• Journal of Food Hygiene and Safety
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• v.35 no.3
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• pp.252-260
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• 2020

This study was conducted to improve the standard method for vitamin B₁₂ and biotin contained in foods for special dietary uses to ensure the specificity of the complex matrix properties of foods. For the food code, the test method was improved to determine vitamin B₁₂ and biotin by high-performance liquid chromatography (HPLC)-UV using column-switching after concentration using immunoaffinity column. The immunoaffinity columns contain a gel suspension of monoclonal antibody specific to the vitamin of interest so that it can be used to concentrate the vitamin B₁₂ and biotin and remove interferences from the food extracts. Moreover, validation of advanced new methods was carried out to support the suitability of the proposed analytical procedure (specificity, linearity, detection limits (LOD), quantitative limits (LOQ), accuracy, and precision). The improved analytical method is being used to monitor relevant food items on sale. The results of this study showed that the new analytical method is suitable and appropriate for managing food intended for special dietary uses.

• YAKHAK HOEJI
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• v.47 no.6
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• pp.438-443
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• 2003

For the investigations of the usefulness of immunoglobulin Y (IgY), we attempted to produce and isolate IgY from egg yolk of white Leghorn hens immunized with fetuin as a model antigen. We used three methods to optimize the recovery of IgY: water dilution, polyethylene glycol, and carrageenan. The daily yield of anti-fetuin IgY from egg yolk was also examined, and it was isolated using a fetuin-affinity column at a yield of IgY of 2.7% from total IgY Furthermore, peroxidase-labeled antifetuin IgY was prepared, and was used to determine the minimum sensitivity against fetuin, which was found to occur to a fetuin concentration of 1 ng/$m\ell$.

• Korean Journal of Food Science and Technology
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• v.41 no.3
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• pp.258-264
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• 2009

The principal objective of this study was to estimate the measurement uncertainty associated with determination of deoxynivalenol (DON), a mycotoxin generated by Fusarium strain, in food. In service of this goal, wheat as a food matrix was analyzed via high performance liquid chromatography-ultraviolet (HPLC-UV) detection using an immunoaffinity column for clean-up. The uncertainty sources in the measurement process were identified by sample weight, final volume, and sample concentration in extraction volume with components including standard stock solution, working standard solution, 5 standard solutions, calibration curve, matrix, and instrument. The expanded uncertainty for DON at a concentration of 300 ${\mu}g/kg$ was estimated as 71.62 ${\mu}g/kg$ using a coverage factor of two, which provides a confidence level of approximately 95%. The most influential component in the uncertainty sources was the recovery of the wheat matrix, followed by the calibration curve. These results indicate that all efforts may be directed toward reducing the uncertainties of the recovery of the wheat matrix and the calibration curve to obtain a reliable HPLC-UV method for DON analysis in wheat.

• Journal of Food Hygiene and Safety
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• v.26 no.1
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• pp.1-11
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• 2011

Nivalenol (NIV), deoxynivalenol (DON), T-2 toxin (T-2) and zearalenone (ZEN) are mycotoxins produced by some Fusarium species known to be very frequently contaminated in feed. The study for simultaneous analysis and contamination survey in animal feed carried out. All mycotoxins were analysed by using high performance liquid chromatography tandem mass with internal standard. The limits of detection (LOD) were $2.0\;{\mu}g/kg$, $1.0\;{\mu}g/kg$, $1.0\;{\mu}g/kg$ and $0.1\;{\mu}g/kg$ for NIV, DON, T-2 and ZEN, respectively. Two hundred and thirty nine samples of feed were collected. The average concentration of DON was $212.3\;{\mu}g/kg$, $207.8\;{\mu}g/kg$ and $812.1\;{\mu}g/kg$ in chicken, pig and cattle feed, respectively. The average concentration of ZEN was $31.2\;{\mu}g/kg$, $35.6\;{\mu}g/kg$ and $147.2\;{\mu}g/kg$ for them, respectively. Especially, the levels of contamination for DON and ZEN were higher than those of NIV or T-2. And, the levels of contamination for four Fusarium mycotoxins in cattle feed appeared higher than those of pig and chicken feed. It was investigated that the high level of mycotoxin contamination in cattle feed was caused by com gluten feed of ingredients for feed, mainly.

• Horticultural Science & Technology
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• v.17 no.6
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• pp.742-746
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• 1999

Contents of mineral element and cytokinin in the xylem sap of 'Keumdongee' and 'Tongilhwang' oriental melons were compared with those in oriental melons grafted onto 8 rootstocks. The effect of grafting on the fruit quality of oriental melon was also investigated. Flesh firmness varied with rootstocks. Soluble solids contents in the placenta tissue of grafted 'Tongilhwang' were higher than that in the 'Keumdongee'. Electric conductivity of the xylem sap in own-rooted plants was higher in 'Keumdongee' than in 'Tongilhwang', but it increased in 'Tongilhwang' once they were grafted. The sap volume per plant was greater in 'Keumdongee' than in 'Tongilhwang'. The mineral concentrations varied considerably depending on the rootstock used. Xylem sap of grafted oriental melons contained a higher amount of mineral ions, especially $NO_3{^-}$ and $PO_4{^-}$, than did the sap in own-rooted plants. The increase in the mineral levels in sap due to grafting was most apparent in 'Tongilhwang'. Xylem sap from both 'Keumdongee' and 'Tongilhwang' contained trans-zeatin (t-Z), trans-zeatin riboside (t-ZR), and dihydrozeatin riboside (DHZR). Small amounts of isopentenyl adenine (IPA) and isopentenyl adenine riboside (IPAR) were also detected. Trans-zeatin riboside was the most abundant, followed by t-Z. Cytokinin concentration in 'Keumdongee' was not significantly influenced by rootstock type used, although the highest concentration of cytokinins in 'Keumdongee' was obtained with 'Chamtozwa' rootstock. However, the cytokinin concentration in 'Tongilhwang' increased with grafting irrespective of rootstock type used.

• Analytical Science and Technology
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• v.24 no.2
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• pp.150-157
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• 2011

Aflatoxins are secondary metabolites of the molds of Aspergillus flavus and Aspergillus parasiticus. They are highly carcinogenic compounds and can affect a wide range of vegetable commodities such as cereals (especially corn), nuts, peanuts, fruits and oil seeds, in the field and during storage. In fact, oilseeds are often stored for weeks in conditions that promote the mould growth, and the possible consequent presence of aflatoxins in oilseeds can lead to their transfer in oil. In addition, aflatoxins can be found as a natural contaminant in multi-cereals and beans making baby food for infants and young-children. The objective of this study was to validate the liquid extraction method or develop an analytical method for edible oil and infant-children foods. Therefore, this study developed condition of extract for aflatoxins ($B_1$, $B_2$, $G_1$ and $G_2$) in edible oil using a high performance liquid chromatography with florescence detector (HPLC/FLD). Aflatoxins were extracted from edible oil samples by means of MSPD (Matrix solid phased dispersion), utilizing $C_{18}$ as dispersing material and purified by using immunoaffinity column. The gression line coefficients were above 0.999. The recoveries for aflatoxins ranged from 85.9 to 93.0%, and relative standard deviations were below 5.7%. The new developed method of aflatoxins effectively enhanced recoveries by using MSPD-Immunoaffinity column compared with liquid extraction. The analytical method for liquid extraction of aflatoxin was appropriate for infant-children food. Reviewing the current method, the recoveries of aflatoxins ($B_1$, $B_2$, $G_1$ and $G_2$) were 89.5~92.3%.

• Journal of Food Hygiene and Safety
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• v.26 no.3
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• pp.214-221
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• 2011

Deoxynivalenol (DON) and zearalenone (ZEN) are mainly contaminated mycotoxins in feeds. The study was carried out to analyze and survey the contamination of DON and ZEN in one hundred thirteen samples of feeds. After cleaning all samples with immunoaffinity column, the mycotoxins were analysed by using high performance liquid chromatography/fluorescence with diode array detector (HPLC/FLD with DAD). The average recoveries of DON were 88.76 and 95.40% at the levels of 200 and 1,000 ${\mu}g/kg$ and 87.09 and 98.40% of ZEN were recovered at the levels of 100 and 500 ${\mu}g/kg$, respectively. The limit of detection (LOD) were 6.0 and 3.0 ${\mu}g/kg$ for DON and ZEN, respectively. The average concentrations of DON were 372.1, 324.0 and 990.9 ${\mu}g/kg$ in chicken, pig and cattle feed, respectively. Those of ZEN were 76.1, 43.7 and 196.2 ${\mu}g/kg$ for them, individually.

• Journal of Food Hygiene and Safety
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• v.35 no.1
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• pp.13-22
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• 2020

A total of 244 cereal samples (oat, sorghum, adlay, and proso millet) were collected from fields to examine the contamination of Fusarium mycotoxins in cereals during harvest season in 2017 and 2018. The contamination levels of deoxynivalenol (DON), nivalenol (NIV), and zearalenone (ZEA) were analyzed individually by using the immunoaffinity column clean-up method with ultra performance liquid chromatography, and fumonisins (FUM) were analyzed by using the QuEChERS method with liquid chromatography-mass spectrometry. Highest level of NIV contamination (120.0-3277.0 mg/kg) was observed in oat samples among the analyzed cereals. In the adlay samples, DON contamination was the highest (maximum level 730.0 ㎍/kg). The proso millet samples had a high frequency of detection of NIV and ZEA (61.5% and 57.9%, respectively), but the levels were low (average detection level of NIV, 75.6 ㎍/kg, for ZEA, 21.5 ㎍/kg). Among the cereal samples, sorghum had the highest contamination frequency of DON, ZEA, and FUM, and the co-occurrence of Fusarium mycotoxin was 70.0%, which was higher than the average of 29.9%. In order to safely manage Fusarium mycotoxin levels in cereals, continuous research on the development of contamination prevention technologies together with monitoring of mycotoxin contamination is needed.

• Journal of Food Hygiene and Safety
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• v.28 no.1
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• pp.75-82
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• 2013

The simultaneous analysis and monitoring of aflatoxin $B_1$, $G_1$, $B_2$, $G_2$ and ochratoxin A in foods were carried out by HPLC with fluorescence detection. The samples were extracted with methanol/water mixture. The extract was centrifuged, diluted with phosphate buffer saline (PBS), filtered, and applied to an immunoaffinity column containing antibodies specific to both aflatoxins and ochratoxin A. After washing the column with PBS and water, the toxins were eluted from the column with methanol, and quantified by HPLC, with a run time of approximately 30 min. The recoveries for aflatoxin $B_1$, $G_1$, $B_2$, $G_2$ and ochratoxin A in foods were 78.4~101.5%, 73.3~102.1%, 81.7~106.7%, 67.0~104.6% and 78.7~120.8%, respectively. The limits of detection of aflatoxins and ochratoxin A ranged from 0.05 to $0.18{\mu}g/kg$. According to monitoring result with the established method, aflatoxin $B_1$ and ochratoxin A were found in 13 of 151 domestic commercial foods. The contamination levels were $0.32{\sim}1.80{\mu}g/kg$ for aflatoxin $B_1$ and $0.97{\mu}g/kg$ for ochratoxin A. Therefore, this study showed all commercial foods monitored were safe under the Korean standards for aflatoxins and ochratoxin A.

• Journal of Food Hygiene and Safety
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• v.26 no.2
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• pp.142-149
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• 2011

An isocratic high performance liquid chromatography (HPLC) method for routine analysis of deoxynivalenol in noodles was validated and estimated the measurement uncertainty. Noodles (dried noodle and ramyeon) were analyzed by HPLC-ultraviolet detection using immunoaffinity column for clean-up. The limits of detection (LOD) and quantification (LOQ) were 7.5 ${\mu}g$/kg and 18.8 ${\mu}g$/kg, respectively. The calibration curve showed a good linearity, with correlation coefficients $r^2$ of 0.9999 in the concentration range from 20 to 500 ${\mu}g$/kg. Recoveries and Repeatabilities expressed as coefficients of variation (CV) spiked with 200 and 500 ${\mu}g$/kg were $82{\pm}2.7%$ and $87{\pm}1.3%$% in dried noodle, and $97{\pm}1.6%$ and $91{\pm}12.0%$ in ramyeon, respectively. The uncertainty sources in measurement process were identified as sample weight, final volume, and sample concentration in extraction volume as well as components such as standard stock solution, working standard solution, 5 standard solutions, calibration curve, matrix, and instrument. Deoxynivalenol concentration and expanded uncertainty in two matrixes spiked with 200 ${\mu}g$/kg and 500 ${\mu}g$/kg were estimated to be $163.8{\pm}52.1$ and $435.2{\pm}91.6\;{\mu}g$/kg for dried noodle, and $194.3{\pm}33.0$ and $453.2{\pm}91.1\;{\mu}g$/kg for ramyeon using a coverage factor of two which gives a level of statistical confidence with approximately 95%. The most influential component among uncertainty sources was the recovery of matrix, followed by calibration curve.