A Review: Sample Preparation and Chromatographic Technologies for Detection of Aflatoxins in Foods

Metabolomic profiles of the infection pathways of Calcarisporium cordycipiticola on the cultivated and medicinal mushroom, Cordyceps militaris

Cordyceps militaris is a widely cultivated mushroom with multiple medicinal properties. However, the emergence of white mildew disease caused by Calcarisporium cordycipiticola has become a serious dilemma, leading to economic losses in its industrial production. The genome of Ca. cordycipiticola possesses more secondary metabolite biosynthetic gene clusters and a smaller number of genes encoding for carbohydrate-active enzyme secretion than other mycoparasites. To uncover those functional metabolites correlated with the infection process, metabolomic profiles between healthy C. militaris fruit bodies (CK) and healthy (HFB) and diseased (DFB) parts of infected C. militaris fruit bodies by Ca. cordicipiticola were compared based on untargeted metabolomic analyses. The function of different metabolites during the pathogen infection and host response processes were further analyzed according to their respective metabolic pathways. Results of key metabolic pathway analyses suggested that a sterigmatocystin-like metabolite functions as one of the virulence factors of white mildew disease on C. militaris, whereas S-adenosyl-L-methionine represents a hub intermediate in both processes of pathogen infection and host response, highlighting the relevance of methyl group turnovers in this battle. More importantly, the detection of toxic metabolites in diseased C. militaris fruiting bodies suggests that this macrofungus contaminated by Ca. cordycipiticola should not be consumed due to the risk that it may contain related instead toxins. This study hypothesizes on the scenario of key metabolic biosynthesis in the battle between Ca. cordycipiticola and C. militaris. Our instead findings not only shed light on the interaction between the pathogen and the host but also provide crucial insights for the development of effective prevention and control strategies in the future.

Application of nanomaterials in the detection of pesticide residues in spices

With the development of global trade and the improvement of consumer safety awareness, the problem of pesticide residues in spices has received considerable attention. At the same time, with the advancement of nanotechnology, nanomaterials have shown great potential in pesticide residue detection. Given the wide variety of spices and their complex matrices, there has been a lack of a comprehensive review on the application of nanomaterials in pesticide residue detection in spices until now. In this study, the advancements in research on newly developed nanomaterials were examined for the detection of pesticide residues in spices over the last 10 years, focusing on the applications of carbon nanotubes, graphene and its derivatives, metal nanoparticles, metal-organic frameworks, molecularly imprinted polymers, and quantum dots. Additionally, this study also explores the advantages and challenges of different nanomaterials' applications and predicts their development trends, aiming to provide a reference for future research.

Effective extraction and sensitive detection of aflatoxins in wheat by polymeric ionic liquid-based magnetic adsorbent with multiple interactions

In this study, polymeric ionic liquids (PILs) modified magnetic nanoparticles were used to extract four aflatoxins (AFs) from wheat samples, providing a convenient and cost-effective sample preparation technique for AFs detection in the complex food matrix. The extraction parameters were optimized in terms of the amount of adsorbent, adsorption time, type and volume of desorption solvent, desorption time, and salt addition. The results showed that the proposed method had high sensitivity, good repeatability, and wide linear range. The limits of detection (S/N=3) of four AFs were 0.05-0.41 μg kg-1. The accuracy was also evaluated using spiked wheat samples and acceptable relative recovery of four AFs at different fortification levels were obtained, ranging from 50.3 %-110.4 %. It was indicated that both the anion species and the alkyl chain length of cation in PILs significantly affected the extraction efficiency. Meanwhile, multiple interactions, including hydrogen bonding, π-π and p-π, and hydrophobic interactions between the adsorbent and the AFs, were responsible for the effective extraction.

Synthesis of GO-SiO2/ZnO/Fe3O4 nano adsorbent for preconcentration of aflatoxins in food samples using SPE-HPLC-FLD method

This study demonstrates a new extraction method for determination of aflatoxins (AFs) in food samples by a GO-SiO2/ZnO/Fe3O4 nanocomposite as new and effective sorbent. The nanocomposite structure was confirmed by FT-IR, XRD, EDX, FE-SEM, TEM, and mapping techniques. Optimization of the extraction process was conducted by investigating pH, adsorbent amount, sample volume, and solvent volume using central composite design (CCD). The method showed good linearity for AFs B1, B2, G1, and G2 within specified ranges. Detection and quantification limits were 0.06-0.53 and 0.20-1.62 ng mL-1, respectively. The high performance liquid chromatography with fluorescence detector assisted by solid phase extraction (SPE-HPLC-FLD) method was applied to food samples, achieving recoveries of 70.15-97.08 %. Accuracy was confirmed through recovery measurements in spiked samples, with ranges of 70.15-97.85 % in wheat, 70.01-91.97 % in chickpeas, and 71.29-93.92 % in white pepper. Reusability and cost-effectiveness suggest its potential for preconcentration and determination of AFs in food samples.

Recent Advances in Polysaccharide-Based Electrospun Nanofibers for Food Safety Detection

The continuous advancement of food safety analytical technologies is ensuring food safety and regulatory compliance. Electrospinning, a versatile fabrication platform, has emerged as a transformative methodology in materials science due to its unique capacity to generate nanoscale fibrous architectures with tunable morphologies. When combined with the inherent biodegradability and biocompatibility of polysaccharides, electrospun polysaccharide nanofibers are positioning themselves as crucial components in innovative applications in the fields of food science. This review systematically elucidates the fundamental principles and operational parameters governing electrospinning processes, with particular emphasis on polysaccharide-specific fiber formation mechanisms. Furthermore, it provides a critical analysis of state-of-the-art applications involving representative polysaccharide nanofibers (e.g., starch, chitosan, cellulose, sodium alginate, and others) in food safety detection, highlighting their innovative application in livestock (chicken, pork, beef), aquatic (yellow croaker, Penaeus vannamei, Plectorhynchus cinctus), fruit and vegetable (olive, peanut, coffee), and dairy (milk) products. The synthesis of current findings not only validates the unique advantages of polysaccharide nanofibers but also establishes new paradigms for advancing rapid, sustainable, and intelligent food safety technologies. This work further proposes a roadmap for translating laboratory innovations into industrial-scale applications while addressing existing technological bottlenecks.

High efficient adsorption of aflatoxins in peanuts by novel covalent organic framework through multiple interactions

Aflatoxins are the most toxic and high-profile mycotoxins with high occurrence in grain and nuts. To effectively adsorb and sensitively detect aflatoxins in peanuts, two novel covalent organic frameworks (TF-COF, TH-COF) were fabricated by Schiff-base reaction of N,N,N',N'-tetra (p-aminophenyl)-p-phenylenediamine with 2,3,5,6-tetra-fluoroterephthaldehyde and terephthalendehyde, respectively. The TF-COF shows higher adsorption capacity (35-44 mg g-1) for aflatoxins than TH-COF (26-37 mg g-1) because abundant fluorine functional groups in TF-COF offer more adsorption sites. A sensitive and practical method for determining aflatoxins (G2, G1, B2 and B1) in peanuts was developed by combining TF-COF-based extraction technology with high performance liquid chromatography-fluorescence detector. The method provides outstanding performance with linear range of 0.025 ng g-1-20.0 ng g-1, detection limits of 0.008 ng g-1-0.15 ng g-1, recovery of 86.3 %-116 %, and relative standard deviation below 7.8 %. This study opens a new avenue to develop functionalized COF with distinguished performance for adsorbing hazards in food and/or environmental samples.

Peanuts (Arachis hypogaea L.) and Mycotoxins: Analytical Approaches, Prevalence, and Innovative Detoxification

Mycotoxins are secondary metabolites originating from several species of fungi that have proven to demonstrate high toxicity. In addition, potential contamination sources can promote increased human exposure to the adverse effects of these toxins. For this reason, it was necessary to develop several analytical methods that allow detection with the highest possible sensitivity for these toxic metabolites. Furthermore, since these methods involve high cost, are lengthy, and have sensitivity requirements, the development of multi-analyte detection methods is indispensable. The increasing consumption of groundnuts (legumes) as well as nuts (such as almonds, walnuts, and pistachios) and dried fruit (raisins and dried figs) has increased the risk of poisoning and the harmful effects of mycotoxins, which has encouraged studies for the creation of these methods. This review addresses the most representative methods applied to analyze and quantify mycotoxins in groundnuts (peanuts) together with decontamination techniques. The methodologies presented in this review are primarily based on analytical techniques for nuts and dried fruits. However, each of these methodologies can also be applied to peanut analysis for comparison and use. It is also relevant to highlight the importance of the development of multi-analyte methods in order to identify multiple mycotoxins using a single method, saving time, costs, and resources.

A recent overview of the application of emerging extraction medium-based sample preparation for the determination of aflatoxins and their precursors in food samples

Food safety problem caused by aflatoxins (AFs) has become a major concern worldwide. However, due to the complexity of food matrices and the low concentration of analytes, the accurate and sensitive determination of AFs and their precursors in the biosynthetic pathway is extremely challenging, so the development of efficient sample preparation techniques has been urgently required. This paper reviews the recent advances in sample preparation based on some emerging extraction media for the determination of AFs and their precursors in different food samples, including ionic liquids (ILs) and IL-based composites, metal-organic frameworks (MOFs) and covalent organic frameworks (COFs). These extraction media can be combined with different sample preparation techniques, such as dispersive liquid-liquid microextraction, solid-phase extraction, and magnetic/dispersive solid-phase extraction, mainly depending on their physicochemical properties. They exhibit efficient extraction and enrichment performance towards AFs and their precursors, which is attributed to their multiple-interaction mechanism and/or porous structure. This review also presents the current challenges and future prospects of these emerging extraction media for sample preparation of AFs and their precursors from food.

Evaluation of basil essential oils for antifungal and anti-aflatoxigenic activity against Aspergillus flavus

Essential oils of basil herbs such as nyazbo or sweet basil (Ocimum basilicum), holy basil or tulsi (O. tenuiflorum), and African or clove basil (O. gratissimum) have traditionally been used for their therapeutic potential. These medicinal herbs are being cultivated and consumed globally, and the increasing demand for antimicrobial and antifungal natural products has led to the assessment of the potential of essential oils of medicinal plants to inhibit mycelial growth rather than synthetic fungicides. Thus, the present study explored natural alternatives to inhibit mycelial growth (Aspergilus flavus) and aflatoxin production. Linalool (25.40%), methyl chavicol (37.63%), and eugenol (39.52%) were identified as chief compounds in the EOs of O. basilicum, O. tenuiflorum, and O. gratissimum respectively. Ocimum tenuiflorum EO demonstrated the highest inhibitory activity at 0.75 µL mL- 1 against Aspergillus flavus and totally inhibited the synthesis of aflatoxin B1 (AFB1). The AFB2 production was completely inhibited at 0.25 µL mL- 1 by O. tenuiflorum EO, while O. basilicum and O. gratissimum EOs showed inhibition against AFB2 at 0.50 µL mL- 1, and 1.0 µL mL- 1, respectively. The present study suggests that EOs of basil herbs could be a potential natural alternative of synthetic fungicides to inhibit the fungal growth and aflatoxin production.

Repackable microfluidic molecularly imprinted solid-phase extraction coupled with mass spectrometry (μMISPE-MS) for rapid analysis of mycotoxin in agri-foods: an example of zearalenone

Mycotoxins are detectable in 60-80% of food crops, posing significant threats to human health and food security, and causing substantial economic losses. Most mitigation approaches focus on detecting mycotoxins with standard methods based on liquid chromatography coupled with mass spectrometry (LC-MS). Typical MS methods require extensive sample preparation and clean-up due to the matrix effect, followed by time-consuming LC separation, complicating the analysis process and limiting analytical throughput. This study reports the development of a repackable microfluidic molecularly imprinted solid-phase extraction coupled with mass spectrometry (μMISPE-MS) method for rapid detection of zearalenone in agri-food samples. Silica microspheres coated with molecularly imprinted polymers were synthesized as the sorbent for analyte enrichment and sample clean-up. A cost-effective microfluidic chip was designed and fabricated as the μMISPE platform with fully automated operation, including on-line microcolumn packing and unpacking. With optimized solvent conditions and on-chip μMISPE protocol, the entire analytical process from sample to answer was completed within 15 min and achieved high recoveries (71-94%) for corn and rice samples at residue levels of 0.05-0.5 ppm (within Canadian regulatory limits of 0.2-10 ppm). This μMISPE-MS method provides a promising tool for improving mycotoxin monitoring in agri-food systems and is generalizable to other rapid analyses of targeted chemicals in complex matrices.

Ultrasensitive aflatoxin B1 detection based on vertical organic electrochemical transistor

Herein, we presented an ultrasensitive Aflatoxin B1 (AFB1) detection platform based on vertical organic electrochemical transistor (vOECT) first time. Chitosan-graphene nanosheets nanocomposites and AFB1 antibodies were modified on commercial electrodes as immunosensors, in series with gate electrodes of vOECT, operated at enhancement mode with ultrahigh transconductance gm 94 mS to amplify current signals. When AFB1 is added, the impedance of the immunosensors increased due to antigen-antibody immune binding, resulting in a potential decrease in reaction cell. Then, the potential decrease leads to an effective gate voltage VGeff increase, contributing to a significant drain-source current IDS decrease as a consequence of ultrahigh gm of vOECT. As a result, the presented vOECT platform exhibited an ultrahigh sensitivity of ∼1 mA/dec, and an ultralow detection limit of 0.01 fg/mL (S/N = 3), superior to all previous reported values. Furthermore, the platform exhibited satisfactory stability and specificity, and was applied to detect AFB1 in corn samples.

Determination of aflatoxin B1 in peanuts based on millimetre wave

This study introduces a novel method for swift detection of AFB1 in peanuts using millimetre wave technology. The research team devised a portable millimetre-wave detection device employing a double-external-difference mixing structure. The device measured millimetre-wave transmission coefficients in the 20 GHz - 40 GHz frequency range for peanut samples. Results showed that the PCA-KNN model excelled in qualitative AFB1 detection, achieving 100 % accuracy in the prediction set. In quantitative analysis, by condensing the feature variables into a 16-dimensional space, the BOSS-PSO-SVR model enhanced performance. Compared to the full transmission coefficient SVR model, the BOSS-PSO-SVR model exhibited improved coefficients of determination (RP2), reducing root mean square error of prediction (RMSEP) from 36.49 μg∙kg-1 to 19.08 μg∙kg-1, and enhancing relative prediction deviation (RPD) from 3.17 to 6.06. This study concludes that the integration of a custom miniaturized millimetre-wave device with appropriate chemometric methods facilitates rapid and accurate detection of peanut AFB1 levels.

A Cu/β-cyclodextrin/reduced graphene oxide nanocomposite for efficient and multi-aflatoxin detection in rice, ginger and bean samples

Aflatoxins (AFs) are some of the most important mycotoxins or fungal toxins that cause contamination of food products and are considered a threat to human and animal health. An efficient Cu/β-cyclodextrin/reduced graphene oxide nanocomposite (Cu/β-CD/rGO) has been prepared and applied as a new solid-phase extraction adsorbent for the separation and preconcentration of four AFs (B1, B2, G1, and G2) using high-performance liquid chromatography with fluorescence detection (HPLC-FLD). The successful synthesis of the prepared nanocomposite was confirmed using Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). The impacts of pH, amount of adsorbent, sample volume, desorption solvent volume, and salt concentration on the recovery of AFs were precisely investigated and optimized by central composite design (CCD). Under the optimal conditions, the introduced method demonstrated good linearity in the range of 0.4-5.4, 0.08-1.08, 0.4-5.4, and 0.08-1.08 ng g-1 for AFs B1, B2, G1 and G2, respectively. The limits of detection and quantification for the four AFs were obtained in the range of 0.06-0.53 and 0.20-1.62 ng g-1, respectively. The accuracy of the method was evaluated using recovery measurements in spiked real samples such as rice, bean, and ginger samples, and satisfactory recoveries were obtained in the range of 83.5-109.0% with good precision (RSDs between 2.4 and 8.6%). The results of this research revealed that our developed method is sensitive, highly effective, and convenient to perform for the trace analysis of AFs in different real samples.

Aflatoxins in cereal based products-an overview of occurrence, detection and health implication

Aflatoxins are naturally produced toxins by specific molds, namely Aspergillus flavus and Aspergillus parasiticus. These toxins can be found in various agricultural products, including crops like maize, peanuts, cottonseed, and tree nuts. They have the potential to contaminate the food supply during different stages of production, processing, and storage. Aflatoxin is a very poisonous substance that has been linked to adverse health effects in both humans and animals. It is essential to detect and monitor aflatoxins to ensure the safety of food. Efficient and precise analytical techniques, such as chromatography and immunoassays, have been used to accurately measure the levels of aflatoxins in different substances. Regulatory bodies and worldwide associations have determined maximum permissible limits for aflatoxins in food and nourishment products to protect the well-being of the general public. Effectively addressing aflatoxin contamination necessitates a comprehensive approach that encompasses various strategies in agriculture, post-harvest practices, and regulatory measures. Continuous research and collaborative endeavors are crucial in order to minimize aflatoxin exposure and mitigate the associated risks. This review offers a comprehensive examination of the presence, health consequences, and elimination techniques associated with aflatoxins.

Elastin-like polypeptide-functionalized nanobody for column-free immunoaffinity purification of aflatoxin B1

A column-free immunoaffinity purification (CFIP) technique for sample preparation of aflatoxin B1 (AFB1) was developed using an AFB1-specific nanobody (named G8) and an elastin-like polypeptide (ELP). The reversible phase transition between liquid and solid in response to temperature changes was exhibited by the ELP which was derived from human elastin. The G8 was tagged with ELPs of various lengths (20, 40, 60, and 80 repeat units) at the C-terminus using recursive directional ligation (RDL). Coding sequences were then subcloned into pET30a at the multiple cloning sites. Bioactive recombinant proteins were produced by expressing them as inclusion bodies in Escherichia coli BL21 (DE3), then dissolved and refolded. Analysis by indirect competitive enzyme-linked immunosorbent assay (icELISA) and transition temperature (Tt) measurement confirmed that the refolded G8-ELPs preserved the ability to recognize AFB1 as well as phase transition when the temperature rose above Tt. To establish the optimal conditions for cleaning AFB1, the effects of various parameters on recovery were investigated. The recovery in ELISA tests was 95 ± 3.67% under the optimized CFIP workflow. Furthermore, the CFIP-prepared samples were applied for high-performance liquid chromatography (HPLC) detection. The recovery in the CFIP-HPLC test ranged from 54 ± 1.86% to 98 ± 3.58% for maize, rice, soy sauce, and vegetable oil samples. To the best of our knowledge, this is the first report combining the function of both nanobody and ELP to develop a cleanup technique for small molecules in a complex matrix. The CFIP for the sample pretreatment was easy to use and inexpensive. In contrast to conventional immunosensitivity materials, the reagent utilized in the CFIP was entirely biosynthesized without any chemical coupling reactions. This suggests that the nanobody-ELP may serve as a useful dual-functional reagent for the development of sample cleaning or purification methods.

Mycotoxins in Food: Cancer Risks and Strategies for Control

Mycotoxins are toxic compounds produced by fungi such as Aspergillus, Penicillium, and Fusarium, contaminating various food crops and posing severe risks to food safety and human health. This review discusses mycotoxins' origins, significance, and impact, particularly in relation to cancer risk. Major mycotoxins like aflatoxins, ochratoxins, fumonisins, zearalenone, and patulin are examined, along with their sources and affected foods. The carcinogenic mechanisms of these toxins, including their biochemical and molecular interactions, are explored, as well as epidemiological evidence linking mycotoxin exposure to cancer in high-risk populations. The review also highlights critical methodologies for mycotoxin detection, including HPLC, GC-MS, MS, and ELISA, and the sample preparation techniques critical for accurate analysis. Strategies for controlling mycotoxin contamination, both pre- and post-harvest, are discussed, along with regulations from organizations like the FAO and WHO. Current challenges in detection sensitivity, cost, and control effectiveness are noted. Future research is needed to develop innovative analytical techniques, improve control strategies, and address the influence of climate change on mycotoxin production. Finally, global collaboration and emerging technologies are essential for advancing mycotoxin control and enhancing food safety.

Comprehensive and heart-cutting multidimensional liquid chromatography-mass spectrometry and its applications in food analysis

In food analysis, conventional one-dimensional liquid chromatography methods sometimes lack sufficient separation power due to the complexity and heterogeneity of the analyzed matrices. Therefore, the use of two-dimensional liquid chromatography (2D-LC) turns out to be a powerful tool to consider, especially when coupled to mass spectrometry (MS). This review presents the most remarkable 2D-LC-MS food applications reported in the last 10 years, including a critical discussion of the multiple approaches, modulation strategies as well as the importance of the optimization of the different analytical aspects that will condition the 2D-LC-MS performance. The presence of contaminants in food (food safety), the food quality, and authenticity or the relationship between the beneficial effects of food and human health are some of the fields in which most of the 2D-LC-MS applications are mainly focused. Both heart-cutting and comprehensive applications are described and discussed in this review, highlighting the potential of 2D-LC-MS for the analysis of such complex samples.

Advances in Aptamer-Based Biosensors for the Detection of Foodborne Mycotoxins

Foodborne mycotoxins (FBMTs) are toxins produced by food itself or during processing and transportation that pose an enormous threat to public health security. However, traditional instrumental and chemical methods for detecting toxins have shortcomings, such as high operational difficulty, time consumption, and high cost, that limit their large-scale applications. In recent years, aptamer-based biosensors have become a new tool for food safety risk assessment and monitoring due to their high affinity, good specificity, and fast response. In this review, we focus on the progress of single-mode and dual-mode aptasensors in basic research and device applications over recent years. Furthermore, we also point out some problems in the current detection strategies, with the aim of stimulating future toxin detection systems for a transition toward ease of operation and rapid detection.

Aflatoxins: Occurrence, biosynthesis, mechanism of action and effects, conventional/emerging detection techniques

Aflatoxins (AFs) are toxic secondary metabolites prevalent in various food and agricultural products, posing significant challenges to global food safety. The detection and quantification of AFs through high-precision analytical techniques are crucial in mitigating AF contamination levels and associated health risks. Variousmethods,including conventional and emerging techniques, have been developed for detecting and quantifyingAFsinfood samples. This review provides an in-depth analysis of the global occurrence of AF in food commodities, covering their biosynthesis, mode of action, and effects on humans and animals. Additionally, the review discusses different conventional strategies, including chromatographic and immunochemical approaches, for AF quantification and identification in food samples. Furthermore, emerging AF detection strategies, such as solid-state gas sensors and electronic nose technologies, along with their applications, limitations, and future perspectives, were reviewed. Sample purification, along with their respective advantages and limitations, are also discussed herein.

Fluorine-functionalized covalent organic framework as efficient solid phase extraction sorbent for adsorption of aflatoxins in nuts

In this study, a new fluorine-functionalized covalent organic framework (F-COF) was designed and fabricated by the direct polycondensation of tris(4-aminophenyl)amine and 2,3,5,6-tetra-fluoroterephthaldehyde for the first time. F-COF exhibited a remarkably enhanced adsorption capability compared with that of the fluorine-free COF. The favorable adsorption of aflatoxins was attributed to multiple interactions including pseudo hydrogen bond, F-O, π-π, F-π interactions and hydrophobic interactions between F-COF and aflatoxins. By coupling F-COF based solid phase extraction with high-performance liquid chromatography equipped with fluorescence detector, a rapid and sensitive method for determining aflatoxins (aflatoxin B1, B2, G1 and G2) in nuts (peanuts and pistachios) was established. Under optimal conditions (35 mg F-COF, 100 mL sample solution, 3 mL min-1 as sample loading rate, pH<7, 0.2 mL acetonitrile as desorption solvent), the limits of detection for aflatoxins were 0.02-0.30 ng g-1. The linear range was 0.08-16.0 ng g-1 and the recoveries of the F-COF-based method were 83.5-114 % with relative standard deviations less than 8.0 %.

Discrimination of toxigenic and non-toxigenic Aspergillus flavus in wheat based on nanocomposite colorimetric sensor array

A novel method was developed for the early detection of wheat infected with Aspergillus flavus (A. flavus) using a nanocomposite colorimetric sensors array (CSA). LC-MS analysis revealed the presence of Aflatoxin B1 (AFB1) and Aflatoxin B2 (AFB2) on day seven, demonstrating mycotoxin variabilities in infected wheat. HS-SPME-GC-MS analysis detected 2-methylbutyral, a gas exclusively associated with toxigenic A. flavus. The CSA was modified using three nanoparticles of MOF and successfully used to detect the wheat infected with A. flavus. Discrimination of different types of infected wheat samples was achieved using the RGB difference map and Principal Component Analysis (PCA) model. Additionally, the Linear Discriminant Analysis (LDA) model accurately predicted the presence of toxigenic A. flavus at various stages of infection. These findings highlight the promising capabilities of nanocomposite CSA for early-stage detection of A. flavus infection in wheat.

A comparative review on methods of detection and quantification of mycotoxins in solid food and feed: a focus on cereals and nuts

Many emerging factors and circumstances urge the need to develop and optimize the detection and quantification techniques of mycotoxins in solid food and feed. The diversity of mycotoxins, which have different properties and affinities, makes the standardization of the analytical procedures and the adoption of a single protocol that covers the attributes of all mycotoxins a tedious or even an impossible mission. Several modifications and improvements have been undergone in order to optimize the performance of these methods including the extraction solvents, the extraction methods, the clean-up procedures, and the analytical techniques. The techniques range from the rapid screening methods, which lack sensitivity and specificity such as TLC, to a spectrum of more advanced protocols, namely, ELISA, HPLC, and GC-MS and LC-MS/MS. This review aims at assessing the current studies related to these analytical techniques of mycotoxins in solid food and feed. It discusses and evaluates, through a critical approach, various sample treatment techniques, and provides an in-depth examination of different mycotoxin detection methods. Furthermore, it includes a comparison of their actual accuracy and a thorough analysis of the observed benefits and drawbacks.

Nanoscale Materials Applying for the Detection of Mycotoxins in Foods

Trace amounts of mycotoxins in food matrices have caused a very serious problem of food safety and have attracted widespread attention. Developing accurate, sensitive, rapid mycotoxin detection and control strategies adapted to the complex matrices of food is crucial for in safeguarding public health. With the continuous development of nanotechnology and materials science, various nanoscale materials have been developed for the purification of complex food matrices or for providing response signals to achieve the accurate and rapid detection of various mycotoxins in food products. This article reviews and summarizes recent research (from 2018 to 2023) on new strategies and methods for the accurate or rapid detection of mold toxins in food samples using nanoscale materials. It places particular emphasis on outlining the characteristics of various nanoscale or nanostructural materials and their roles in the process of detecting mycotoxins. The aim of this paper is to promote the in-depth research and application of various nanoscale or structured materials and to provide guidance and reference for the development of strategies for the detection and control of mycotoxin contamination in complex matrices of food.

Development of deep eutectic solvent-based microwave-assisted extraction combined with temperature controlled ionic liquid-based liquid phase microextraction for extraction of aflatoxins from cheese samples

In this study, for the first time, a deep eutectic solvent-based microwave-assisted extraction was combined with ionic liquid-based temperature controlled liquid phase microextraction for the extraction of several aflatoxins from cheese samples. Briefly, the analytes are extracted from cheese sample (3 g) into a mixture of 1.5 mL choline chloride:ethylene glycol deep eutectic solvent and 3.5 mL deionized water by exposing to microwave irradiations for 60 s at 180 W. The liquid phase was taken and mixed with 55 μL 1-hexyl-3-methylimidazolium hexafluorophosphate. By cooling the solution in the refrigerator centrifuge, a turbid state was obtained and the analytes were extracted into the ionic liquid droplets. The analytes were determined by high-performance liquid chromatography equipped with fluorescence detector. Low limits of detection (9-23 ng kg-1 ) and quantification (30-77 ng kg-1 ), high extraction recovery (66%-83%), acceptable enrichment factor (40-50), and good precision (relative standard deviations ≤ 5.2%) were obtained using the offered approach. These results reveal the high extraction capability of the method for determination of aflatoxins in the cheese samples. In this method, there was no need for organic solvents and it can be considered as green extraction method.

Simultaneous determination of multiple mycotoxins in corn and wheat by high efficiency extraction and purification based on polydopamine and ionic liquid bifunctional nanofiber mat

Due to the universality and harmfulness of mycotoxin co-contamination in cereals, it is of great significance to simultaneously monitor various mycotoxins co-polluted to ensure food safety and public health. In this work, a nanofiber mat modified by polydopamine and ionic liquid (PDA-IL-NFsM) was prepared and utilized as a solid-phase extraction (SPE) adsorbent for the simultaneous quantitative detection of multiple mycotoxins in corn and wheat. The PDA-IL-NFsM can form multiple retention mechanisms with the targets through hydrogen bond, π-π interaction, electrostatic or hydrophobic interaction, it shows favorable simultaneous adsorption performance (adsorption efficiency mostly higher than 88.27%) for fifteen mycotoxins in seven classes. Moreover, it can significantly reduce the matrix effect (lower than -13.69%), showing a good purification effect on the sample matrix. Based on the superior performance of PDA-IL-NFsM, a simple sample preparation method was established. The sample extract is simply diluted with water for SPE, and the eluent can be directly collected for ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) analysis. The detection limit can reach 0.04-4.21 μg kg^-1, the recovery was 80.09%-113.01%, and the relative standard deviations of intra-day and inter-day precision were 2.80%-14.81% and 0.68%-13.80% respectively. The results show that the proposed method has good sensitivity, accuracy and precision, and has practical application potential.

Characterization of Particle-Size-Based Homogeneity and Mycotoxin Distribution Using Laser Diffraction Particle Size Analysis

Sample homogeneity dictates whether analyzing a test portion of an entire sample can provide representative information about incurred mycotoxins. In this study, we evaluated particle-size-distribution-based homogeneity of laboratory mycotoxin samples using laser diffraction particle size analysis and International Organization for Standardization (ISO) Guide 35: 2017. Incurred whole corn, compound feed, peanut butter, and wheat flour (500 g each) were comminuted using wet, cryogenic, or dry milling. We used a sample dividing (riffling) device to obtain representative subsamples (25 g each) and developed a laser diffraction particle size analysis procedure by optimizing key parameters such as the refractive index, absorption, and stirring rate. The homogeneity of the particle size distribution within laboratory subsamples was characterized using the optimized laser diffraction procedure. An assessment of homogeneity was also performed for individual mycotoxins in each incurred matrix sample following the procedure described in ISO Guide 35. The concentrations of the incurred mycotoxins were determined using liquid chromatography-mass spectrometry (LC-MS). Within- and between-subsample variances of incurred aflatoxin B1 in peanut butter; deoxynivalenol in corn, compound feed, and wheat flour; and fumonisins in compound feed corroborated that when the particle size measurements were less than 850 µm, mycotoxins concentrations were consistent across independent test portions, which was confirmed using an analysis of variance (F-test). This study highlights the benefits of laser diffraction particle size analysis and suggests its use as a test procedure to evaluate homogeneity in new sample commodities.

Analysis of 16 mycotoxins in genuine traditional Chinese medicine for five medicinal parts: Classification of analytical method based on PANI@CS extraction-UPLC-MS/MS

A novel PANI@CS solid-phase dispersive extractant combined with ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) was developed for the first time, which was used for high-throughput, multi-component, real-time online rapid pretreatment and quantitative classification of 16 mycotoxins from five different medicinal parts of 13 genuine traditional Chinese medicines (TCMs). Ultra performance liquid chromatography combined with triple quadrupole mass spectrometry was used for separation and ESI detection. An internal standard isotope matching calibration was used for quantification purposes to compensate for matrix effects. The limits of detection (LOD) of 16 mycotoxins ranged from 0.1 to 6.0 μg/kg. The linear coefficients (R²) were ≥0.996 in the linear range from 10.0 to 200 μg/L. The recoveries of the 16 mycotoxins ranged from 90.1% to 105.8%, and the relative standard deviations (RSDs) ranged from 1.3% to 4.1%. Thirteen TCMs from five representative medicinal parts were selected and tested under the best sample preparation procedure and chromatographic analysis conditions. The results showed that the method could improve the sensitivity and accuracy of the sample analysis, improve the selectivity and reproducibility of the decolorization and purification of TCMs, which is suitable for the practical application of mycotoxin in trace analysis. This method can also provide a new idea for accurate, efficient, rapid and multi-component online detection of mycotoxins for quality and safety control of TCMs.

Handheld Fluorescence Spectrometer Enabling Sensitive Aflatoxin Detection in Maize

Aflatoxins are among the main carcinogens threatening food and feed safety while imposing major detection challenges to the agrifood industry. Today, aflatoxins are typically detected using destructive and sample-based chemical analysis that are not optimally suited to sense their local presence in the food chain. Therefore, we pursued the development of a non-destructive optical sensing technique based on fluorescence spectroscopy. We present a novel compact fluorescence sensing unit, comprising both ultraviolet excitation and fluorescence detection in a single handheld device. First, the sensing unit was benchmarked against a validated research-grade fluorescence setup and demonstrated high sensitivity by spectrally separating contaminated maize powder samples with aflatoxin concentrations of 6.6 µg/kg and 11.6 µg/kg. Next, we successfully classified a batch of naturally contaminated maize kernels within three subsamples showing a total aflatoxin concentration of 0 µg/kg, 0.6 µg/kg and 1647.8 µg/kg. Consequently, our novel sensing methodology presents good sensitivity and high potential for integration along the food chain, paving the way toward improved food safety.

"Green" Extraction and On-Site Rapid Detection of Aflatoxin B1, Zearalenone and Deoxynivalenol in Corn, Rice and Peanut

The common mycotoxins in polluted grains are aflatoxin B1(AFB1), zearalenone (ZEN) and deoxynivalenol (DON). Because of the potential threat to humans and animals, it is necessary to detect mycotoxin contaminants rapidly. At present, later flow immunoassay (LFIA) is one of the most frequently used methods for rapid analysis. However, multistep sample pretreatment processes and organic solvents are also required to extract mycotoxins from grains. In this study, we developed a one-step and "green" sample pretreatment method without using organic solvents. By combining with LFIA test strips and a handheld detection device, an on-site method for the rapid detection of AFB1, ZEN and DON was developed. The LODs for AFB1, ZEN and DON in corn are 0.90 μg/kg, 7.11 μg/kg and 10.6 μg/kg, respectively, and the working ranges are from 1.25 μg/kg to 40 μg/kg, 20 μg/kg to 2000 μg/kg and 35 μg/kg to 1500 μg/kg, respectively. This method has been successfully applied to the detection of AFB1, ZEN and DON in corn, rice and peanut, with recoveries of 89 ± 3%-106 ± 3%, 86 ± 2%-108 ± 7% and 90 ± 2%-106 ± 10%, respectively. The detection results for the AFB1, ZEN and DON residues in certified reference materials by this method were in good agreement with their certificate values.

Comprehensive and heart-cutting multidimensional liquid chromatography-mass spectrometry and its applications in food analysis

In food analysis, conventional one-dimensional liquid chromatography methods sometimes lack sufficient separation power due to the complexity and heterogeneity of the analysed matrices. Therefore, the use of two-dimensional liquid chromatography (2D-LC) turns out to be a powerful tool to consider, especially when coupled to mass spectrometry (MS). This review presents the most remarkable 2D-LC-MS food applications reported in the last 10 years, including a critical discussion of the multiple approaches, modulation strategies as well as the importance of the optimisation of the different analytical aspects that will condition the 2D-LC-MS performance. The presence of contaminants in food (food safety), the food quality and authenticity or the relationship between the beneficial effects of food and human health are some of the fields in which most of the 2D-LC-MS applications are mainly focused. Both heart-cutting and comprehensive applications are described and discussed in this review, highlighting the potential of 2D-LC-MS for the analysis of such complex samples.

The Hydrophobic Extract of Sorghum bicolor (L. Moench) Enriched in Apigenin-Protected Rats against Aflatoxin B1-Associated Hepatorenal Derangement

Aflatoxin B1 (AFB1) is a recalcitrant metabolite produced by fungi species, and due to its intoxications in animals and humans, it has been classified as a Group 1 carcinogen in humans. Preserving food products with Sorghum bicolor sheath can minimise the contamination of agricultural products and avert ill health occasioned by exposure to AFB1. The current study investigated the ameliorating effect of Sorghum bicolor sheath hydrophobic extract (SBE-HP) enriched in Apigenin (API) on the hepatorenal tissues of rats exposed to AFB1. The SBE-HP was characterised using TLC and LC-MS and was found to be enriched in Apigenin and its methylated analogues. The study used adult male rats divided into four experimental cohorts co-treated with AFB1 (50 µg/kg) and SBE-HP (5 and 10 mg/kg) for 28 days. Biochemical, enzyme-linked immunosorbent assays (ELISA) and histological staining were used to examine biomarkers of hepatorenal function, oxidative status, inflammation and apoptosis, and hepatorenal tissue histo-architectural alterations. Data were analysed using GraphPad Prism 8.3.0, an independent t-test, and a one-way analysis of variance. Co-treatment with SBE-HP ameliorated an upsurge in the biomarkers of hepatorenal functionality in the sera of rats, reduced the alterations in redox balance, resolved inflammation, inhibited apoptosis, and preserved the histological features of the liver and kidney of rats exposed to AFB1. SBE-HP-containing API is an excellent antioxidant regiment. It can amply prevent the induction of oxidative stress, inflammation, and apoptosis in the hepatorenal system of rats. Therefore, supplementing animal feeds and human foods with SBE-HP enriched in Apigenin may reduce the burden of AFB1 intoxication in developing countries with a shortage of effective antifungal agents.

Recent Insights into Sample Pretreatment Methods for Mycotoxins in Different Food Matrices: A Critical Review on Novel Materials

Mycotoxins pollution is a global concern, and can pose a serious threat to human health. People and livestock eating contaminated food will encounter acute and chronic poisoning symptoms, such as carcinogenicity, acute hepatitis, and a weakened immune system. In order to prevent or reduce the exposure of human beings and livestock to mycotoxins, it is necessary to screen mycotoxins in different foods efficiently, sensitively, and selectively. Proper sample preparation is very important for the separation, purification, and enrichment of mycotoxins from complex matrices. This review provides a comprehensive summary of mycotoxins pretreatment methods since 2017, including traditionally used methods, solid-phase extraction (SPE)-based methods, liquid-liquid extraction (LLE)-based methods, matrix solid phase dispersion (MSPD), QuEChERS, and so on. The novel materials and cutting-edge technologies are systematically and comprehensively summarized. Moreover, we discuss and compare the pros and cons of different pretreatment methods and suggest a prospect.

Advances in immunoassay-based strategies for mycotoxin detection in food: From single-mode immunosensors to dual-mode immunosensors

Mycotoxin contamination in foods and other goods has become a broad issue owing to serious toxicity, tremendous threat to public safety, and terrible loss of resources. Herein, it is necessary to develop simple, sensitive, inexpensive, and rapid platforms for the detection of mycotoxins. Currently, the limitation of instrumental and chemical methods cannot be massively applied in practice. Immunoassays are considered one of the best candidates for toxin detection due to their simplicity, rapidness, and cost-effectiveness. Especially, the field of dual-mode immunosensors and corresponding assays is rapidly developing as an advanced and intersected technology. So, this review summarized the types and detection principles of single-mode immunosensors including optical and electrical immunosensors in recent years, then focused on developing dual-mode immunosensors including integrated immunosensors and combined immunosensors to detect mycotoxins, as well as the combination of dual-mode immunosensors with a portable device for point-of-care test. The remaining challenges were discussed with the aim of stimulating future development of dual-mode immunosensors to accelerate the transformation of scientific laboratory technologies into easy-to-operate and rapid detection platforms.

Determination of aflatoxin B1 by novel nanofiber-packed solid-phase extraction coupled with a high performance liquid chromatography-fluorescence detector

A novel analytical proposal based on nanofiber-packed solid-phase extraction coupled with high performance liquid chromatography-fluorescence detector (HPLC-FLD) has been successfully developed for determining aflatoxin B1 (AFB1) in foods. Four types of nanofibers, including polystyrene (PS) nanofibers, polypyrrole (PPY) nanofibers, polystyrene-acrylic resin (PS-AR) nanofibers, and polystyrene-polyvinyl pyrrolidone (PS-PVP) nanofibers, were fabricated by electrospinning and utilized to prepare a home-made extraction device. In this study, the factors of different fibers, namely, fiber dosage, pH of extraction solution, type of salt ion, concentration of salt ion, and volume of the eluent were optimized. Under optimized conditions, the method showed good linearity in the range of 0.1-40 ng mL^-1 with a correlation coefficient greater than 0.999 and good inter-day accuracy (90.8-112.7% recovery) and precision (1.8-3.6% intra-day RSDs, 2.6% inter-day RSD), and the limit of detection (LOD) was 0.05 ng mL^-1. Due to its cost-effective, time-saving, environmentally friendly, and simple performance, it has the potential to be utilized to determine aflatoxins in complicated matrices.

Current Developments of Analytical Methodologies for Aflatoxins' Determination in Food during the Last Decade (2013-2022), with a Particular Focus on Nuts and Nut Products

This review aims to provide a clear overview of the most important analytical development in aflatoxins analysis during the last decade (2013-2022) with a particular focus on nuts and nuts-related products. Aflatoxins (AFs), a group of mycotoxins produced mainly by certain strains of the genus Aspergillus fungi, are known to impose a serious threat to human health. Indeed, AFs are considered carcinogenic to humans, group 1, by the International Agency for Research on Cancer (IARC). Since these toxins can be found in different food commodities, food control organizations worldwide impose maximum levels of AFs for commodities affected by this threat. Thus, they represent a cumbersome issue in terms of quality control, analytical result reliability, and economical losses. It is, therefore, mandatory for food industries to perform analysis on potentially contaminated commodities before the trade. A full perspective of the whole analytical workflow, considering each crucial step during AFs investigation, namely sampling, sample preparation, separation, and detection, will be presented to the reader, focusing on the main challenges related to the topic. A discussion will be primarily held regarding sample preparation methodologies such as partitioning, solid phase extraction (SPE), and immunoaffinity (IA) related methods. This will be followed by an overview of the leading analytical techniques for the detection of aflatoxins, in particular liquid chromatography (LC) coupled to a fluorescence detector (FLD) and/or mass spectrometry (MS). Moreover, the focus on the analytical procedure will not be specific only to traditional methodologies, such as LC, but also to new direct approaches based on imaging and the ability to detect AFs, reducing the need for sample preparation and separative techniques.

Development of High-Throughput Sample Preparation Procedures for the Quantitative Determination of Aflatoxins in Biological Matrices of Chickens and Cattle Using UHPLC-MS/MS

Aflatoxins (AFs) frequently contaminate food and animal feeds, especially in (sub) tropical countries. If animals consume contaminated feeds, AFs (mainly aflatoxin B1 (AFB1), B2 (AFB2), G1 (AFG1), G2 (AFG2) and their major metabolites aflatoxin M1 (AFM1) and M2 (AFM2)) can be transferred to edible tissues and products, such as eggs, liver and muscle tissue and milk, which ultimately can reach the human food chain. Currently, the European Union has established a maximum level for AFM1 in milk (0.05 µg kg-1). Dietary adsorbents, such as bentonite clay, have been used to reduce AFs exposure in animal husbandry and carry over to edible tissues and products. To investigate the efficacy of adding bentonite clay to animal diets in reducing the concentration of AFB1, AFB2, AFG1, AFG2, and the metabolites AFM1 and AFM2 in animal-derived foods (chicken muscle and liver, eggs, and cattle milk), chicken and cattle plasma and cattle ruminal fluid, a sensitive and selective ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method has been developed. High-throughput sample preparation procedures were optimized, allowing the analysis of 96 samples per analytical batch and consisted of a liquid extraction using 1% formic acid in acetonitrile, followed by a further clean-up using QuEChERS (muscle tissue), QuEChERS in combination with Oasis® Ostro (liver tissue), Oasis® Ostro (egg, plasma), and Oasis® PRiME HLB (milk, ruminal fluid). The different procedures were validated in accordance with European guidelines. As a proof-of-concept, the final methods were used to successfully determine AFs concentrations in chicken and cattle samples collected during feeding trials for efficacy and safety evaluation of mycotoxin detoxifiers to protect against AFs as well as their carry-over to animal products.

One sample multi-point calibration curve as a novel approach for quantitative LC-MS analysis: the quantitation of six aflatoxins in milk and oat-based milk as an example

Preparing of calibration curves are critical steps for accurate quantitative LC-MS bioanalysis. Traditional multi-sample external calibration curve (MSCC) is labor-intensive and prone to error. In this study, a novel strategy of one sample multi-point calibration curve (OSCC) using multiple isotopologue reaction monitoring (MIRM) was proposed and validated using LC-MS for the quantitation of six aflatoxins in milk and oat-based milk samples. The developed MIRM-OSCC methodology is comprehensively validated and the results indicated that the established method exhibits good performance in selectivity, sensitivity, accuracy and precision. Furthermore, the OSCC could realize sample dilution by monitoring the MIRM channel with less intensity for samples beyond the upper limit of quantification, without the need of sample dilution, which improves the assay throughput. Considering the advantages of excluding the MSCC preparation and sample dilution in OSCC, this strategy can be widely applied in various fields such as drugs, food safety and environmental analysis.

Understanding Current Methods for Sampling of Aflatoxins in Corn and to Generate a Best Practice Framework

Aflatoxin contamination in corn is a significant issue, posing substantial health threats to humans and animals. Aflatoxin testing protects consumer health, ensures the safe global trade of corn, and verifies compliance with legislation; however, effective sampling procedures are essential to ensure reliable results. While many sampling procedures exist, there is no evidence to indicate which is the best approach to ensure accurate detection. Using scientific and gray literature sources, this review analyzed sampling procedures to determine an optimum approach to guide the development of standard practices. Results revealed that sampling is the major source of error in the accurate assessment of aflatoxin levels in food and crucial for obtaining reliable results. To guarantee low variability and sample bias-increased sample size and sampling frequency, the use of automatic dynamic sampling techniques, adequate storage, and homogenization of aggregate samples for analysis are advised to ensure a representative sample. However, there is a lack of evidence to support this or indicate the current utilization of the reviewed procedures. Inadequate data prevented the recommendation of sample sizes or frequency for optimum practice, and thus, further research is required. There is an urgent need to make sampling procedures fit-for-purpose to obtain accurate and reliable aflatoxin measurements.

Aflatoxins in Cereals and Cereal-Based Products: Occurrence, Toxicity, Impact on Human Health, and Their Detoxification and Management Strategies

Cereals and cereal-based products are primary sources of nutrition across the world. However, contamination of these foods with aflatoxins (AFs), secondary metabolites produced by several fungal species, has raised serious concerns. AF generation in innate substrates is influenced by several parameters, including the substrate type, fungus species, moisture content, minerals, humidity, temperature, and physical injury to the kernels. Consumption of AF-contaminated cereals and cereal-based products can lead to both acute and chronic health issues related to physical and mental maturity, reproduction, and the nervous system. Therefore, the precise detection methods, detoxification, and management strategies of AFs in cereal and cereal-based products are crucial for food safety as well as consumer health. Hence, this review provides a brief overview of the occurrence, chemical characteristics, biosynthetic processes, health hazards, and detection techniques of AFs, along with a focus on detoxification and management strategies that could be implemented for food safety and security.

Mycotoxins Contamination in Rice: Analytical Methods, Occurrence and Detoxification Strategies

The prevalence of mycotoxins in the environment is associated with potential crop contamination, which results in an unavoidable increase in human exposure. Rice, being the second most consumed cereal worldwide, constitutes an important source of potential contamination by mycotoxins. Due to the increasing number of notifications reported, and the occurrence of mycotoxins at levels above the legislated limits, this work intends to compile the most relevant studies and review the main methods used in the detection and quantification of these compounds in rice. The aflatoxins and ochratoxin A are the predominant mycotoxins detected in rice grain and these data reveal the importance of adopting safety storage practices that prevent the growth of producing fungi from the Aspergillus genus along all the rice chain. Immunoaffinity columns (IAC) and QuECHERS are the preferred methods for extraction and purification and HPLC-MS/MS is preferred for quantification purposes. Further investigation is still required to establish the real exposition of these contaminants, as well as the consequences and possible synergistic effects due to the co-occurrence of mycotoxins and also for emergent and masked mycotoxins.

Immunoaffinity Cleanup and Isotope Dilution-Based Liquid Chromatography Tandem Mass Spectrometry for the Determination of Six Major Mycotoxins in Feed and Feedstuff

In this study, a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for simultaneous determination of deoxynivalenol, aflatoxin B₁, zearalenone, ochratoxin A, T-2 toxin and fumonisin B₁ in feed and feedstuff was established. The sample was extracted with an acetonitrile–water mixture (60:40, v/v), purified by an immunoaffinity column, eluted with a methanol–acetic acid mixture (98:2, v/v), and reconstituted with a methanol–water mixture (50:50, v/v) after drying with nitrogen. Finally, the reconstituted solution was detected by LC-MS/MS and quantified by isotope internal standard method. The six mycotoxins had a good linear relationship in a certain concentration range, the correlation coefficients were all greater than 0.99, the limits of detection were between 0.075 and 1.5 µg·kg⁻¹, and the limits of quantification were between 0.5 and 5 µg·kg⁻¹. The average spike recoveries in the four feed matrices ranged from 84.2% to 117.1% with relative standard deviations less than 11.6%. Thirty-six actual feed samples were analyzed for mycotoxins, and at least one mycotoxin was detected in each sample. The proposed method is reliable and suitable for detecting common mycotoxins in feed samples.

A Strategy for Sample Preparation: Using Egg White Gel to Promote the Determination of Aflatoxin M1 Content in Milk Samples

The analysis of food samples is a challenging task. The high complexity of food matrices hinders the extraction and detection of analytes from them. Therefore, the correct preparation of food samples is a crucial step for their subsequent analysis, as it achieves the proper isolation and preconcentration of analytes and removes the interfering proportion of the food matrix before instrumental analysis. We aimed to develop a method that not only satisfies the requirement of detecting trace compounds in complex matrices but also achieves a "greener" approach by reducing the use of organic solvents and non-degradable materials to minimize the health hazards posed to the operators as well as pollution to the environment. In this study, we prepared egg white as a concentrated gel and used this material for the biological purification of milk samples. After the milk protein was removed by acidification and salting, the residual amount of aflatoxin M1 in milk samples was quantitatively determined by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The results showed that the novel egg white purification method possessed advantages over the immunoaffinity technique used as the reference method in extraction recovery, sensitivity, repeatability, and operability. The limit of detection (LOD) was 0.001 μg/kg. In spiked samples containing 0.01 μg/kg to 2 μg/kg of AFM1, the average recovery was 88.3-94.7%, with a precision of 6.1-11.0%. Improved repeatability was obtained by significantly reducing the operation time and resource requirements compared with the immunoaffinity technique currently used internationally. This study provides a reference for the further improvement of the relevant international standards in place for the detection of aflatoxin M1 in milk.

Development of a Lateral Flow Strip with a Positive Readout for the On-Site Detection of Aflatoxin B1

Aflatoxin B₁ is one of the contamination indicators for food safety monitoring. The rapid and effective assessment and determination of AFB₁ in food is of great importance to dietary safety. The lateral flow assay shows advantages in its simplicity, and rapidity, and provides a visual readout, while the available lateral flow assay for AFB₁ requires a competitive format that produces readings inversely proportional to the AFB₁ concentration, which is counterintuitive and may lead to a potential misinterpretation of the results. Herein, we developed a positive readout aptamer-based lateral flow strip (Apt-strip) for the detection of AFB₁. This Apt-strip relies on the competition between AFB₁ and fluorescein-labeled complementary DNA strands (FAM-cDNA) for affinity binding to limited aptamers against AFB₁ (AFB₁-Apt). In the absence of AFB₁, AFB₁-Apt hybridizes with FAM-cDNA. No signal at the T-line of the Apt-strip was observed. In contrast, AFB₁-Apt binds to AFB₁ in the sample, and then a part of the FAM-cDNA is hybridized with the free AFB₁-Apt, at which time the other unreacted FAM-cDNA is captured by A35-Apt on the T-line. The signal was observed. This method achieved fast detection of AFB₁ with a detection limit (DL) of 0.1 ng/mL, positive readout, and increased sensitivity.

The presence and transfer characteristics of aflatoxins in medicinal herbs: From raw materials to edible dispensing granules

In this study, a sensitive and accurate immunoaffinity columns coupled with high performance liquid chromatography method was established to monitor the presence of aflatoxins-aflatoxin B₁ , aflatoxin B₂ , aflatoxin G₁ , and aflatoxin G₂ -in different medicinal herbs. The proposed method was found to be suitable for the detection of aflatoxins in eight kinds of herbs and their corresponding granules. Two batches of Arecae semen were positive for aflatoxins, with high residue levels of different aflatoxins. To better understand the presence and transfer of aflatoxins during the formulation of dispensing granules from the herbs, the aflatoxins-free herbs were artificially inoculated with Aspergillus flavus to explore aflatoxins production. Both aflatoxin B₁ and aflatoxin B₂ were detected in all inoculated samples, while aflatoxin G₂ was only detected in Astragali radix samples. Additionally, the presence of aflatoxin B₁ was extremely high compared to other aflatoxins. More specifically, the transfer rate of the aflatoxin B₁ and the total aflatoxins from original herbs to granules were both approximately 40%. These findings indicated that the preparation of herbs into dispensing granules reduced the content of aflatoxins. The high-level presence of aflatoxins in inoculated herbs indicated that greater attention is needed to the safety of Aspergillus flavus-contaminated herbs. This article is protected by copyright. All rights reserved.

Impact of different extraction processes on aflatoxin contamination in peanut oil

Aflatoxins (AFs) are genotoxic carcinogens and are a growing concern in peanuts and peanut products. This study aims to impact of different extraction processes on the transition of AFs from peanuts to oils. Peanuts were collected from nine different factories in Osmaniye, Turkey, during the period of November 2017-May 2018. While no aflatoxin G₁ (AFG₁) and aflatoxin G₂ (AFG₂) were detected in peanuts, aflatoxin B₁ (AFB₁) and aflatoxin B₂ (AFB₂) were determined in all peanut samples at levels varying from 26.7 to 234.7 µg kg^-1 and from 4.44 to 44.0 µg kg^-1, respectively. No AFs were quantified in oils obtained by the industrial application method. The ratios of AFB₁ transitions to oils obtained by solvent extraction, cold pressing of roasted peanuts and cold pressing methods were 9.0-79.8%, 11.3-75.3% and 9.3-77.6%, respectively. The concentrations of AFB₂ in oils obtained by solvent extraction, cold pressing of roasted peanuts and cold pressing methods were 0.46-17.2 µg kg^-1, 0.84-33.0 µg kg^-1 and 1.02-36.3 µg kg^-1, respectively. This is the first demonstration of the impact of different extraction processes on the transition of AFs from peanuts to oils.

Effect of humidity on aflatoxin contamination for selected African leafy vegetables

In this study, the aflatoxin contamination level of selected freshly harvested and dried African leafy vegetables was investigated after inoculation with Aspergillus flavus spores and incubation at 32%, 74%, 84%, and 96% static relative humidity. The study question was whether Aspergillus sp. growth on selected vegetables: Corchorus olitorius, Crotalaria ochroleuca, Vigna unguiculata, Solanum villosum, and Amaranthus blitum can produce aflatoxins. The experiment was replicated thrice and a control sample was included for each replicate. An Agilent 1260 Infinity HPLC system was used for analysis and we quantified the following aflatoxins; B1, B2, G1, and G2 in the selected vegetables. Our results show that aflatoxin B1, G1, and G2 were all present, with the B1 being prevalent. The contamination level increased with relative humidity increase for both freshly harvested and dried vegetables. However, the dried vegetables had a lower contamination level in comparison with freshly harvested. The findings affirm the importance of post-harvest crop preservation to avoid mycotoxin contamination. The vegetables can suffer aflatoxin contamination when exposed to high moisture and ambient temperature and drying is a suitable method of vegetable preservation.

Mycotoxins occurrence in medicinal herbs dietary supplements and exposure assessment

The multimycotoxin analysis of aflatoxins (AFs), zearalenone (ZEA), ochratoxin A (OTA), enniatins (ENNs) and beauvericin (BEA) was performed in 85 samples of medicinal herbs dietary supplements. The samples were classified in 64 samples of one herbal ingredient and 21 mixed samples. The extraction was performed by QuEChERS method and the determination by liquid chromatography coupled to ion-trap tandem mass spectrometry (LC–MS/MS-IT). Then, the risk characterization to mycotoxins through the consumption of medicinal herbs dietary supplements was assessed. The results showed that ZEA, OTA, ENNs and BEA showed in the samples with incidences between 1 and 34%, being ENNB the most detected mycotoxin. Mycotoxins contents ranged from LOQ to 3850.5 µg/kg while the mean of positives samples were 65.5 µg/kg (ENNA), 82.7 µg/kg (ENNA1), 88.7 µg/kg (ENNB), 324.9 µg/kg (ENNB1), 137.9 µg/kg (BEA) and 1340.11 µg/kg (ZEA), respectively. OTA was detected in one herbal mix tablet for insomnia at concentration of 799 μg/kg. In herbal drugs the European Pharmacopoeia Commission has implemented limits of 2 µg/kg for AFB1 and 4 µg/kg for total AFs. In the present study AFs have not been detected in the analyzed medicinal herbs dietary supplements. The Estimated Daily Intakes (EDIs) values were calculated using a deterministic method, considering two exposure scenarios (lower bound (LB) and upper bound (UB)). The values obtained were in general far below the Tolerable Daily Intakes (TDIs) established.