• Journal of the Society of Cosmetic Scientists of Korea
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• v.40 no.3
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• pp.307-311
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• 2014

2,3,5-Triphenyltetrazolium chloride (TTC) is used as a redox indicator in culture media. It is colorless in the oxidized form and is reduced to formazan, an insoluble pigment, by dehydrogenases in actively growing microbial cells. The aim of this study was to assess by microbial test of the pathogenic microorganisms using TTC reduction. The pathogenic microorganisms were reduced in medium by dehydrogenase to produce insoluble red formazan. We observed that the optimization method of TTC allowed more than 12 h incubation in 0.04% concentration. Also, the growth of microorganisms with media was increased formazan production. We confirmed that microorganisms were quickly observed to grow colonies cultured red color without affecting the growth of microorganisms. It is suggested that the microbial test using TTC can provide better and quicker test method in cosmetics development.

• Environmental Engineering Research
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• v.14 no.1
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• pp.63-67
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• 2009

Escherichia coli K-12 (E. coli K-12) is a representative indicator globally used for distinguishing and monitoring dynamic fates of pathogenic microorganisms in the environment. This study investigated how to most critically quantify lacZ ($\beta$-galactosidase) gene in E. coli K-12 by two different real-time polymerase chain reaction (real-time PCR) in association with three different DNA extraction practices. Three DNA extractions, i.e., sodium dodecyl sulfate (SDS)/proteinase K, magnetic beads and guanidium thiocyanate (GTC)/silica matrix were each compared for extracting total genomic DNA from E. coli K-12. Among them, GTC/silica matrix and magnetic beads beating similarly worked out to have the highest (22-23 ng/${\mu}L$) concentration of DNA extracted, but employing SDS/proteinase K had the lowest (10 ng/${\mu}L$) concentration of DNA retrieved. There were no significant differences in the quantification of the copy numbers of lacZ gene between SYBR Green I qPCR and QProbe-qPCR. However, SYBR Green I qPCR obtained somewhat higher copy number as $1{\times}10^8$ copies. It was decided that GTC/silica matrix extraction or magnetic beads beating in combination with SYBR Green I qPCR can be preferably applied for more effectively quantifying specific gene from a pure culture of microorganism.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.5
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• pp.755-761
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• 2006

Recently, there is growing interest in ultraviolet (UV) irradiation as a disinfection technic in drinking water production due to its effectiveness to inactivate microorganisms such as Crytosporidium parvum without forming disinfection byproducts. However, UV disinfection is known for its drawback such as photoreactivation. Despite many works concerning the photoreactivation, most of works were focused on indicator or non pathogenic microorganisms. The objective of this study is to examine the photoreactivation of Pseudomonas aeruginosa which is an opportunistic pathogen as UV radiation by LP and MP UV lamp was applied. The result showed that P. aeruginosa had high photo repair efficiency regardless of the type of UV irradiation. Both of the effective log repair values of LP and MP UV irradiation were found approximately 2.6 log. In addition, photo repaired P. aeruginosa was not significantly different in forming biofilm in comparison with non treated P. aeruginosa.

• Food Science of Animal Resources
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• v.31 no.3
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• pp.405-412
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• 2011

The purpose of this study was to isolate and characterize bacteriocin-producing bacteria against Clostridium perfringens from domestic animals to determine their usefulness as probiotics. The feces of cattle and chicken were used as sources to isolate bacteriocin-producing bacteria using the spot-on-lawn method. In total, 900 bacterial stains were isolated from domestic animal feces, and 19 strains were finally selected after determining the inhibitory activity against the pathogenic indicator C. perfringens KCTC 3269. Eighteen strains of Bacillus subtilis and one strain of Brevibacillus parabrevis were identified by 16s rRNA sequencing. Most of the bacterial strains isolated were resistant to 0.5% bile salts and remained viable after 2 h at pH 3.0. Additionally, some B. subtilis strains showed strong inhibitory activity against Listeria monocytogenes. We isolated and screened B. subtilis strains CB 153 and CB 189 from cattle and B. subtilis MSC 156 and B. parabrevis MSC 164 from chickens using probiotic selection criteria such as inhibition activity against C. perfringens and tolerance to acid and bile salts. The isolated bacteriocin-producing bacteria and/or bacteriocin have the potential to be used as probiotics in the livestock industry.

• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.3
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• pp.84-93
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• 2003

Photoreactivation of microorganism following UV-disinfection is one of the research topics of interest in assessing the UV-disinfection performance. Apparent photoreactivation was examined under fluorescent lamp and solar radiation as well as in darkness. Total coliform, fecal coliform, and Escherichia coli were used as indicator microorganisms, and their concentration was monitored with time after UV-disinfection. Under the darkness, their initial concentration of 10∼30 MPN/100 mL increased to the level of 100 MPN/100 mL after 24 hours, which implied that part of damaged microorganisms by UV-disinfection might be repairable with time. Under the fluorescent lamp, photoreactivation was more apparent that their concentration increased up to 1,000 MPN/100 mL which might significantly impair the water uses specially in reuse of reclaimed wastewater. However, their concentration further decreased down to below 2 MPN/100 mL under the solar radiation primarily due to additional disinfection by solar radiation rather than photoreactivation. Samples not disinfected by UV-disinfection also demonstrated substantial decrease of their concentration under solar radiation from about 5,000 MPN/100 mL to less than 30 MPN/100 mL in 24 hours. But direct reuse of effluent without disinfection is not recommended because natural decay by solar radiation may take time and be affected by climatic conditions. The result suggests that photoreactivation of pathogenic microorganisms may not be concerned in agricultural reuse of reclaimed wastewater because solar radiation may provide further disinfection after UV-disinfection.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.33 no.3
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• pp.355-364
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• 2023

Objectives: The objective of the present study was to identify mycobacterial infection in retired dusty workers who were ineligible for medical care benefits for work-related pneumoconiosis. Methods: Sputum samples were collected from 170 retired dusty workers living in Gangwon-do. The mycobacterial culture was grown in 2% Ogawa medium and Mycobacteria Growth Indicator Tube(MGIT). Mycobacterial species were identified using MolecuTech REBA Myco-ID^Ⓡ. Results: Thirty-one(18.2%) out of 170 sputum samples were identified as positive for culture. Among the positive culture samples, eleven(6.5%) were identified as mycobacterial species. The proportion of mycobacteria was M. avium 2.3%(4/170), M. fortuitum complex 1.2%(2/170), M. intracellulare 1.2%(2/170), M. abscessus 0.6%(1/170), M. tuberculosis(MTB) complex 0.6%(1/170), and MYC(NTM except 19 species) 0.6%(1/170). Conclusions: In comparison with previous studies, the incidence rate of tuberculosis(TB) in retired dusty workers who were ineligible for medical care benefits for work-related pneumoconiosis was higher than in close contact with TB patients, workers exposed to silica, and patients with silicosis. And the proportion of non-tuberculosis mycobacteria(NTM) was higher than that of MTB.

• The Korean Journal of Food & Health Convergence
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• v.9 no.6
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• pp.9-19
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• 2023

Lactobacillus plantarum and Leuconostoc mesenteroides are crucial functional starters and predominant isolates in a wide range of fermented foods, particularly kimchi, whose constituents exhibit bioactive properties. We previously developed a methodology using anion exchange resins to purify peptidyl compounds from Lb. plantarum LBP-K10. Antibacterial cultures of Lb. plantarum LBP-K10 were obtained from the respective cultures' supernatants and filtrates. However, conclusive evidence of the efficacy of kimchi filtrates in eradicating pathogenic bacteria is lacking. We aimed to simulate the potential effects of antibacterial filtrates that contained antibacterial compounds which were derived from cultures of Lb. plantarum LBP-K10. We acquired the kimchi filtrates using a combination of centrifugation and filtration methodologies, without the requirement for inoculation. The filtered liquid from Chinese cabbage kimchi, inoculated with Lb. plantarum LBP-K10 as a starter culture, and the non-inoculated liquid from Chinese cabbage kimchi (referred to as CCK and CCKRef, respectively) were were examined. CCK demonstrated greater inhibitory activity and a more significant bactericidal effect against the bacterial indicator strains. The minimum inhibitory concentration demonstrated comparable outcomes in tests against both Gram-positive and Gram-negative bacteria. This research offers a groundbreaking examination that displays the effectiveness of profiling peptidyl compounds within kimchi filtrates for curing bacterial infections.

• Journal of Environmental Health Sciences
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• v.39 no.5
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• pp.456-464
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• 2013

Objectives: The aim of this study was to investigate the microbial contamination levels in elevators in apartment buildings and to provide information on such microbial contamination. Methods: A total of 144 samples, including from the exterior buttons, interior buttons, elevator handrails, walls, ventilators and airborne bacteria were collected in the morning and afternoon from July to August 2013 for six different elevators. The samples were used to detect sanitary indicator bacteria (total bacteria, coliform, and Escherichia coli), pathogenic bacteria (E. coli O157, L. monocytogenes, Salmonella spp., B. cereus, S. aureus) and fungi. Results: Contamination levels of total bacteria were 0.3-3.8 and 0.0-2.4 log CFU/100 $cm^2$ in the morning and afternoon, respectively. In the case of coliform bacteria, the levels were 0.0-3.7 log CFU/100 $cm^2$ in the morning and 0.0-0.3 log CFU/100 $cm^2$ in the afternoon. However, E. coli was not detected among all samples. Bacillus cereus, pathogenic bacteria, was only detected in 13 (11%) among 144 samples. E. coli O157, L. monocytogenes, Salmonella spp. and S. aureus were not detected among all samples. Comparing the samples collected in the morning and afternoon, we could confirm that the samples in the afternoon were cleaner. Conclusions: This study indicates that the samples in the afternoon were cleaner because these samples were collected following routine cleaning. Also, the levels of contamination in the elevators were low and the sanitary conditions were comparatively well-managed. Therefore it is deemed necessary for elevators be cleaned regularly to provide good conditions for people using elevators.

• Journal of Food Hygiene and Safety
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• v.27 no.4
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• pp.427-431
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• 2012

This study was conducted to monitor and evaluate microbial contamination during manufacturing process in 6 red pepper powder factories. Red pepper powder samples were taken from manufacturing facilitates, working area and workers' hands to determine sanitary indicator bacteria (SIB) such as aerobic bacteria and coliform group as well as pathogenic indicator bacteria (PIB) such as Staphylococcus aureus, E.coli, Salmonella spp., Listeria monocytogenes, and Bacillus cereus. The results indicated that SIB in primary materials was detected as low as 3 log units and E.coil and Staphylococcus aureus of PIB were detected. After grinding process, aerobic bacteria, fungi, and coliform group increased 52% and 108%, respectively. In final products, PIB was not detected except for one found Staphylococcus aureus by which workers' hands were contaminated. Moreover, UV detectors in all the manufacturers were not able to reduce bacteria. Thus, this data suggest that a stringent safety management be needed to prevent cross contamination, and also reconsider effectiveness of facility.

• Food Science of Animal Resources
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• v.34 no.5
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• pp.614-621
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• 2014

This study was conducted to isolate and characterize bacteriocin-producing bacteria against Clostridium perfringens (C. perfringens) from domestic animals to determine their usefulness as probiotics. Bacteriocin-producing bacteria were isolated from pig feces by the spot-on-lawn method. A total of 1,370 bacterial stains were isolated, and six were tentatively selected after identifying the inhibitory activity against the pathogenic indicator C. perfringens KCTC 3269 and KCTC 5100. The selected strains were identified as Enterococcus faecalis (E. faecalis) by 16s rRNA sequencing. Most of the isolated bacterial strains were resistant to 0.5% bile salts for 48 h and remained viable after 2 h at pH 3.0. Some E. faecalis also showed strong inhibitory activity against Listeria monocytogenes KCTC 3569, KCTC 3586 and KCTC 3710. In the present study, we finally selected E. faecalis AP 216 and AP 45 strain based on probiotic selection criteria such as antimicrobial activity against C. perfringens and tolerance to acid and bile salts. The bacteriocins of E. faecalis AP 216 and AP 45 strains were highly thermostable, showing anticlostridial activities even after incubation at $121^{\circ}C$ for 15 min. These bacteriocin-producing bacteria and/or bacteriocins could be used in feed manufacturing as probiotics as an alternative to antibiotics in the livestock industry.