• Korean Journal of Microbiology
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• v.54 no.4
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• pp.410-419
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• 2018

It is urgently required to construct safety data on agricultural by-products imported for use as medium materials for domestic mushroom production. However, research on microorganisms is insufficient. This study was conducted to investigate the presence of bacteria that have the possibility of harmful effects on human, plants and mushroom in wheat straw, peatmoss, cottonseed hull, cottonseed meal, and beet pulp imported from Australia, Canada, China, Egypt, Germany. Bacteria were found in the range of $1.35{\times}10^2$ to $8.34{\times}10^6CFU/g$. As a result of 16S rDNA sequence analysis, total of 19 genera and 45 species of bacteria were identified. Bacillus genus was dominant, followed by Paenibacillus genus. At the species level, diverse species was in the order of Firmicute, Proteobacteria and Actinobacteria. Regarding the agricultural by-products, straw and peat moss had more diverse bacteria than other agricultural by-products. Among the indentified bacteria, 6 species of 5 genera (Enterobacter asburiae, Enterobacter ludwigii, Stenotrophomonas maltophilia, Pseudomonas monteilii, Bacillus anthracis, and Cellulosimicrobium funkei) were present as potent harmful bacteria to human. Surprisingly, both the human and plant pathogenic Klebsiella pneumoniae subsp. pneumonia was present. Bacillus altitudinis was present as a plant pathogen. Lysinibacillus sphaericus, an insect pathogen, and Ochrobactrum pseudogrignonense, a mushroom pathogen, were also present. The results of this study confirmed that several kinds of pathogenic bacteria were present in the agricultural by-products for the mushroom cultivation medium imported into Korea. Our work suggests that hygiene inspection and management is urgently needed for imported agricultural by-products to be safely used for mushroom production.

• Journal of Microbiology and Biotechnology
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• v.12 no.4
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• pp.610-616
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• 2002

The growth-inhibiting effects of Pinus densiflpora leaf-derived materials on nine human intestinal bacteria were investigated using the impregnated paper disk method, and their activities were compared with those of 13 commercially available terpenes. The biologically active constituent of the extract of P densiflora leaf was characterized as the monoterpene (1R)-(+)-$\alpha$-pinene by various spectroscopic analyses. Responses varied according to bacterial strain, chemicals, and dose. At 10 mg/disk, limonene and (1R)-(+)-$\alpha$-pinene strongly inhibited the growth of Clostridium perfringens, Staphylococcus aureus, and Escherichia coli, without adverse effects on the growth of five lactic acid-bacteria (Bifidobacterium adolescentis, B. bifidum, B. longum, Lactobacillus acidophilus, and L. casei). Little or no inhibition against seven bacteria was observed with anethole, borneol, camphor, caryophyllene, 1,8-cineole, estragole, linalool, and $\alpha$-terpineol. Structure-activity relationship revealed that (1R)-(+)-$\alpha$-pinene had more growth-inhibiting activity against C. perfringens than (1R)-(+)-$\beta$-, (1S-(-)-$\alpha$-, and (1S-(-)-$\beta$-pinenes. Furthermore, the growth-inhibition against L. casei was much more pronounced in (1R)-(+)-$\beta$- and (In-(-)-$\beta$-pinenes than (1R)-(+)-$\alpha$- and (1S)-(-)-$\alpha$-pinenes. These results indicate that the (+)-$\alpha$ form seems to be required against C. perfringens and $\beta$ form against L. casei for growth-inhibiting activity. Morphologically, most strains of C. perfringens were damaged and disappeared at 5 and 2 mg/disk of (1R)-(+)-$\alpha$-pinene. Morphological study revealed that (1R)-(+)-$\alpha$-pinene had more growth-inhibiting activity against C. perfringens than (1R)-(+)-$\beta$-, (1S)-(-)-$\alpha$-, and (1S)-(-)-$\beta$-pinenes. As naturally occurring growth-inhibiting agents, the Pinus leaf-derived materials described above could be useful preventive agents against diseases caused by harmful intestinal bacteria such as clostridia.

• Korean Journal of Environmental Agriculture
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• v.30 no.2
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• pp.118-124
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• 2011

BACKGROUND: Development of water recycle technologies is important for human health and sustainable agriculture. However, few studies have been conducted to examine the purification methods or the water quality of reclaimed wastewater in Korea. METHODS AND RESULTS: In this study, the different wastewaters including reclaimed wastewater and waste nutrient solution (NS) were evaluated. The changes of water quality in reclaimed wastewater and NS were determined using ultraviolet (UV) treatment and sand filtration with charcoal. Our results showed that one of the most critical limitations of reusing wastewater was the presence of harmful pathogens that possibly cause human health risks. CONCLUSION(s): This study suggests that the application of UV treatment or combined with sand filtration on reclaimed wastewater and waste NS effectively removes the total coliform bacteria below the harmful or acceptable level. For future studies, a long-term field monitoring after applying reclaimed wastewater or NS is needed.

• Journal of Microbiology and Biotechnology
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• v.13 no.4
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• pp.529-536
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• 2003

The growth-inhibitory activity of Cassia tora seed-derived materials against seven intestinal bacteria was examined in vitro, and compared with that of anthraquinone, anthraflavine, anthrarufin, and 1-hydroxyanthraquinone. The active constituent of C. tore seeds was characterized as quinizarin, using various spectroscopic analyses. The growth responses varied depending on the compound, dose, and bacterial strain tested. At 1 mg/disk, quinizarin exhibited a strong inhibition of Clostridium perfringens and moderate inhibition of Staphylococcus aureus without any adverse effects on the growth of Bifidobacterium adolescentis, B. bifidum, B. longum, and Lactobacillus casei. Furthermore, the isolate at 0.1 mg/disk showed moderate and no activity against C. perfringens and S. aureus. The structure-activity relationship revealed that anthrarufin, anthraflavine, and quinizarin moderately inhibited the growth of S. aureus. However. anthraquinone and 1-hydroxyanthraquinone did not inhibit the human intestinal bacteria tested. As for the morphological effect of 1 mg/disk quinizarin, most strains of C. perfringens were damaged and disappeared, indicating that the strong activity of quinizarin was morphologically exhibited against C. perfringens. The inhibitory effect on aflatoxin $B_1$ biotransformation by anthraquinones revealed that anthrarufin ($IC_50,\;11.49\mu\textrm{M}$) anthraflavine ($IC_50,\;26.94\mu\textrm{M}$), and quinizarin ($IC_50,\;4.12\mu\textrm{M}$), were potent inhibitors of aflatoxin ${B_1}-8,9-epoxide$ formation. However, anthraquinone and 1-hydroxyanthraquinone did not inhibit the mouse liver microsomal sample to convert aflatoxin $B_1$ to aflatoxin ${B_1}-8,9-epoxide$. These results indicate that the two hydroxyl groups on A ring of anthraquinones may be essential for inhibiting the formation of aflatoxin ${B_1}-8,9-epoxide$. Accordingly, as naturally occurring inhibitory agents, the C. tora seed-derived materials described could be useful as a preventive agent against diseases caused by harmful intestinal bacteria, such as clostridia, and as an inhibitory agent for the mouse liver microsomal conversion of aflatoxin $B_1$ to aflatoxin ${B_1}-8,9-epoxide$.

• Journal of Microbiology and Biotechnology
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• v.16 no.11
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• pp.1684-1689
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• 2006

Airborne microorganisms, which are currently termed bioaerosols, have received attention owing to the harmful effects they have on human health. As the concern over airborne microorganisms grows, there also grows an urgent need to study and develop efficient methods for controlling them. In this study, thermal energy using a thermal tube was tested as a control method, mainly against airborne E. coli. For a comparison, B. subtilis var. niger spores were utilized in the experimentation. It was found that the widely known inactivation conditions for microorganisms were not adequate against airborne microorganisms. The experimental results demonstrated the need for extensive studies that should investigate adequate and economic conditions to control against airborne bacteria. In this study, thermal energy exposed by the thermal tube demonstrated an inactivation performance for controlling E. coli bioaerosols.

• The Korean Journal of Food And Nutrition
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• v.36 no.3
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• pp.193-201
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• 2023

Prebiotics are known as components of intestinal microbiota that can improve and maintain human health status by stimulating the growth and activity of the intestinal tract as a method of controlling the intestinal environment. In this study, we examined whether 2'-fucosyllactose (FL) could affect intestinal microbial population and bowel activity. Water content and frequency of mouse feces were increased in the 2'-FL treated group at a high concentration (1,000 mg/kg), with brightness of the color enhanced and physical properties diluted. In addition, intestinal microbial analysis showed that harmful bacteria Clostridium and Staphylococcus strains were decreased and beneficial bacteria such as Lactobacillus strains were markedly increased in the group treated with a high concentration of 2'-FL compared to those in the control group. These findings suggest that administration of 2'-FL can maintain healthy bowel activity by reducing harmful bacteria population and improving diluted physical properties.

• Korean journal of food and cookery science
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• v.15 no.6
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• pp.555-564
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• 1999

The objective of this study was to investigate the preference of root vegetables and the inhibitory effect of the vegetables on harmful enzymes of intestinal bacteria. Two hundred fifty respondents in Seoul area surveyed to obtain information from Sep. 30 to Oct. 30, 1998. Respondents preferred Inpuomoea batatas (sweet potato, 4.05), Solanum tuberosum(potato, 3.97), Allium cepa(onion, 3.68), Codonopsis lanceolata(3.64) and Raponus sativus(redish, 3.60). The growth of B. breve K-110 was effectively increased by adding 0.5% extract of Solanum tuberosum(139%), Codonopsis lamceolate(145%), Dioscorea japonica(164%), Colocisia antiquorum(144%) extract to the medium. B. breve K-100 for beneficial bacteria, and E. coli HGU-3 or Bacteroides JY-6 for harmful bacteria were used to determine the inhibitory effect of root vegetables on harmful intestinal enzymes after co-culturing harmful and beneficial bacteria. The extract of Solanum tuberosum, Codonopsis lanceolata, Dioscorea japonica (yam) and Colocisia antiquorum (taroes) showed inhibitory effect on ${\beta}$-glucuronidase and tryptophanase of intestinal bacteria. The macromolecules were isolated from Solanum tuberosum, Codonopsis lanceolata, Dioscorea japonica and Colocisia antiquorum by Sephadex G-100 column chromatography. By adding these isolated marcromolecules to the medium, the growth of B. breve K-100 were also increased and high inhibitory effects on the ${\beta}$-glucuronidase and tryptophanase were measured. These results suggested that the harmful enzymes of intestinal bacteria were inhibited by consuming Solanum tuberosum, Codonopsis lanceolata, Dioscorea japonica and Colocisia antiquorum. Therefore, they could prevent gastrointestinal diseases.

• Journal of Food Hygiene and Safety
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• v.38 no.5
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• pp.279-286
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• 2023

Rapid and accurate detection of pathogenic bacteria is crucial for various applications, including public health and food safety. However, existing bacteria detection techniques have several drawbacks as they are inconvenient and require time-consuming procedures and complex machinery. Recently, the precision and versatility of CRISPR/Cas system has been leveraged to design biosensors that offer a more efficient and accurate approach to bacterial detection compared to the existing techniques. Significant research has been focused on developing biosensors based on the CRISPR/Cas system which has shown promise in efficiently detecting pathogenic bacteria or virus. In this review, we present a biosensor based on the CRISPR/Cas system that has been specifically developed to overcome these limitations and detect different pathogenic bacteria effectively including Vibrio parahaemolyticus, Salmonella, E. coli O157:H7, and Listeria monocytogenes. This biosensor takes advantage of the CRISPR/Cas system's precision and versatility for more efficiently accurately detecting bacteria compared to the previous techniques. The biosensor has potential to enhance public health and ensure food safety as the biosensor's design can revolutionize method of detecting pathogenic bacteria. It provides a rapid and reliable method for identifying harmful bacteria and it can aid in early intervention and preventive measures, mitigating the risk of bacterial outbreaks and their associated consequences. Further research and development in this area will lead to development of even more advanced biosensors capable of detecting an even broader range of bacterial pathogens, thereby significantly benefiting various industries and helping in safeguard human health

• Microbiology and Biotechnology Letters
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• v.50 no.4
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• pp.465-476
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• 2022

The importance of beneficial microorganisms, particularly probiotics, that coexist in the human body, is being increasingly recognized. Probiotics are representative health functional foods that provide health benefits to humans through the production of various metabolites, including short-chain fatty acids. However, the health benefits are strain-specific, and the use of each probiotic strain should follow guidelines that assure its safety. Accurate identification of the strain should be managed through genetic and phenotypic analyses of the strain. Besides, the functionality of probiotics should be disclosed in vitro and in vivo so that they can be used as legal functional ingredients (i.e., individual standards). In this review, we deal with the guidelines, including the technical factors related to probiotic strains. The common health effects of probiotic strains include proliferation of beneficial bacteria, control of harmful bacteria, and facilitation of bowel activities. Probiotics with various functionalities (e.g., body fat and cholesterol reduction, vaginal health, and improvement of skin's immune system) have been investigated as "individual standards of raw materials for health functional foods" provided by MFDS. In the future, various biotechnologies including synthetic biology can be applied to produce customized probiotics to improve human health.

• Journal of Applied Biological Chemistry
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• v.44 no.2
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• pp.65-70
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• 2001

Ethanol extracts of 38 vegetables were subjected to an in vitro screening for their growth-inhibitory activities towards Bifidobacterium bifidum, B. longum, Clostridium perfringens, Lactobacillus acidophilus, L. casei, and Escherichia coli using paper disc agar diffusion methods under anaerobic conditions. The responses varied with both bacterial strain and vegetable species. In a test with 20 mg/disc, Zingiber officinale extracts showed significant growth-inhibitory responses against B. bifidum, and strong inhibitions against L. casei were detected in the extracts of Chrysanthemum coronarium var. spatiosum and Lactuca sativa. The extracts of Allium sativum, Capsicum annuum, L. esculentum, L. esculentum var. cerasiforme, and Z. officinale showed strong inhibitory activities against C. perfringens, while moderate growth-inhibitory responses were observed in the extracts of C. ffutescens, Cucurbita moschata, Daucus carota var. sativa, and Rubus coreanus. However, all vegetable extracts showed no inhibitions against B. longum, L. acidophilus, and E. coli. In tests with 5 mg/disc, moderate inhibitions were observed in the extracts of C. coronarium var. spatiosum and L. sativa against L. casei and Z. officinale against B. bifidum. Vegetables extracts, except for C. coronarium var. spatiosum, L. sativa, and Z. officinale, did not affect the growth of beneficial bacteria. Strong inhibitory responses against C. perfringens were detected in the extracts of C. annuum and L. esculentum var. cerasiforme. Daily intake of vegetables may be important in the prevention of human diseases caused by the intestinal bacteria.