• Food Science and Preservation
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• v.18 no.5
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• pp.627-635
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• 2011

This study was conducted to assess the effects of the removal of pesticide residues and microorganisms from yuja (Citrus junos Sieb ex Tanaka) using a surface-washing system, under the following washing conditions: 0.11, 0.42, and 0.73 m/s spray rotation speeds; 0.6, 0.9, and 1.2 MPa water pressure and 0.046, 0.092, and 0.138 m/s conveying speeds. Tap-water treatment was used as the control. The washing efficiency when using squid ink was highly correlated with the conveying speed and the spray rotation speed. In addition, the highest washing efficiency was achieved when the water pressure was 0.9 MPa. The microorganisms were reduced to 0.40 log CFU/g for the tap-water treatment, and all the treatments, except those at the conveying speed of 0.138 m/s and the spray rotation speed of 0.11 rpm (6.07 log CFU/g), produced higher removal efficiencies compared with the tap-water treatment. Reductions of 2.20 and 2.05 log CFU/g were achieved at the spray rotation speeds of 0.42 and 0.73, respectively. The largest reductions were observed when the conveying speed was 0.046 m/s. Higher pesticide residue removal efficiency values were obtained at slower conveying speeds and higher spray rotation speeds. Higher than 50% removal efficiency was achieved when the spray rotation speed was 0.046 m/s for spirodichlofen, deltamethrin, benomyl, thiophanate-methyl, and acequinocyl. Especially, the removal efficiency for benomyl and thiophanate-methyl was more than 90%. It can thus be concluded that the pesticide residues in yuja can be effectively reduced by washing the latter with a less-than-0.092-m/s conveying speed and a higher-than-0.42-m/s spray rotation speed.

• Journal of Food Hygiene and Safety
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• v.37 no.4
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• pp.260-270
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• 2022

In this study, we tested for pesticide residues in 114 samples representing 20 different types of fruit circulating in Gyeonggido. A total of 341 pesticides were identified via a multi-residue method using GC-NPD, GC-ECD, GC-MSMS, and LC-MSMS. In whole fruit, pesticides were detected in 48 cases, with a concentration range of 0.0025-0.1663 mg/kg. In the peels, pesticides were detected in 85 cases, with a concentration range of 0.0026-4.7185 mg/kg and a higher average concentration than was found in whole fruit. In the pulp, pesticides were detected in 8 cases, with a concentration range of 0.0021-0.0993 mg/kg. In most of the peels, pesticides were detected below MRL. In the kiwi peel, deltamethrin (with an MRL of 0.05 mg/kg) was detected at 0.1020 mg/kg. Since MRLs are applied to whole fruit, these levels are not unsuitable for ingestion. However, washing is recommended before ingestion to promote healthier and safer inclusion of the peel in the diet. Continuous monitoring of the peel and pulp is indicated.

• Journal of Food Hygiene and Safety
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• v.38 no.4
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• pp.211-216
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• 2023

A total of 100 commercially available olive oil products were analyzed for 179 pesticide residues using gas chromatography-tandem mass spectrometry (GC/MS/MS). The olive oil samples were mixed with organic solvents, centrifuged and frozen to remove fat, and pesticide residues were analyzed using the "quick, easy, cheap, effective, rugged, and safe" (QuEChERS) method. The determination coefficient (R²) of the analysis method used in this study was ≥0.998. The detection limit of the method ranged 0.004-0.006 mg/kg and its quantitative limit ranged 0.012-0.017 mg/kg. The recovery rate (n=5) measured at the level ranging 0.01-0.02, 0.1, and 0.5 mg/kg ranged 66.8-119.5%. The relative standard deviation (RSD) was determined to be ≤5.7%, confirming that this method was suitable for the "Guidelines for Standard Procedures for Preparing Food Test Methods". The results showed that a total of 151 pesticides (including difenoconazole, deltamethrin, oxyfluorfen, kresoxim-methyl, phosmet, pyrimethanil, tebuconazole, and trifloxystrobin) were detected in 64 of the 100 olive oil products. The detection range of these pesticide residues was 0.01-0.30 mg/kg. The percentage acceptable daily intake (%ADI) of the pesticides calculated using ADI and estimated daily intake (EDI) was 0.0001-0.1346, indicating that the detected pesticides were present at safe levels. This study provides basic data for securing the safety of olive oil products by monitoring pesticide residues in commercially available oilve oil products. Collectively, the analysis method used in this study can be used as a method to analyze residual pesticides in edible oils.

• Korean Journal of Food Science and Technology
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• v.44 no.5
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• pp.628-633
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• 2012

This study investigated the washing efficiency of electrolyzed water for the removal of microorganisms and pesticide residues from Chinese cabbage. Initial total bacteria and coliform counts were 6.64 and 3.56 log cfu/g respectively. After washing, total bacteria count of tap water (TW) were 5.97 log cfu/g and low alkaline electrolyzed water (LAlEW) and strong acidic electrolyzed water (SAcEW) were 1.63-4.67 log cfu/g. Especially SAcEW-100 was found to the most effective method of washing the cabbages. After washing, the coliform count was dramatically reduced. The removal rate of pesticide residues by NaClO treatment (36.93-50.13%) was greater than that of TW treatment (32.28-38.46%). The removal rate of LAlEW-100 and SAcEW-100 was 63.79 and 78.30% respectively, and was higher than those of TW and NaClO treatments. The vitamin C content of the Chinese cabbages after all treatments did not differ significantly. Consequentially, the electrolyzed water was found to be effective to remove bacteria and pesticide residues from Chinese cabbage without affecting quality.

• Korean journal of applied entomology
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• v.48 no.1
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• pp.53-57
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• 2009

Biological Characteristics of Lycorma delicatula and insecticidal activity of some insecticides against nymphs of L. delicatula was investigated. Nymph of L. delicatula had 4 instars, and color of body was black. There were white spots on the body of 1st-3rd nymph. Upper body became red at 4th nymph. Adult forewings were brownish, and had black spots. Color of hind wing were red. The egg mass was covered with a yellowish brown secretion. The adult of L. delicatula emerged once a year. Among test insecticides, deltamethrin 1% EC and fenitrothion 50% EC showed very quick and strong insecticidal activity against the 2nd-3rd nymphs of L. delicatula. Imidacloprid 4% SL and clothianidin 8% SC showed 100% insecticidal activity at 24h after treatment. Thiacoprid 10% SC revealed the weakest insecticidal activity among the insecticides tested.

• Korean journal of applied entomology
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• v.32 no.3
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• pp.259-264
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• 1993

The experiment was carried out to investigate Insecticide susceptibility of the spiraea aphid (Aphis citricola) in apple orchards In Korea, using dipping method. Although insecticIde susceptibility vaned with local and seasonal populations, the susceptibility to demeLon S-rnethyl and phosphamidons was different from that Lo the other insecticides. The LCso values were 10 ppm for deltamethrin and chloropyrifos, 103 ~ 629 ppm for demeton S-methy1, acephate, phosphamidon, monocrotophos and vamldothion, 12,200 ppm for EPN, and 1,745 ppm for pirimicarb. 'When Insecticide susceptibility was compared between the S-clone selected from a population on the host plant spiraea and the R-clone selected from a population on the apple tree, the resistance ratio as expressed by RIS ratio of $LC_{50}$ was 78 for phosphamidon and 546 for pirimicarb. Esterase zymogram determined by the agar gel electrophoresIs revealed a significant difference between the clones. The activity of the E2, E5, E6 and E7 of the R-clone was higher than that of the S-clone, It is suggesLed that the Increased esterase activity may be involved in the mechanism of insecticide resistance in the spiraea aphid, although the involvement of other factor(s) may not be ruled out.

• Journal of Dairy Science and Biotechnology
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• v.33 no.1
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• pp.27-34
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• 2015

The aim of this study was to optimize a simple, fast, and economic analytical method for the simultaneous determination of various pesticides (aldrin, p,p'-DDT, o,p'-DDT, p,p'-DDE, ${\alpha}$-endosulfan, ${\beta}$-endosulfan, dieldrin, heptachlor, permethrin, chlordane, deltamethrin, diazinon, bifenthrin, methoprene, propargite, fenpropathrin, cypermethrin, fenvalerate, and fenpropathrin) in milk by using dispersive solid phase extraction (SPE). In this study, two different extraction methods (low temperature cleanup and liquid-liquid partitioning), which were followed by a cleanup process based on dispersive-SPE, were evaluated and compared for the 19 pesticides. The results for all the pesticides were determined by gas chromatography mass spectrometry (GC/MS) with selected-ion monitoring mode, and the matrix effect of the method was evaluated. Comparison of these approaches yielded higher and more consistent recoveries of most pesticides at fortification levels of $1{\mu}g/mL$ using low-temperature fat precipitation, followed by cleanup process based on dispersive-SPE with PSA and C18 as sorbents, than other preparation process. The relative standard deviation was <20 % and the combination of this method were very effective for the cleanup.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2003.10a
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• pp.57-69
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• 2003

It is well known that many pesticides possess hormonal activity, and affect the developments of wildlife and mammals including human. Currently, pyrethroid insecticides are in worldwide use to control in and outdoor pests, providing potential far environmental exposure. Hormonal activities of these pyrethroid insecticides, however, have been little studied, and the developmental effects of them were no reported. Therefore, we firstly examined the potential estrogenic activities of some pyrethroid insecticides (permethrin, cypermethrin, tetramethrin, deltamethrin, sumithrin, fenvalerate and bioallethrin) by immature rat uterotrophic assay, luciferase reporter gene assay and Calbindin-D$\sub$9k/ (CaBP-9k) gene expression assay. Uterine wet weights were increased by permethrin and the permethrin-induced weights were inhibited by ICI 182780 in the uterolrophic assay. On the other hand tetramethrin significantly reduced uterine and vaginal wet weights, and also inhibited the E2-induced weight increases at all doses tested. Cypermethrin and sumithrin had a tendency to increase uterine weights, although not statistically significant. Permethrin and cypermethrin dose-dependently increased the luciferase activity in reporter gene assay. Northern blot analysis showed that permethrin induced CaBP-9k mRNA expression whereas tetramethrin inhibted. Subsequent studies were conducted to investigate the possible developmental effects of four pyrethroid insecricides (permethrin, cypermethrin, sumithrin and teramethrin). Either diethlbestrol (DES) or 17${\beta}$ -estradiol (E2) was used as a reference control in this study. Pyrethroid insecticides were administered to Sprague Dawley rats via subcutaneous injection at 6 to 18 days of gestation or 1 to 5 days after birth. In utero treatment of permethrin (10mg/kg/day) in female rat resulted in significant increases in uterine and ovarian weights while significant decreases in serum E2 concentration, uterine and ovarian ER${\alpha}$ mRNA levels. Sumithrin and permethrin led to acceleration in vaginal opening of female rat, while delay in preputial separation of male after neonatal treatment. Anogenital distances of PND 18 were significantly reduced in sumthrin-treated, and permerhrin-treated male rats after neonatal treatment. All the pyrethroid insecticides tested caused significant increases in uterine weights on PND 18, while significant reductions in the first diestrus phase when neonataly treated. In addition, exposure to pyrethroids in neonatal period led to significant reduction in relative brain weight in female rat on PND 18, but its weight was recovered in diestrus phase. In summary, Our experimental data demonstrate the possibilities of developmental effects of pyrethroid insecticides via estrogenic or antiestrogenic activity.

• Journal of Food Hygiene and Safety
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• v.14 no.2
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• pp.201-215
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• 1999

Limited information is available on the acceptability of Korean MRLs(maximum residue limits) and the health risk based on the pesticide exposure by food intake. The aim of this study was to evaluate TMDI(theoretical maximum daily intake) and EDI(estimated daily intake) for Korean by using MRLs, food intake, residue data, and correction factors, and compare with ADI(acceptable daily intake) in order to estimate the health risk based on the pesticide exposure. The study was performed in three steps. In the frist step, the residual pesticides in each category of food were investigated using the pesticide residue analytical data(1995-96) from officially approved organizations and the analytical data for poultry was adopted from Korean food code method. In the second step, TMDI was estimated from MRLs and food factors, and was compared with ADI. In the third step, the effectiveness of each culinary treatment (washing, peeling, steaming, boiling, and salting) was evaluated and EDI was calculated using pesticide residue data, food factor, and correction factor by treatment. TMDI obtained from MRLs and food intake, and food intake was summed as 1,100.99 g, which was 79.1% of total consumption. The percent ratio of TMDI to ADI for 156 pesticides was mostly below 80% and only 30 pesticides exceeded the ADI. In particular, non-treated EDI from pesticide residue data and food intake was summed up to about 43 $\mu\textrm{g}$/day/capita, and the rank was procymidone(8.6 $\mu\textrm{g}$) > maleic hydrazide(8.2 $\mu\textrm{g}$) > EPN(3.7 $\mu\textrm{g}$) > deltamethrin(3.5 $\mu\textrm{g}$) > cypermethrin(3.0 $\mu\textrm{g}$). The treated EDI calculated from pesticide residue data, food intake, and correction factor by culinary treatment was summed up to 13.7 $\mu\textrm{g}$/day/captia. The percentage of ADI was TMDI(79.74%) > non-treated EDI (0.17%) > treated EDI (0.04%), and the exposure level of Korean population to whole pesticides was below the level to produce health risk. Oncogenic risk of five pesticides used in Korea whose oncogenic potency(Q*) was known were assessed from TMDI and treated EDI. Dietary oncogenic risk for Korean was estimated to be 2.0$\times$10-3 on the basis of TMDI, 8.3$\times$10-7 on the basis of treated EDI. The oncogenic risk from TMDI exceeded the risk level(1$\times$10-6) of EPA, whereas the oncogenic risk from treated EDI and real exposure level lower than that of EPA.

• Korean journal of applied entomology
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• v.36 no.2
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• pp.172-178
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• 1997

There was a great variation in insecticide susceptibilities among field and laboratory populations of the beet armyworm, Spodoptera exigua (Hiibner). Unselected laboratory population, which had been reared for 6-7 generations in our laboratory without exposure to insecticides, was more susceptible than its parental field population in all tested insecticides. Two selected laboratory populations with parathion or deltamethrin showed much higher insecticide tolerance than did the unselected laboratory population in their own selection insecticide. The variation of the insecticide susceptibilities was highly correlated with esterase and acetylcholinesterase activities. Field and the selected laboratory populations had lower acetylcholinesterase activities and higher esterase activities than did the unselected laboratory population. Acetylcholinesterase of the field and the selected laboratory populations had higher Km values than did that of the unselected. In a population, Km values were varied among different developmental stages; acetylcholinesterase of the fifth instar larvae had the highest Km value among those of the other larval stages. Twenty one esterase bands were separated on 6.5% nondenaturing polyacrylamide gel from the whole body extracts of the fifth instar larvae. E2, E7, E8, Ell, El6, and El7 esterase bands were developed more frequently in the insecticides-selected populations than in the unselected population. These results suggest that the variation of insecticide susceptibilities of the beet armyworm includes both biochemical mechanisms: target site insensitivity and enhanced activity of detoxification enzyme.