Development of Methods for Determination of Aflatoxins

A stable and reusable aluminum-based metal-organic framework for the effective extraction of four aflatoxins from vegetable oils

The high specific surface area of metal-organic framework (MOF) materials endows them with efficient adsorption capabilities, thereby facilitating sample purification. In this study, a novel aluminum-based MOF (Al-MOF) was synthesized and employed as a solid-phase extraction (SPE) adsorbent for the purification of aflatoxins B1 (AFB1), AFB2, AFG1, and AFG2 in vegetable oils. It was revealed that Al-MOF adsorbs aflatoxins through hydrogen bonding and π-π interactions. Under optimal SPE conditions, liquid chromatography-tandem mass spectrometry analysis yielded limits of detection ranging from 0.06 to 0.25 μg/kg and limits of quantification from 0.21 to 0.84 μg/kg for the four aflatoxins. Recovery rates at concentrations of 5, 10, and 20 μg/kg ranged from 74 % to 110 %, with coefficients of variation below 11 %. This method achieves efficient and cost-effective purification of aflatoxins in vegetable oils. Compared to national standard methods, this approach offers advantages such as lower material costs, ease of storage, and reusability.

Isolation and evaluation of probiotics from traditional Chinese foods for aflatoxin B1 detoxification: Geotrichum candidum XG1 (yeast) and mechanistic insights

Identifying aflatoxin-detoxifying probiotics remains a significant challenge in mitigating the risks associated with aflatoxin contamination in crops. Biological detoxification is a popular technique that reduces mycotoxin hazards and garners consumer acceptance. Through multiple rounds of screening and validation tests, Geotrichum candidum XG1 demonstrated the ability to degrade aflatoxin B1 (AFB1) by 99-100%, exceeding the capabilities of mere adsorption mechanisms. Notably, the degradation efficiency was demonstrably influenced by the presence of copper and iron ions in the liquid medium, suggesting a potential role for proteases in the degradation process. Subsequent validation experiments with red pepper revealed an 83% reduction in AFB1 levels following fermentation with G. candidum XG1. Furthermore, mass spectrometry analysis confirmed the disruption of the AFB1 furan ring structure, leading to a subsequent reduction in its toxicity. Collectively, these findings establish G. candidum XG1 as a promising candidate for effective aflatoxin degradation, with potential applications within the food industry.

Guest adaptative supramolecular sensing strategy for warning the risky aflatoxins in contaminated cereals

In the face of diversified analytes, it is a great challenge and infeasible task to design and synthesize corresponding macrocyclic hosts to realize the ideal supramolecular sensing. Herein, we proposed a novel supramolecular sensing strategy, guest adaptative assay (GAA), in which analyte was quantitatively transformed under mild conditions to perfectly adapt to macrocyclic host. As a health-threatening "landmine" in cereals, aflatoxins were converted by the aid of alkali hydrolysis to satisfactorily obtain aflatoxins transformants in ionic state, resulting in sensitive response by the guanidinocalix[5]arene•fluorescein reporter pair. Surprisingly, the established strategy not only exhibited effective practicality in screening out high-risk cereals contaminated with aflatoxins, but also relieved the laborious task of macrocycle design and screening in supramolecular sensing.

Innovative approaches for mycotoxin detection in various food categories

Mycotoxins (MTs), produced by filamentous fungi, represent a severe hazard to the health of humans and food safety, affecting the quality of various agricultural products. They can contaminate a wide range of foods, during any processing phase before or after harvest. Animals and humans who consume MTs-contaminated food or feed may experience acute or chronic poisoning, which may result in serious pathological consequences. Accordingly, developing rapid, easy, and accurate methods of MTs detection in food becomes highly urgent and critical as a quality control and to guarantee food safety and lower health hazards. In this review, we highlighted and discussed innovative approaches like biosensors, fluorescent polarization, capillary electrophoresis, infrared spectroscopy, and electronic noses for MT identification pointing out current challenges and future directions. The limitations, current challenges, and future directions of conventional detection methods versus innovative methods have also been highlighted and discussed.

Determination of multi-mycotoxins in vegetable oil via liquid chromatography-high resolution mass spectrometry assisted by a complementary liquid-liquid extraction

The simultaneous determination of multi-mycotoxins in food commodities are highly desirable due to their potential toxic effects and mass consumption of foods. Herein, liquid chromatography-quadrupole exactive orbitrap mass spectrometry was proposed to analyze multi-mycotoxins in commercial vegetable oils. Specifically, the method featured a successive liquid-liquid extraction process, in which the complementary solvents consisted of acetonitrile and water were optimized. Resultantly, matrix effects were reduced greatly. External calibration approach revealed good quantification property for each analyte. Under optimal conditions, the recovery ranging from 80.8% to 109.7%, relative standard deviation less than 11.7%, and good limit of quantification (0.35 to 45.4 ng/g) were achieved. The high accuracy of proposed method was also validated. The detection of 20 commercial vegetable oils revealed that aflatoxins B1 and B2, zearalenone were observed in 10 real samples. The as-developed method is simple and low-cost, which merits the wide applications for scanning mycotoxins in oil matrices.

Synthesis of a core-shell magnetic covalent organic framework for the enrichment and detection of aflatoxin in food using HPLC-MS/MS

A porous magnetic covalent organic framework, Fe3O4@TPBD-TPA (terephthalaldehyde (TPA) , N, N, N', N'-tetrakis(p-aminophenyl)-p-phenylenediamine (TPBD)), was synthesized using the Schiff base reaction under mild reaction conditions. This adsorbent exhibited excellent adsorption performance for aflatoxins. The adsorption capacity of Fe3O4@TPBD-TPA for aflatoxins ranged from 64.4 to 84.4 mg/g. A magnetic solid-phase extraction combined with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method based on Fe3O4@TPBD-TPA was developed for the efficient determination of four types of aflatoxins in food samples (maize, maize oil, peanut, and peanut oil). The determination coefficients (R2) were ≥0.9972. The method exhibited detection limits ranging from 0.01 to 0.06 μg/kg and spiked recoveries of 80.0 to 113.1%. The intra-day and inter-day precision were less than 6.77%, indicating good repeatability. The adsorbent showed promising prospects for the efficient enrichment of trace amounts of aflatoxins in complex food matrices.

Current physical techniques for the degradation of aflatoxins in food and feed: Safety evaluation methods, degradation mechanisms and products

Aflatoxins are the most toxic natural mycotoxins discovered so far, posing a serious menace to the food safety and trading economy of the world, especially developing countries. How to effectively detoxify has persistently occupied a place on the list of "global hot-point" concerns. Among the developed detoxification methods, physical methods, as the authoritative techniques for aflatoxins degradation, could rapidly induce irreversible denaturation of aflatoxins. This review presents a brief overview of aflatoxins detection and degradation product structure identification methods. Four main safety evaluation methods for aflatoxins and degradation product toxicity assessment are highlighted combined with an update on research of aflatoxins decontamination in the last decade. Furthermore, the latest applications, degradation mechanisms and products of physical aflatoxin decontamination techniques including microwave heating, irradiation, pulsed light, cold plasma and ultrasound are discussed in detail. Regulatory issues related to "detoxification" are also explained. Finally, we put forward the challenges and future work in studying aflatoxin degradation based on the existing research. The purpose of supplying this information is to help researchers have a deeper understanding on the degradation of aflatoxins, break through the existing bottleneck, and further improve and innovate the detoxification methods of aflatoxins.

Recent Advances in Mycotoxin Determination in Fish Feed Ingredients

Low-cost plant-based sources used in aquaculture diets are prone to the occurrence of animal feed contaminants, which may in certain conditions affect the quality and safety of aquafeeds. Mycotoxins, a toxic group of small organic molecules produced by fungi, comprise a frequently occurring plant-based feed contaminant in aquafeeds. Mycotoxin contamination can potentially cause significant mortality, reduced productivity, and higher disease susceptibility; thus, its timely detection is crucial to the aquaculture industry. The present review summarizes the methodological advances, developed mainly during the past decade, related to mycotoxin detection in aquafeed ingredients, namely analytical, chromatographic, and immunological methodologies, as well as the use of biosensors and spectroscopic methods which are becoming more prevalent. Rapid and accurate mycotoxin detection is and will continue to be crucial to the food industry, animal production, and the environment, resulting in further improvements and developments in mycotoxin detection techniques.

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.

Dispersive micro solid phase extraction based ionic liquid functionalized ZnO nanoflowers couple with chromatographic methods for rapid determination of aflatoxins in wheat and peanut samples

Aflatoxins (AFs) contaminate agricultural products in a wide range of ways during their harvesting, storage and transport. Therefore, the detection of AFs has certain practical significance. Herein, a dispersive micro solid phase extraction (D-µSPE) technology was constructed based on 1-hexyl-3-methylimidazolium hexafluorophosphate ([HMIM][PF₆]) fabricated ZnO nanoflowers for AFs extraction from food matrix before HPLC procedure. The key parameters affecting the extraction efficiency were studied. Under optimal experimental conditions, the method showed excellent linearity with high correlation coefficients (≥0.994). LOD and LOQ were 0.034 and 0.114 μg/kg for AFB1, 0.024 and 0.082 μg/kg for AFB2, 0.067 and 0.226 μg/kg for AFG1 and 0.025 and 0.084 μg/kg for AFG2. The recovery of actual samples spiked with analytes (at 5, 15 and 20 μg/kg) were from 93.8 to 105.1%. Overall, an accurate AFs analysis method was developed and could be applied to the determination of AFs in various food and agricultural products.

Co-occurrence of mycotoxins: A review on bioanalytical methods for simultaneous analysis in human biological samples, mixture toxicity and risk assessment strategies

Mycotoxins are the toxic chemical substances that are produced by various fungal species and some of these are harmful to humans. Mycotoxins are ubiquitous in nature and humans could be exposed to multiple mycotoxins simultaneously. Unfortunately, exposure to mixed mycotoxins is not very well studied. Various studies have demonstrated the capacity of mycotoxins to show synergistic effect in the presence of other mycotoxins, thus, increasing the risk of toxicity. Hence, it is important to monitor mixed mycotoxins in human biological samples which would serve as a crucial information for risk assessment. Through this review paper, we aim to summarize the mixture toxicity of mycotoxins and the various bio-analytical techniques that are being used for the simultaneous analysis of mixed mycotoxins in human biological samples. Different sample preparation and clean-up techniques employed till date for eliminating the interferences from human biological samples without affecting the analyses of the mycotoxins are also discussed. Further, a brief introduction of risk assessment strategies that have been or could be adopted for multiple mycotoxin risk assessments is also mentioned. To the best of our knowledge, this is the first review that focuses solely on the occurrence of multiple mycotoxins in human biological samples as well as their risk assessment strategies.

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.

Mycotoxins of Concern in Children and Infant Cereal Food at European Level: Incidence and Bioaccessibility

Cereals are of utmost importance for the nutrition of infants and children, as they provide important nutrients for their growth and development and, in addition, they are easily digestible, being the best choice for the transition from breast milk/infant formula to solid foods. It is well known that children are more susceptible than adults to toxic food contaminants, such as mycotoxins, common contaminants in cereals. Many mycotoxins are already regulated and controlled according to strict quality control standards in Europe and around the world. There are, however, some mycotoxins about which the level of knowledge is lower: the so-called emerging mycotoxins, which are not yet regulated. The current review summarizes the recent information (since 2014) published in the scientific literature on the amounts of mycotoxins in infants’ and children’s cereal-based food in Europe, as well as their behaviour during digestion (bioaccessibility). Additionally, analytical methods used for mycotoxin determination and in vitro methods used to evaluate bioaccessibility are also reported. Some studies demonstrated the co-occurrence of regulated and emerging mycotoxins in cereal products used in children’s food, which highlights the need to adopt guidelines on the simultaneous presence of more than one mycotoxin. Although very little research has been done on the bioaccessibility of mycotoxins in these food products, very interesting results correlating the fiber and lipid contents of such products with a higher or lower bioaccessibility of mycotoxins were reported. LC-MS/MS is the method of choice for the detection and quantification of mycotoxins due to its high sensibility and accuracy. In vitro static digestion models are the preferred ones for bioaccessibility evaluation due to their simplicity and accuracy.

High Precisive Prediction of Aflatoxin B1 in Pressing Peanut Oil Using Raman Spectra Combined with Multivariate Data Analysis

This study proposes a label-free rapid detection method for aflatoxin B₁ (AFB₁) in pressing peanut oil based on Raman spectroscopy technology combined with appropriate chemometric methods. A DXR laser Raman spectrometer was used to acquire the Raman spectra of the pressed peanut oil samples, and the obtained spectra were preprocessed by wavelet transform (WT) combined with adaptive iteratively reweighted penalized least squares (airPLS). The competitive adaptive reweighted sampling (CARS) method was used to optimize the characteristic bands of the Raman spectra pretreated by the WT + airPLS, and a partial least squares (PLS) detection model for the AFB₁ content was established based on the features optimized. The results obtained showed that the root mean square error of prediction (RMSEP) and determination coefficient of prediction (RP2) of the optimal CARS-PLS model in the prediction set were 22.6 µg/kg and 0.99, respectively. The results demonstrate that the Raman spectroscopy combined with appropriate chemometrics can be used to quickly detect the safety of edible oil with high precision. The overall results can provide a technical basis and method reference for the design and development of the portable Raman spectroscopy system for the quality and safety detection of edible oil storage, and also provide a green tool for fast on-site analysis for regulatory authorities of edible oil and production enterprises of edible oil.

Construction of a magnetic covalent organic framework for magnetic solid-phase extraction of AFM1 and AFM2 in milk prior to quantification by LC-MS/MS

A magnetic covalent organic framework (M-COF) was designed and selected as sorbent for magnetic solid-phase extraction (MSPE) of AFM1 and AFM2 in milk, followed by LC-MS/MS analysis. The application of 2,5-Dihydroxy-1,4-benzenedicarboxaldehyde (Dt) and 4',5'-bis(4-aminophenyl)-[1,1':2',1″-terphenyl]-4,4″-diamine (BAPTPDA) as monomers endows M-COF excellent properties for adsorbing AFM1 and AFM2. The morphology, structure, stability, and magnetism of the Fe₃O₄@COF(BAPTPDA-Dt) were characterized by various techniques including scanning electron microscopy, transmission electron microscopy, FTIR, thermogravimetric analysis, and vibrating sample magnetometer. The Fe₃O₄ microspheres were covered by COF shells. Fe₃O₄@COF exhibited excellent magnetism and stability. Some parameters that may influence the adsorption efficiency of MSPE were also optimized, making the extraction process more effective, time-saving (about 3 min), and less organic-reagent-consuming (only 4 mL of acetonitrile required). It is noteworthy that the Fe₃O₄@COF(BAPTPDA-Dt) can be reutilized more than 8 times. The AFM1 and AFM2 were determined by LC-MS/MS. The LODs for AFM1 and AFM2 were in the range 0.0069 to 0.0078 μg kg^-1. A wide linearity range (0.01-100 μg kg^-1) with coefficients of determination (R²) ranging from 0.9998 to 0.9999 was obtained. The recoveries at four spiked concentrations (0.05, 0.5, 5, and 50 μg kg^-1) in the milk matrix ranged from 85.2 to 106.5%. The intraday RSDs and the interday RSDs were in the range 1.74-4.58% and 2.65-6.69%, respectively. The matrix effect (9.3% for AFM1 and 6.7% for AFM2) was also significantly lower than that observed in other work . Overall, the established method has provided a powerful tool for rapid pretreatment and sensitive determination of AFM1 and AFM2 in milk with negligible matrix effect, presenting important value in toxicant determination.

Study on Contamination with Some Mycotoxins in Maize and Maize-Derived Foods

Crops can be contaminated by fungi which produce mycotoxins. Many fungal strains are responsible for producing varied mycotoxins. The research carried out so far has described over 400 different mycotoxins. They have chemical and physical properties that significantly differ, and they are produced by several different existing fungi. The intake of mycotoxins through food can be achieved directly, by feeding on contaminated food, or indirectly from foods of animal origin. The mycotoxin contamination of food and food products for certain animals is a phenomenon studied worldwide, in countries in Europe but also in Asia, Africa and America. The purpose of this study is to develop an evaluation of the mycotoxins prevalent in corn and corn-derived products produced in Romania. A total of 38 maize samples and 19 corn-derivative samples were investigated for the presence of mycotoxins specific to these products, such as deoxynivalenol, zearalenone and fumonisins. Fumonisins had the highest presence and zearalenone had the lowest. The limits determined for the three mycotoxins were always in accordance with legal regulations.

Methodological Approaches for Monitoring Five Major Food Safety Hazards Affecting Food Production in the Galicia-Northern Portugal Euroregion

The agri-food industry has historically determined the socioeconomic characteristics of Galicia and Northern Portugal, and it was recently identified as an area for collaboration in the Euroregion. In particular, there is a need for action to help to ensure the provision of safe and healthy foods by taking advantage of key enabling technologies. The goals of the FOODSENS project are aligned with this major objective, specifically with the development of biosensors able to monitor hazards relevant to the safety of food produced in the Euroregion. The present review addresses the state of the art of analytical methodologies and techniques-whether commercially available or in various stages of development-for monitoring food hazards, such as harmful algal blooms, mycotoxins, Listeria monocytogenes, allergens, and polycyclic aromatic hydrocarbons. We discuss the pros and cons of these methodologies and techniques and address lines of research for point-of-care detection. Accordingly, the development of miniaturized automated monitoring strategies is considered a priority in terms of health and economic interest, with a significant impact in several areas, such as food safety, water quality, pollution control, and public health. Finally, we present potential market opportunities that could result from the availability of rapid and reliable commercial methodologies.

Chromatographic Analysis of Aflatoxigenic Aspergillus flavus Isolated from Malaysian Sweet Corn

High-performance liquid chromatography (HPLC) provides a quick and efficient tool for accurately characterizing aflatoxigenic and non-aflatoxigenic isolates of Aspergillus flavus. This method also provides a quantitative analysis of AFs in Aspergillus flavus. The method’s recovery was assessed by spiking a mixture of AF at different concentrations to the testing medium. The validity of the method was confirmed using aflatoxigenic and non-aflatoxigenic strains of A. flavus. The HPLC system, coupled with a fluorescence detector and post-column photochemical reactor, showed high sensitivity in detecting spiked AFs or AFs produced by A. flavus isolates. Recovery from medium spiked with 10, 20, 60, and 80 ppb of AFs was found to be 73–86% using this approach. For AFB1 and AFB2, the limit of detection was 0.072 and 0.062 ppb, while the limit of quantification was 0.220 and 0.189 ppb, respectively. The AFB1 concentrations ranged from 0.09 to 50.68 ppb, while the AFB2 concentrations ranged between 0.33 and 9.23 ppb. The findings showed that six isolates produced more AFB1 and AFB2 than the acceptable limit of 5 ppb. The incidence of aflatoxigenic isolates of A. flavus in sweet corn and higher concentrations of AFB1 and AFB2 emphasize the need for field trials to explore their real potential for AF production in corn.

The Existing Methods and Novel Approaches in Mycotoxins' Detection

Mycotoxins represent a wide range of secondary, naturally occurring and practically unavoidable fungal metabolites. They contaminate various agricultural commodities like cereals, maize, peanuts, fruits, and feed at any stage in pre- or post-harvest conditions. Consumption of mycotoxin-contaminated food and feed can cause acute or chronic toxicity in human and animals. The risk that is posed to public health have prompted the need to develop methods of analysis and detection of mycotoxins in food products. Mycotoxins wide range of structural diversity, high chemical stability, and low concentrations in tested samples require robust, effective, and comprehensible detection methods. This review summarizes current methods, such as chromatographic and immunochemical techniques, as well as novel, alternative approaches like biosensors, electronic noses, or molecularly imprinted polymers that have been successfully applied in detection and identification of various mycotoxins in food commodities. In order to highlight the significance of sampling and sample treatment in the analytical process, these steps have been comprehensively described.

A Lateral Flow Method for Aflatoxin B1 in Dry Dog Food: An Inter-Laboratory Trial

BACKGROUND

Dogs are highly susceptible to aflatoxins, the mycotoxins which most commonly cause acute dog illnesses and deaths following the consumption of contaminated food.

OBJECTIVE

In this study, a screening method to detect aflatoxin B1 (AFB1) in dry dog food was further evaluated at the FDA action level of 20 ng/g. A fourth-round multi-laboratory trial was performed. In contrast to the previous work, a different source of dog food was used in the multi-laboratory trial and more participants were involved.

METHOD

The tested lateral flow method employs a modified procedure of the "Rosa® AFQ-Fast Test Kit" from Charm Sciences Inc. A total of 60 unfortified blank study samples, 220 study samples fortified at 20 ng/g, and 80 study samples fortified at 9-11 ng/g were prepared by an independent party and analyzed in 10 collaborating laboratories in a blinded manner.

RESULTS

The pass rates were 98.3 and 94.5% for unfortified and 20 ng/g fortified study samples, respectively.

CONCLUSIONS

The method is suitable for aflatoxin B1 screening at the FDA action level of 20 ng/g in a complex matrix such as dry dog food.

HIGHLIGHTS

This work completes extensive method performance evaluation through four rounds of multi-laboratory trials.

Use of near-infrared spectroscopy on predicting wastewater constituents to facilitate the operation of a membrane bioreactor

The use of near-infrared (NIR) spectroscopy in wastewater treatment has continuously expanded. As an alternative to conventional analytical methods for monitoring constituents in wastewater treatment processes, the use of NIR spectroscopy is considered to be cost-effective and less time-consuming. NIR spectroscopy does not distort the measured sample in any way as no prior treatment is required, making it a waste-free technique. On the negative side, one has to be very well versed with chemometric techniques to interpret the results. In this study, filtered and centrifuged wastewater and sludge samples from a lab-scale membrane bioreactor (MBR) were analysed. Two analytical methods (conventional and NIR spectroscopy) were used to determine and compare major wastewater constituents. Particular attention was paid to soluble microbial products (SMPs) and extracellular polymeric substances (EPSs) known to promote membrane fouling. The parameters measured by NIR spectroscopy were analysed and processed with partial least squares regression (PLSR) and artificial neural networks (ANN) models to assess whether the evaluated wastewater constituents can be monitored by NIR spectroscopy. Very good results were obtained with PLSR models, except for the determination of SMP, making the model qualitative rather than quantitative for their monitoring. ANN showed better performance in terms of correlation of NIR spectra with all measured parameters, resulting in correlation coefficients higher than 0.97 for training, testing, and validation in most cases. Based on the results of this research, the combination of NIR spectra and chemometric modelling offers advantages over conventional analytical methods.

Aflatoxin contamination and recommendations to improve its control: a review

Aflatoxin producing fungi cause contamination of food and feed resulting in health hazards and economic loss. It is imperative to develop workable control measures throughout the food chain to prevent and reduce aflatoxin contamination. This is a critical review of contemporary published papers in the field. It is a review of reports from the original aflatoxin researches conducted on foods, from 2015-2020. Most of the reports show high aflatoxin contaminations in food at levels that exceed a regulatory limit of 20 μg/kg and 4 μg/kg set for foods for human consumption in the USA and European Union, respectively. The highest aflatoxin concentration (3,760 μg/kg) was observed in maize. Some of the strategies being deployed in aflatoxin control include application of biocontrol agents, specifically of Aflasafe™, development of resistant crop varieties, and application of other good agricultural practices. We recommend the adoption of emerging technologies such as combined methods technology (CMT) or hurdle technology, one health concept (OHC), improved regulations, on-line monitoring of aflatoxins, and creative art intervention (CAI) to prevent or restrict the growth of target aflatoxin causative fungi.

Advances in Antibody Preparation Techniques for Immunoassays of Total Aflatoxin in Food

Aflatoxin (AF) contamination is a major concern in the food and feed industry because of its prevalence and toxicity. Improved aflatoxin detection methods are still needed. Immunoassays are an important method for total aflatoxin (TAF) analysis in food due to its technical advantages such as high specificity, sensitivity, and simplicity, but require high-quality antibodies. Here, we first review the three ways to prepare high-quality antibodies for TAF immunoassay, second, compare the advantages and disadvantages of antigen synthesis methods for B-group and G-group aflatoxins, and third, describe the status of novel genetic engineering antibodies. This review can provide new methods and ideas for the development of TAF immunoassays.

Detection of Aflatoxins in Different Matrices and Food-Chain Positions

Aflatoxins, produced mainly by filamentous fungi Aspergillus flavus and Aspergillus parasiticus, are one of the most carcinogenic compounds that have adverse health effects on both humans and animals consuming contaminated food and feed, respectively. Aflatoxin B1 (AFB1) and aflatoxin B2 (AFB2) as well as aflatoxin G1(AFG1) and aflatoxin G2 (AFG2) occur in the contaminated foods and feed. In the case of dairy ruminants, after the consumption of feed contaminated with aflatoxins, aflatoxin metabolites [aflatoxin M1 (AFM1) and aflatoxin M2 (AFM2)] may appear in milk. Because of the health risk and the official maximum limits of aflatoxins, there is a need for application of fast and accurate testing methods. At present, there are several analytical methods applied in practice for determination of aflatoxins. The aim of this review is to provide a guide that summarizes worldwide aflatoxin regulations and analytical methods for determination of aflatoxins in different food and feed matrices, that helps in the decision to choose the most appropriate method that meets the practical requirements of fast and sensitive control of their contamination. Analytical options are outlined from the simplest and fastest methods with the smallest instrument requirements, through separation methods, to the latest hyphenated techniques.

Bimodal porous silica nanomaterials as sorbents for an efficient and inexpensive determination of aflatoxin M1 in milk and dairy products

An extraction procedure was developed for the determination of aflatoxin M₁ in milk and dairy products. A sorbent based on UVM-7 mesoporous silica was used as solid phase for the sample clean-up, and the analyte determination was carried out by HPLC coupled to a fluorescence detector. The material architecture was characterized by transmission electronic microscopy, X-ray diffraction, ²⁹Si NMR and nitrogen adsorption-desorption. After the optimization of extraction parameters, the influence of the matrix has been evaluated, obtaining recoveries in the range 78-105% for whole and skimmed milk and yogurt matrix. The reusability of the material was also proved. The sensitivity of the method was also evaluated, and a LOQ (0.015 μg kg^-1) below the European legislation limit was obtained. The procedure was successfully applied for the determination of aflatoxin M₁ in real samples. The results were compared with those obtained with a reference method, being the results statistically comparable.

Sensitive Aflatoxin B1 Detection Using Nanoparticle-Based Competitive Magnetic Immunodetection

Food and crop contaminations with mycotoxins are a severe health risk for consumers and cause high economic losses worldwide. Currently, different chromatographic- and immuno-based methods are used to detect mycotoxins within different sample matrices. There is a need for novel, highly sensitive detection technologies that avoid time-consuming procedures and expensive laboratory equipment but still provide sufficient sensitivity to achieve the mandated detection limit for mycotoxin content. Here we describe a novel, highly sensitive, and portable aflatoxin B1 detection approach using competitive magnetic immunodetection (cMID). As a reference method, a competitive ELISA optimized by checkerboard titration was established. For the novel cMID procedure, immunofiltration columns, coated with aflatoxin B1-BSA conjugate were used for competitive enrichment of biotinylated aflatoxin B1-specific antibodies. Subsequently, magnetic particles functionalized with streptavidin can be applied to magnetically label retained antibodies. By means of frequency mixing technology, particles were detected and quantified corresponding to the aflatoxin content in the sample. After the optimization of assay conditions, we successfully demonstrated the new competitive magnetic detection approach with a comparable detection limit of 1.1 ng aflatoxin B1 per mL sample to the cELISA reference method. Our results indicate that the cMID is a promising method reducing the risks of processing contaminated commodities.

Facile dispersive solid-phase extraction based on humic acid for the determination of aflatoxins in various edible oils

Aflatoxins (AFs), as the secondary metabolites of the toxigenic fungi Aspergillus flavus and Aspergillus parasiticus, are well known to be extremely harmful to humans and animals because of their high toxicity, mutagenicity, carcinogenicity, and teratogenicity. Recurring and increasing studies on AF ingestion incidents indicate that AF contamination is a serious food safety issue worldwide. Currently, immunoaffinity chromatography (IAC) has become the most conventional sample clean-up method for determining AFs in foodstuffs. However, the IAC method may be limited to some laboratories because it requires the use of expensive disposable cartridges and the IA procedure is time-consuming. Herein, to achieve the cost-effective determination of AFs in edible oils, we developed a dispersive solid-phase extraction (DSPE) clean-up method based on humic acids (HAs), which is followed by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) analysis. HAs could be directly used as a DSPE sorbent after simple treatment without any chemical modification. In the HA-DSPE, AFs could remain on the HA sorbent by both hydrophobic and hydrophilic interactions, whereas the oil matrix was retained on HA via only hydrophobic interactions. The oil matrix could be sufficiently washed off by n-hexane, whereas the AFs could still be retained on HA; thus, the selective extraction of AFs and clean-up of oil matrices were achieved. Under the optimal conditions of HA-DSPE, satisfactory recoveries ranging from 81.3% to 106.2% for four AFs (B1, B2, G1, and G2) were achieved in various oil matrices i.e. blended oil, mixed olive oil, tea oil, sunflower seed oil, rapeseed oil, sesame oil, soybean oil, rice oil, corn oil, and peanut oil. Minor matrix effects ranging from 89.3% to 112.9% were obtained for the four AFs, which were acceptable. Moreover, the LODs of AFs between 0.063 and 0.102 μg kg-1 completely meet the regulatory levels fixed by the Food and Drug Administration (FDA), the European Union (EU), China, or other countries. The proposed methodology was further validated using a naturally contaminated peanut oil, and the results indicated that the accuracy of the HA-DSPE could match the accuracy of the referenced IAC. In addition, HA-DSPE can be used to directly treat diluted edible oil without liquid-liquid extraction and HA is cheap and can be easily obtained from the market worldwide; these advantages make the proposed methodology simple, low-cost, and accessible for the determination of AFs in edible oils.

Current research and prevention of aflatoxins in China

Since their discovery in the 1960s, aflatoxins were found to have a considerable impact on the health of humans and animals as well as the country’s economy and international trade. Aflatoxins are often found in nuts, cereals and animal feeds, which has a significant danger to the food industry. Over the years, several steps have been undertaken worldwide to minimise their contamination in crops and their exposure to humans and animals. China is one of the largest exporters and importers of food and animal feed. As a result, many studies have been carried out in China related to aflatoxins, including their distribution, pollution, detection methods, monitoring, testing and managing. Chinese scientists studied aflatoxins in microbiological, toxicological, ecological effects as well as policies relating to their controlling. China has thus put into practice a number of strategies aiming at the prevention and control of aflatoxins in order to protect consumers and ensure a safe trade of food and feed, and the status and enlargement of these strategies are very important and useful for many consumers and stakeholders in China. Therefore, this article aims at the detriment assessments, regulations, distribution, detection methods, prevention and control of aflatoxins in China. It equally provides useful information about the recent safety management systems in place to fight the contamination of aflatoxins in food and feed in China.

Human Biomonitoring of Mycotoxins in Blood, Plasma and Serum in Recent Years: A Review

This manuscript reviews the state-of-the-art regarding human biological monitoring (HBM) of mycotoxins in plasma serum and blood samples. After a comprehensive and systematic literature review, with a focus on the last five years, several aspects were analyzed and summarized: a) the biomarkers analyzed and their encountered levels, b) the analytical methodologies developed and c) the relationship between biomarker levels and some illnesses. In the literature reviewed, aflatoxin B1-lysine (AFB1-lys) and ochratoxin A (OTA) in plasma and serum were the most widely studied mycotoxin biomarkers for HBM. Regarding analytical methodologies, a clear increase in the development of methods for the simultaneous determination of multiple mycotoxins has been observed. For this purpose, the use of liquid chromatography (LC) methodologies, especially when coupled with tandem mass spectrometry (MS/MS) or high resolution mass spectrometry (HRMS), has grown. A high percentage of the samples analyzed for OTA or aflatoxin B1 (mostly as AFB1-lys) in the reviewed papers were positive, demonstrating human exposure to mycotoxins. This review confirms the importance of mycotoxin human biomonitoring and highlights the important challenges that should be faced, such as the inclusion of other mycotoxins in HBM programs, the need to increase knowledge of mycotoxin metabolism and toxicokinetics, and the need for reference materials and new methodologies for treating samples. In addition, guidelines are required for analytical method validation, as well as equations to establish the relationship between human fluid levels and mycotoxin intake.

Mycotoxin contamination and control strategy in human, domestic animal and poultry: A review

Mycotoxins are secondary metabolites produced mainly by fungi belonging to the genera Aspergillus, Fusarium, Penicillium, Claviceps, and Alternaria that contaminate basic food products throughout the world, where developing countries are becoming predominantly affected. Currently, more than 500 mycotoxins are reported in which the most important concern to public health and agriculture include AFB1, OTA, TCTs (especially DON, T-2, HT-2), FB1, ZEN, PAT, CT, and EAs. The presence of mycotoxin in significant quantities poses health risks varying from allergic reactions to death on both humans and animals. This review brings attention to the present status of mycotoxin contamination of food products and recommended control strategies for mycotoxin mitigation. Humans are exposed to mycotoxins directly through the consumption of contaminated foods while, indirectly through carryover of toxins and their metabolites into animal tissues, milk, meat and eggs after ingestion of contaminated feeds. Pre-harvest (field) control of mycotoxin production and post-harvest (storage) mitigation of contamination represent the most effective approach to limit mycotoxins in food and feed. Compared with chemical and physical approaches, biological detoxification methods regarding biotransformation of mycotoxins into less toxic metabolites, are generally more unique, productive and eco-friendly. Along with the biological detoxification method, genetic improvement and application of nanotechnology show tremendous potential in reducing mycotoxin production thereby improving food safety and food quality for extended shelf life. This review will primarily describe the latest developments in the formation and detoxification of the most important mycotoxins by biological degradation and other alternative approaches, thereby reducing the potential adverse effects of mycotoxins.

Multimycotoxin Determination in Tunisian Farm Animal Feed

Mycotoxins presence was evaluated in animal feed marketed in Tunisia for the first time ever. A QuEChERS method was performed to analyze the natural copresence of 22 mycotoxins (enniatins, beauvericin, ochratoxin A, aflatoxins, alternariol monomethyl ether, alternariol, tentoxin, zearalenone, deoxynivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, nivalenol, neosolaniol, diacetoxyscirpenol, T-2 toxin, and HT-2 toxin) in 122 Tunisian marketed feed samples, intended for poultry (n = 43), cattle (n = 35), rabbit (n = 12), sheep (n = 16), and horse (n = 16). Analytes detection and quantification were done using both liquid chromatography and gas chromatography coupled to tandem mass spectrometry. The analytical method showed good linearity (R > 0.996) and sensitivity, the limits of quantification ranged from 0.1 ng/g (enniatin A1) to 225 ng/g (3-acetyldeoxynivalenol). Eighty-five percent of the analyzed samples were positive. Poultry (n = 43) and rabbit (n = 12) feed samples were the most contaminated. Enniatin B was the most prevalent mycotoxin with values ranged between 0.5 ng/g for horse feed and 40 ng/g for poultry feed, followed by deoxynivalenol detected from 16 ng/g in cattle feed to 250 ng/g in poultry feed. None exceeded the limits set by EU recommendations for animal feed. Mycotoxins co-occurrence was observed at most by five different mycotoxins (26%) and up to eight mycotoxins was recorded in 5% of samples. Furthermore, a relatively high copresence rate of different fusariotoxins was registered. Even if no toxicological concern was clearly revealed, the contamination is a real fact and will probably present influence on meat production and on food safety.

Prevalent Mycotoxins in Animal Feed: Occurrence and Analytical Methods

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

A novel fluorescence aptasensor based on mesoporous silica nanoparticles for selective and sensitive detection of aflatoxin B1

Based on the mesoporous silica nanoparticles (MSN), a novel, simple and label-free aptamer biosensor was designed for the detection of aflatoxin B₁ (AFB₁). Here, the aptamers were used as molecular recognition probes and "gated molecules" while Rh6G was loaded into the interior of the particles as the signal probe. In the absence of AFB₁, the "gate" was closed to prevent the leakage of the signal probe because of the immobilization of aptamers on the surface of MSN-NH₂. With the presence of AFB₁, the "gate" could be opened to release the signal probe for the specifical binding of aptamers to AFB₁. Our results showed that the fluorescence intensity was positively correlated with the concentration of AFB₁ (0.5-50 ng mL^-1), with the detection limit as low as 0.13 ng mL^-1. What's more, this design provides a new approach for rapid, sensitive and selective detection based on aptamers and it could be applied to numerous other analytes if appropriate aptamers are available.

Use of Visible-Near-Infrared (Vis-NIR) Spectroscopy to Detect Aflatoxin B1 on Peanut Kernels

Current methods for detecting aflatoxin contamination of agricultural and food commodities are generally based on wet chemical analyses, which are time-consuming, destructive to test samples, and require skilled personnel to perform, making them impossible for large-scale nondestructive screening and on-site detection. In this study, we utilized visible-near-infrared (Vis-NIR) spectroscopy over the spectral range of 400-2500 nm to detect contamination of commercial, shelled peanut kernels (runner type) with the predominant aflatoxin B₁ (AFB₁). The artificially contaminated samples were prepared by dropping known amounts of aflatoxin standard dissolved in 50:50 (v/v) methanol/water onto peanut kernel surface to achieve different contamination levels. The partial least squares discriminant analysis (PLS-DA) models established using the full spectra over different ranges achieved good prediction results. The best overall accuracy of 88.57% and 92.86% were obtained using the full spectra when taking 20 and 100 parts per billion (ppb), respectively, as the classification threshold. The random frog (RF) algorithm was used to find the optimal characteristic wavelengths for identifying the surface AFB₁-contamination of peanut kernels. Using the optimal spectral variables determined by the RF algorithm, the simplified RF-PLS-DA classification models were established. The better RF-PLS-DA models attained the overall accuracies of 90.00% and 94.29% with the 20 ppb and 100 ppb thresholds, respectively, which were improved compared to using the full spectral variables. Compared to using the full spectral variables, the employed spectral variables of the simplified RF-PLS-DA models were decreased by at least 94.82%. The present study demonstrated that the Vis-NIR spectroscopic technique combined with appropriate chemometric methods could be useful in identifying AFB₁ contamination of peanut kernels.