47 research outputs found
Surveys of rice sold in Canada for aflatoxins, ochratoxin A and fumonisins
Approximately 200 samples of rice (including white, brown, red, black, basmati and jasmine, as well as wild rice) from several different countries, including the United States, Canada, Pakistan, India and Thailand, were analysed for aflatoxins, ochratoxin A (OTA) and fumonisins by separate liquid Chromatographic methods in two different years. The mean concentrations for aflatoxin B1 (AFB1) were 0.19 and 0.17 ng gâ1 with respective positive incidences of 56% and 43% (â„ the limit of detection (LOD) of 0.002 ng gâ1). Twenty-three samples analysed in the second year also contained aflatoxin B2 (AFB2) at levels â„LOD of 0.002 ng gâ1 The five most contaminated samples in each year contained 1.44â7.14 ng AFB1 gâ1 (year 1) and 1.45â3.48 ng AFB1 gâ1 (year 2); they were mostly basmati rice from India and Pakistan and black and red rice from Thailand. The average concentrations of ochratoxin A (OTA) were 0.05 and 0.005 ng gâ1 in year 1 and year 2, respectively; incidences of samples containing â„LOD of 0.05 ng gâ1 were 43% and 1%, respectively, in the 2 years. All positive OTA results were confirmed by LC-MS/MS. For fumonisins, concentrations of fumonisin B1 (FB1) averaged 4.5 ng gâ1 in 15 positive samples (â„0.7 ng gâ1) from year 1 (n = 99); fumonisin B2 (FB2) and fumonisin B3 (FB3) were also present (â„1 ng gâ1). In the second year there was only one positive sample (14 ng gâ1 FB1) out of 100 analysed. All positive FB1 results were confirmed by LC-MS/MS
Determination of fumonisins B1 and B2 in Portuguese maize and maize-based samples by HPLC with fluorescence detection
Abstract Fumonisins B1 (FB1) and fumonisin B2 (FB2) are the main members of a family of mycotoxins produced by Fusarium verticillioides, Fusarium proliferatum, and other fungi species of the section Liseola. The present work shows the results of comparative studies using two different procedures for the analysis of fumonisins in maize and maize-based samples. The studied analytical methods involve extraction with methanol/water, dilution with PBS, and clean-up through immunoaffinity columns. Two reagents (o-phthaldialdehyde and naphthalene-2,3-dicarboxaldehyde) were studied for formation of fluorescent derivatives. The separation and identification were carried out by high-performance liquid chromatography with fluorescence detection. The optimized method for analysis of fumonisins in maize involved extraction with methanol/water (80:20), clean-up with an immunoaffinity column, and derivatization with naphthalene-2,3-dicarboxaldehyde (NDA). The limit of detection was 20 ”g kg-1 for FB1 and 15 ”g kg-1 for FB2. Recoveries of FB1 and FB2 ranged from 79% to 99.6% for maize fortified at 150 ”g kg-1 and 200 ”g kg-1, respectively, with within-day RSDs of 3.0 and 2.7%. The proposed method was applied to 31 samples, and the presence of fumonisins was found in 14 samples at concentrations ranging from 113 to 2,026 ”g kg-1. The estimated daily intake of fumonisins was 0.14 ”g kg-1 body weight per day