Simultaneous determination of trichothecene mycotoxins and zearalenone in cereals by gas chromatography-mass spectrometry

An electrochemical aptamer-sensing strategy based on a Ti3C2Tx MXene synergistic Ti-MOF amplification signal for highly sensitive detection of zearalenone

A refined electrochemical aptamer sensing technique using PEI@Ti-MOF@Ti3C2Tx-MXene was developed for the sensitive detection of ZEN in food samples. A titanium-based metal-organic skeleton (NH2-MIL-125) was synthesized in situ using 2-aminoterephthalic acid as the organic ligand and tetrabutyl titanate as the metal center, followed by the simultaneous hybridization of Ti3C2Tx-MXene to synthesize a Ti-MOF@Ti3C2Tx-MXene composite material. These composites were subsequently functionalized with PEI and covalently linked to form a sensing platform on gold electrodes. Integrating a metal-organic framework (MOF) with MXene materials not only improved the electrochemical properties compared to those of individual elements but also decreased the stacking effect and increased the number of binding sites for the aptamer. The limit of detection (LOD) of this sensor was 1.64 fg mL-1. Additionally, the sensor could efficaciously detect ZEN in cornmeal and beer samples, exhibiting outstanding stability, reproducibility, and selectivity. This highlighted its effectiveness in applications in quality supervision and food safety.

Is chemical analysis suitable for detecting mycotoxins in agricultural commodities and foodstuffs?

The assessment of the risks of mycotoxins to humans through consuming contaminated foods resulted in specific legislation that evaluates the presence, quantities, and type of mycotoxins in agricultural commodities and foodstuffs. Thus, to ensure compliance with legislation, food safety and consumer health, the development of suitable analytical procedures for identifying and quantifying mycotoxins in the free or modified form, in low-concentration and in complex samples is necessary. This review reports the application of the modern chemical methods of analysis employed in mycotoxin detection in agricultural commodities and foodstuffs. It is reported extraction methods with reasonable accuracy and those present characteristics according to guidelines of Green Analytical Chemistry. Recent trends in mycotoxins detection using analytical techniques are presented and discussed, evaluating the robustness, precision, accuracy, sensitivity, and selectivity in the detection of different classes of mycotoxins. Sensitivity coming from modern chromatographic techniques allows the detection of very low concentrations of mycotoxins in complex samples. However, it is essential the development of more green, fast and more suitable accuracy extraction methods for mycotoxins, which agricultural commodities producers could use. Despite the high number of research reporting the use of chemically modified voltammetric sensors, mycotoxins detection still has limitations due to the low selectivity from similar chemical structures of mycotoxins. Furthermore, spectroscopic techniques are rarely employed due to the limited number of reference standards for calibration procedures.

Detection of T-2 Toxin in Wheat and Maize with a Portable Mass Spectrometer

T-2 toxin is a mycotoxin routinely found as a contaminant of cereal grains worldwide. A portable mass spectrometer was adapted to enable the detection of T-2 toxin in wheat and maize by APCI-MS. In order to facilitate rapid testing, a rapid cleanup was used. The method was able to detect T-2 toxin in soft white wheat, hard red wheat, and yellow dent maize and could be used to screen for T-2 at levels above 0.2 mg/kg. The HT-2 toxin was only detectable at very high levels (>0.9 mg/kg). Based on these results, the sensitivity was not sufficient to allow the application of the screening method to these commodities at levels recommended by the European Commission. With a cut-off level of 0.107 mg/kg, the method correctly classified nine of ten reference samples of wheat and maize. The results suggest that portable MS detection of T-2 toxin is feasible. However, additional research will be needed to develop an application sensitive enough to meet regulatory requirements.

Evaluation of Zearalenones and Their Metabolites in Chicken, Pig and Lamb Liver Samples

Zearalenone (ZON), zearalanone (ZAN) and their phase I metabolites: α-zearalenol (α-ZOL), β-zearalenol (β-ZOL), α-zearalalanol (α-ZAL) and β-zearalalanol (β-ZAL) are compounds with estrogenic activity that are metabolized and distributed by the circulatory system in animals and can access the food chain through meat products from livestock. Furthermore, biomonitoring of zearalenones in biological matrices can provide useful information to directly assess mycotoxin exposure; therefore, their metabolites may be suitable biomarkers. The aim of this study was to determine the presence of ZON, ZAN and their metabolites in alternative biological matrices, such as liver, from three different animals: chicken, pig and lamb, in order to evaluate their exposure. A solid-liquid extraction procedure coupled to a GC-MS/MS analysis was performed. The results showed that 69% of the samples were contaminated with at least one mycotoxin or metabolite at varying levels. The highest value (max. 152.62 ng/g of β-ZOL) observed, and the most contaminated livers (42%), were the chicken liver samples. However, pig liver samples presented a high incidence of ZAN (33%) and lamb liver samples presented a high incidence of α-ZOL (40%). The values indicate that there is exposure to these mycotoxins and, although the values are low (ranged to 0.11-152.6 ng/g for α-ZOL and β-ZOL, respectively), analysis and continuous monitoring are necessary to avoid exceeding the regulatory limits and to control the presence of these mycotoxins in order to protect animal and human health.

Recent Progress in Rapid Determination of Mycotoxins Based on Emerging Biorecognition Molecules: A Review

Mycotoxins are secondary metabolites produced by fungal species, which pose significant risk to humans and livestock. The mycotoxins which are produced from Aspergillus, Penicillium, and Fusarium are considered most important and therefore regulated in food- and feedstuffs. Analyses are predominantly performed by official laboratory methods in centralized labs by expert technicians. There is an urgent demand for new low-cost, easy-to-use, and portable analytical devices for rapid on-site determination. Most significant advances were realized in the field bioanalytical techniques based on molecular recognition. This review aims to discuss recent progress in the generation of native biomolecules and new bioinspired materials towards mycotoxins for the development of reliable bioreceptor-based analytical methods. After brief presentation of basic knowledge regarding characteristics of most important mycotoxins, the generation, benefits, and limitations of present and emerging biorecognition molecules, such as polyclonal (pAb), monoclonal (mAb), recombinant antibodies (rAb), aptamers, short peptides, and molecularly imprinted polymers (MIPs), are discussed. Hereinafter, the use of binders in different areas of application, including sample preparation, microplate- and tube-based assays, lateral flow devices, and biosensors, is highlighted. Special focus, on a global scale, is placed on commercial availability of single receptor molecules, test-kits, and biosensor platforms using multiplexed bead-based suspension assays and planar biochip arrays. Future outlook is given with special emphasis on new challenges, such as increasing use of rAb based on synthetic and naïve antibody libraries to renounce animal immunization, multiple-analyte test-kits and high-throughput multiplexing, and determination of masked mycotoxins, including stereoisomeric degradation products.

Development of Indirect Competitive ELISA and Visualized Multicolor ELISA Based on Gold Nanorods Growth for the Determination of Zearalenone

In this study, a zearalenone (ZEN) hapten was designed and prepared against the mycotoxin ZEN, and the original coating ZEN-ovalbumin (ZEN-OVA) was prepared by conjugation with OVA. Based on the gold nanorods (AuNRs) of uniform size and stable properties synthesized by the seed-mediated method, the indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and the AuNRs growth-based multicolor ELISA for detecting ZEN toxin were further established. Under the optimal experimental conditions, the coating amount of ZEN-OVA: 0.025 μg/well, antibody (Ab) dilution factor: 32,000 times, blocking solution: 0.5% skimmed milk powder, enzyme-labeled secondary Ab diluted 10,000 times, and a pH of the PBS buffer at 7.4, the sensitivity (IC₅₀) of the established ic-ELISA for ZEN detection reached 0.85 ± 0.04 μg/L, and the limit of detection (IC₁₅) reached 0.22 ± 0.08 μg/L. In the multicolor ELISA based on the growth of AuNRs, as the content of ZEN increased, the mixed solution exhibited a significant color change from brownish red to colorless. ZEN concentration as low as 0.1 μg/L can be detected by the naked eye (brown red to dark gray). This study provided an effective analysis strategy for the rapid screening and accurate monitoring of the ZEN contaminant in foods.

1 An HPLC-MS/MS Method Using a Multitoxin Clean-up Column for Analysis of Seven Mycotoxins in Aquafeeds

BACKGROUND

In Guangdong Province of China, the climate here is very wet, so there are many different fungus living in the aquatic feeds, which produce mycotoxins. These compounds contaminate agriculture products world-wide and represent a great threat to human health. It is necessary to determine their contamination level in aquatic feeds.

OBJECTIVE

A high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) method was developed for the quantitative analysis of aflatoxin B1, aflatoxin M1, T-2 toxin, HT-2 toxin, deoxynivalenol, ochratoxin, and zearalenone in the fish and shrimp feed.

METHODS

Samples were extracted with acetonitrile-water (V: V = 3:1), and degreased with acetonitrile-saturated hexane. Such obtained extract was cleaned up with a multitoxin column. The target compounds were separated on a C18 chromatographic column and analyzed simultaneously by electrospray ionization mass spectrometry in both positive or negative ion mode. Detected compounds were quantified by using the matrix-matched external standard method.

RESULTS

Under the optimized conditions, good linearities for the analytes in corresponding concentration range were obtained with correlation coefficients (r2) higher than 0.9948. LOD ranged from 1.83 to 12.63 μg/kg, and LOQ ranged from 5.49 to 37.89 μg/kg. Average recoveries for the target mycotoxins at three spiked levels ranged from 80.5% to 116.5% with RSD ranging from 2.4% to 10.4%. 23 real aquafeed samples were determined by this method, and 7 kinds of toxins were all detected.

CONCLUSIONS

Obtained results showed that developed method could be successfully applied for the simultaneous determination of mycotoxins in aquatic feeds.

Ultrasensitive immunoassay for detection of zearalenone in agro-products using enzyme and antibody co-embedded zeolitic imidazolate framework as labels

Zearalenone (ZEN) has a potential hazard to human health, and is frequently found in agro-products. To minimize ZEN exposure to consumers, a novel metal-organic framework-based immunoassay system using zeolitic imidazolate framework-encapsulated horseradish peroxidase and goat anti-mouse IgG (HRP/Ab@ZIF-L) as labels was proposed for rapid and ultrasensitive detection of ZEN in agro-products. The HRP/Ab@ZIF-L not only maintained recognition ability of antibody and catalytic activity of enzyme, but also protected encapsulated proteins against high temperature, organic solvents and long term storage. Under optimal conditions, the detection limit of HRP/Ab@ZIF-L-based immunoassay reached 0.5 ng/L for ZEN, which was approximately 126-fold lower than that of conventional HRP-based immunoassay. Moreover, the proposed method showed an excellent selectivity, and a good dynamic linear detection for ZEN in the range of 0.5 ng/L to 0.476 μg/L. The recoveries of ZEN from spiked corn and wheat samples ranged from 84.50% to 96.70% with the relative standard deviation under 8.9%. In brief, the proposed immunoassay method has potential application for rapid and ultrasensitive detection of ZEN in agro-products.

Trichothecenes in Food and Feed, Relevance to Human and Animal Health and Methods of Detection: A Systematic Review

Trichothecene mycotoxins are sesquiterpenoid compounds primarily produced by fungi in taxonomical genera such as Fusarium, Myrothecium, Stachybotrys, Trichothecium, and others, under specific climatic conditions on a worldwide basis. Fusarium mold is a major plant pathogen and produces a number of trichothecene mycotoxins including deoxynivalenol (or vomitoxin), nivalenol, diacetoxyscirpenol, and T-2 toxin, HT-2 toxin. Monogastrics are sensitive to vomitoxin, while poultry and ruminants appear to be less sensitive to some trichothecenes through microbial metabolism of trichothecenes in the gastrointestinal tract. Trichothecene mycotoxins occur worldwide however both total concentrations and the particular mix of toxins present vary with environmental conditions. Proper agricultural practices such as avoiding late harvests, removing overwintered stubble from fields, and avoiding a corn/wheat rotation that favors Fusarium growth in residue can reduce trichothecene contamination of grains. Due to the vague nature of toxic effects attributed to low concentrations of trichothecenes, a solid link between low level exposure and a specific trichothecene is difficult to establish. Multiple factors, such as nutrition, management, and environmental conditions impact animal health and need to be evaluated with the knowledge of the mycotoxin and concentrations known to cause adverse health effects. Future research evaluating the impact of low-level exposure on livestock may clarify the potential impact on immunity. Trichothecenes are rapidly excreted from animals, and residues in edible tissues, milk, or eggs are likely negligible. In chronic exposures to trichothecenes, once the contaminated feed is removed and exposure stopped, animals generally have an excellent prognosis for recovery. This review shows the occurrence of trichothecenes in food and feed in 2011-2020 and their toxic effects and provides a summary of the discussions on the potential public health concerns specifically related to trichothecenes residues in foods associated with the exposure of farm animals to mycotoxin-contaminated feeds and impact to human health. Moreover, the article discusses the methods of their detection.

Mycotoxins in food: a review on liquid chromatographic methods coupled to mass spectrometry and their experimental designs

The development of a multi-mycotoxins method using LC-MS/MS is necessary and it is clear that the development of such method involves many compromises in the choice of the different parameters. This review summarizes applications using conventional experimental designs and some recent studies using response surface methodology (RSM) as a mathematical modeling tool for the optimization of extraction procedures. The authors also discuss pros and cons of the different procedures. To our knowledge, it is the first review on experimental design for the development of multi-mycotoxin methods. This review could be useful in the development and optimization of LC-MS/MS methods with the aim of describing experimental design and variables (factors) that are likely to affect sensitivity and specificity.

Quantification of zearalenone and α-zearalenol in swine liver and reproductive tissues using GC-MS

The mycotoxin zearalenone (ZEN) is a common contaminant of swine feed which has been related to a wide range of reproductive anomalies in swine, such as pelvic organ prolapse, anestrous, and pseudopregnancy. New information is needed to understand how ZEN and related metabolites accumulate in swine reproductive tissues. We conducted a feeding study to track ZEN and the metabolite α-zearalenol (α-ZEL) in swine liver and reproductive tissues. Thirty pubertal gilts were randomly assigned one of three treatments, with ten pigs in each treatment group: (1) base feed with solvent for 21 days, (2) ZEN-spiked feed for seven days followed by base feed with solvent for 14 days, and (3) ZEN-spiked feed for 21 days. At the end of the trial, liver, anterior vagina, posterior vagina, cervix, uterus, ovaries, and broad ligament were collected from pigs. ZEN was found in the anterior vagina, posterior vagina, cervix, and ovaries, with significantly higher concentrations in the cervix relative to other reproductive tissues. ZEN and α-ZEL were found in liver tissue from pigs in each treatment group. Our results show that ZEN accumulates more in the cervix than other reproductive tissues. The presence of ZEN in reproductive tissues may be indicative of ZEN-related reproductive symptoms. Future work could examine how ZEN concentrations vary in reproductive tissues as a factor of the pigs age, weight, sex, or parity, to establish parameters that make pig more sensitive to ZEN.

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A feeding trial was conducted where gilts consumed varying amounts of zearalenone.

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Zearalenone was found in the anterior vagina, posterior vagina, cervix, and ovaries.

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Zearalenone concentrations were highest in the cervix.

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Zearalenone and alpha-zearalenol were found in the liver.

Synthesis and application of magnetic-surfaced pseudo molecularly imprinted polymers for zearalenone pretreatment in cereal samples

Zearalenone (ZEA) is a fungal contaminant widely found in grains. In cereal samples, trace zearalenone was extracted and enriched using magnetic-surfaced pseudo molecularly imprinted polymers (SPMIPs) and detected. SPMIPs were prepared with Fe₃O₄ as the magnetic core, modified halloysites nanotubes as supporting materials, and selective imprinted polymers as shells. Vinyl was modified on the surface of halloysites nanotube. SPMIPs were synthesized with pseudo templates. SPMIPs as the adsorbent of dispersed-solid phase extraction (μ-SPE) were used to purify and enrich ZEA from maize samples. After optimized, the pretreatment method was evaluated. The linearity of the method was ranged within 10-200 ng mL^-1. LOD and LOQ were 2.5 ng mL^-1 and 8 ng mL^-1 respectively. The ZEA spiking recoveries in maize samples ranged within 74.95-88.41% were with good RSDs lower than 4.25%. The developed method was successful applied in maize, oat, and wheat sample treatments and compared.

Development of an immunoaffinity chromatography and LC-MS/MS method for the determination of 6 zearalenones in animal feed

A novel and simple method for detecting 6 zearalenones in animal feed using liquid chromatography coupled with triple quadrupole mass spectrometry (LC-MS/MS) and immunoaffinity columns (IAC) was developed. The chromatographic peaks of the 6 zearalenones were successfully identified by comparing their retention times and mass spectrum with reference standards. The mobile phase was composed of mobile phase A (water) and B (0.5% formic acid in ACN). Method validation was performed with linearity, sensitivity, selectivity, accuracy and precision. The limits of detection (LODs) for the instrument used to study zearalenones ranged from 0.3 to 1.1 μg/kg, and the limits of quantification (LOQs) ranged from 1.0 to 2.2 μg/kg. Average recoveries of the 6 zearalenones ranged from 82.5% to 106.4%. Method replication resulted in intra-day and inter-day peak area variation of <3.8%. The developed method was specific and reliable and is suited for the routine analysis of zearalenones in animal feed.

Fluoroimmunoassays for the detection of zearalenone in maize using CdTe/CdS/ZnS quantum dots

CdTe/CdS/ZnS quantum dots (QDs) were synthesized in aqueous phase and conjugated with a new anti-zearalenone (ZEN) monoclonal antibody. Using this novel fluorescent probe, a fluoroimmunoassay (FLISA) and a rapid immunochromatographic strip (ICTS) were developed for the detection of ZEN in maize. Our proposed FLISA allowed for ZEN determination in the range of 0.038-0.977 ng/mL with an IC₅₀ of 0.162 ng/mL and a limit of detection (LOD) of 0.012 ng/mL occurring in maize. The rapid ICTS had a visual LOD of 1.0 ng/mL in buffer solution and 1.5 ng/mL in maize extract. These two QDs-based immunoassays were all successfully verified by commercial ELISA kits. The results confirmed that: firstly, the FLISA can be used as a robust method for the sensitive detection of ZEN; and secondly, the ICTS is ideally suited for rapidly screening large numbers of samples.

T-2 Toxin/HT-2 Toxin and Ochratoxin A ELISAs Development and In-House Validation in Food in Accordance with the Commission Regulation (EU) No 519/2014

T-2 toxin/HT-2 toxin (T-2/HT-2) and ochratoxin A (OTA) are mycotoxins that can contaminate a variety of agricultural commodities. To protect consumers' health, indicative limits for T-2/HT-2 and maximum limits for OTA have been set by the European Commission, requiring food business operators and controlling agencies to conduct routine checks for the presence of these harmful contaminants. Screening methods are increasingly used for monitoring purposes. Due to the demand for new and improved screening tools, two individual detection methods, T-2/HT-2 and OTA enzyme-linked immunosorbent assays (ELISAs), were developed in this study. The T-2/HT-2 ELISA was based on a T-2 monoclonal antibody with an IC50 (50% inhibitory concentration) of 0.28 ng/mL and 125% cross-reactivity with HT-2. As regards the OTA ELISA, a new sensitive monoclonal antibody specific to OTA with an IC50 of 0.13 ng/mL was produced. Both developed ELISA tests were then validated in agricultural commodities in accordance with the new performance criteria guidelines for the validation of screening methods for mycotoxins included in Commission Regulation (EU) No 519/2014. The T-2/HT-2 ELISA was demonstrated to be suitable for the detection of T-2/HT-2 in cereals and baby food at and above the screening target concentration (STC) of 12.5 μg/kg and 7.5 μg/kg, respectively. The OTA ELISA was shown to be applicable for the detection of OTA in cereals, coffee, cocoa and wine at and above the STC of 2 μg/kg, 2.5 μg/kg, 2.5 μg/kg and 0.4 ng/mL, respectively. The accuracy of both ELISAs was further confirmed by analysing proficiency test and reference samples. The developed methods can be used for sensitive and high-throughput screening for the presence of T-2/HT-2 and OTA in agricultural commodities.

Two New Fluorogenic Aptasensors Based on Capped Mesoporous Silica Nanoparticles to Detect Ochratoxin A

Aptamers have been used as recognition elements for several molecules due to their great affinity and selectivity. Additionally, mesoporous nanomaterials have demonstrated great potential in sensing applications. Based on these concepts, we report herein the use of two aptamer-capped mesoporous silica materials for the selective detection of ochratoxin A (OTA). A specific aptamer for OTA was used to block the pores of rhodamine B-loaded mesoporous silica nanoparticles. Two solids were prepared in which the aptamer capped the porous scaffolds by using a covalent or electrostatic approach. Whereas the prepared materials remained capped in water, dye delivery was selectively observed in the presence of OTA. The protocol showed excellent analytical performance in terms of sensitivity (limit of detection: 0.5-0.05 nm), reproducibility, and selectivity. Moreover, the aptasensors were tested for OTA detection in commercial foodstuff matrices, which demonstrated their potential applicability in real samples.

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.

QuEChERS Purification Combined with Ultrahigh-Performance Liquid Chromatography Tandem Mass Spectrometry for Simultaneous Quantification of 25 Mycotoxins in Cereals

A method based on the QuEChERS (quick, easy, cheap, effective, rugged, and safe) purification combined with ultrahigh performance liquid chromatography tandem mass spectrometry (UPLC–MS/MS), was optimized for the simultaneous quantification of 25 mycotoxins in cereals. Samples were extracted with a solution containing 80% acetonitrile and 0.1% formic acid, and purified with QuEChERS before being separated by a C18 column. The mass spectrometry was conducted by using positive electrospray ionization (ESI+) and multiple reaction monitoring (MRM) models. The method gave good linear relations with regression coefficients ranging from 0.9950 to 0.9999. The detection limits ranged from 0.03 to 15.0 µg·kg⁻¹, and the average recovery at three different concentrations ranged from 60.2% to 115.8%, with relative standard deviations (RSD%) varying from 0.7% to 19.6% for the 25 mycotoxins. The method is simple, rapid, accurate, and an improvement compared with the existing methods published so far.

A rapid Raman detection of deoxynivalenol in agricultural products

Mycotoxin results in financial damage and considerable safety risks. In this paper, the possibility of portable Raman system-based surface-enhanced Raman scattering (SERS) for a rapid detection of deoxynivalenol (DON) a mycotoxin in cereals was investigated. Under an optimized condition, SERS analysis for pure DON solution has a wide dynamic concentration range from 10^-7M to 10^-2M with the limit of detection (LOD) down to 100nM. Density functional theory (DFT) analysis at the level of B3LYP/6-311++G(d, p) was also preformed for vibrational assignment. For practical application, the LOD of the proposed Raman method for both DON-contaminated corns and kidney beans were validated as 10^-6M and the LOD for DON-contaminated oats was 10^-4M. As a perspective, the SERS-based technology could be developed into an alternatively promising assay for on-field detection of DON residues at various cereals due to it high sensitivity and selectivity.

Development of an immunochromatographic test strip for simultaneous qualitative and quantitative detection of ochratoxin A and zearalenone in cereal

BACKGROUND

Ochratoxin A (OTA) and zearalenone (ZEN) are natural products of filamentous fungi that are harmful to humans and animals exposed to them even in extremely low concentration. The immunochromatographic test strip has become a popular diagnostic tool for detecting analytes. Its major advantages are that results can be obtained within 5-10 min, all needed reagents are included in the strip and it can be used to detect OTA and ZEN contamination in spots. In this study a colloidal gold-based immunochromatographic test strip of competitive format was developed for the rapid simultaneous qualitative and quantitative detection of OTA and ZEN in corn and other cereals.

RESULTS

The test strip results with the naked eye showed that the sensitivities were 6 µg kg(-1) OTA and 20 µg kg(-1) ZEN in cereal, while those with a TSR3000 membrane strip reader showed that the IC50 values of OTA and ZEN were 1.7905 and 4.3514 ng mL(-1) and the lower detection limit (LDL) values were 0.7697 and 1.2000 µg kg(-1) respectively. These results were confirmed by high-performance liquid chromatography.

CONCLUSION

The immunochromatographic test strip developed in this study could be used for the rapid simultaneous, qualitative and quantitative screening of OTA and ZEN in corn samples. © 2015 Society of Chemical Industry.

Development of a sensitive monoclonal-based enzyme-linked immunosorbent assay for monitoring T-2 toxin in food and feed

The consumption of food or feed contaminated with high levels of T-2 toxin may cause adverse health effects in humans and other animals. In this study, to monitor T-2 toxin rapidly in food and feed, a sensitive and specific monoclonal antibody (mAb) against T-2 toxin was generated and a simple and rapid indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) developed. T-2 toxin was first converted to T-2-hemisuccinate (T-2HS) and T-2-hemiglutarate (T-2HG), which were then conjugated to bovine serum albumin (BSA) and ovalbumin (OVA) to prepare an immunogen and coating antigen, respectively. After the inoculation of female Balb/c mice and cell fusions, one cell line, 4D8, with the IgG1 isotype was obtained. The 4D8 antibody exhibited the ability specifically to recognise T-2 toxin with IC50 1.46 µg l(-1). Based on this 4D8 mAb, an optimised ic-ELISA protocol was developed using only methanol-water (7:3, v/v) in feed and cereal samples and ethyl acetate in muscle samples. The limits of detection of T-2 toxin in various sample matrices varied from 0.07 to 15.8 µg kg(-1); the recoveries ranged from 50.3% to 113.6%; and the CVs were less than 19.0%. These results suggest that the prepared mAb and the developed ic-ELISA method will be a useful tool for detecting T-2 toxin in foods and feeds.

Recent trends in rapid environmental monitoring of pathogens and toxicants: potential of nanoparticle-based biosensor and applications

Of global concern, environmental pollution adversely affects human health and socioeconomic development. The presence of environmental contaminants, especially bacterial, viral, and parasitic pathogens and their toxins as well as chemical substances, poses serious public health concerns. Nanoparticle-based biosensors are considered as potential tools for rapid, specific, and highly sensitive detection of the analyte of interest (both biotic and abiotic contaminants). In particular, there are several limitations of conventional detection methods for water-borne pathogens due to low concentrations and interference with various enzymatic inhibitors in the environmental samples. The increase of cells to detection levels requires long incubation time. This review describes current state of biosensor nanotechnology, the advantage over conventional detection methods, and the challenges due to testing of environmental samples. The major approach is to use nanoparticles as signal reporter to increase output rather than spending time to increase cell concentrations. Trends in future development of novel detection devices and their advantages over other environmental monitoring methodologies are also discussed.

Occurrence of four Fusarium mycotoxins, deoxynivalenol, zearalenone, T-2 toxin, and HT-2 toxin, in wheat, barley, and Japanese retail food

A survey of the contamination of wheat, barley, and Japanese retail food by four Fusarium mycotoxins, deoxynivalenol (DON), zearalenone (ZEN), T-2 toxin (T-2), and HT-2 toxin (HT-2), was performed between 2010 and 2012. A method for the simultaneous determination of the four mycotoxins by liquid chromatography-tandem mass spectrometry was validated by a small-scale interlaboratory study using two spiked wheat samples (DON was spiked at 20 and 100 μg/kg and ZEN, T-2, and HT-2 at 6 and 20 μg/kg in the respective samples). The recovery of the four mycotoxins ranged from 77.3 to 107.2%. A total of 557 samples of 10 different commodities were analyzed over 3 years by this validated method. Both T-2 and HT-2 were detected in wheat, wheat flour, barley, Job's tears products, beer, corn grits, azuki beans, soybeans, and rice with mixed grains. Only T-2 toxin was detected in sesame seeds. The highest concentrations of T-2 toxin (48.4 μg/kg) and HT-2 toxin (85.0 μg/kg) were present in azuki beans and wheat, respectively. DON was frequently detected in wheat, wheat flour, beer, and corn grits. The contamination level of wheat was below the provisional standard in Japan (1,100 μg/kg). The maximum contamination level of DON was present in a sample of a Job's tears product (1,093 μg/kg). ZEN was frequently detected in Job's tears products, corn grits, azuki beans, rice with mixed grains, and sesame seeds. A sample of a Job's tears product presented the highest ZEN contamination (153 μg/kg). These results indicate that continuous monitoring by multiple laboratories is effective and necessary due to the percentage of positive samples detected.

Multi-mycotoxin analysis of finished grain and nut products using high-performance liquid chromatography-triple-quadrupole mass spectrometry

Mycotoxins in foods have long been recognized as potential health hazards due to their toxic and carcinogenic properties. A simple and rapid method was developed to detect 26 mycotoxins (aflatoxins, ochratoxins, fumonisins, trichothecenes, and ergot alkaloids) in corn, rice, wheat, almond, peanut, and pistachio products using high-performance liquid chromatography-triple-quadrupole mass spectrometry. Test portions of homogenized grain or nut products were extracted with acetonitrile/water (85:15, v/v), followed by high-speed centrifugation and dilution with water. Mean recoveries (± standard deviations) were 84 ± 6, 89 ± 6, 97 ± 9, 87 ± 12, 104 ± 16, and 92 ± 18% from corn, rice, wheat, almond, peanut, and pistachio products, respectively, and the matrix-dependent instrument quantitation limits ranged from 0.2 to 12.8 μg/kg, depending on the mycotoxin. Matrix effects, as measured by the slope ratios of matrix-matched and solvent-only calibration curves, revealed primarily suppression and were more pronounced in nuts than in grains. The measured mycotoxin concentrations in 11 corn and wheat reference materials were not different from the certified concentrations. Nineteen mycotoxins were identified and measured in 35 of 70 commercial grain and nut products, ranging from 0.3 ± 0.1 μg/kg (aflatoxin B1 in peanuts) to 1143 ± 87 μg/kg (fumonisin B1 in corn flour). This rapid and efficient method was shown to be rugged and effective for the multiresidue analysis of mycotoxins in finished grain and nut products.

Simultaneous determination of deoxynivalenol, and 15- and 3-acetyldeoxynivalenol in cereals by HPLC-UV detection

Fusarium head blight is an important cereal crop disease, which not only causes yield losses but also mycotoxin contamination in wheat and other cereal grains. Developing an accurate, rapid and efficient assay is critical to minimise the risk of Fusarium mycotoxins for human and animal health. In this study, HPLC with UV detection was used to separate and quantify deoxynivalenol, 15-acetyldeoxynivalenol and 3-acetyldeoxynivalenol in cereals. Samples were extracted with water, and the extracting solution was precipitated by adding an equal volume of ethanol followed by solid-phase extraction. The analytes were separated on a reversed-phase C18 column by a mobile phase composed of acetonitrile and 1 mM H3PO4 with gradient elution. 15- and 3-acetyldeoxynivalenol showed effective baseline separation. All analytes were well-resolved from matrix co-extractives and detected at 224 nm. The results showed good linearity of calibration curves (R2 ranged from 0.997 to 0.999) and excellent precision for inter- and intra-day determinations. Average recovery rates for the tested matrices ranged from 71 to 92%. The limits of detection and quantification ranged from 16 to 25 ng/g and 48 to 60 ng/g, respectively. The results indicate that the feasibility and practicality of the presented LC-UV method are excellent and that the method is suitable for routine analysis of DON and its acetyl derivatives in cereal grains.

Determination of mycotoxins in bee pollen by gas chromatography-tandem mass spectrometry

Bee pollen, promoted as a natural food supplement, is consumed increasingly by people to maintain a healthy diet. Depending on environmental conditions, pollen can also be an optimum medium for growth of molds such as Fusarium and Penicillium . A quick, easy, cheap, rapid, and safe (QuEChERS) extraction procedure followed by a gas chromatography-tandem mass spectrometry (GC-MS/MS) determination of eight selected Fusarium toxins in bee pollen was developed and optimized. Recovery studies at 20, 80, and 1000 μg/kg showed values between 73 and 95% with relative standard deviations (RSDs) of <15% for all studied mycotoxins. Limits of quantitation (LOQ) ranged from 1 to 4 μg/kg. The proposed method was applied to the analysis of 15 commercial samples. Two of 15 samples showed quantifiable values for neosolaniol and nivalenol.

Multi-mycotoxin analysis in wheat semolina using an acetonitrile-based extraction procedure and gas chromatography-tandem mass spectrometry

A new analytical method for the rapid and simultaneous determination of ten mycotoxins including patulin, zearalenone and eight trichothecenes (nivalenol, fusarenon-X, diacetoxyscirpenol, 3-acetyl-deoxynivalenol, neosolaniol, deoxynivalenol, T-2 and HT-2) in wheat semolina has been developed and optimized. Sample extraction and purification were performed with a modified QuEChERS-based (acronym of Quick, Easy, Cheap, Effective, Rugged and Safe) procedure and determined by gas chromatography (GC) coupled to triple quadrupole instrument (QqQ). This is the first paper on the application of GC-QqQ-MS/MS to analysis of mycotoxins. Careful optimization of the gas chromatography-tandem mass spectrometry parameters was achieved in order to attain a fast separation with the best sensitivity allowing a total run time of 16 min. The validation was performed by analyzing recovery samples at three different spiked concentrations, 20, 40 and 80 μg kg(-1), with four replicates (n=4) at each concentration. Recoveries ranged from 74% to 124% and the intra-day precision and inter-day precision, expressed as relative standard deviation, were lower than 13% and 17%, respectively for all studied compounds, except for zearalenone. Limits of quantification (LOQ) were lower than 10 μg kg(-1) for all studied mycotoxins. Eight concentration levels were used for constructing the calibration curves which showed good linearity between LOQ and 100 times LOQ concentration levels (linear range). Matrix-matched calibration for applying the method in routine analysis is recommended for reliable quantitative results. The method validated was successfully applied to fifteen wheat semolina samples detecting occurrence of mycotoxins at concentrations below the maximum permissible level.