• The Korean Journal of Pesticide Science
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• v.17 no.4
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• pp.343-349
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• 2013

Environment-friendly agro-materials tend to be preferred to chemical insecticides recently. For this reason, many studies are conducted to develop environment-friendly insecticides containing natural materials. The purpose of this study was to assess ecotoxicity for pepper extract and cassia oil (11.5+46%, A), pepper extract and cassia oil (23+34%, B), and pepper extract and lavender oil (40+10%, C). They are expected to prevent from pests especially diamondback moth, and can be used for agro-materials. Their formulation was emusifiable concentration (EC). Target species used to assess acute toxicity were aquatic invertebrate (Daphina magna), fish (Cyprinus carpio), honeybee (Apis mellifera L.) and earthworm (Eisenia fetida). The $EC_{50}$ value of A, B, and C to aquatic invertebrate were 0.46, 1.9, 0.25 mg $L^{-1}$ respectively and these values were moderately toxic according to standard of USEPA. In case of acute toxicity test to fish, the $LC_{50}$ of A, B, and C were 1.9, 2.9, 3.8 mg $L^{-1}$ respectively. A was category II in acute toxicity of fish and not acceptable to evaluation criteria of environment-friendly agro-materials. B and C were category III and acceptable. Acute contact and oral toxicity test to honeybee were conducted and the $LD_{50}$ of A, B, and C were > 100 ${\mu}g$ a.i. $bee^{-1}$ in both of tests. It indicated they were low toxic to honeybee. In case of acute toxicity test to earthworm, $LC_{50}$ of A, B, and C were 695, 988, and 564 mg $kg^{-1}$. In conclusion, pepper extract+cassia oil 57% EC and pepper extract+lavender oil 50% EC were expected to be used for environment-friendly insecticide materials with low risk against ecosystem and contribute to developing environment-friendly agro-materials.

• The Korean Journal of Pesticide Science
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• v.14 no.4
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• pp.339-346
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• 2010

The acute toxicity test of high bio-active plant essential oils was conducted with Lavender, Lemon eucalyptus and Cassia oils selected to develop environment-friendly insecticides. The results of acute oral toxicity using rats showed that $LD_{50}$ of over 2,000 mg/kg bw for Lavender, Lemon eucalyptus and Cassia oils. The calculated acute dermal $LD_{50}$ value of all testing materials was over 4,000 mg/kg bw. The Skin irritation test indicated that Lavender and Lemon eucalyptus oil have no irritation while Cassia oil has a moderate irritation. For the Eye Irritation test, the result showed no irritation for Lavender and Lemon Eucalyptus oil and irritation for Cassia oils. However, the irritation was not showed for Eye Irritationwashing test of Cassia oil. Consequently, the Lavender and Lemon eucalyptus oils were showed to be low in toxicity whereas Cassia oil indicated to cause a moderate irritation on the skin and eyes.

• The Korean Journal of Pesticide Science
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• v.15 no.3
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• pp.231-237
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• 2011

Highly bio-active plant essential extracts and oils from pepper, clove bud, rosemary and origanum which are selected to develop environment-friendly insecticides was studied for their acute toxicity. The results of acute oral toxicity using rats showed $LD_{50}$ value of over 2,000 mg/kg bw for pepper, clove bud, rosemary and origanum oils. The calculated acute dermal $LD_{50}$ value of pepper was over 4,000 mg/kg bw and anther testing materials was over 4,000 mg/kg bw. The skin irritation test showed that pepper, clove bud and rosemary oils had no irritation while origanum oil had a moderate irritation. According to the eye irritation test, it showed that there was no irritation for pepper and rosemary oils, while there were irritation for clove bud and origanum oils. Consequently, pepper and rosemary oils were shown to be low in toxicity whereas clove bud oil was indicated to cause a mild eye irritability and origanum oil, causing a moderate skin and eye irritability.

• Korean Journal of Environmental Agriculture
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• v.39 no.4
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• pp.343-351
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• 2020

BACKGROUND: Irrigation water is known to be one of the major sources of bacterial contamination in agricultural products. In addition, anti-microbial resistance (AMR) bacteria in food products possess serious threat to humans. This study was aimed at investigating the prevalence of foodborne bacteria in irrigation water and evaluating their anti-microbial susceptibility. METHODS AND RESULTS: Surface water (n = 66 sites) and groundwater (n = 40 sites) samples were collected from the Gyeongi and Gangwon provinces of South Korea during April, July, and October 2019. To evaluate the safety of water, fecal indicators (Escherichia coli) and foodborne pathogens (E. coli O157:H7, Salmonella spp., and Listeria monocytogenes) were examined. E. coli isolates from water were further tested for antimicrobial susceptibility using VITEK2 system. Overall, detection rate of foodborne pathogens in July was highest among three months. The prevalence of pathogenic E. coli (24%), Salmonella (3%), and L. monocytogenes (3%) was higher in surface water, while only one ground water site was contained with pathogenic E. coli (2.5%). Of the 343 E. coli isolates, 22.7% isolates were resistant to one or more antimicrobials (ampicillin (18.7%), trimethoprim-sulfamethoxazole (7.0%), and ciprofloxacin (6.7%)). CONCLUSION: To enhance the safety of agricultural products, it is necessary to frequently monitor the microbial quality of water.

• The Plant Pathology Journal
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• v.38 no.3
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• pp.194-202
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• 2022

Erwinia amylovora and Erwinia pyrifoliae cause fire blight and black-shoot blight, respectively, in apples and pears. E. pyrifoliae is less pathogenic and has a narrower host range than that of E. amylovora. Fire blight and black-shoot blight exhibit similar symptoms, making it difficult to distinguish one bacterial disease from the other. Molecular tools that differentiate fire blight from black-shoot blight could guide in the implementation of appropriate management strategies to control both diseases. In this study, a primer set was developed to detect and distinguish E. amylovora from E. pyrifoliae by conventional polymerase chain reaction (PCR). The primers produced amplicons of different sizes that were specific to each bacterial species. PCR products from E. amylovora and E. pyrifoliae cells at concentrations of 10⁴ cfu/ml and 10⁷ cfu/ml, respectively, were amplified, which demonstrated sufficient primer detection sensitivity. This primer set provides a simple molecular tool to distinguish between two types of bacterial diseases with similar symptoms.

• Journal of Food Hygiene and Safety
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• v.34 no.6
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• pp.542-550
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• 2019

To detect Escherichia coli from agri-food and production environments, a device based on IoT (internet of things) technology that can check test results in real time on a mobile phone has been developed. The efficiency of the developed device, which combines an incubator equipped with a UV lamp, a high-resolution camera and software to detect E. coli in the field, was evaluated by measuring the device's temperature, detection limit, and detection time. The device showed a difference between its programmed temperature setting and actual temperature of about 1.0℃. In a detection limit test performed with a single-colony inoculation, a color change to yellow and a florescent signal were detected after 12 and 15 h incubations, respectively. The incubation time also decreased along with increasing bacteria levels. When applying the developed method and device to various samples, including utensils, gloves, irrigation water, seeds, and vegetables, detection rates of E. coli using the device were higher than those of the Korean Food Code method. These results show that the developed protocol and device can efficiently detect E. coli from agri-food production environments and vegetables.

• Korean Journal of Environmental Agriculture
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• v.33 no.4
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• pp.414-418
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• 2014

BACKGROUND: Benzene, toluene, ethylbenzene and xylene (BTEX), which are volatile aromatic hydrocarbons and main constituents of gasoline, are neuro-carcinogenic organic pollutants in soil and groundwater. Korea Ministry of Environment has established the maximum permissible level of BTEX in arable soil to 1, 20, 50 and 15 mg/kg, respectively. METHODS AND RESULTS: To understand an arable soil contamination by BTEX, we collected 92 samples from the arable lands around oil reservoir, and analyzed the BTEX residue using a GC-MS with head-space sampler. A linear correlation between BTEX concentration and peak areas was detected with coefficient correlations in the range of 0.9807-0.9995. The method LOQ of BTEX was 0.002, 0.014, 0.084, and 0.038 mg/kg, respectively. Recoveries of 0.5 mg/kg BTEX were found to be 73.7-96.9%. The precision was reliable since RSD percentage (0.7-7.5%) was below 30, which was the normal percent value. Also, BTEX in all samples were detected under the LOQ. CONCLUSION: These results showed that the investigated arable soils around airport and oil reservoir in Korea were not contaminated by oils.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.1
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• pp.38-47
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• 2011

This study focused on health risk assessment via multi-routes of As exposure to establish a target cleanup level (TCL) in abandoned mines. Soil, ground water, and rice samples were collected near ten abandoned mines in November 2009. The As contaminations measured in all samples were used for determining the probabilistic health risk by Monte-Carlo simulation techniques. The human exposure to As compound was attributed to ground water ingestion. Cancer risk probability (R) via ground water and rice intake exceeded the acceptable risk range of $10^{-6}{\sim}10^{-4}$ in all selected mines. In particular, the MB mine showed the higher R value than other mines. The non-carcinogenic effects, estimated by comparing the average As exposure with corresponding reference dose were determined by hazard quotient (HQ) values, which were less than 1.0 via ground water and rice intake in SD, NS, and MB mines. This implied that the non-carcinogenic toxic effects, due to this exposure pathway had a greater possibility to occur than those in other mines. Besides, hazard index (HI) values, representing overall toxic effects by summed the HQ values were also greater than 1.0 in SD, NS, JA, and IA mines. This revealed that non-carcinogenic toxic effects were generally occurred. The As contaminants in all selected mines exceeded the TCL values for target cancer risk ($10^{-6}$) through ground water ingestion and rice intake. However, the As level in soil was greater than TCL value for target cancer risk via inadvertent soil ingestion pathway, except for KK mine. In TCL values for target hazard quotient (THQ), the As contaminants in soil did not exceed such TCL value. On the contrary, the As levels in ground water and polished rice in SD, NS, IA, and MB mines were also beyond the TCL values via ground water and rice intake. This study concluded that the health risks through ground water and rice intake were greater than those though soil inadvertent ingestion and dermal contact. In addition, it suggests that the abandoned mines to exceed the risk-based TCL values are carefully necessary to monitor for soil remediation.

• Journal of Microbiology and Biotechnology
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• v.27 no.12
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• pp.2141-2150
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• 2017

This study was conducted to develop a screening method using Colilert-18 and a device for the detection of E. coli from agri-food production environments and fresh vegetables. The specificity and sensitivity of Colilert-18 by temperature ($37^{\circ}C$ and $44^{\circ}C$) were evaluated with 38 E. coli and 78 non-E. coli strains. The false-positive rate was 3.8% (3/78) and 0% (0/78) at $37^{\circ}C$ and $44^{\circ}C$, respectively. The detection limit of E. coli at $37^{\circ}C$ at <1.0 log CFU/250 ml was lower than that at $44^{\circ}C$. The efficiency of the developed device, which comprised an incubator equipped with a UV lamp to detect E. coli in the field, was evaluated by measuring the temperature and UV lamp brightness. The difference between the set temperature and actual temperature of the developed device was about $1.0^{\circ}C$. When applying the developed method and device to various samples, including utensils, gloves, irrigation water, seeds, and vegetables, there were no differences in detection rates of E. coli compared with the Korean Food Code method. For sanitary disposal of culture samples after experiments, the sterilization effect of sodium dichloroisocyanurate (NaDCC) tablets was assessed for use as a substitute for an autoclave. The addition of one tablet of NaDCC per 50 ml was sufficient to kill E. coli cultured in Colilert-18. These results show that the developed protocol and device can efficiently detect E. coli from agri-food production environments and vegetables.

• Reproductive and Developmental Biology
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• v.36 no.2
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• pp.133-139
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• 2012

This study aims to examine the effect of Genetically Modified ${\beta}$-Carotene Biofortified Rice rice developed by simultaneous expression technology in NAAS on biological immunity. Accordingly, this study added Genetically Modified ${\beta}$-Carotene Biofortified Rice 25, 50% and general rice 50% as control group into diet and provided rats with the prescribed feeds and then measured the contents of immunoglobulin and cytokine in blood. As a result, male and female IgM, IgE, male IgG1, female IgG2a and TNF-a, IL5 and IL12 showed no significant difference; male IgG2a tended to decrease dependently on the combined concentration of Genetically Modified ${\beta}$-Carotene Biofortified Rice; female IgG1 showed significance with control group, but its association with diet was not found. The higher the dietary mixing ratio, the more the male and female IFN-a and female IL-4 contents, regardless of rice variety, and it was found that female IL6 content decreased significantly, but its association with diet was not found. The risk of beta carotene-enriched rice into environment and human body has not been reported yet. The digestion of Genetically Modified ${\beta}$-Carotene Biofortified Rice can be seen as "safe" as this test result showed no big difference between general rice and Genetically Modified ${\beta}$-Carotene Biofortified Rice, and its usability is full of suggestions.