• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.4
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• pp.637-642
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• 2010

Pre-treatment steps of fresh produce as Saengshik raw materials are followed by initial clean-up, dipping, primary washing, and cutting. Hypochlorous acid solution was applied in the dipping step to reduce natural microflora. Also, procedures were changed by cutting, dipping and then primary washing, and the efficacy of hypochlorus acid was evaluated. Potatoes, carrots, kales, and angelicas were submerged in water or 100 ppm of hypochlorous acid for 5 min. After initial clean-up, the aerobic plate counts of potatoes, carrots, kales and angelicas were 4.7, 5.3, 5.6, and 5.7 log CFU/g, respectively. When samples were submerged into water, it only reduced the population of natural microflora by 0.2 to 1.1 log CFU/g, whereas when treated with hypochlorous acid, it reduced the population by 0.5 to 2.8 log CFU/g. Reductions of natural microflora in green leafy vegetables were more highly achieved than bulbs such as potatoes and carrots. However, the numbers of natural microflora were increased after cutting step. To control the cross contamination at the cutting process, the process was changed as follows: initial clean-up, cutting, dipping in hypochlorous acid, and then primary washing. It showed effective reduction of the population by 2.3 to 3.2 log CFU/g. Hypochlorous acid solution could be useful as a sanitizer for surface washing of fresh vegetables.

• Journal of Life Science
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• v.29 no.11
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• pp.1294-1303
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• 2019

Perchlorate is an anionic pollutant that is very soluble and stable in water. It has been detected not only in soil/ground water but also in surface water, drinking water, food, fish, and crops. Perchlorate inhibits iodine uptake by the thyroid gland and reduces production of thyroid hormones that are primarily responsible for regulation of metabolism. Although various technologies have been developed to remove perchlorate from the environment, biodegradation is the method of choice since it is economical and environmentally friendly. However there is limited information on perchlorate biodegradation in salt environment such as salt water. Therefore this paper reviews biodegradation of perchlorate in salt water and related microorganisms. Most biodegradation research has employed heterotrophic perchlorate removal using organic compounds such as acetate as electron donors. Biodegradation research has focused on perchlorate removal from spent brine generated by ion exchange technology that is primarily employed to clean up perchlorate-contaminated ground water. Continuous removal of perchlorate at up to 10% NaCl was shown when bioreactors were inoculated with enriched salt-tolerant perchlorate-reducing bacteria. However the reactors did not show long-term stable removal of perchlorate. Microorganisms belonging to ${\beta}$- and ${\gamma}$-Proteobacteria were dominant in bioreactors used to remove perchlorate from salt water. This review will help our understanding of perchlorate removal from salt water to develop a decent biotechnology for the process.

• Korean Journal of Food Science and Technology
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• v.54 no.1
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• pp.103-108
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• 2022

This study investigated the strains and fermentation characteristics of used to ferment a mixture of rice and soybeans to manufacture low-salt doenjang for flavoring. The soybean and rice mixture was fermented using three selected strains of Aapergillus oryzae and Bacillus sp. The changes in quality of the fermented products were found to be dependent on the aging period. Therefore, the strain and a suitable aging period were seleted based on the increases in AN, total sugar, and reducing sugar. The fermented products were prepared and mixed, using the selected or commercially available strains (the sample and control, respectively), to create low-salt doenjang. Following this, their characteristics were compared. The sample had a higher content of taste-related ingredients(free amino acid, nucleic acid-related substances) than the control. Using the selected strain to ferment a rice and soybean mixture will thus be expected to enhance the flavor of industrially produced seasoned doenjang.

• Research in Plant Disease
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• v.20 no.2
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• pp.112-118
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• 2014

A liquid bio-formulation containing chitinolytic bacteria, chitin and their products was assessed for its potential biological control against root-knot nematodes on cucumber. The bio-formulation was prepared by cultures of three chitinolytic bacteria, Chromobacterium sp. strain C-61, Lysobacter engymogenes and Serratia plymuthica in minimal medium supplemented with chitin. Under pot conditions, the bio-formulation showed better growth of cucumber plants, and less root galls and population density of Meloidogyne spp. than control media without the bio-formulation. In a greenhouse, 75-fold diluted bio-formulations were treated instead of water around cucumber plants through hoses for drip irrigation six times at 5-day intervals from the transplanting date. After 30 and 60 days, the treatment provided about 7% and 10% enhancement in the plant height and about 78% and 69% reduction in population density of Meloidogyne spp. in the rhizosphere, respectively. In addition, the experiments showed that the control effects occurred only in the soils contacted with the bio-formulation. Undiluted bio-formulations were drenched three times at 10-day intervals around cucumber plants severely infested with Meloidogyne spp. The treatment showed about 37% plant enhancement without dead plants compared with 37% death in the untreated control, and about 82% nematode reduction. These results suggest that the bio-formulation can be practically used to control the root-knot nematode on cucumber.

• Food Science of Animal Resources
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• v.25 no.1
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• pp.13-19
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• 2005

The radio-sensitivity of pathogens and the effect of irradiation on microbiologican safety and mutagenicity of meat products such as seasoned and cooked beef and ham were investigated. Samples were radiation-sterilized and inoculated at 10/sup 7/ cfu/g with each of the four pathogens including Salmonella typhimurium, Escherichia coli, Staphylcoccus aureus, and Listeria ivanovii. No viable cells of pathogens were observed in the sample irradiated with 3 kGy. The D/sub 10/ value of inoculated pathogens in seasoned and cooked beef and ham were 0.24∼0.48 and 0.39∼0.45, respectively. Results of Ames test performed with non-irradiated and irradiated seasoned and cooked beef and ham were both negative at the level of 625, 1,250, 2,500, 50,000, and! 10,000 ㎍ sample/plate, respectively. Results indicate that low dose (2∼3 kGy) irradiation is effective to ensure safety for seasoned and cooked beef and ham with toxicological wholesomeness.

• Korean Journal of Food Science and Technology
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• v.54 no.1
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• pp.75-79
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• 2022

Fresh, washed ginseng can be contaminated with microorganism loads as high as 6.5 log CFU/g for total bacteria and 4.3 log CFU/g for mold. The goal of this study was to test eight antibacterial agents on ginseng. Immersing fresh ginseng washed in 1% (w/w) sodium citrate, sodium diacetate, sodium acetate, citric acid, and sodium lactate solution for 1 h resulted in a bactericidal effect of 31.0-97.5% for total bacteria. Among the organic acids, sodium citrate had the best antibacterial effect, with total bacteria reduced from 6.5 log to 4.9 log CFU/g. A 1% (w/w) vitamin B₁ lauryl sulfate solution with surfactant function by hydrophilic and hydrophobic sites can reduce 2.7 log CFU/g (99.8% inactivation) on total bacteria. In the 1% (w/w) calcium oxide solution, total bacteria were reduced by 3 log, showing an excellent inactivation effect of 99.9%. Calcium oxide is a highly useful material for inactivation of microorganisms in fresh ginseng.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.1B
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• pp.153-160
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• 2008

To estimate microbial contaminant loading discharged from diffuse sources, rainfall runoff of six rainfall events were monitored at three study watersheds of forestry and agricultural land use. Monitored indicator microorganism constituents were total coliform (TC), fecal coliform (FC), Escherichia coli (EC), and fecal streptococcus (FS). Soil loss during elevated flow rate caused higher suspended solid concentrations. Indicator microorganism concentrations were closely related with flow rate. TC event mean concentration (EMC) from unpolluted forestry was $5.3{\times}10^3CFU/100ml$, FC EMC was $1.4{\times}10^3CFU/100ml$, EC EMC was $1.1{\times}10^3CFU/100ml$, and FS EMC was $2.9{\times}10^2CFU/100ml$. From a watershed with agricultural-forestry land use, TC EMC was $1.7{\times}10^5CFU/100ml$, FC EMC was $8.5{\times}10^4CFU/100ml$, EC EMC was $8.9{\times}10^4CFU/100ml$, and FS EMC was $3.4{\times}10^4CFU/100ml$. Mixed land use of agricultural-forestry with bigger area, TC EMC was $1.9{\times}10^5CFU/100ml$, FC EMC was $9.6{\times}10^4CFU/100ml$, EC EMC was $7.0{\times}10^4CFU/100ml$, and FS EMC was $5.1{\times}10^4CFU/100ml$.

• Journal of the Mineralogical Society of Korea
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• v.20 no.4
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• pp.357-366
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• 2007

Microorganisms participate in a variety of geochemical processes such as weathering and formation of minerals, leaching of precious metals from minerals, and cycling of organic matter The objective of this study was to investigate biogeochemical processes of iron leaching from magnetite ore by iron-reducing bacteria isolated from intertidal flat sediments, southwestern part of Korea. Microbial iron leaching experiments were performed using magnetite ore, Shinyemi magnetite ore, in well-defined media with and without bacteria at room temperature for a month. Water soluble Fe and Mn during the leaching experiments were determined by ICP analysis of bioleached samples, and the resulting precipitated solids were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The extent of iron leaching from magnetite in the aerobic conditions (Fe = 15 mg/L and Mn = 3.41 mg/L) was lower than that in the anaerobic environments (Fe = 32.8 mg/L and Mn = 5.23 mg/L). The medium pH typically decreased from 8.3 to 7.2 during a month incubation. The Eh of the initial medium decreased from +144.9 mV to -331.7 mV in aerobic environments and from -2.3 mV to -494.6 mV in anaerobic environments upon incubation with the metal reducing microorganisms. The decrease in pH is due to glucose fermentation producing organic acids and $CO_2$. The ability of bacteria to leach soluble iron from crystalline magnetite could have significant implications for biogeochemical processes in sediments where Fe(III) in magnetite represents the largest pool of electron acceptor as well as to use as a novel biotechnology for leaching precious and heavy metals from raw materials.

• Microbiology and Biotechnology Letters
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• v.20 no.1
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• pp.1-5
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• 1992

Antibacterial activity of the water-soluble portion of Ulmus pzcmila L. extract against 10 bacterial species was studied by both cylinder plate dilution method and broth dilution test tube method. Inhibitory effect of the extract on the bacteria was also investigated by plotting bacterial survival at various concentration of the extract. The crude extract exhibited antibacterial activity against all of the tested bacterial species with exception of K pneurnoniae. The fractions of the extract prepared by CM Sephadex-C 50 ion exchange chromatography were also subjected to test the antibacterial activity, and the activity was studied after autoclaving for 20 minutes.

• Microbiology and Biotechnology Letters
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• v.26 no.5
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• pp.373-378
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• 1998

This study was performed to investigate antimicrobial effects and their actions of the ethanol extracts of 12 spices against Lactobacillus plantarum and Leuconostoc mesenteroides, which are related to Kimchi fermentation. The cardamon, thyme, and cumin ethanol extracts among 12 spices showed antimicrobial activities against Lac. plantarum, not against Leu. mesenteroides through paper disc method. The growth of Lac. plantarum was inhibited in MRS broth containing each extracts of cardamon (>4%), thyme (>4%) and cumin (>1%). SDS-PAGE and transmission electron micrographs showed that the cell walls and membranes were disrupted and the cytoplasmic components were leaked in strains treated with ethanol extracts.