• The Journal of Korean Academy of Prosthodontics
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• v.33 no.3
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• pp.569-583
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• 1995

Disinfection of dental impressions are necessary due to contamination with patient’s saliva and blood, which is a potential for cross-infection. The purpose of this study was to evaluate the effects of disinfection of four hydrophilic rubber impression materials with three disinfecting solutions, on the dimensional stability and surface hardness of improved stone casts. Three hydrophilic vinyl polysiloxane impression materials(Express, Reprosil, Exafine) and one polyether impression material(Impregum-F) were mixed according to the manufacturer’s directions and impressions were made on a ADA specification No. 19 stainless-steeldie. On removal of the impressions, each impression was immersed in one of the disinfectants(Banicide, Potadine, Clorox) for 10 minutes. After disinfection, type IV improved stone. casts were poured. On this cast, the linear dimension and surface hardness were measuredusing a Measurescope(Nikon, Japan) and a Barcol hardness tester(Barber, Colman Co U. S. A). The results were as follows : 1. The improved stone casts from disinfected Reprosil and Impregum-F impression material did not show dimensional changes(P>0.01). Those from disinfected Express and Exafine impression material showed dimensional changes(P<0.01). The amount of shrinkage was not clinically significant. 2. The improved stone casts from disinfected Express impression material did not exhibit changes in surface hardness(P>0.01), but those from disinfected Reprosil, Exafine, Imp regnum-F impression material showed changes in surface hardness(P<0.01). 3. The dimensinal stability and surface hardness of the improved stone casts were satisfactory using Banicide on Express, all disinfectants used in this study on Reprosil, Potadin and Clorox on Exafine, Banicide and Clorox on Impregum-F. According to these results, immersion disinfection of hydrophilic rubber impression mate rials did not adversely affect the resultant casts. Nevertheless compatibility tests of impression materials and disinfectants should be done when disinfecting impressions.

• Journal of Environmental Health Sciences
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• v.44 no.5
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• pp.409-420
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• 2018

Objectives: An outbreak of humidifier disinfectant-related respiratory disease has not only been a massive disaster for end users, but it is also a concern for the workers of the manufacturers. This study presents the results of a questionnaire survey on the health effects among workers involved in the manufacture of humidifier disinfectants. Methods: Seven sites where humidifier disinfectants were manufactured were identified. A questionnaire survey was conducted to assess the physical symptoms experienced by workers related to humidifier disinfectants. Among a total of 177 workers, 42 subjects were available for the survey. Results: Twenty-one of the 42 respondents reported that they experienced respiratory or skin and mucosal irritation symptoms during work. Of the respondents who experienced symptoms, 14 believed that their symptoms were related to the work process and reported that the symptoms were experienced while working. However, no respondents reported ongoing symptoms or sequelae during the investigation period, and this result could not minimize selection bias due to low response rates. We then compared the characteristics of the group who experienced suspicious symptoms with those of the group without any symptoms. There was no statistically significant difference between two groups. Conclusions: We could not find significant health effects related to the humidifier disinfectant manufacturing process, although 21 respondents experienced stimulant symptoms and 14 respondents believed that the symptoms were related to the work process. Due to the long period of time after occupational exposure and the lack of data, there were many limitations to this study. However, this is one of the few follow-up investigations of workers related to this large-scale disaster in South Korea and the limitations of this study highlight the need to follow up with a nationwide database rather than an occasional survey.

• The Journal of the Korean dental association
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• v.22 no.9 s.184
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• pp.793-801
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• 1984

Though oral microgranisms were among the first to be observed by humans, the interest in oral microbiology lagged. When it became apparent that the oral microflora did influence systemic disease of the body, interest was aroused in the nature and kinds of the microgranisms. The risk of infection in dental procedures is due to the abundant flora of the mouth. This hazard can be reduced to some extent by the use of a local disinfectant. The present studies were undertaken to evaluate and compare the various disinfectants which are commonly used in clinics and hospitals. The results were as follows. 1. The bactericidal activity of the disinfectants mainly depends upon the kinds of the agents, not upon the kinds of the microorganisms. 2. In H₂O₂(3%), the bactericidal activity was greatly related to the contact time. So, at least 4 minitues of contract time was required to use it as an oral antiseptic. 3. In ethyl alcohol (70%), Pseudomonas aeruginosa and Streptococcus salivarius surived a little after 15 seconds of contact time, but, no other colony was discovered after more than 15 seconds of contact time in any kins of microorganisms. 4. Merthiolate (0.1%) showed low antibacterial activity, more in Gram-positive organisms and less in Gram-negative organisms. 5. Benzalkonium chloride (0.1%) and povidone-iodine (10%) showed the most excellent results, revealing no surviving organisms only after 14 seconds of contact time.

• Journal of environmental and Sanitary engineering
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• v.24 no.2
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• pp.40-48
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• 2009

Unusual bloom of toxic cyanobacteria in water bodies have drawn attention of environmentalists world over. Major bloom of Anabaena, Microcystis in water storage reservoir, rivers and lake leading to adverse health effects have been reported from Australia, England and many part of the world. These cyanobacterial cells can release intercellular matter like toxin in water and these intercellular matter can increase the concentration of organic matter. Cellysis can occur when algal cells meet the disinfectants like chlorine in water treatment plant and the resultant rising up of DOC(Dissolved Organic Carbon) or TOC(Total Organic Carbon) can increase the formation of disinfection by products. Disinfectants that kill microorganisms react with the organic or inorganic matter in raw water. In general disinfectants oxidize the matter in raw water and the resultant products can be harmful to human. There are always conflict about which is more important, disinfection or minimizing disinfection by products. The best treatment process for raw water is the process of the lowest disinfection by products and also the the lowest microorganism. In this study the cultured cells, Microcytis Aeruginosa(MA), Anabaena Flos-aquae(AF), Anabaena Cylindrica(AC), and the cells obtained in Daechung Dam(DC) whose dominant species was Anabaena Cylindrica were subjected to chlorination. Chlorination oxidizes inorganic and organic compounds and destruct live cells in raw water. Chloroform was analyzed for the cultured cells which were treated with $20mg/\ell$ dose of chlorine. In general chloroform is easily formed when dissolved organic matter react with chlorine. The cultured cells contributes the concentration of dissolved organic carbon and also that of total organic carbon which might be potent precusors of chloroform formed. The correlations of the concentration of chloroform, DOC and TOC were investigate in this study.

• Journal of Dairy Science and Biotechnology
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• v.39 no.3
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• pp.104-112
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• 2021

This study was conducted to evaluate the efficacy of commercial disinfectants at inactivating Enterobacter sakazakii (Cronobacter spp.) in water. Disinfectant I contained 6.15% sodium hypochlorite, and disinfectant II contained both 2.25% n-alkyl dimethylbenzyl ammonium chloride and 2.25% n-alkyl ethylbenzyl ammonium chloride. Disinfectant I was added to distilled water to obtain a range of residual chloride concentrations at 50 ppm intervals with a maximum of 1-1,000 ppm. Disinfectant II was prepared at concentrations ranging from 1-200 ppm with 5 ppm intervals. Exposure time for all solutions was 10 min. In total, 58 E. sakazakii (Cronobacter spp.) strains were tested in this study. Nine isolates were obtained from clinical samples, and 49 isolates were obtained from environmental samples. Seven strains (6 clinical and 1 environmental) were able to survive in 100 ppm disinfectant I, and a maximum of 5 ppm of disinfectant II. Fifty one strains (3 clinical and 48 environmental) were not killed in 10 ppm of disinfectant I and 1 ppm of disinfectant II in water. In conclusion, this study demonstrated that clinical E. sakazakii (Cronobacter spp.) strains displayed 5- to 10-fold higher resistance to disinfectants than environmental E. sakazakii (Cronobacter spp.) strains. Disinfectant II, containing quaternary ammonium compounds, was shown to be more potent in inactivating E. sakazakii (Cronobacter spp.) in water used to clean infant formula manufacturing equipment than disinfectant I.

• Journal of Environmental Health Sciences
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• v.47 no.4
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• pp.310-319
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• 2021

Background: Humidifier disinfectant exposure is an ongoing issue, and there is still considerable related controversy. Various approaches are needed to secure scientific evidence on the extent of the victims' damages and for the determination of appropriate compensation. Objectives: The purpose of this study was to assess the association between humidifier disinfectant (HD) use and academic achievement in Korean children. Methods: This study used data from the 8th Panel Study on Korean Children in 2015. For the final study, 1,598 cases were used. T-tests and multiple linear regression analyses were conducted to determine whether the use of humidifier disinfectant is a factor that affects academic ability. Results: Children in groups using humidifier disinfectant showed statistically significantly lower scores in all areas of language, including reading, speaking and writing, and statistically lower scores in all areas of mathematics, including counting, addition and subtraction. In the multiple regression analysis results, which control for the effects of various demographic/social variables, the use of humidifier disinfectants showed statistically significant beta coefficients (β: -0.357, p<0.001), negatively affecting children's language ability. As for the 'math' variable, which was created by combining counting, addition, and subtraction scores, the use of humidifier disinfectants as independent variables also showed statistically significant beta coefficients (β: -0.200, p<0.001), negatively affecting children's math ability. Conclusions: The results of the study showed that depending on whether or not humidifier disinfectants were used, there are differences in children's language abilities, such as reading, speaking, and writing, as well as in their mathematical abilities, such as counting, adding, and subtracting numbers. These findings are thought to serve as a scientific basis for extending the perspective from health effects to more diverse areas of demographic and social impact related to humidifier disinfectant damage and compensation.

• Biomedical Science Letters
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• v.27 no.4
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• pp.264-269
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• 2021

The purpose of this study was to evaluate the disinfecting efficacy of peracetic acid (PAA), sodium hypochlorite (NaOCl) and phenol, which are representative disinfectants in medical environments using four types of multi-drug resistance (MDR) clinical isolates with healthcare-associated infections (HAI). 26 antibiotic susceptibility tests were conducted for the four types of MDR clinical isolates in the same way as for clinical specimens. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of the disinfectants were determined by using in vitro liquid medium dilution method and inoculation of the plate medium. Both the MIC and MBC of phenol against MRSA and VRE were 3.1%, while those against KPC and MRPA were 6.2%. The MIC and MBC of peracetic acid (PAA) against MRSA, VRE, KPC, and MRPA were 0.18%. The MIC and MBC of sodium hypochlorite (NaOCl) against MRSA were 0.39% and 0.78%, respectively. Both values of MIC and MBC were 0.78% for VRE. In addition, KPC and MRPA showed 0.39% for MIC and 0.78% for MBC. For all MDR strains used in this study, sodium hypochlorite and peracetic acid showed significant sterilizing efficiency, while no clear correlation was identified between antibiotic resistance clinical isolated and ability of disinfection.

• Journal of Veterinary Science
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• v.21 no.3
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• pp.34.1-34.10
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• 2020

Background: A nationwide outbreak of foot-and-mouth disease (FMD) in South Korea caused massive economic losses in 2010. Since then, the Animal and Plant Quarantine Agency (QIA) has enhanced disinfection systems regarding livestock to prevent horizontal transmission of FMD and Avian influenza (AI). Although the amount of disinfectant used continues to increase, cases of FMD and AI have been occurring annually in Korea, except 2012 and 2013. Objectives: This study measured the concentration of the disinfectant to determine why it failed to remove the horizontal transmission despite increased disinfectant use. Methods: Surveys were conducted from February to May 2017, collecting 348 samples from disinfection systems. The samples were analyzed using the Standards of Animal Health Products analysis methods from QIA. Results: Twenty-three facilities used inappropriate or non-approved disinfectants. Nearly all sampled livestock farms and facilities-93.9%-did not properly adjust the disinfectant concentration. The percentage using low concentrations, or where no effective substance was detected, was 46.9%. Furthermore, 13 samples from the official disinfection station did not use effective disinfectant, and-among 72 samples from the disinfection station-88.89% were considered inappropriate concentration, according to the foot-and-mouth disease virus guidelines; considering the AIV guideline, 73.61% were inappropriate concentrations. Inappropriate concentration samples on automatic (90.00%) and semi-automatic (90.90%) disinfection systems showed no significant difference from manual methods (88.24%). Despite this study being conducted during the crisis level, most disinfectants were used inappropriately. Conclusions: This may partially explain why horizontal transmission of FMD and AI cannot be effectively prevented despite extensive disinfectant use.

• Journal of Food Hygiene and Safety
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• v.37 no.5
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• pp.317-322
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• 2022

Corynebacterium pseudotuberculosis is the causative agent of caseous lymphadenitis (CLA), a chronic contagious disease in small ruminants. The prevalence of CLA has been reported to be >50% in Korean black goats. CLA is difficult to control due to a lack of efficient vaccines and treatment methods. Effective disinfection of the farm environment may be an alternative strategy for reducing the spread of C. pseudotuberculosis. The objective of this study was to evaluate the efficacy of commercial disinfectants against CLA. The six commercial disinfectants, largely composed of sodium dichloroisocyanurate, sodium hypochlorite, potassium monopersulfate triple salt, quaternary ammonium, citric acid, and copper sulfate, were tested against five different genotypes of C. pseudotuberculosis isolated from goat farms in Korea. Efficacy tests were performed in accordance with the disinfectant efficacy test guidelines recommended by the Animal and Plant Quarantine Agency of Korea with slight modifications. All disinfectants except for copper sulfate exhibited >99.99% killing efficacy under hard water conditions following 30 min of incubation, which is the recommended standard treatment time according to guidelines. The minimum bactericidal treatment time was evaluated by employing treatments for durations of 1, 5, and 15 min. The most effective compounds under hard water conditions were sodium dichloroisocyanurate, potassium monopersulfate triple salt, and sodium hypochlorite, exhibiting >99.99% killing efficacy after 1 min of treatment. In the aqueous solution forms, citric acid and the quaternary ammonium compound were the most effective, but required at least 5 min to kill >99.99% of the bacteria. The current study characterizes the killing efficacy of six commercial disinfectant active compounds against C. pseudotuberculosis. Thus, this study provides essential information regarding the efficacy of the disinfectants used to control CLA in goat farms.

• Journal of Life Science
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• v.17 no.9 s.89
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• pp.1278-1283
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• 2007

The 30% resistant frequencies of pathogenic bacteria were identified against generally utilizing disinfectants. Among the used disinfectants, foodsef, Taego, and Iodo 175 were dictated by lower sensitivities against pathogenic bacteria, as well as higher resistant frequencies when compared with other disinfectants. The resistant frequencies against antibiotics were also dictated by 30% through MIC (minimal inhibitory concentration) and paper disc methods. Especially, the used bacteria exhibited resistances against gentamycin, kanamycin, and streptomycin, which included in all aminoglycoside group. The MBT-01108 material, which extracted and purified from a powder obtained by processing of Opunita ficus-indica var. saboten Makino trunk, did not develop or grow resistant bacteria. Interestingly, the multi-drug resistant bacteria such as MRSA, resistant Pseudomonas aeruginosa, VRE, and E. coli 0157 did not resistant against MBT-01108 material. These results suggest that MBT-01108 material uses as an anti-microbial agent.