhoea virus (BVDV), hepatitis A virus (HAV), and porcine parvovirus (PPV) were all selected for this study. Enveloped viruses such as HIV-1, BHV, and BVDV were effectively inactivated to undetectable levels by 70% ethanol treatment. However HAV and PPV showed high resistance to 70% ethanol treatment with the log reduction factors of 1.85 and 1.15, respectively. HIV-1, BHV, and BVDV were effectively inactivated to undetectable levels by decellularization process. All the viruses tested were completely inactivated to undetectable levels by EO gas treatment. The cumulative log reduction factors of HIV-1, BHV, BVDV, HAV, and PPV were $\geq12.71$, $\geq18.08$, $\geq14.92$, $\geq6.57$, and $\geq7.18$, respectively. These results indicate that the production process for $SureDerm^{TM}$ has a sufficient virus-reducing capacity to achieve a high margin of the virus safety.

• Restorative Dentistry and Endodontics
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• v.25 no.1
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• pp.116-122
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• 2000

On the instrumented root canal wall, amorphous, irregular smear layer can be observed with Scanning Electron Microscope(SEM). The purpose of this study was to evaluate the effect of the presence or absence of smear layer on the adhesion of Staphylococcus aureus to the dentin of the root canal. Human incisors, extracted within 7 days, with no caries, no fracture, no calcification of canal, were selected. After cutting crown portion at cemento-enamel junction, root canal preparation was done by modified crown-down technique using Profile and Gates - Glidden Drill. During canal preparation, 10ml physiologic saline solution(group1&3) or 10ml 3.5% NaOCl(group2&4) was used as irrigation solution. And 10ml physiologic saline solution(group1&3) or 10ml 0.5M EDTA(group2&4) was applicated for final flush. After vertical sectioning and ethylene oxide gas sterilization, samples(group1&2) were immersed into BHIYHM broth inoculated with Staphylococcus aureus (ATCC 31153) and incubated for 3hrs at $37^{\circ}C$. All samples were prepared for and observed with SEM(JEOL JSM840S). The data were analyzed by Mann-Whitney rank sum test. The conclusions are as follows ; 1. Smear layer covers entire root canal surface after root canal preparation. 2. Smear layer has been removed away and the entrances of dentinal tubules have opened widely, when applying 0.5M EDTA and 3.5% NaOCl. 3. A significantly higher number of bacteria were adhered to the root canal dentin without smear layer(p<0.0001). 4. Smear layer produced during root canal preparation impedes bacterial adhesion and colonization to dentin matrix, therefore inhibits canal reinfection.