Natural Occurrence, Legislation, and Determination of Aflatoxins Using Chromatographic Methods in Food: A Review (from 2010 to 2019)

Molecularly imprinted polymer based on covalent organic framework coated steel substrate as the mass spectrometric ionization source for the direct detect of aflatoxins in complex food matrices

Ambient mass spectrometry allows direct analysis of various sample types with minimal or no pretreatment. However, due to the influence of matrix effects, there are sensitivity and issues in analyzing trace analytes in complex food samples. In this work, we developed a spray mass spectrometry platform based on SSS@TPBD-TPA@MIPs (Stainless steel substrate (SSS), terephthalaldehyde (TPA), N, N, N', N'-tetrakis(p-aminophenyl)-p-phenylenediamine (TPBD), molecularly imprinted polymer (MIP)), for rapid, in situ, high-throughput, highly enrichment efficiency and highly selective trace analysis of aflatoxins. By simplifying the sample pretreatment and directly applying high voltage for ESI-MS, the analysis can be completed within 1 min. The established method base on SSS@TPBD-TPA@MIPs exhibited high sensitivity and accuracy when determine trace level AFs in maize and peanuts. The results demonstrated a good linear relationship within the range of 0.01-10 μg/L, with the determination coefficient (R2) ≥ 0.9956. The limits of detection (LODs) was 0.035-0.3 ng/mL and limits of quantitation (LOQs) was 0.12-0.99 ng/mL, with acceptable recovery rate of 82.09-115.66 % and good repeatability represented by the relative standard deviation (RSD) less than 17.43 %. Furthermore, SSS@TPBD-TPA@MIPs exhibited excellent reusability, with more than 8 repeated uses, and showed good adsorption performance.

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.

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.

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.

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.

Aflatoxin Contamination, Its Impact and Management Strategies: An Updated Review

Aflatoxin, a type of mycotoxin, is mostly produced by Aspergillus flavus and Aspergillus parasiticus. It is responsible for the loss of billions of dollars to the world economy, by contaminating different crops such as cotton, groundnut, maize, and chilies, and causing immense effects on the health of humans and animals. More than eighteen different types of aflatoxins have been reported to date, and among them, aflatoxins B1, B2, G1, and G2 are the most prevalent and lethal. Early detection of fungal infection plays a key role in the control of aflatoxin contamination. Therefore, different methods, including culture, chromatographic techniques, and molecular assays, are used to determine aflatoxin contamination in crops and food products. Many countries have set a maximum limit of aflatoxin contamination (2-20 ppb) in their food and agriculture commodities for human or animal consumption, and the use of different methods to combat this menace is essential. Fungal infection mostly takes place during the pre- and post-harvest stage of crops, and most of the methods to control aflatoxin are employed for the latter phase. Studies have shown that if correct measures are adopted during the crop development phase, aflatoxin contamination can be reduced by a significant level. Currently, the use of bio-pesticides is the intervention employed in many countries, whereby atoxigenic strains competitively reduce the burden of toxigenic strains in the field, thereby helping to mitigate this problem. This updated review on aflatoxins sheds light on the sources of contamination, and the on occurrence, impact, detection techniques, and management strategies, with a special emphasis on bio-pesticides to control aflatoxins.

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.

A simple extraction method with no lipid removal for the determination of aflatoxins in almonds by liquid chromatography tandem-mass spectrometry (LC-MS/MS)

The present study describes a simple and rapid method for the determination of aflatoxins in almonds using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Aflatoxins were extracted using a modified QuEChERS method with little sample preparation, excluding the use of laborious purification procedures. Extracts were frozen overnight to separate the majority of lipids. The method was successfully validated for almonds. Linearity was demonstrated in the range 0.125-20 µg/kg. Limits of quantification (LOQ) ranged from 0.34 to 0.5 μg/kg. Matrix effect was not significant for the aflatoxins. Satisfactory recoveries were obtained at spike levels below 1 μg/kg and between 1 and 10 μg/kg. Relative standard deviations (RSDs) of repeatability and reproducibility were below 15%. The method was successfully tested with two proficiency tests in almond powder and peanut paste, with acceptable z-scores (-2 ≤ z ≤ 2). Only one of 11 local almond samples contained detectable aflatoxins, at concentrations below the maximum permitted level.

Immunoassays for rapid mycotoxin detection: state of the art

The widespread presence of mycotoxins in nature not only poses a huge health risk to people in terms of food but also causes incalculable losses to the agricultural economy. As a rapidly developing technology in recent years, the mycotoxin immunoassay technology has approached or even surpassed the traditional chromatography technology in some aspects. Using this approach, the lateral flow immunoassay (LFIA) has attracted the interest of researchers due to its user-friendly operation, short time consumption, little interference, low cost, and ability to process a large number of samples at the same time. This paper provides an overview of the immunogens commonly used for mycotoxins, the development of antibodies, and the use of gold nanoparticles, quantum dots, carbon nanoparticles, enzymes, and fluorescent microsphere labeling materials for the construction of LFIAs to improve detection sensitivity. The analytical performance, detection substrates, detection limits or detection ranges of LFIA for mycotoxins have been listed in recent years. Finally, we describe the future outlook for the field, predicting that portable mobile detection devices and simultaneous quantitative detection of multiple mycotoxins is one of the important directions for future development.

Validation of HPLC and Enzyme-Linked Immunosorbent Assay (ELISA) Techniques for Detection and Quantification of Aflatoxins in Different Food Samples

BACKGROUND

In Jordan as in other worldwide countries, mycotoxins are considered a serious national problem in food supplies. As a result, almost all nations are setting and adopting different regulations targeting the control of mycotoxins levels in the domestic food supply, including the problem of reliable sampling and analysis methods.

OBJECTIVE

It is necessary to improve and give evidence of analytical abilities of laboratories within Jordan and developing countries enabling them to monitor mycotoxins effectively in food to overcome non-tariff obstacles.

METHODS

We analyzed 40 samples from wheat, corn, dried fig and dried coffee beans for total aflatoxin content using High Pressure Liquid Chromatography (HPLC) and Enzyme Linked Immunesorbent Assay (ELISA) methods.

RESULTS

40% of samples from wheat, 60% from corn, 30% from dried fig, and 50% from dried coffee beans were found positive when speaking of total aflatoxins, with average values between 1.14 and 4.12 μg/kg. Obtained results allow considering all tested food samples as fit for human consumption if compared with the labeled regulatory limit of allowed aflatoxins in the European Union. In detail, the limit of detection and the limit of quantification for methods used in this study were significantly lower than the maximum limits established by the European Union.

HIGHLIGHTS

The procedure used in this study is suitable for detection of mycotoxins at very low concentration.