• The Korean Journal of Pesticide Science
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• v.12 no.4
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• pp.323-334
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• 2008

This experiment was carried out to analyze for pesticide residues in 17 different types of the special of geographical indication. We purchased 3 cereal grains, nuts and seeds, 3 fruits, 8 vegetables, mushrooms and other plants (Korean medicines) mainly at the agricultural cooperative's joints markets. Total 209 pesticides including multi-analysed pesticides (204) and single-analysed pesticides (5 ; acephate, methamidophos, monocrotophos, omethoate, vamidothion) were analysed with a GC/MS/MS, an HPLC/UVD (PDA) and a GC/FPD. No. 83 method and single-analysed method (Screening of multi-pesticide residue in the special products of geographical indication) of Korea Food Code was selected for validation in recovery and interferences of matrice. The results were as follows: among the selected 17 the special products, the residual pesticides were detected in 8 types of the special products (40 in 302 samples, detection ratio; 13.2%). All of the samples were not detected over MRLs, but tebuconazole, procymidone and isoprothioran were detected with considerable high frequency. These results could be used as KFDA official methods for the analysis of pesticide residues in foods and reference data will be provided to the related institutions.

• Korean Journal of Food Science and Technology
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• v.41 no.6
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• pp.636-643
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• 2009

Residual fluoroquinolone levels in animal foods retailed in Korea were monitored according to the method outlined in Korea Food Code using HPLC-FLD and HPLC-ESI-MS/MS for confirmation. The optimum ion transitions were $360{\rightarrow}316$, 342 m/z for enrofloxacin, $332{\rightarrow}314$, 288 m/z for ciprofloxacin, $320{\rightarrow}301$, 230 m/z for norfloxacin, $334{\rightarrow}315$, 290 m/z for pefloxacin, $362{\rightarrow}318$, 261, 334 m/z for ofloxacin, and $262{\rightarrow}201$, 126 m/z for flumequin. Enrofloxacin, ciprofloxacin and norfloxacin residues were found in 12 out of 388 samples. These antibiotics were only found in chicken samples, while no residues were found in beef, pork, milk and egg samples. Using this monitoring method, detection rates of 3.1, 1.3, and 0.3% were obtained for enrofloxacin, ciprofloxacin and norfloxacin, respectively. The levels of enrofloxacin, ciprofloxacin and norfloxacin detected in food samples ranged from 0.01 to 0.73 mg/kg in 12 samples, 0.01-0.03 mg/kg in 5 samples, and 0.12 mg/kg in only a sample, respectively.

• Preventive Nutrition and Food Science
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• v.18 no.4
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• pp.263-268
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• 2013

In this study, the quick HPLC-MS/MS method for the simultaneous separation of 2-acetyl-4(5)-tetrahydroxybuthylimidazole (THI) and 4-(5)-methylimidazole (4-MI) in alkaline medium was used for caramel color and processed foods in Korea. After a simple sample pretreatment, 51 4-MI-labeled samples were positive for 4-MI and 2 also contained THI. The concentration of 4-MI was 260.5~24, $499.3{\mu}g/kg$ in caramel color, less than $LOD{\sim}1,712.5{\mu}g/kg$ in sauce, 1,242.3, $5,972.2{\mu}g/kg$ in balsamic vinegar, $2,118.3{\sim}5,802.4{\mu}g/kg$ in complex seasoning, $82.7{\sim}5,110.6{\mu}g/kg$ in curry, and $29.9{\sim}464.4{\mu}g/kg$ in soft drinks. The recovery rate of 4-MI was 97.1~111.0% in sauce and 81.9~110.0% in powder and that of THI was 83.6{\sim}106.4% in sauce and 61.2{\sim}99.4% in powder. Our results concluded a safe amount of 4-MI and THI compared to the limit of Korea additive code but the processed foods do not have a limit of caramel color and 4-MI in Korea. Therefore, research and monitoring of 4-MI and THI is needed for processed foods in Korea.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.12
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• pp.1779-1784
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• 2009

Establishment of simultaneous analysis method and monitoring for individually analyzing residual eight ergosterol biosynthesis inhibitors, EBI (difenoconazole, diniconazole, fenarimol, fenbuconazole, hexaconazole, myclobutanil, nuarimol and paclobutrazol) pesticides in commercial agricultural products, were conducted. The simultaneous analysis method for the pesticides was established using a GC/MS/MS for EBI pesticides. Residual amount of those pesticides were investigated in 989 commercial agricultural products (fifteen kinds of cereal grains, vegetables, beans, nuts, fruits and mushrooms) from seven metropolitan cities and eight provinces. In EBI pesticides analysis, linearity of GC/MS/MS analysis was 0.9974-0.9992, and that of recoveries were 86-135% with relative standard deviations (RSD) <20%. The limit of quantification (LOQ) of the method ranged from 0.5 to 5.0 mg/kg for eight EBI pesticides. According to the monitoring of the EBI pesticides in commercial agricultural products, difenoconazole, fenarimol, hexaconazole showed various residual levels (total frequency of 8/989 detection, 0.8%). Paclobutrazole showed in excess levels of the MRLs (maximum residue limits) for pesticides in one chard sample by the Korea Food Code. As a result of exposure assessment on the detected 8 individual pesticides, all pesticides (difenoconazole, fenarimol, hexaconazole, paclobutrazole) were evaluated as safe level in comparison to toxicologically acceptable daily intake.

• 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.

• Journal of Food Hygiene and Safety
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• v.25 no.2
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• pp.133-142
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• 2010

This study was performed to investigate awareness of hand washing, hand washing behavior, and the levels of indicator microorganisms on hands of food handlers who work in the food court and cafeteria of a university campus. The three methods used were questionnaire survey by interview, direct observation in restrooms, and microbiological examination according to the Food Code of Korea. A positive attitude toward hand washing compliance was reported by the responded food handlers; however, improper hand washing and poor hand hygiene of the food handlers were recognized by the unnoticed direct observation. Significant differences were found between the questionnaire survey and the direct observation (p < 0.05) in hand washing compliance after using the toilet, duration of hand washing, use of hand washing agent, washing different parts of the hands, hand-drying method, temperature of water, and method of turning off the water. Samples taken from their hands before work showed higher level of standard plate count, total and fecal coliforms, and Escherichia coli than those taken after washing with water. After washing hands with antiseptic liquid soap, the bacterial populations including Staphylococcus aureus on hands were dramatically reduced. This study indicates that there is a remarkable difference between the food handlers' awareness of hand washing and their hand washing behavior. Poor hand washing compliance and hand hygiene were indicated by the positive results of total and fecal coliforms, E. coli, and S. aureus on hands of some food handlers. The findings of this study suggest that the hand hygiene of the food handlers need to be improved. More training/education on hand washing and hand hygiene of the food handlers should be necessary.

• Journal of Food Hygiene and Safety
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• v.35 no.2
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• pp.109-117
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• 2020

This study aimed to develop an analytical method for determination of 18 dyes in livestock and fishery products by liquid chromatograph-tandem mass spectrometry (LC-MS/MS). The developed method was validated for linearity, accuracy, limit of quantifications (LOQ) and recovery based on the CODEX guideline (CAC/GL-71). Target matrices (beef, pork, chicken, egg, milk, flatfish, eel, and shrimp) were extracted using acetonitrile (containing 1% of acetic acid) and then, purified with C₁₈ and primary secondary amine (PSA). Calibration linearity was obtained (r²>0.98) and LOQs were 0.002 mg/kg in animal products. The recoveries of dyes were ranged from 63 to 112% and relative standard deviations (RSDs, %) were less than 15%. The residues of 18 dyes were investigated in real samples (n=124) collected from retail markets in South Korea. As a result, a total of seven samples showed positive results for target analytes in fish samples. However, there was no violation according to the maximum residue limits set by the Korean Food Code. The proposed method will be used for routine analysis of dye residues in livestock and fishery products.

• Journal of Food Hygiene and Safety
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• v.33 no.6
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• pp.466-473
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• 2018

An analytical method of sodium polyacrylate in processed food products was developed and monitored by using size-exclusion chromatography. GF-7M HQ column and UV/VIS detector were selected based on peak shape and linearity. Flow rate, column oven temperature, and mobile phase were selected as 0.6 mL/min, $45^{\circ}C$, and 50 mM sodium phosphate buffer of pH 9.0, respectively. Samples for analysis of sodium polyacrylate were extracted with 50 mM sodium phosphate buffer of pH 7.0 for 3 hr at $20^{\circ}C$ and 150 rpm. Analytical method validation revealed proper selectivity and calibration curve was selected in the range of 50-500 mg/L, and correlation coefficient of calibration curve was more than 0.9985. Limit of detection of sodium polyacrylate was 10.95 mg/kg and limit of quantification was 33.19 mg/kg. Accuracy and coefficient of variation for sodium polyacrylate analysis was 99.6-127.6%, 3.0-8.3% for intra-day and 94.3-121.9%, 1.3-2.6% for inter-day, respectively. Sodium polyacrylate was detected in 40 samples among monitored 125 processed food products. Detected contents were less than 0.2%, limited by the Food Additives Code. Results suggest the established size-exclusion chromatography method could be used to analyze sodium polyacrylate in processed food products.

• Journal of Food Hygiene and Safety
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• v.26 no.2
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• pp.154-159
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• 2011

Inadequate food handling and poor hand hygiene playa major role in the occurrence of foodborne diseases. The objective of this study was to find out if the level of microbial contamination on the hands of food preparers varies by time during their working period. This study focused on the contamination of aerobic plate count, total and fecal coliforms, Escherichia coli, Staphylococcus aureus, and Salmonella spp. Sampling from left hand and right hand of twenty food preparers was done with glove-juice method at every two hours during their work. Microbiological testing was conducted according to the Food Code of Korea. The microbiological load on the hands was changed over time. Samples taken from their hands before work and at 8 hours showed higher levels of bacteria than those taken at 2, 4, and 6 hours during work and/or after work (p < 0.05). The contamination levels of microorganisms were consistently higher in right hand than in left hand. Poor hand hygiene practices were indicated by the positive results for total and fecal coli forms, E. coli, S. aureus, and Salmonella spp. on the hands of some food preparers. This study indicates food preparers' hands can be a vehicle of pathogen during their work. The results of this study emphasize the importance of hand hygiene education and training targeting the food preparers.

• Journal of Food Hygiene and Safety
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• v.33 no.2
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• pp.124-130
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• 2018

The Ministry of Food and Drug Safety (MFDS) is amending its test methods for the use of health functional foods (dietary food supplement), in order to establish regulatory standards and specifications in Korea. In this regard, we continue to pursue and perform our research on the analytical method development for the items being researched and reviewed. In this study, we have developed a sensitive and selective test method that could simultaneously separate and determinate six major bioactive flavonolignans in silymarin, which are based on the use of a liquid chromatographic-tandem mass spectrometry (LC-MS/MS). The standard calibration curves presented a linearity effect with the correlation coefficient ($r^2$) > 0.999. The limits of detection (LODs) and limits of quantitation (LOQs) were in the range of $0.3{\sim}9.0{\mu}g/L$ and $0.8{\sim}27.3{\mu}g/L$, respectively. The recovery results ranged between 96.2~98.6% at 3 different concentration levels, and its relative standard deviations (RSDs) were less than 5% as noted in this study. The proposed analytical method was characterized with a noted high resolution of the individual silymarin constituents, and the assay was fully validated as well. Our research can provide a significant scientific evidence that can be useful to amend the silymarin test method for the Health Functional Food Code.