Fumonisins (FBs) and zearalenone (ZEN) are mycotoxins which occur naturally in grains and cereals, especially maize, causing negative effects on animals and humans. Along with the need for constant monitoring, there is a growing demand for rapid, non-destructive methods. Among these, Near Infrared Spectroscopy (NIR) has made great headway for being an easy-to-use technology. NIR was applied in the present research to quantify the contamination level of total FBs, i.e., fumonisin B1+fumonisin B2 (FB1+FB2), and ZEN in Brazilian maize. From a total of six hundred and seventy-six samples, 236 were analyzed for FBs and 440 for ZEN. Three regression models were defined: one with 18 principal components (PCs) for FB1, one with 10 PCs for FB2, and one with 7 PCs for ZEN. Partial least square regression algorithm with full cross-validation was applied as internal validation. External validation was performed with 200 unknown samples (100 for FBs and 100 for ZEN). Correlation coefficient (R), determination coefficient (R2), root mean square error of prediction (RMSEP), standard error of prediction (SEP) and residual prediction deviation (RPD) for FBs and ZEN were, respectively: 0.809 and 0.991; 0.899 and 0.984; 659 and 69.4; 682 and 69.8; and 3.33 and 2.71. No significant difference was observed between predicted values using NIR and reference values obtained by Liquid Chromatography Coupled to Tandem Mass Spectrometry (LC-MS/MS), thus indicating the suitability of NIR to rapidly analyze a large numbers of maize samples for FBs and ZEN contamination. The external validation confirmed a fair potential of the model in predicting FB1+FB2 and ZEN concentration. This is the first study providing scientific knowledge on the determination of FBs and ZEN in Brazilian maize samples using NIR, which is confirmed as a reliable alternative methodology for the analysis of such toxins.

The presence of mycotoxins in dried distillers’ grains with solubles (DDGS), a by-product of bioethanol production from maize, has been a matter of concern due to the increasing global utilisation of this ingredient in animal feed. In this study, 186 samples of maize DDGS produced in Brazil were analysed for the presence of major mycotoxins: aflatoxins (B1, B2, G1, and G2), fumonisins (B1 and B2), zearalenone (ZEN), deoxynivalenol (DON) and ochratoxin A (OTA). Samples were provided by the local industry between January 2017 and October 2020, and mycotoxins were quantified by LC-MS/MS. More than 98% of the analysed samples were contaminated with mycotoxins, from which 59.9% had a single mycotoxin, 29.9% two mycotoxins, and 9.1% more than two mycotoxins. The most prevalent metabolites were fumonisin B1 and B2, being detected in 98.8% (mean 3,207 μg/kg) and 97.6% (mean 1,243 μg/kg) of the samples, respectively; aflatoxin B1 had the third highest positivity, with 32.3% (mean 1.47 μg/kg), followed by ZEN, with 18.01% (mean 18.2 μg/kg), DON, with 12.9% (mean 59.6 μg/kg), and OTA was not detected. Co-occurrence of total aflatoxins (AFT = aflatoxin B1+B2+G1+G2) and total fumonisins (FBT = fumonisin B1+B2) was observed in 32.07% of the samples analysed for these mycotoxins. Co-occurrence of AFT and ZEN was found in 7.84% of the samples analysed for such mycotoxins, while FBT and DON co-occurred at 13.01%. AFT, FBT, DON and ZEN co-occurred in only one sample (0.84%). Except for FBT, a considerable number of samples presented the evaluated mycotoxins below their respective limit of quantification (LOQ) with percentages of 67.61% for AFT, 81.99% for ZEN, 87.07% for DON and 100% for OTA. Since the production of bioethanol and its by-products is growing worldwide, including in Brazil, mycotoxicological monitoring of maize DDGS is crucial to identify the effects of mycotoxins occurrence in animal feed formulated with this ingredient.

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Mycotoxin contamination of stored cereals often occurs in a highly heterogeneous manner, necessitating the use of representative sampling to minimise analytical errors. The objective of this study was to compare mycotoxin analysis in stored maize and wheat using two sampling processes. Samples were obtained from four maize silos and two wheat silos. A pneumatic probe was introduced in the centre and at the four central points of each quadrant, from the top to the bottom of the silo (12 m). For sampling process A, this was divided into three samples (upper third, middle third and lower third of the silo height). No sample subdivision took place for sampling process B. LC-MS/MS was used for analysis of aflatoxins (AF), fumonisins (FB), zearalenone (ZEA) and deoxynivalenol (DON) in maize and DON and ZEA in wheat. Sampling procedures were compared with respect to the variability of the collected data. AF, FB, ZEA and DON were detected in 77.5, 100.0, 56.7 and 0.0% of the maize samples, respectively, and the mean concentration differed significantly between silos. In wheat, 100.0 and 97.5% of the samples were contaminated with DON and ZEA, respectively, and there was no significantly difference in mean concentration between silos. There was no significant difference (P>0.05) in the coefficients of variation (CVs) of AF (54.9 and 58.6%), FB (19.4 and 27.3%) and ZEA (68.9 and 85.5%) between sampling processes A and B in maize silos. The DON CV in sampling process A (10.1%) was lower (P<0.05) than the CV in sampling process B (22.2%) in wheat silos. Overall, the two sampling processes provided analytical results with the same variability in maize and different variability for DON in wheat, where process A yielded results with lower variability.

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