• The Korean Journal of Pesticide Science
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• v.17 no.1
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• pp.60-64
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• 2013

This study was performed in order to assess the risk of pesticide operator in korean rice paddy. The amount of exposure was calculated based on the informations of 48 kind of items that are used the form of a spraying in korean rice paddy. The risks of these pesticides were assessed to compare the exposure dosage with AOEL (acceptable operator exposure level) which was released form developed countries. When the operator spraying pesticides using motor sprayer, 17 items showed the risk for operator if the operator have not worn the personal protective equipment (PPE), and 6 items showed the risk for operator if the operator have worn the PPE. These result were indicated that the risk of pesticide operator was very high in korean rice paddy.

• Korean Journal of Environmental Agriculture
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• v.39 no.2
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• pp.106-113
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• 2020

BACKGROUND: Bumblebees have been shown to be very effective pollinators for most greenhouse tomatoes. Neonicotinoid insecticides are one of the most widely used pesticides in tomato crops in Korea. METHODS AND RESULTS: This study was carried out to investigate the toxicity of four neonicotinoid insecticides (clothianidin, dinotefuran, imidacloprid and thiamethoxam) to bumblebees based on the OECD guidelines (No.246, 247). The 48 hr LD₅₀ (㎍ a.i. /bumblebee) values in the acute contact toxicity tests were determined as follows: clothianidin, 0.467; dinotefuran, 3.741; imidacloprid, 3.967; and thiamethoxam, 0.747. The 48 hr LD₅₀ values in the acute oral toxicity tests were determined as follows: clothianidin, 0.005; dinotefuran, 0.056; imidacloprid, 0.325; and thiamethoxam, 0.018. The acute contact and oral toxicity of the test insecticides to bumblebees from most to least toxic was clothianidin > thiamethoxam > dinotefuran > imidacloprid. CONCLUSION: This study provided the basic toxicological data of neonicotinoid insecticides for bumblebees. In the near future, acute toxicity and mixture toxicity of other pesticides to bumblebees could be determined using this method.

• Korean Journal of Environmental Agriculture
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• v.37 no.3
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• pp.229-234
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• 2018

BACKGROUND: in vitro micronucleus test (vitMNT) is one of the promising alternative testing methods in genotoxicity test and was adopted as OECD test guideline for chemical registration. This study was conducted to optimize the cytoplasm conditions in vitMNT using Chinese hamster lung (CHL) cell. METHODS AND RESULTS: In this study cytokinesis-block micronucleus test was conducted. Mitomycin C and colchicine were used as positive control chemicals and were treated for three hours (short time) or twenty-four hours (long time). Giemsa solution was used for cell staining. For optimization of vitMNT, the final fixative was prepared as five concentrations (0%, 1%, 3%, 5%, and 25%) of acetic acid in methanol, and treatment times of the final fixative were varied under four conditions (immediately, one hour, four hours, and one day). CONCLUSION: Acetic acid at 1% in methanol as the final fixative was most adequate to preserve the cytoplasm around the nucleus in the interphase cells. Also, fixative treatment time of cell suspension for one to four hours may minimize the cell rupture. These results can be helpful for getting an accurate result promptly due to clear visual distinction to score micronucleus in vitMNT using giemsa solution.

• Journal of Food Hygiene and Safety
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• v.31 no.6
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• pp.458-464
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• 2016

Mulberry is considered a healthy food for antioxidants and many other beneficial nutrients. However, food safety concerns exist as this commodity scarcely passes through a sanitizing step due to the fragile nature of mulberry fruits. Fermented mulberry wort is one traditional way to utilize and preserve mulberries by mixing with sugars although hygienic practices are not often implemented. The purpose of this study was to investigate the fate of foodborne pathogens in fermented mulberry wort. Microbial population of inoculated E. coli in mulberry wort showed a decreasing pattern as the fermentation progressed. A quicker decrease was observed in the mulberry wort mixed with sugar at 1 to 0.8 ratio (w/w, mulberry: sugar) compared to 1 to 1 ratio, which could be due to the amount of acids generated during the fermentation process. When fully-fermented mulberry wort was contaminated with foodborne pathogens, they all decreased in population although their deceasing patterns varied depending on the species of tested bacteria. Steep deceases in population of inoculated foodborne pathogens were observed when the fermented wort was stored at $30^{\circ}C$ in comparisons to the other storage temperature, 5 and $20^{\circ}C$, regardless of bacterial species. This study necessitates the optimization of a sanitizing process during fermentation and storage of mulberry wort.

• The Korean Journal of Pesticide Science
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• v.15 no.4
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• pp.417-433
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• 2011

The study tested QuEChERS (quick, easy, cheap, effective, rugged and safe) sample preparation and HPLC-MS/ MS analysis for measurement of pesticide residues in fruit and vegetable. 240 kinds of pesticides spiked at three levels of 90, 45, 9 ng/g in lettuce and apple. For QuEChERS sample preparation, graphitized carbon black (GCB) was used for only lettuce in dispersive-SPE as absorbent. Matrix-matched standard calibration was used for quantitative analysis of HPLC-MS/MS. 218 pesticides (91%) in apple and 207 pesticides (86%) in lettuce showed recoveries in the range of 70~120% with $RSD{\leq}20%$. The lowest calibrated level (LCL) were 4.5 ng/g for 192 pesticides, 9 ng/g for 42 pesticides, 45 ng/g for 3 pesticides and 3 pesticides were not detected at all concentration levels. The results showed that the QuEChERS sample preparation and HPLC-MS/MS analysis can be applied to multi-residue analysis of pesticides in vegetables and fruits.

• Korean Journal of Weed Science
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• v.31 no.4
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• pp.368-374
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• 2011

This experiment was conducted to Investigate the herbicidal activity of naturally developed d-Limonene on the control of Sicyos angulatus L. which is destructive to biodiversity and ecosystem under greenhouse and open field condition. Among the tested concentrations, most efficacy of early foliar application(leaf stage with 1.5 and 3) of d-Limonene was found in $70mg\;mL^{-1}$, followed by $35mg\;mL^{-1}$, $17.5mg\;mL^{-1}$ in that order under greenhouse condition. The higher the d-Limonene concentration, the better the effect in greenhouse condition. In leaf stage with 2, 3 and 5 under open field condition, the higher the d-Limonene concentrations, the higher the weeding effect. The remarkable effect was, particularly, found in d-Limonene with $70mg\;mL^{-1}$ while little was found in the plants with d-Limonene with $35mg\;mL^{-1}$. In the case of 15 leaf stage of S. angulatus L. treated with d-Limonene under outside treatment effect was low. The treatment effect of d-Limonene under open field compared with greenhouse condition was more significant. It can be recommended that d-Limonene with $70mg\;mL^{-1}$ could control S. angulatus L. by 5 leaf stage.

• Weed & Turfgrass Science
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• v.5 no.4
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• pp.187-190
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• 2016

This study was conducted to determine phytotoxicity of domestic rice varieties and characteristic of sensitive gene involved in herbicide reaction of 4-HPPD (4-hydroxy phenylpyruvate dioxygenase) inhibiting herbicides. The five rice varieties were grown for 2 to 3 leaf stage on seedling trays and then transplanted into plastic pot: 4-Japonica type (Sangjubyeo, Sambaekbyeo, Sanduljinmi and Kumyoung) varieties and 1-Indica type variety (IR8). We trialled standard (14 g a.i. $10a^{-1}$) and double fold (28 g a.i. $10a^{-1}$) dose of benzobicyclon treatment at 10 days after transplanting in order to investigate phytoxicity. The Japonica-type Sangjubyeo showed no rice injury but Indica-type IR8 show 4-5 (standard) and 5-6 (double fold) phytoxicity levels. In spite of Japonica-type, Sanduljinmi and kumyoung showed 3-4 and 4-5 levels. Target resistant gene, Hydroxyphenylpyruvate dioxygenase inhibitor sensitive gene No.1 (HIS1) have been isolated from five domestic rice cultivars (Sangjubyeo, Sambaekbyeo, Sanduljinmi, Kumyoung and IR8). Results of the sequence through PCR, all five tested rice cultivars had HIS1 gene regardless to rice cultivars. And the difference between rice varieties from sequence of HIS1 were identified some variation in genes.

• Korean Journal of Food Science and Technology
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• v.43 no.2
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• pp.134-141
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• 2011

Two-hundred Bacillus cereus isolated from perilla leaf cultivation areas in Miryang, Korea were investigated for toxin genes and antibiotic susceptibility. Toxigenic patterns of isolates were identified to be 11 groups through toxin gene profiles. 21% of strains isolated from the perilla leaves had both enterotoxin and emetic toxin. Toxin genes entFM (100%), nheA (100%) and hblA, C, D (65.5%) were frequently found in the perilla leaves, whereas EM (21.0%) was less common. Most isolates were susceptible to 10 antibiotics, but they were highly resistant to penicillin (100%), ampicillin (100%), oxacillin (94.9%), amoxicillin-clavulanic acid (95.6%), cefazolin (78.2%), and rifampicin (58.0%). These results indicate that food-borne outbreak caused by B. cereus might lead to diarrhea and emetic syndromes.

• Journal of Food Hygiene and Safety
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• v.30 no.3
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• pp.249-257
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• 2015

The purposes of this study were to develop a small scale post-harvest facility, and consequently to evaluate the effects of applying the facility along with hygiene education on the level of microbial safety in Korean leeks production. A total of 135 samples were collected at three Korean leeks farms in Yangju, Gyeonggi province. Food safety indicators (Aerobic plate count (APC), coliform count, and Escherichia coli) and foodborne pathogens (E. coli O157:H7, Salmonella spp., Staphylococcus aureus, Listeria monocytogenes, and Bacillus cereus) on/in the samples were assessed. The microbial load measured as APC with harvesting tools such as comb, chopping board, and knife, at the farms where the small scale post-harvest facility had been operated (Farms A and B) was lower than that at another farm having no post-harvest facility (Farm C) by 1.44~2.33 log CFU / $100cm^2$. Moreover, the chopping board from Farm C was observed being contaminated with B. cereus at 6.03 log CFU / $100cm^2$. The coliform counts from the samples increased by 0.57~1.89 log CFU/g after leeks was submerged in ground water for washing. E. coli was recovered from leeks, soil, and the ground water used in the washing process, while no E. coli O157:H7, Salmonella spp., and L. monocytogenes was detected. Our results indicated that the small scale post-harvest facility developed in this study as well as the hygiene education played an important role in enhancing the level of microbial food safety in the leeks production environment. However, a disinfection technique could be needed during the washing step in order to prevent a potential contamination.

• Korean Journal of Environmental Agriculture
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• v.35 no.3
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• pp.211-215
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• 2016

BACKGROUND: The commercial biopesticides containing Chenopodium ambrosioides L. extracts which have been registered as one of the ingredients of the commercial biopesticide by the organic agriculture materials, and have been widely used in Republic of Korea. However, the quantitative analysis method of the active substances for the commercial biopesticides containing C. ambrosioides L. extract has not been conducted.METHODS AND RESULTS: To analyze the quantitative analysis of ascaridole, carvacrol, and p-cymene as active substances of C. ambrosioides L. extract, hydrophilic lipophilic balance cartridge was used for solid phase extraction. The active substances were analyzed by the gas chromatography with flame ionization detector. The limit of quantitation values of ascaridole, carvacrol, and p-cymene were 10, 5, and 2 mg/L, and the recovery rates were 96.3, 84.0, and 82.5% in liquid products and 98.3, 99.1, and 97.3% in solid products, respectively. The total content of ascaridole, carvacrol, and p-cymene in the commercial biopesticides was ranged from 0.08 to 12.75%.CONCLUSION: From these results, this method was suitable for the quantitative analysis of the active substances of commercial biopesticides containing C. ambrosioides L. extract.