• Journal of Microbiology and Biotechnology
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• v.33 no.4
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• pp.419-429
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• 2023

Ultraviolet C (UV-C, 200-280 nm) light has germicidal properties that inactivate a wide range of pathogenic and spoilage microorganisms. UV-C has been extensively studied as an alternative to thermal decontamination of fruit juices. Recent studies suggest that the efficacy of UV-C irradiation in reducing microorganisms in fruit juices is greatly dependent on the characteristics of the target microorganisms, juice matrices, and parameters of the UV-C treatment procedure, such as equipment and processing. Based on evidence from recent studies, this review describes how the characteristics of target microorganisms (e.g., type of microorganism/strain, acid adaptation, physiological states, single/composite inoculum, spore, etc.) and fruit juice matrices (e.g., UV absorbance, UV transmittance, turbidity, soluble solid content, pH, color, etc.) affect the efficacy of UV-C. We also discuss the influences on UV-C treatment efficacy of parameters, including UV-C light source, reactor conditions (e.g., continuous/batch, size, thickness, volume, diameter, outer case, configuration/arrangement), pumping/flow system conditions (e.g., sample flow rate and pattern, sample residence time, number of cycles), homogenization conditions (e.g., continuous flow/recirculation, stirring, mixing), and cleaning capability of the reactor. The collective facts indicate the immense potential of UV-C irradiation in the fruit juice industry. Existing drawbacks need to be addressed in future studies before the technique is applicable at the industrial scale.

• Journal of Food Hygiene and Safety
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• v.33 no.1
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• pp.31-37
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• 2018

This study was conducted to evaluate the microbiological safety of leafy vegetables (perilla leaf and lettuce) in relation to cultivation methods. A total of 2,304 samples were collected from plants, harvesting tools and soil mulching film during the production and harvest stages from organic- and conventional- farms. From the samples, sanitary indicator microorganisms (total aerobic bacteria, coliforms, E. coli., Environmental Listeria, and yeast and mold) and pathogenic microorganisms (S. aureus, B. cereus, Salmonella spp., Clostridium spp., and L. monocytogenes) were analyzed. In the production stage of leafy vegetables, the sanitary indicator microorganisms was not detected regardless of cultivation method or it was detected to be less than $3.4\;Log\;CFU/100cm^2$. B. cereus and S. aureus were found to be 0.22~1.55 Log CFU/g in perilla leaf and lettuce produced by organic farms, and S. aureus was not detected and B. cereus was found to be 0.42~2.19 Log CFU/g in conventional farms. There were no significant differences between two cultivation methods. In the harvesting tools and soil mulching film, the contamination levels of sanitary indicator microorganisms and pathogenic microorganisms was low regardless of the cultivation method. However, there was a positive correlation ($R^2=0.4526$) in that the higher the microbial contamination level in the harvesting tool, the higher the microbial contamination on the surface of the plant. In addition, sanitary indicator microorganisms and pathogenic microorganisms were not detected or low in soil mulching during the production of organic leafy vegetables. As a result of this study, microbial hygiene control by soil mulching and harvesting tools was more important than difference of cultivation method in production of leafy vegetables.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1687-1689
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• 2008

In the detection of pathogenic microorganisms ATP-bioluminescence reaction is a fascinating method. ATP(adenosine triphosphate) is an energy source of all kinds of living organism and ATP-bioluminescence reaction uses this ATP. However, ATP exists not only in the cells but also outside the cells. Therefore ATP-bioluminescence reaction only with intracellular ATP is very important in pathogenic microorganism detection. Because of that reason we developed a microfluidic channel containing Dielectrophoretic zone which capture microorganisms and eliminating and washing extracellular ATP with ATP-degarading enzymes, adenosine phosphate deaminase and apyrase. Microorganisms are captured by pDEP force at the DEP electrode zone and only extracellular ATPs are washed and eliminated outside the zone.

• Journal of Environmental Science International
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• v.33 no.3
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• pp.205-215
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• 2024

Antibiotics are substances produced by microorganisms that kill or inhibit and are essential for infectious diseases management. This study aimed to provide basic data for overcoming antibiotic resistance in the marine bacterium LJ-18. The API 20NE and API 50CH kits were used to identify this microorganism. Morphological, physiological, and biochemical properties were investigated using MacFaddin's manuals. Subsequently, isolated LJ-18 was found to belong to a genus of Streptomyces that forms mycelia. LJ-18 also grew well at 28-32℃ on modified Bennett's agar. To isolate and purify the antibacterial compound, LJ-18 culture was divided into ethyl acetate and distilled water fractions. Considerable antimicrobial activity against various pathogenic microorganisms, including methicillin-resistant Staphylococcus aureus (MRSA), was confirmed in the C₁₈ ODS open column fractions. Peak 2 compound was obtained using reversed-phase HPLC. As a result, this compound had a significant antimicrobial activity against various pathogenic microorganisms. In particular, it showed strong activity against MRSA, Mycobacterium smegmatis, Bacillus subtilis, Bacillus cereus, and Staphylococcus aureus.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.110-116
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• 2019

To investigate the antagonistic inhibitory effects in a mixed culture between probiotics and various pathogenic microorganisms, 140 probiotics were identified using a 16 rRNA sequencing phylogenetic analysis method, and various probiotics strains were isolated from Korean kimchi from January to December 2016. The antagonistic inhibition test of a mixed culture of four probiotics (Enterococcus faecalis, Lactobacillus plantarum, Lactobacillus rhamnosus, and Lactobacillus reuteri) with excellent antimicrobial activity and six pathogenic microorganisms (Candida albicans, Salmonella Enteritidis, E. coli O157:H7, Shigella flexneri, Staphylococcus aureus, and Pseudomonas aeruginosa)showed that the growth of most probiotics strains increased normally after culture, but growth was inhibited almost completely in most pathogenic microorganisms, except for S. Enteritidis. This antagonistic inhibitory effect in vitro was attributed to the low pH of the lactic acid and organic acid produced during fermentation. As a result, four probiotics strains isolated from Korean Kimchi are very likely to be developed as therapeutic agents for female yeast infections and colon and skin care. In the future, these therapeutic agents will help improve public health related to probiotics.

• Mycobiology
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• v.37 no.1
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• pp.48-52
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• 2009

Essential oils are mixtures of volatile, lipophilic compounds originating from plants. Some essential oils have useful biological activities including antimicrobial, spasmolytic, antiplasmodial, and insect-repelling activities. In this study, we tested the antimicrobial activity of essential oil prepared from the aromatic plant, Cymbopogon citrates, against three important plant pathogenic and medical microorganisms, Pectobacterium carotovorum, Colletotrichum gloeosporioides, and Aspergillus niger. It effectively inhibited the growth of the bacterium, Pectobacterium carotovorum, in a dose-dependent fashion, and 0.5% of the oil inhibited the growth of bacteria completely. Similarly, the essential oil inhibited the growth of plant pathogenic fungus, Colletotrichum gloeosporioides, and the addition of 1% of essential oil completely inhibited the growth of fungus even after 5 days of culture. Finally, it effectively inhibited the growth of the medically and industrially important fungal species, Aspergillus spp. These results suggest that the essential oil from Cymbopogon citrates may be an environmentally safe alternative to inhibit antimicrobial agents for various uses.

• Journal of Korean Society of Water and Wastewater
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• v.33 no.5
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• pp.379-388
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• 2019

Chlorination and UV illumination are being widely applied to inactivate a number of pathogenic microbials in the environment. Here, we evaluated the inactivation efficiency of individual and combined treatments of chlorination and UV under various aqueous conditions. UV dosage was required higher in waste water than in phosphate buffer to achieve the similar disinfecting efficiency. Free chlorine generated by electrolysis of waste water was abundant enough to inactivate microbials. Based on these, hybrid system composed of sequential treatment of electrolysis-mediated chlorination and UV treatment was developed under waste water conditions. Compared to individual treatments, hybrid system inactivated bacteria (i.e., E. coli and S. typhimurium) and viruses (i.e., MS-2 bacteriophage, rotavirus, and norovirus) more efficiently. The hybrid system also mitigated the photo re-pair of UV-driven DNA damages of target bacteria. The combined results suggested the hybrid system would achieve high inactivation efficiency and safety on various pathogenic microbials in wastewater.

• Korean Journal of Agricultural Science
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• v.42 no.1
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• pp.29-35
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• 2015

This study was performed to analyze the distribution and antimicrobial resistance of pathogenic microorganisms isolated from the carcass and environments of chicken processing plant located in Gyeonggi province from October to November in 2010. Chicken slaughterhouse was visited 3 times and totally 40 samples were collected from chicken carcass before and after washing (n=14), chicken cuts (n=7), cooling water (n=8), brine (n=2), cutting knives (n=7) and working plate (n=2). Whole-chicken rinsing technique (for chicken carcasses) and swab technique (for working plate and knives) were used to analyze the distribution of pathogenic microorganisms. In addition, brine and chilling water from storage tanks were gathered using sterilized tubes and used as samples. The matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) for whole cell fingerprinting in combination with a dedicated bioinformatic software tool was used to identify the isolated microorganisms. The pathogenic microorganisms, such as Bacillus cereus (n=8) and Staphylococcus aureus (n=9), were isolated form the chicken processing process (chicken carcasses of before and after chilling, chicken cuts, and working plate). The antimicrobial susceptibility of those isolated microorganisms was analyzed using 21 antimicrobial agents. In the case of B. cereus, it showed 100% of resistance to subclasses of penicillins and peptides, and it also resistant to cephalothin, a member of critically important antimicrobials (CIA), however there was no resistance (100% susceptible) to vancomycin and chloramphenicol. S. aureus showed 100% resistance to subclasses of peptides and some of penicillins (penicillin and oxacillin), however, it showed 100% susceptibility to cephalosporins (cefazolin and cephalothin). All of the tested pathogens showed multi drug resistance (MDR) more than 4 subclasses and one of B. cereus and S. aureus showed resistance to 9 subclasses. After the ban on using the antimicrobials in animal feed in July 2011, there would be some change in microbial distribution and antimicrobial resistance, and it still has a need to be analyzed.

• Mycobiology
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• v.48 no.5
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• pp.392-398
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• 2020

This study was conducted to understand the dynamics of microbial communities of soil microorganisms, and their distribution and abundance in the indigenous microorganisms (IMOs) manipulated from humus collected from the forest near the crop field. The soil microorganisms originated from humus and artificially cultured microbial-based soil amendments were characterized by molecular and biochemical analyses. The bacterial population (2 × 10⁶~13 × 10⁶ CFU/g sample) was approximately 100-fold abundant than the fungal population (2 × 10⁴~8 × 10⁴ CFU/g sample). The 16S rDNA and ITS sequence analyses showed that the bacterial and fungal communities in humus and IMOs were mainly composed of Bacillus and Pseudomonas, and Trichoderma and Aspergillus species, respectively. Some of the bacterial isolates from the humus and IMOs showed strong inhibitory activity against soil-borne pathogenic fungi Fusarium oxysporum and Sclerotinia sclerotiorum. These bacteria also showed the siderophore production activity as well as phosphate solubilizing activity, which are requisite traits for biological control of plant pathogenic fungi. These results suggest that humus and IMOs could be a useful resource for sustainable agriculture.

• Herbal Formula Science
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• v.27 no.4
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• pp.257-267
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• 2019

Objectives: The purpose of this study was to establish experimental evidence for the antimicrobial effects of 51 herbal formulae commonly used in traditional Korean medical institutions. Methods: The antimicrobial activities of herbal formulae were screened using the disc diffusion method against 10 pathogenic microorganisms (Bacillus cereus, Staphylococcus aureus, Listeria monocytogenes, Vibrio parahaemolyticus, Escherichia coli DH5α, E. coli O157, Salmonella enteritidis, Yersinia enterocolitica, Shigella flexneri, and Helicobacter pylori). Of the 51 herbal formulae, 13 herbal formulae with antimicrobial activity were selected and their dose-dependency were confirmed. Results: Nine herbal formulae, including Gyeji-tang, Dangguisu-san, Saengmaek-san, Samul-tang, Ssanghwa-tang, Socheongryong-tang, Yukmijihwang-tang, Jakyakgamcho-tang, and Paljung-san, presented antibacterial activity against B. cereus. The effects of Saengmaek-san and Paljung-san was sustained for 48 hr. On L. monocytogenes, Dangguisu-san and Hyangsapyeongwi-san showed antimicrobial activity, but only Hyangsapyeongwi-san maintained the activity for 48 hr. Thirteen herbal formulae such as Galgeun-tang, Gyeji-tang, Dangguisu-san, Mahwang-tang, Banhasasim-tang, Saengmaek-san, Socheongryong-tang, Yukmijihwang-tang, Jakyakgamcho-tang, Cheonwangbosim-dan, Palmijihwang-tang, Paljung-san, and Hwanglyeonhaedok-tang showed antimicrobial activity against V. parahaemolyticus, and the activity was maintained for 48 hr. The 51 herbal formulae did not show any antimicrobial activity against seven strains such as E. coli DH5α, E. coli O157, S. aureus, S. enteritidis, Y. enterocolitica, S. flexneri, and H. pylori. Conclusions: Nine, two, and thirteen herbal formulae showed antimicrobial activities against B. cereus, L. monocytogenes, and V. parahaemolyticus in a dose-dependent manner, respectively. The results of antimicrobial activity of 51 herbal formulae against 10 microorganisms might be used as the basis for new application of herbal formulae.