Determination of deoxynivalenol (DON) and its derivatives: Current status of analytical methods

A programmable multichannel chemiluminescence immunoassay sensor for automatic quantification of the total amount of fumonisin B1, B2 and B3

A programmable multichannel chemiluminescence immunoassay sensor was developed based on the biotin-streptavidin system for the automatic quantification of the total amount of fumonisin B1, B2 and B3 in maize samples. First, the key parameters, such as the reaction time and reagent dosage were optimized to improve the sensitivity. All reagents were subsequently added to the corresponding wells of the reagent strips, which were further sealed to create a total fumonisin quantification kit. Finally, six samples were automatically and simultaneously analyzed within 20 min with the aid of a fully automated mycotoxin immunoassay analyzer. The limit of detection of this method is 16.32 μg/kg, with cross-reactivity for eight common mycotoxins being less than 0.66 %, and the spiking recovery rates ranging from 89.7 % to 103.7 %. In conclusion, the proposed programmable multichannel chemiluminescent immunoassay sensor provides a reliable, sensitive and practical detection tool for automated and high-throughput detection of FBs.

Magnetic beads-based double-stranded DNA fluorescent aptasensor biosensor for deoxynivalenol detection

Deoxynivalenol (DON) is one of the most harmful mycotoxins that poses great health threats to human and animals. Herein, a simple and sensitive magnetic beads-based fluorescent biosensor was successfully prepared for detection of DON in cereals. A stable double-stranded DNA (dsDNA, biotin-sDNA+FAM-cDNA/AP) was formed on the surface of streptavidin-coated magnetic beads (SMBs). DON could specifically bind to aptamer probe (AP), thereby releasing cDNA labeled with 6-carboxyfluorescein (FAM) (FAM-cDNA). After magnetic separation, the amount of FAM-cDNA was analyzed to achieve the detection of DON. Under the optimal conditions, the established aptasensor displayed excellent performance for DON analysis with the nice linear relationship (R2 = 0.9972) in the range of 0.1-50 ng/mL, high sensitivity (detection limit of 0.033 ng/mL) and selectivity. The total analysis time including samples preparation was around 200 min. The designed sensor was validated by determining the recoveries (95.48-112.48 %) in real paddy, wheat and maize samples, and its applicability to them was also verified by super-high performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). The current study proposed a promising strategy for DON detection, and could easily be extended for the analysis of other targets through the rational design of the sequences of aptamer probe and cDNA.

Prediction of Deoxynivalenol contamination in wheat kernels and flour based on visible near-infrared spectroscopy, feature selection and machine learning modelling

Contamination of wheat by the mycotoxin Deoxynivalenol (DON), produced by Fusarium fungi, poses significant challenges to the quality of crop yield and food safety. Visible and near-infrared (vis-NIR) spectroscopy has emerged as a promising, non-destructive, and efficient tool for detecting mycotoxins in cereal crops and foods. This study aims to utilize vis-NIR spectroscopy, coupled with a feature selection technique and machine learning modelling, to predict and classify DON contamination in wheat kernels and flour. A total of ninety-five samples, collected from commercial wheat fields in Lithuania and Belgium, were scanned using a vis-NIR (400-1650 nm) spectrophotometer. The DON content was subsequently determined by a liquid chromatography-mass spectrometry (LC-MS). The data were preprocessed and analyzed using random forest classifier (RFC), and regressor (RFR), extra trees classifier (ETC), and regressor (ETR), AdaBoost classifier (ABC), and regressor (ABR) for classification and regression tasks, respectively. To enhance model accuracy, recursive feature elimination (RFE) algorithm to select the most informative wavebands was applied, and the random over-sampler (ROS) was adopted to mitigate the imbalance of data in DON classes. Results showed that the feature selection approach improved the prediction and classification accuracy of the models. Notably, the performance of the algorithms was better for the flour samples compared to the kernels. The most effective DON prediction model was achieved with the ETR-RFE modelling approach for the flour samples, demonstrating high accuracy [determination coefficient (R2) = 0.94 and root mean square error of prediction (RMSEP) = 3.42 mg.kg-1]. On the other hand, the ETC applied to the full spectrum data along with ROS, achieved the highest classification accuracy of 89.5 %. These results demonstrate the potential of using vis-NIR with RF-RFE modelling approach, for rapid analysis of DON levels in wheat kernel and flour.

Deoxynivalenol Determination Using Innovative Lateral Flow Device Technology

Deoxynivalenol (DON), generally the most widespread mycotoxin in wheat, is regulated by the EU regulation in cereals and cereal-derived products. Its presence can be detected by chromatographic or rapid methods; the latter technique is generally used in control analysis, fulfilling the needs of the stakeholders of the wheat grain chain. Lateral flow strips are often used for the rapid detection of different mycotoxins in several agricultural products; regarding DON determination, different lateral flow immunochromatography strips are currently available, also providing quantitative results. The purpose of this work was to evaluate the accuracy of an innovative lateral flow device coupled to a bench top device, following a digital approach. The proposed method was compared to an LC-MS/MS method, analyzing 50 naturally contaminated wheat samples. The results obtained using the two methods were very similar and, applying a paired t-test, the mean difference between measurements resulted not significantly different (α = 0.003). The correlation between the results showed a slope of the line close to 1 (m = 0.9904) and a regression coefficient (r) of 0.9968.

Fluorescence immunochromatographic assay for deoxynivalenol using immunomagnetic bead purification

Deoxynivalenol (DON) contaminates various complex matrices, necessitating straightforward, effective cleanup and precise detection methods. This study employed immunomagnetic beads for sample purification and utilized a competitive time-resolved fluoro-immuno-chromatographic assay to achieve quantitative detection of DON in corn and its by-products. The limits of detection and quantification were 104 μg/kg and 243 μg/kg, respectively. Significant cross-reactivity was absent with most common toxins, except for 3-acetyl-deoxynivalenol, which exhibited a cross-reaction rate of 3167%. The recovery rates ranged from 86% to 117%, with coefficients of variation between 6.9% and 9.5%. The correlation coefficient with HPLC was 0.977. This method is rapid, accurate, and requires no large-scale equipment, facilitating on-site detection directly.

A ratiomectic aptasensor with enhanced signals based on peroxidase-like enzymes and NH2-MIL-101@MoS2 for trace detection of deoxynivalenol in traditional Chinese herbs

The accumulation of the deoxynivalenol (DON) in the human body poses a significant health risk that is often overlooked, and we urgently need an ultra-sensitive rapid detection platform. Due to the porosity of NH2-MIL-101@MoS2, an increased loading of toluidine blue (TB) serves to create a signal reference. Cobalt@carbon (CoC) derived from metal organic frameworks was combined with NH2-MIL-101(NH2-MIL-101@CoC) to form an enzyme-free Nanoprobe (Apt-pro) with significant catalytic properties. The ratio (IBQ /ITB) was changed by varying the electrochemical signal of benzoquinone (BQ) (IBQ) and the amount of TB deposition (ITB). This aptasensor was successfully applied to detect DON in malt and peach seed, which exhibited a great linear range from 1 fg/mL to 10 ng/mL and low detection limit of 0.31 fg/mL for DON.

Advancements, limitations and challenges in hyperspectral imaging for comprehensive assessment of wheat quality: An up-to-date review

The potential of hyperspectral imaging technology (HIT) for the determination of physicochemical and nutritional components, evaluation of fungal/mycotoxins contamination, wheat varieties classification, identification of non-mildew-damaged wheat kernels, as well as detection of flour adulteration is comprehensively illustrated and reviewed. The latest findings (2018-2023) of HIT in wheat quality evaluation through internal and external attributes are compared and summarized in detail. The limitations and challenges of HIT to improve assessment accuracy are clearly described. Additionally, various practical recommendations and strategies for the potential application of HIT are highlighted. The future trends and prospects of HIT in evaluating wheat quality are also mentioned. In conclusion, HIT stands as a cutting-edge technology with immense potential for revolutionizing wheat quality evaluation. As advancements in HIT continue, it will play a pivotal role in shaping the future of wheat quality assessment and contributing to a more sustainable and efficient food supply chain.

Interconnectable 3D-printed sample processing modules for portable mycotoxin screening of intact wheat

BACKGROUND

The increasing demand for food and feed products is stretching the capacity of the food value chain to its limits. A key step for ensuring food safety is checking for mycotoxin contamination of wheat. However, this analysis is typically performed by rather complex and expensive chromatographic methods, such as liquid chromatography-tandem mass spectrometry (LC-MS/MS). These costly methods require extensive sample preparation that is not easily carried out at different points along the food supply chain. To overcome such challenges in sample processing, an inexpensive and portable sample preparation device was needed, that required low skill, for rapid sample-to-result mycotoxin screening.

RESULTS

We describe 3D-printed and interconnectable modules for simple, integrated and on-site sample preparation, including grinding of wheat kernels, and solvent-based extraction. We characterized these 3D-printed modules for mycotoxin screening and benchmarked them against a laboratory mill using commercial lateral flow device(s) (LFD) and in-house validated LC-MS/MS analysis. Different integrated sieve configurations were compared based on grinding efficiency, and we selected a sieve size of 2 mm allowing grinding of 10 g of wheat within 5 min. Moreover, 10 first time-users were able to operate the grinder module with minimal instructions. Screening for deoxynivalenol (DON) in naturally contaminated samples at the regulatory/legal limit (1.25 mg kg-1) was demonstrated using the developed 3D-printed prototype. The whole process only takes 15 min, from sample preparation to screening result. The results showed a clear correlation (R2 = 0.96) between the LFD and LC-MS/MS.

SIGNIFICANCE

Our findings demonstrate the potential of 3D-printed sample handling equipment as a valuable extension of existing analytical procedures, facilitating the on-site implementation of rapid methods for the determination of mycotoxins in grains. The presented prototype is inexpensive with material costs of 2.5€, relies on biodegradable 3D printing filament and can be produced with consumer-grade printers, making the prototype readily available. As a future perspective, the modular character of our developed tool kit will allow for adaptation to other hard food commodities beyond the determination of DON in wheat.

Dual-mode sensing chip for photoelectrochemical and electrochromic visual determination of deoxynivalenol mycotoxin

The successful development of a dual-mode sensing chip for deoxynivalenol (DON) detection using photoelectrochemical (PEC) and electrochromic visualization techniques is reported. By laser etching technology, different functional areas, including the photoanode, the cathode, and the electrochromic area, are fabricated on indium tin oxide (ITO) glass. Then, these three areas are further respectively modified with PEC active materials, platinum nanoparticles, and Prussian blue. Under light illumination, photocurrents generate between the photoanode and the cathode due to the separation of photo-induced electrons and holes in the TiO2/3DNGH material. Meanwhile, the photo-induced electrons are transferred to Prussian blue on the visualization area, which will be reduced to colorless Prussian white. The binding of DON molecules and aptamers can promote electron transfer and reduce the recombination of electrons and holes, allowing for simultaneous quantitative detection of DON using either the photocurrent or color change. The sensor chip has a broad detection range of DON concentrations of 1 fg⋅mL-1 to 100 pg⋅mL-1 in the PEC mode with the limit of detection of 0.37 fg⋅mL-1, and 1 to 250 ng⋅mL-1 in the visualization mode with the limit of detection of 0.51 ng⋅mL-1. This portable dual-mode sensor chip can be used in both laboratory and field settings without the need for specialized instruments, making it a powerful tool for ensuring food safety. At the same time, the analysis of the standard addition method of the actual sample by using the sensor chip shows that, in the PEC mode, the recoveries of the dual-mode aptasensor chip were 91.3 to 99.0% with RSD values of 1.73~2.55%, and in visualization mode, the recoveries of the dual-mode aptasensor chip were 99.2 to 102.0% with RSD values of 1.00~6.21%, which indicate good accuracy and reproducibility.

Natural occurrence of ustiloxins in rice from five provinces in China and the removal efficiencies of different milling steps

BACKGROUND

The widespread incidence of "false smut" disease in rice has caused extensive ustiloxin contamination around the world. Until now there has been a lack of knowledge regarding the natural occurrence of ustiloxins in paddy. The development of efficient removal methods is also still a challenge that remains unexplored.

RESULTS

In the current study, three main ustiloxins - ustiloxin A (UA), ustiloxin B (UB), and ustiloxin G (UG) - were determined simultaneously by ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) in 206 paddy samples collected in 2021 from five rice-producing provinces in China. The predominant ustiloxin was UA with an occurrence of 46.1% and an average concentration of 49.71 μg kg-1 . This was followed by UB (31.1%, 13.31 μg kg-1 ) and UG (18.4%, 9.19 μg kg-1 ). No targeted ustiloxins were detected in white rice samples randomly collected from supermarkets in Shanghai. To reveal the causes, two approaches were tested for the removal of the ustiloxins: most of the targeted ustiloxins (>93%) were removed in brown rice by husking and, subsequently, all targeted ustiloxins (100%) were removed by whitening.

CONCLUSION

A wide distribution of ustiloxins was discovered in paddy samples in this study. The UA contaminations were significantly different depending on their origin, with the highest occurrence in paddy from Shanghai and Jiangsu, southeast coast provinces in China. Contamination by UG was also found in paddy for the first time and was strongly correlated with those of UA and UB. A combination of husking and whitening has been verified to be a practicable and promising way to ensure efficient removal and food safety. © 2023 Society of Chemical Industry.

Toward Machine Learning-Driven Mass Spectrometric Identification of Trichothecenes in the Absence of Standard Reference Materials

While a significant body of work exists on the detection of commonly known trichothecene toxins, biological, environmental, and other transformational processes can generate many under-characterized and unknown modified trichothecenes. Lacking both analytical reference standards and associated mass spectral databases, identification of these modified compounds reflects both a challenge and a critical gap from forensic and public health perspectives. We report here the application of machine learning (ML) techniques toward identification of discriminative fragment ions from mass spectrometric data that can be exploited to detect evidence of type A and B trichothecenes. The goal of this work is to establish a new method for the identification of unknown, though structurally similar trichothecenes, by leveraging objective ML techniques. Discriminative fragments derived from a series of gradient-boosted machine learners are then used to develop ML-driven precursor ion scan (PIS) methods on a triple quadrupole mass spectrometer (QQQ) for screening of "unknown unknown" trichothecenes. Specifically, we apply the PIS method to a laboratory-synthesized trichothecene, a first step in demonstrating the power of alternative, machine learning-driven mass spectrometric methods.

Enhanced Competitive Immunomagnetic Beads Assay Assisted with PAMAM-Gold Nanoparticles Multi-Enzyme Probes for Detection of Deoxynivalenol

Contamination of deoxynivalenol (DON) in grains has attracted widespread concern. It is urgently needed to develop a highly sensitive and robust assay for DON high-throughput screening. Antibody against DON was assembled on the surface of immunomagnetic beads orientationally by the aid of Protein G. AuNPs were obtained under the scaffolding of poly(amidoamine) dendrimer (PAMAM). DON-horseradish peroxidase (HRP) was combined on the periphery of AuNPs/PAMAM by a covalent link to develop DON-HRP/AuNPs/PAMAM. Magnetic immunoassay based on DON-HRP/AuNPs/PAMAM was optimized and that based on DON-HRP/AuNPs and DON-HRP was adopted as comparison. The limits of detection (LODs) were 0.447 ng/mL, 0.127 ng/mL and 0.035 ng/mL for magnetic immunoassays based on DON-HRP, DON-HRP/Au and DON-HRP/Au/PAMAM, respectively. Magnetic immunoassay based on DON-HRP/AuNPs/PAMAM displayed higher specificity towards DON and was utilized to analyze grain samples. The recovery for the spiked DON in grain samples was 90.8-116.2% and the method presented a good correlation with UPLC/MS. It was found that the concentration of DON was in the range of ND-3.76 ng/mL. This method allows the integration of dendrimer-inorganic NPs with signal amplification properties for applications in food safety analysis.

Type B Trichothecenes in Cereal Grains and Their Products: Recent Advances on Occurrence, Toxicology, Analysis and Post-Harvest Decontamination Strategies

Type B trichothecenes (deoxynivalenol, nivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol) and deoxynivalenol-3-glucoside (DON-3G) are secondary toxic metabolites produced mainly by mycotoxigenic Fusarium fungi and have been recognized as natural contaminants in cereals and cereal-based foods. The latest studies have proven the various negative effects of type B trichothecenes on human health. Due to the widespread occurrence of Fusarium species, contamination by these mycotoxins has become an important aspect for public health and agro-food systems worldwide. Hence, their monitoring and surveillance in various foods have received a significant deal of attention in recent years. In this review, an up-to-date overview of the occurrence profile of major type B trichothecenes and DON-3G in cereal grains and their toxicological implications are outlined. Furthermore, current trends in analytical methodologies for their determination are overviewed. This review also covers the factors affecting the production of these mycotoxins, as well as the management strategies currently employed to mitigate their contamination in foods. Information presented in this review provides good insight into the progress that has been achieved in the last years for monitoring type B trichothecenes and DON-3G, and also would help the researchers in their further investigations on metabolic pathway analysis and toxicological studies of these Fusarium mycotoxins.

Electronic Nose for the Rapid Detection of Deoxynivalenol in Wheat Using Classification and Regression Trees

Mycotoxin represents a significant concern for the safety of food and feed products, and wheat represents one of the most susceptible crops. To manage this issue, fast, reliable, and low-cost test methods are needed for regulated mycotoxins. This study aimed to assess the potential use of the electronic nose for the early identification of wheat samples contaminated with deoxynivalenol (DON) above a fixed threshold. A total of 214 wheat samples were collected from commercial fields in northern Italy during the periods 2014−2015 and 2017−2018 and analyzed for DON contamination with a conventional method (GC-MS) and using a portable e-nose “AIR PEN 3” (Airsense Analytics GmbH, Schwerin, Germany), equipped with 10 metal oxide sensors for different categories of volatile substances. The Machine Learning approach “Classification and regression trees” (CART) was used to categorize samples according to four DON contamination thresholds (1750, 1250, 750, and 500 μg/kg). Overall, this process yielded an accuracy of >83% (correct prediction of DON levels in wheat samples). These findings suggest that the e-nose combined with CART can be an effective quick method to distinguish between compliant and DON-contaminated wheat lots. Further validation including more samples above the legal limits is desirable before concluding the validity of the method.

Development of a reliable UHPLC-MS/MS method for simultaneous determination of zearalenone and zearalenone-14-glucoside in various feed products

A reliable ultra-high-performance liquid chromatography-tandem mass spectrometry method (UHPLC-MS/MS) was developed for the simultaneous determination of two mycotoxins, that is, zearalenone (ZEN) and zearalenone-14-glucoside (ZEN-14G) in formula feed, concentrated feed, and premixed feed products. An improved sample pretreatment was achieved with the hydrophilic-lipophilic balance (HLB) cartridges efficiently removing the impurities and enriching the target analytes in different feeds. The critical parameters affecting the performance of the solid-phase extraction (SPE) procedure were carefully optimized, and 20% acetonitrile in water as the loading solution, 50% methanol in water as the washing solvent, and 5 ml of methanol as the elution solvent yielded the optimal purification efficiencies. The established method was thoroughly validated in terms of linearity (R 2 ≥ 0.999), sensitivity (limit of quantification in the range of 0.50-5.00 μg kg-1), recovery (89.35 ± 2.67% to 110.93 ± 1.56%), and precision (RSD, 3.00-14.20%), and it was then successfully applied to investigate a total of 60 feed samples. Among them, 50 samples were found to be contaminated with ZEN (an incidence of 83.3%) at levels ranging from 0.63 to 615.24 μg kg-1, whereas 22 samples were contaminated with ZEN-14G (an incidence of 36.7%) in the range of 0.89-15.31 μg kg-1. The developed method proved to be a specific and reliable tool for intensive monitoring of ZEN and ZEN-14G in complex feed matrices.

CRISPR-Cas12a-mediated luminescence resonance energy transfer aptasensing platform for deoxynivalenol using gold nanoparticle-decorated Ti3C2Tx MXene as the enhanced quencher

Deoxynivalenol (DON) is a typical mycotoxin in cereals and poses tremendous threats to the ecological environment and public health. Therefore, exploiting sensitive and robust analytical methods for DON is particularly important. Here, we fabricated a CRISPR-Cas12a-mediated luminescence resonance energy transfer (LRET) aptasensor to detect DON by using single-stranded DNA modified upconversion nanoparticles (ssDNA-UCNPs) as anti-interference luminescence labels and gold nanoparticle-decorated Ti₃C₂T_x MXene nanosheets (MXene-Au) as enhanced quenchers. The DON aptamer can activate the trans-cleavage activity of Cas12a to indiscriminately cut nearby ssDNA-UCNPs into small fragments, which prevents ssDNA-UCNPs from adsorbing onto MXene-Au, and the upconversion luminescence (UCL) remains. Upon the binding of the aptamer with DON, the trans-cleavage activity of Cas12a was suppressed, and the ssDNA-UCNPs were not cleaved and easily adsorbed onto MXene-Au, which caused UCL quenching. Under optimized conditions, the limit of detection was determined to be 0.64 ng/mL with a linear range of 1 - 500 ng/mL. In addition, the sensor was successfully applied to detect DON in corn flour and Tai Lake water with recoveries of 96.2 - 105% and 95.2 - 104%, respectively. This platform achieves a sensitive and specific analysis of DON and greatly broadens the detection range of CRISPR-Cas sensors for non-nucleic acids hazards in the environment and food.

Lycopene Protects Intestinal Epithelium from Deoxynivalenol-Induced Oxidative Damage via Regulating Keap1/Nrf2 Signaling

Deoxynivalenol (DON) is a threatening mycotoxin primarily present in the agricultural environment, especially in food commodities and animal forages, and exerts significant global health hazards. Lycopene (LYC) is a potent antioxidant carotenoid mainly present in tomatoes and other fruits with enormous health benefits. The present study was designed to ascertain whether LYC could protect DON-induced intestinal epithelium oxidative injury by regulating Keap1/Nrf2 signaling in the intestine of mice. A total of forty-eight mice were randomly distributed into four groups (n = 12), Control (CON), 10 mg/kg BW LYC, 3 mg/kg BW DON, and 3 mg/kg DON + 10 mg/kg LYC BW (DON + LYC). The experimental groups were treated by intragastric administration for 11 days. Our results showed that LYC significantly increased average daily feed intake (ADFI), average daily gain (ADG), and repaired intestinal injury and barrier dysfunction, as evident by increased trans-epithelial electrical resistance (TEER) and decreased diamine oxidase (DAO) activity, as well as up-regulated tight junction proteins (occludin, claudin-1) under DON exposure. Furthermore, LYC treatment stabilized the functions of intestinal epithelial cells (Lgr5, PCNA, MUC2, LYZ, and Villin) under DON exposure. Additionally, LYC alleviated DON-induced oxidative stress by reducing ROS and MDA accumulation and enhancing the activity of antioxidant enzymes (CAT, T-SOD, T-AOC, and GSH-Px), which was linked with the activation of Nrf2 signaling and degradation of Keap1 expression. Conclusively, our findings demonstrated that LYC protects intestinal epithelium from oxidative injury by modulating the Keap1/Nrf2 signaling pathway under DON exposure. These novel findings could lead to future research into the therapeutic use of LYC to protect the DON-induced harmful effects in humans and/or animals.

Determination of Deoxynivalenol and Its Derivative in Corn Flour and Wheat Flour Using Automated On-line Solid-Phase Extraction Combined with LC-MS/MS

An automated on-line solid-phase extraction (SPE) combined with LC-MS/MS method was developed for determination of deoxynivalenol (DON), 3-acetyl-DON and 15-acetyl-DON in corn flour and wheat flour samples. The extraction solvent of the samples was injected into the automated on-line SPE system to remove matrix interference. After washing step, the targets were eluted from the SPE cartridge into liquid chromatography (LC) column. Several SPE parameters including injection volume, elution volume and eluting flow rate were assessed and optimized. Method validation was evaluated and good linearity was obtained (R² > 99%) with the limit of detection of 0.1-0.2 μg/kg. Recoveries were evaluated in spiked corn flour and wheat flour samples at three concentrations and the values ranged from 86.5% to 99.7%. The benefit of the present method with automated on-line SPE system is the ability to inject directly pure extracts into LC-MS/MS, offering faster analyses and improving analysis efficiency.

Co-Occurrence and Levels of Mycotoxins in Fish Feeds in Kenya

This study determined the presence, levels and co-occurrence of mycotoxins in fish feeds in Kenya. Seventy-eight fish feeds and ingredients were sampled from fish farms and fish feed manufacturing plants and analysed for 40 mycotoxins using high-performance liquid chromatography-high resolution mass spectrometry. Twenty-nine (73%) mycotoxins were identified with 76 (97%) samples testing positive for mycotoxins presence. Mycotoxins with the highest prevalences were enniatin B (91%), deoxynivalenol (76%) and fumonisin B1 (54%) while those with the highest maximum levels were sterigmatocystin (<30.5-3517.1 µg/kg); moniliformin (<218.9-2583.4 µg/kg) and ergotamine (<29.3-1895.6 µg/kg). Mycotoxin co-occurrence was observed in 68 (87%) samples. Correlations were observed between the fumonisins; enniatins B and zearalenone and its metabolites. Fish dietary exposure estimates ranged between <0.16 and 43.38 µg/kg body weight per day. This study shows evidence of mycotoxin presence and co-occurrence in fish feeds and feed ingredients in Kenya. Fish exposure to these levels of mycotoxins over a long period of time may lead to adverse health effects due to their possible additive, synergistic or antagonist toxic effects. Measures to reduce fish feed mycotoxin contamination should be taken to avoid mycotoxicosis in fish and subsequently in humans and animals through residues.

Determination of deoxynivalenol and its major conjugates in cereals using an organic solvent-free extraction and IAC clean-up coupled in-line with HPLC-PCD-FLD

A method for the determination of deoxynivalenol (DON) and its major conjugates in cereals was developed including an immunoaffinity column (IAC) clean-up coupled in-line with high-performance liquid chromatography, post-column derivatisation and fluorescence detection. An IAC for DON with cross-reactivity to 15-AcDON, 3-AcDON and DON-3-G enabled this approach. The isolated analytes were introduced into the chromatographic system without aliquotation employing the hot water elution technique, resulting in the desired low LOQ values for monitoring these analytes in cereals. The absence of any organic solvent during sample preparation in combination with an in-line IAC clean-up renders the method simple, fast, and environmentally friendly. Special attention was paid to inherent IACs properties such as cross-reactivity, analytes' competition and capacity. The method was applied to determine DON and its major conjugates in barley, wheat and maize in the range of 10-1000 µg kg^-1 of DON, 10-300 µg kg^-1 of DON-3-G and 15-AcDON and 10-100 µg kg^-1 of 3-AcDON. The apparent recoveries varied from 87% to 110% (average of 98%) and the intermediate precision was below 13.5% RSD (except for DON-3-G in wheat). Fifteen maize, wheat and barley samples were analysed revealing levels of DON conjugates that accounted from 9% to 60% of the "total DON" content (m/m). In general, the frequency and the measured mass fractions decreased in the following order: DON>DON-3-G>15-AcDON>3-AcDON.

Rapid and nondestructive determination of deoxynivalenol (DON) content in wheat using multispectral imaging (MSI) technology with chemometric methods

Wheat is susceptible to contamination by deoxynivalenol (DON) which is regarded as a class III carcinogen. In this paper, a rapid and nondestructive method for DON content determination and contamination degree discrimination in wheat was developed by using a multispectral imaging (405-970 nm) system. Genetic algorithm (GA) and principal component analysis (PCA), as preprocessing methods, were used to obtain the best spectral characteristics. The determination model was established by combining preprocessing methods and chemometric methods including partial least squares (PLS), support vector machines (SVM) and back propagation neural network (BPNN). The best quantitative determination result was obtained based on GA-SVM with a correlation coefficient of prediction (Rp), root mean square error of prediction (RMSEP) and residual predictive deviation (RPD) of 0.9988, 365.3 μg kg-1 and 8.6, respectively. Furthermore, the accuracy of contamination degree classification was up to 94.29% in the prediction set by using the PCA-PLS model. The results showed that the combination of multispectral imaging technology and chemometrics was an effective and nondestructive method for the determination of DON in wheat.

Natural Occurrence of Deoxynivalenol and Its Acetylated Derivatives in Chinese Maize and Wheat Collected in 2017

Deoxynivalenol (DON), along with 3-acetyl-deoxynivalenol (3-ADON) and 15-acetyl-deoxynivalenol (15-ADON), occur in grains and cereal products and is often hazardous to humans and livestock. In this study, 579 wheat samples and 606 maize samples intended for consumption were collected from China in 2017 and analyzed to determine the co-occurrence of type-B trichothecenes (DON, 3-ADON, and 15-ADON). All the wheat samples tested positive for DON, while 99.83% of the maize samples were DON-positive with mean DON concentrations of 165.87 and 175.30 μg/kg, respectively. Per the Chinese standard limits for DON, 3.63% of wheat and 2.97% of the maize samples were above the maximum limit of 1000 μg/kg. The DON derivatives (3-ADON and 15-ADON) were less frequently found and were present at lower levels than DON in wheat. 3-ADON and 15-ADON had incidences of 13.53% and 76.40%, respectively, in maize. By analyzing the distribution ratio of DON and its derivatives in wheat and maize, DON (95.51%) was the predominant toxin detected in wheat samples, followed by 3.97% for the combination of DON + 3-ADON, while DON + 3-ADON + 15-ADON and DON + 15-ADON were only found in 0.17% and 0.35% of wheat samples, respectively. Additionally, a large amount of the maize samples were contaminated with DON + 15-ADON (64.19%) and DON (22.11%). The samples with a combination of DON + 3-ADON and DON + 3-ADON + 15-ADON accounted for 1.32% and 12.21%, respectively. Only one maize sample did not contain all three mycotoxins. Our study shows the necessity of raising awareness of the co-occurrence of mycotoxin contamination in grains from China to protect consumers from the risk of exposure to DON and its derivatives.

Paper-Based Microfluidic Device (DON-Chip) for Rapid and Low-Cost Deoxynivalenol Quantification in Food, Feed, and Feed Ingredients

Mycotoxin contamination causes over $5 billion of economic loss per year in the North American food and feed industry. A rapid, low-cost, portable, and reliable method for on-site detection of deoxynivalenol (DON), a representative mycotoxin predominantly occurring in grains, would be helpful to control mycotoxin contamination. In this study, a paper-based microfluidic chip capable of measuring DON (DON-Chip) in food, feed, and feed ingredients was developed. The DON-Chip incorporated a colorimetric competitive immunoassay into a paper microfluidic device and used gold nanoparticles as a signal indicator. Furthermore, a novel ratiometric analysis method was proposed to improve detection resolvability. Detection of DON in the aqueous extracts from solid food, feed, or feed ingredients was successfully validated with a detection range of 0.01-20 ppm (using dilution factors from 10 to 10⁴). Compared with conventional methods, the DON-Chip method could greatly reduce the cost and time of mycotoxin detection in the food and feed industry.

Identification and determination of deoxynivalenol (DON) and deepoxy-deoxynivalenol (DOM-1) in pig colostrum and serum using liquid chromatography in combination with high resolution mass spectrometry (LC-MS/MS (HR))

Deoxynivalenol (DON) is one of the most common mycotoxins produced by field fungi (especially Fusarium). Contamination of livestock feed is a significant risk factor, especially for pigs that are highly susceptible to the toxic effects of deoxynivalenol. In this study, validated ultra-high performance liquid chromatography (U-HPLC) combined with a HR-Orbitrap-MS analysis method is described for the identification and quantitative determination of the mycotoxin compounds (DON and deepoxy-deoxynivalenol (DOM-1)) in pig colostrum (milk) and serum. Pre-treatment of the samples involved a deproteinisation step with methanol followed by a purification step by solid phase extraction (HLB cartridges). The chromatographic separation was performed on a C18 column with 1.7 μm-particle size using a water-methanol mobile phase. Detection of analytes was achieved on the tandem hybrid mass spectrometer Q Exactive, with a heated electrospray ionisation probe measured in positive mode (H-ESI+). For the confirmation of identification, a mass spectrometer was utilized in the full scan mode with resolving power (PR) = 140,000 (FWHM) and for quantification analysis, it was utilized in the parallel reaction monitoring mode (PRM). The method has been fully validated according to the requirements of Commission Decision 2002/657/EC for confirmatory analyses, plus the addition of a mass accuracy (MA) parameter. For the confirmation of the presence of these analytes in pig colostrum and serum, matching of the retention time with mass accuracy for the precursor ion from MS and product ions from MS/MS was used. A deuterium isotopically labelled internal standard and a matrix-matched calibration curve were employed for quantification. The linear range of quantification was 0.5-20 μg L^-1 and the correlation coefficient (R²) was >0.999 for all calibrations. The limit of detection for DON and DOM-1 in colostrum was 0.48 μg L^-1 and 0.54 μg L^-1, respectively, and in serum 0.24 μg L^-1 and 0.36 μg L^-1, respectively. The limit of quantification for DON and DOM-1 in colostrum was 0.80 μg L^-1 and 0.89 μg L^-1, respectively, and in serum 0.39 μg L^-1 and 0.60 μg L^-1, respectively. The method was successfully evaluated using the obtained samples of pig colostrum and serum.

Fumonisins: Impact on Agriculture, Food, and Human Health and their Management Strategies

The fumonisins producing fungi, Fusarium spp., are ubiquitous in nature and contaminate several food matrices that pose detrimental health hazards on humans as well as on animals. This has necessitated profound research for the control and management of the toxins to guarantee better health of consumers. This review highlights the chemistry and biosynthesis process of the fumonisins, their occurrence, effect on agriculture and food, along with their associated health issues. In addition, the focus has been put on the detection and management of fumonisins to ensure safe and healthy food. The main focus of the review is to provide insights to the readers regarding their health-associated food consumption and possible outbreaks. Furthermore, the consumers' knowledge and an attempt will ensure food safety and security and the farmers' knowledge for healthy agricultural practices, processing, and management, important to reduce the mycotoxin outbreaks due to fumonisins.

Prevalent Mycotoxins in Animal Feed: Occurrence and Analytical Methods

Today, we have been witnessing a steady tendency in the increase of global demand for maize, wheat, soybeans, and their products due to the steady growth and strengthening of the livestock industry. Thus, animal feed safety has gradually become more important, with mycotoxins representing one of the most significant hazards. Mycotoxins comprise different classes of secondary metabolites of molds. With regard to animal feed, aflatoxins, fumonisins, ochratoxins, trichothecenes, and zearalenone are the more prevalent ones. In this review, several constraints posed by these contaminants at economical and commercial levels will be discussed, along with the legislation established in the European Union to restrict mycotoxins levels in animal feed. In addition, the occurrence of legislated mycotoxins in raw materials and their by-products for the feeds of interest, as well as in the feeds, will be reviewed. Finally, an overview of the different sample pretreatment and detection techniques reported for mycotoxin analysis will be presented, the main weaknesses of current methods will be highlighted.

Yellow Mealworm Larvae (Tenebrio molitor) Fed Mycotoxin-Contaminated Wheat-A Possible Safe, Sustainable Protein Source for Animal Feed?

The aim of this study was to determine the potential for accumulation of deoxynivalenol (DON) in yellow mealworm larvae (Tenebrio molitor) reared on high DON Fusarium-infected wheat and investigate the effects on production, survival and nutritional traits. Wheat containing 200 μg/kg DON was used as the control diet. A different source of wheat was sorted into six fractions and mixed to obtain low (2000 μg/kg), medium (10,000 μg/kg) and high (12,000 μg/kg) levels of DON. Each diet was replicated five times with 300 or 200 mealworms per replicate for the feeding and breeding trials, respectively. Trial termination occurred when the first two pupae were observed (32–34 days). There was no difference in the concentrations of DON detected in the larvae between diets that ranged from 122 ± 19.3 to 136 ± 40.5 μg/kg (p = 0.88). Excretion of DON was 131, 324, 230 and 742 μg/kg for control, low, medium and high, respectively. Nutritional analysis of larvae showed maximum crude protein of 52% and crude fat of 36%. Ash, fiber, chitin, fatty-acids and amino-acid content were consistent across diets. Survival was greater than 96% for all life stages and average daily gain ranged from 1.9 ± 0.1 to 2.1 ± 0.1 mg/day per mealworm. Larvae accumulated low levels of DON from Fusarium-infected wheat diets suggesting contaminated wheat could be used to produce a sustainable, safe protein source.

Fourier transform near-infrared and mid-infrared spectroscopy as efficient tools for rapid screening of deoxynivalenol contamination in wheat bran

BACKGROUND

Deoxynivalenol (DON) is the most common Fusarium mycotoxin occurring in wheat and wheat-derived products, with several adverse and toxic effects in animals and humans. Although bran fractions produced by milling wheat have numerous health benefits, cereal bran is the part of the grain with the highest concentration of DON, thus representing a risk for consumers. Increased efforts have been made to develop analytical methods suitable for rapid DON screening.

RESULTS

The applicability of Fourier transform near-infrared (FTNIR), or mid-infrared (FTMIR) spectroscopy, and their combination for rapid analysis of DON in wheat bran, was investigated for the classification of samples into compliant and non-compliant groups regarding the EU legal limit of 750 µg kg^-1 . Partial least squares-discriminant analysis (PLS-DA) and principal component-linear discriminant analysis (PC-LDA) were employed as classification techniques using a cutoff value of 400 µg kg^-1 DON to distinguish the two classes. Depending on the classification model, overall discrimination rates were from 87% to 91% for FTNIR and from 86% to 87% for the FTMIR spectral range. The FTNIR spectroscopy gave the highest overall classification rate of wheat bran samples, with no false compliant samples and 18% false noncompliant samples when the PC-LDA classification model was applied. The combination of the two spectral ranges did not provide a substantial improvement in classification results in comparison with FTNIR.

CONCLUSIONS

Fourier transform near-infrared spectroscopy in combination with classification models was an efficient tool to screen many DON-contaminated wheat bran samples and assess their compliance with EU regulations. © 2018 Society of Chemical Industry.

Rapid prediction of deoxynivalenol contamination in wheat bran by MOS-based electronic nose and characterization of the relevant pattern of volatile compounds

BACKGROUND

Deoxynivalenol (DON) is a mycotoxin, mainly produced by Fusarium sp., most frequently occurring in cereals and cereal-based products. Wheat bran refers to the outer layers of the kernel, which has a high risk of damage due to chemical hazards, including mycotoxins. Rapid methods for DON detection in wheat bran are required.

RESULTS

A rapid screening method using an electronic nose (e-nose), based on metal oxide semiconductor sensors, has been developed to distinguish wheat bran samples with different levels of DON contamination. A total of 470 naturally contaminated wheat bran samples were analyzed by e-nose analysis. Wheat bran samples were divided in two contamination classes: class A ([DON] ≤ 400 µg kg^-1 , 225 samples) and class B ([DON] > 400 µg kg^-1 , 245 samples). Discriminant function analysis (DFA) classified wheat bran samples with good mean recognizability in terms of both calibration (92%) and validation (89%). A pattern of 17 volatile compounds of wheat bran samples that were associated (positively or negatively) with DON content was also characterized by HS-SPME/GC-MS.

CONCLUSIONS

These results indicate that the e-nose method could be a useful tool for high-throughput screening of DON-contaminated wheat bran samples for their classification as acceptable / rejectable at contamination levels close to the EU maximum limit for DON, reducing the number of samples to be analyzed with a confirmatory method. © 2018 Society of Chemical Industry.

Simultaneous and rapid determination of deoxynivalenol and its acetylate derivatives in wheat flour and rice by ultra high performance liquid chromatography with photo diode array detection

A simple and reliable method of ultra high performance liquid chromatography coupled with photo-diode array detection has been proposed for the simultaneous determination of deoxynivalenol and its acetylated derivatives in wheat flour and rice, especially focusing on the optimization of sample extraction, cleanup, and chromatographic separation conditions. Sample pretreatment consisted of a first step using a quick, easy, cheap, effective, rugged, and safe based extraction procedure and a subsequent cleanup step based on solid-phase extraction. The method was extensively validated in wheat flour and rice, obtaining satisfactory analytical performance with good linearity (R(2) ≥ 0.999), acceptable recoveries (80.0-104.4%), and repeatability (RSDs 1.3-10.7%). The limits of detection (21.7-57.4 μg/kg) and quantitation (72.3-191.4 μg/kg) for deoxynivalenols were lower than those usually permitted by various countries' legislation in these food matrices. The method was applied to 34 wheat and rice samples. The results were further compared with results of ultra high performance liquid chromatography with electrospray ionization tandem mass spectrometry.

Evaluation of the TLC quantification method and occurrence of deoxynivalenol in wheat flour of southern Brazil

The study evaluated a QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) extraction method for use with a TLC quantification procedure for deoxynivalenol (DON). It also surveyed DON occurrence in wheat flour from the southern region of Brazil. Forty-eight wheat flour samples were analysed, divided into 2 different harvest lots, each consisting of 24 different brands. The detection and quantification limits of the method were 30 and 100 ng of DON on the TLC plate. The various concentrations of DON presented high linearity (R² = 0.99). A negative matrix effect (-28%) of the wheat flour was verified, with suppression of the chromatographic signal of DON, and 80.2-105.4% recovery. The TLC method was reliable for DON evaluation, with a coefficient of variation of less than 10%. High-performance liquid chromatography of lot 2 samples confirmed the presence of DON in all samples identified DON-positive by the TLC technique. Of the 48 wheat flour samples in lots 1 and 2 analysed by TLC, 33.3 and 45.8% of the samples respectively were above the Brazilian legislation limit. Correlations were observed between the water activity and DON content, and between the fungal count and moisture content of the wheat flours.

Risks to human and animal health related to the presence of deoxynivalenol and its acetylated and modified forms in food and feed

Deoxynivalenol (DON) is a mycotoxin primarily produced by Fusarium fungi, occurring predominantly in cereal grains. Following the request of the European Commission, the CONTAM Panel assessed the risk to animal and human health related to DON, 3-acetyl-DON (3-Ac-DON), 15-acetyl-DON (15-Ac-DON) and DON-3-glucoside in food and feed. A total of 27,537, 13,892, 7,270 and 2,266 analytical data for DON, 3-Ac-DON, 15-Ac-DON and DON-3-glucoside, respectively, in food, feed and unprocessed grains collected from 2007 to 2014 were used. For human exposure, grains and grain-based products were main sources, whereas in farm and companion animals, cereal grains, cereal by-products and forage maize contributed most. DON is rapidly absorbed, distributed, and excreted. Since 3-Ac-DON and 15-Ac-DON are largely deacetylated and DON-3-glucoside cleaved in the intestines the same toxic effects as DON can be expected. The TDI of 1 μg/kg bw per day, that was established for DON based on reduced body weight gain in mice, was therefore used as a group-TDI for the sum of DON, 3-Ac-DON, 15-Ac-DON and DON-3-glucoside. In order to assess acute human health risk, epidemiological data from mycotoxicoses were assessed and a group-ARfD of 8 μg/kg bw per eating occasion was calculated. Estimates of acute dietary exposures were below this dose and did not raise a health concern in humans. The estimated mean chronic dietary exposure was above the group-TDI in infants, toddlers and other children, and at high exposure also in adolescents and adults, indicating a potential health concern. Based on estimated mean dietary concentrations in ruminants, poultry, rabbits, dogs and cats, most farmed fish species and horses, adverse effects are not expected. At the high dietary concentrations, there is a potential risk for chronic adverse effects in pigs and fish and for acute adverse effects in cats and farmed mink.

Analytical techniques for deoxynivalenol detection and quantification in wheat destined for the manufacture of commercial products

The concern regarding toxicity from the presence of deoxynivalenol (DON) in wheat that affects both economy and public health leads to the need to find appropriate detection methods for determining the degree of DON contamination in terms of the equipment available and the speed required for obtaining the incidence. The objective of this study was to compare the performance of two alternative analytical techniques for DON quantification for use in the food industry with a reference technique. Samples of wheat and the commercial by-products were analysed by high-performance liquid chromatography (HPLC) with an ultraviolet detector as the reference method and the results compared with those obtained from a rapid lateral-flow immunochromatographic device (Reveal Q+) and of a Fourier-transform-infrared (FTIR) spectroscopy technique. Pearson’s correlation coefficient between the HPLC and Reveal-Q+ data (0.45), although significant (P<0.0003), was lower than that obtained between HPLC and the FTIR method (0.94, P<0.0001). Both methods were considered efficient in quantifying DON levels in wheat-flour samples. This study was aimed at assisting the producers in choosing an appropriate tool for the purpose of analysis and upon consideration of the available equipment.

The metabolic responses of HepG2 cells to the exposure of mycotoxin deoxynivalenol

As the number of reported deoxynivalenol (DON) contamination incidents increased steadily over the past decades, there has been a widespread interest in understanding the cellular mechanisms of the toxicological effects of DON using in vitro systems and omics technologies. The present investigation was conducted to understand the metabolomic changes in human hepatocellular carcinoma cells (HepG2) exposed to 10 μM DON for short term (4 h) and long term (12 h) periods, using a non-targeted metabolomics approach. Our results revealed a remarkable metabolic shift from short term to long term exposure to DON in HepG2 cells. Our metabolomics data also confirmed the role of DON induced oxidative stress in DON toxicity. Coupled with pattern recognition and pathway analysis, effects of DON on redox homeostasis, energy balance, lipid metabolism, and potential toxicological mechanisms were discussed, which would facilitate further studies on the risk assessment of the dietary mycotoxin DON.

An epimer of deoxynivalenol: purification and structure identification of 3-epi-deoxynivalenol

In an investigation of deoxynivalenol (DON)-transformation products by Devosia mutans 17-2-E-8, the major product was identified as 3-epi-DON. This DON-transformation product was analysed by liquid chromatography and identified by congruent retention time and UV/Vis spectrum, as well as mass spectrometric data. Nuclear magnetic resonance (NMR) experiments including correlation spectroscopy (COSY), heteronuclear single quantum coherence (HSQC) and nuclear overhauser effect (NOE) were conducted for structural characterisation of 3-epi-DON. High-speed counter-current chromatography (HSCCC) was applied to scale up the separation of 3-epi-DON from DON in a D. mutans 17-2-E-8 culture. From the culture where 100 mg DON was applied, 56 mg of 3-epi-DON (purity of 96.8%) was obtained from the HSCCC. The purified 3-epi-DON will be used for toxicological characterisation studies of this chemical.