In the current study, 109 commercial nut samples were collected from different Korean markets and analyzed for the contamination of 5 different mycotoxins (aflatoxin, ochratoxin A, deoxynivalenol, zearalenone, and T-2 toxin) using ELISA kits. The results revealed that the most frequently detected mycotoxin was zearalenone (n=36, 33%), followed by aflatoxin (n=31, 28.4%) and ochratoxin A (n=30, 27.5%). Deoxynivalenol and T-2 toxin were also detected in 22 (20.3%) samples, respectively. Among 109 nut samples, 33 samples (30.3%) were contaminated only with one kind of mycotoxin, whereas 43 samples had at least 2 kinds of mycotoxins. Two samples were contaminated with as many as 4 different mycotoxins, and they were both walnuts. Although the monitoring results revealed the amount of aflatoxin contamination was under the safety criteria, there is no current safety guideline for other kinds of mycotoxins or multiple contaminations in Korea. Therefore, further studies should be performed to reveal the distribution of mycotoxin in different foods and propose appropriate safety guidelines for Korean markets.

The objective of this study was to optimize analytical methods for ochratoxin A (OTA) and zearalenone (ZEA) in rice straw silage and winter forage crops using ultra-high performance liquid chromatography (UHPLC). Samples free of mycotoxins were spiked with 50 μg/kg, 250 μg/kg, or 500 μg/kg of OTA and 300 μg/kg, 1500 μg/kg, or 3000 μg/kg of ZEA. OTA and ZEA were extracted by acetonitrile and cleaned-up using an immunoaffinity column. They were then subjected to analysis with UHPLC equipped with a fluorescence detector. The correlation coefficients of calibration curves showed high linearity (R2 ≧ 0.9999 for OTA and R2≧0.9995 for ZEA). The limit of detection and quantification were 0.1 μg/kg and 0.3 μg/kg, respectively, for OTA and 5 μg/kg and 16.7 μg/kg, respectively, for ZEA. The recovery and relative standard deviation (RSD) of OTA were as follows: rice straw = 84.23~95.33%, 2.59~4.77%; Italian ryegrass = 79.02~95%, 0.86~5.83%; barley = 74.93~97%, 0.85~9.19%; rye = 77.99~ 96.67%, 0.33~6.26%. The recovery and RSD of ZEA were: rice straw = 109.6~114.22%, 0.67~7.15%; Italian ryegrass = 98.01~109.44%, 1.65~4.81%; barley = 98~113.53%, 0.25~5.85%; rye = 90.44~108.56%, 2.5~4.66%. They both satisfied the standards of European Commission criteria (EC 401-2006) for quantitative analysis. These results showed that the optimized methods could be used for mycotoxin analysis of forages.

Mycotoxins such as aflatoxin B1 (AFB1), ochratoxin A (OTA) and zearalenone (ZEA) are widespread contaminants of food and feedstuffs. It is very likely, that humans and animals are always exposed to mixtures of mycotoxins rather than to individual compounds. Therefore, risk assessments should consider mixture toxicity data. In the present study the combination of AFB1, OTA and ZEA was tested for genotoxicity in rat bone marrow and blood leukocytes after 15, 30 and 60 days treatment. The level of DNA damage was determined by the comet assay. The tail intensity and Olive tail moment in leukocytes and bone marrow cells were significantly higher than in controls. At the same time, the level of DNA damage in bone marrow cells was higher than in leukocytes. The data suggests that prolonged exposure to mycotoxins combination through food consumption can induce DNA damage contributing to the harmful effects in vivo.

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 μg/kg and 87.09 and 98.40% of ZEN were recovered at the levels of 100 and 500 μg/kg, respectively. The limit of detection (LOD) were 6.0 and 3.0 μg/kg for DON and ZEN, respectively. The average concentrations of DON were 372.1, 324.0 and 990.9 μg/kg in chicken, pig and cattle feed, respectively. Those of ZEN were 76.1, 43.7 and 196.2 μg/kg for them, individually.

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 μg/kg,1.0 μg/kg, 1.0 μg/kg and 0.1 μg/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 μg/kg, 207.8 μg/kg and 812.1 μg/kg in chicken,pig and cattle feed, respectively. The average concentration of ZEN was 31.2 μg/kg, 35.6 μg/kg and 147.2 μg/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 corn gluten feed of ingredients for feed, mainly.

An enzyme-linked immunosorbent assay (ELISA) was established for the detection of zearalenone by using monoclonal antibodies produced by Z-M-26 hybridoma cells when injected into a mouse and zearalenone-oxime-OVA conjugate. Zearalenone-oxime-OVA conjugates were diluted with carbonyl buffer, coated to 96 well microtiter plates at 4℃ overnight and blocked with 1% BSA overnight. One thousand times diluted antibody solution together with standard zearalenone or sample was added to 96-well microtiter plates and stood overnight. A secondary antibody conjugated with HRP was added and an hour later, enzyme substrate (TMBZ) solution was added for color develpment. After 30 minutes, coloring reaction was terminated by adding 2 N H₂SO₄ and the O.D. was measured at 450 nm. Detection range of this method was about 0.1-100 ppb. The established indirect competitive ELISA method was suitable for a rapid and effective analysis of zearalenone in agricultural products.