A total of 230 samples of processed rice and its sub-products or derived products were analysed to establish the co-occurrence of several mycotoxins. Samples were analysed in the period 2007-2009 due to the outbreak of beriberi associated with the consumption of rice stored in inappropriate conditions in Brazil. According to data from the Ministry of Health, 323 cases of disease were registered in 2006, of which at least 47 cases resulted in death. The occurrence of total aflatoxin (AFT) (aflatoxin B(1) + B(2) + G(1) + G(2)), ochratoxin A (OTA), zearalenone (ZON), deoxynivalenol (DON), and citreoviridin (CTV) was 58.7%, 40.0%, 45.2%, 8.3% and 22.5%, respectively. From 166 rice samples analysed, 55% had levels <0.11 µg kg(-1) for AFT. For OTA and ZON, of 165 rice samples analysed, 28% and 29% were contaminated with levels from 0.20 to 0.24 µg kg(-1) and from 3.6 to 290.0 µg kg(-1), respectively. One sample (0.6%) was contaminated with 4872.0 µg kg(-1) of ZON. A total of 91% of rice samples (n = 165) did not contain detectable DON (<30.00 µg kg(-1)), although the highest level of contamination was found to be 244 µg kg(-1). From the total of 65 samples analysed, 94% had no detectable CTV (<0.9 µg kg(-1)), with a range from 0.9 to 31.1 µg kg(-1) in 6% of the samples. The highest levels of contamination were found in rice sub-products or derived products from the husk and rice bran. Co-occurrence was observed for AFT and ZON in 17.0%, AFT and OTA in 24.2%, AFT and CTV in 6.2%, OTA and CTV in 4.6%, and ZON and CTV in 3.1%. These fractions were also the major contributors for the co-occurrence. The results found show the necessity of monitoring rice production.

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Two hundred and fourteen unprocessed corn samples (1997-98 harvest), collected at wholesale markets in different regions in Brazil, were surveyed for the occurrence of mycotoxins. The samples were analysed for aflatoxins B1, B2, G1, G2, zearalenone and fumonisin B1 using in-house validated methods. The occurrence of aflatoxin B1, zearalenone and fumonisin B1 was found in 38.3, 30.4 and 99.1% of the samples, respectively. Aflatoxin B1, zearalenone and fumonisin B1 contamination levels varied from 0.2 to 129, 36.8 to 719, and 200 to 6100 microg/kg, respectively. The co-occurrence of the two carcinogenic mycotoxins aflatoxin B1 and fumonisin B1 was observed in 100% of the aflatoxin-contaminated samples (82 samples). Co-occurrences of aflatoxin B1: zearalenone: fumonisin B1 and aflatoxin B1: aflatoxin B2: fumonisin B1 were found in 18 and 43 samples, respectively.

The objective of this study was to quantitatively evaluate mycotoxins in samples of maize and poultry feed produced in Brazil. A multimycotoxin method based on HPLC-MS/MS was applied to investigate the occurrence of toxical fungal metabolites in 119 samples collected from poultry feed factory integrated poultry farms: maize grain (74), poultry feed (36), and feed factory residue (9). Twenty of 101 fungal metabolites investigated were detected and quantified in the samples: aflatoxins B1, B2, G1, and G2, fumonisins B1, B2, and B3, hydrolyzed fumonisin B1, zearalenone, agroclavine, chanoclavine, deoxynivalenol, and nivalenol, and enniatin A, A1, B, B1, beauvericin, kojic acid, and moniliformin. Most samples were contaminated with more than one mycotoxin. All samples were contaminated with fumonisins, with medians values of 1,840 μg/kg, 239 μg/kg, and 23,676 μg/kg for maize, feed, and factory residue samples, respectively. Surprisingly, beauvericin was detected in more than 90% of samples. The median contaminations of aflatoxin and trichothecenes were low, near LOD values. The factory residue presented highest contamination levels for all mycotoxins. This is the first study dealing with agroclavine, chanoclavine, enniatin A, A1, B, B1, beauvericin, and kojic acid contamination of maize and poultry feeds from Brazil.

An immunoaffinity clean-up-based method for determining ochratoxin A (OTA) in green coffee aiming at one-dimensional thin layer chromatography (TLC) analysis was established. OTA was extracted with a mixture of methanol and aqueous sodium hydrogen carbonate solution, purified through an immunoaffinity column, separated on normal or reversed-phase (RP) TLC plates and detected and quantified by visual and densitometric analysis. The linear equation of the standard calibration curve by densitometric analysis gave R(2) > 0.999 (0.04-84 ng). The mean recovery (R) of OTA from spiked samples (1.8-109 microg kg(-1)) by densitometric and visual analyses were 98.4 and 103.8%, respectively. The relative standard deviations (RSD) for densitometric and visual analysis varied from 1.1 to 24.9% and from 0.0 to 18.8%, respectively. The RSD for naturally contaminated samples by densitometry (three levels of contamination, n = 3) varied from 11.1 to 18.1%. The correlation (R(2)) between high-performance liquid chromatography (HPLC) and densitometry, and between visual and densitometric analysis for spiked samples were > 0.99. The limit of detection (LOD) of the method was 0.5 microg kg(-1) for normal TLC. Toluene-ethyl acetate-88% formic acid (6:3:1 v/v/v) and acetonitrile-methanol-water-glacial acetic acid (35:35:29:10 v/v/v/v) were regarded as the suitable TLC solvents for eluting both standards and samples on normal and RP TLC plates, respectively. Toluene-acetic acid (99:1 v/v) was chosen as the spotting solvent among several others for giving the best sensitivity and resolution of OTA on TLC plates as well as the best recovery of OTA from standard and sample extract residues. Preliminary studies were carried out to investigate the reuse of the immunoaffinity column and the interference of caffeine in the OTA recovery.

A survey of zearalenone (ZEA) in corn from various regions of Brazil was carried out by the analysis of 380 corn samples, of which 30 samples (7.8%) were found to be contaminated in the range of 46.7-719 micrograms/kg. ZEA was extracted with acetonitrile-water (84:16, v/v), cleaned-up on a Romer Mycosep 224 column, separated, detected and quantified by high performance liquid chromatography (HPLC). The in-house method characteristics of linearity, accuracy, precision, and detection limit were defined by means of recovery tests with spiked corn samples in the range of 35.8-716 micrograms/kg and the analysis of a naturally-contaminated sample (n = 7). The mean recovery for ZEA was 99.4% and the relative standard deviation (RSD) varied from 0.7 to 26.6% in the range studied. The method has been shown to be accurate, quick and reliable for determination of zearalenone in corn.

A method for determining fumonisin B1 (FB1) in corn was developed and the clean-up optimized in order to give an extract suitable for one-dimensional thin layer chromatographic (TLC) analysis. FB1 was extracted with a solution of methanol:water (80:20, v/v), purified through an immunoaffinity column and separated on a C18 reversed phase TLC plate. The FB1 was visualized with 0.1 mol/l sodium tetraborate, 0.40 mg/ml fluorescamine in acetonitrile and 0.01 mol/l boric acid:acetonitrile (2:3, v/v) for fluorescence detection, and quantified by densitometric analysis. Water, acetonitrile:water (1:1 v/v) and acetonitrile:water (4:1 v/v) were evaluated as TLC solvents for running both standards and samples together with derivatization procedures aimed at improving separation, resolution, sensitivity and linearity. The mean recovery for FB1 for spiked samples was found to be 85% and the linear equation of standard calibration curve by densitometric analysis gave an r2 value higher than 0.99. The maximum coefficient of variation for replicate analysis of spiked samples was 19%. The absolute amount of FB1 standard detectable on a TLC plate was 2 ng, giving a detection limit for the method of 0.1 mg/kg. The method has been shown to be robust in the application of FB1 monitoring in corn (214 samples) collected in different regions of the country. FB1 was detected in 99% of these samples in the range of 0.2 to 6 mg/kg.