• Journal of Microbiology and Biotechnology
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• 제33권4호
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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.

• 한국식품위생안전성학회지
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• 제33권1호
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• pp.31-37
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• 2018

본 연구는 시설엽채류에서 재배농법별 미생물학적 안전성을 평가하기 위해서 깻잎과 상추를 대상으로 수행하였다. 유기농 및 관행 농가로부터 생산 및 수확 단계에서 식물체, 수확장갑, 수확비구니, 토양피복재 등으로부터 총 2,304개의 시료를 채취하여 Total aerobic bacteria, Coliforms, E.coli, Environmental Listeria, Yeast & mold 등의 위생지표세균과 Staphylococcus aureus, Bacillus cereus, Salmonella spp., Clostridium spp., L. monocytogenes등의 병원성미생물을 분석하였다. 시설엽채류의 생산과정에서는 재배농법에 상관없이 위행지표세균은 검출되지 않거나 $3.4\;Log\;CFU/100cm^2$ 이하로 검출되었다. 유기농법으로 생산되는 깻잎과 상추에서 B. cereus와 S. aureus가 0.22~1.55 Log CFU/g로 조사되었고, 관행농법에서는 S. aureus는 검출되지 않았으며 B. cereus는 0.42~2.19 Log CFU/g으로 조사되었으나 통계적 유의차는 없었다. 수확도구 및 멀칭필름에서도 재배농법과는 관계없이 위생지표세균과 유해균의 오염도는 낮았으며 차이는 없었다. 그러나 수확도구에서의 미생물 오염도가 높아질수록 식물체 표면의 미생물 오염도도 높아지는 정의 상관관계($R^2=0.4526$)가 있었다. 또한 유기농 시설엽채류 생산시 토양 피복시 위생지표세균과 병원성미생물이 검출되지 않거나 피복을 하지 않은 경우에 비하여 낮은 경향을 나타내었다. 본 연구결과, 시설엽채류 생산시 재배농법의 차이보다는 토양피복 및 수확과정의 미생물적 위생관리가 더욱 필요함을 알 수 있었다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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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.

• 한국환경과학회지
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• 제33권3호
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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.

• 한국산학기술학회논문지
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• 제20권12호
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• pp.110-116
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• 2019

Probiotics와 다양한 병원성 미생물간의 혼합배양에서의 길항적 억제효과를 조사하기 위해 2016년 1월부터 12월까지 국내 김치로부터 다양한 probiotics 균주를 분리하여 16S rRNA sequencing을 통한 계통학적 분석을 통해 140주의 프로바이오틱스를 동정하였다. 이중 항균력이 우수한 probiotics 4종(Enterococcus faecalis, Lactobacillus plantarum, Lactobacillus rhamnosus, and Lactobacillus reuteri )과 병원성 미생물 6종 (Candida albicans, Salmonella Enteritidis, E. coli O157:H7, Shigella flexneri, Staphylococcus aureus, and Pseudomonas aeruginosa)간의 혼합배양에서의 길항적 억제시험에서 probiotics 균주들은 대부분 배양 후에 균수가 정상적으로 크게 증가했지만 C. albicans를 포함하여 대부분의 병원성미생물들은 S. Enteritidis 를 제외하고 거의 완전하게 성장이 억제되었다. 이러한 in vitro 에서의 길항적 억제효과는 생성된 젖산과 유기산등의 낮은 pH에 의한 효과인 것으로 생각된다. 이상의 결과로 한국 김치에서 분리된 probiotics 균주 4종은 여성질염, 대장 및 피부관리 관련 치료제로써의 개발 가능성이 매우 큰 것으로 생각되며 향후 이러한 치료제는 probiotics 관련 국민건강 및 보건향상에 크게 기여할 것으로 생각된다.

• Mycobiology
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• 제37권1호
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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.

• 상하수도학회지
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• 제33권5호
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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.

• 농업과학연구
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• 제42권1호
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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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• 제48권5호
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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.

• 대한한의학방제학회지
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• 제27권4호
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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.