Co-occurrence of aflatoxin B1, B2, G1, G2 and ochrotoxin A in Glycyrrhiza uralensis analyzed by HPLC-MS/MS

Pixel-Level Recognition of Trace Mycotoxins in Red Ginseng Based on Hyperspectral Imaging Combined with 1DCNN-Residual-BiLSTM-Attention Model

Red ginseng is widely used in food and pharmaceuticals due to its significant nutritional value. However, during the processing and storage of red ginseng, it is susceptible to grow mold and produce mycotoxins, generating security issues. This study proposes a novel approach using hyperspectral imaging technology and a 1D-convolutional neural network-residual-bidirectional-long short-term memory attention mechanism (1DCNN-ResBiLSTM-Attention) for pixel-level mycotoxin recognition in red ginseng. The "Red Ginseng-Mycotoxin" (R-M) dataset is established, and optimal parameters for 1D-CNN, residual bidirectional long short-term memory (ResBiLSTM), and 1DCNN-ResBiLSTM-Attention models are determined. The models achieved testing accuracies of 98.75%, 99.03%, and 99.17%, respectively. To simulate real detection scenarios with potential interfering impurities during the sampling process, a "Red Ginseng-Mycotoxin-Interfering Impurities" (R-M-I) dataset was created. The testing accuracy of the 1DCNN-ResBiLSTM-Attention model reached 96.39%, and it successfully predicted pixel-wise classification for other unknown samples. This study introduces a novel method for real-time mycotoxin monitoring in traditional Chinese medicine, with important implications for the on-site quality control of herbal materials.

Mycotoxin detection in selected medicinal plants using chromatographic techniques

Mycotoxins are toxic mycological products that when consumed, absorbed or inhaled cause sickness or even the death of humans. Therefore, the present study aimed to evaluate the contamination levels of mycotoxins (aflatoxins, AFB1 , AFB2 , AFG1 , AFG2 , and ochratoxin A, OTA) in selected medicinal herbs and shrubs using thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). A total of 15 samples of medicinal herbs and shrubs were selected. Among them, four samples were aflatoxin contaminated while two samples were ochratoxin A contaminated. The highest level of aflatoxin was detected in Justicia adhathoda (4,704.94 ppb) through HPLC (153.4 ppb) and through TLC, while the lowest level of aflatoxin was detected in Pegnum harmala (205.1 ppb) through HPLC. Similarly, the highest level of OTA was detected in Dodonia viscosa (0.53 ppb) through HPLC (0.5 ppb) and through TLC, while the lowest level was detected in J. adhathoda (O.11 ppb) through HPLC (0.4 ppb) and through TLC. The OTA concentration was very low, being negligible and below permissible limits. The present study concludes that there is a potential risk for the consumption of herbal decoctions. Therefore, regular monitoring and proper management of mycotoxins, including aflatoxins and OTA, in herbal medicines are needed to ensure the safety of herbal drugs to protect consumers.

Determination of ochratoxin A in licorice extract based on modified immunoaffinity column clean-up and HPLC analysis

Contamination of ochratoxin A (OTA) is a common concern for the quality and safety of licorice and its derivatives, while their complex sample matrices always restrict the monitoring and regulation of OTA. Taking the much more concentrated and complicated licorice extract as the representative, a modified analysis method was established for OTA by HPLC. Parameters were comprehensively investigated based on liquid-liquid extraction and immunoaffinity column clean-up. In comparison to other methods, the developed method achieved effective clean-up efficiency and selectivity without tedious procedures and specialized instrumentation. Good linearity (R2 ≥0.9995), low LOD/LOQ (0.10 μg/kg/0.33 μg/kg), and satisfactory recovery (90.0%-96.4%, RSDs <7.0%) indicated the satisfactory sensitivity and reliability of the method. In addition, the applicability and robustness of the method was demonstrated by the analysis of large numbers of licorice extract samples. It is noteworthy that 66.5% of 176 samples were contaminated with OTA, while the concentrations of 9.1% of samples exceeded the maximum limit (ML, 80 μg/kg) defined by the EU. On account of the high contamination frequency and broad concentration range of OTA, the daily intake limit of licorice extract was preliminarily determined to be 123.18-123.93 g/day (chronic exposure) and 24.24 g/day (acute exposure), indicating a potential of acute risk through daily exposure. This calls for improved supervision and regulation for OTA contamination in licorice samples. This study suggests a prospective option for the efficient determination and routine monitoring of OTA in licorice and its derivatives, simultaneously providing a valuable data base for its health risk assessment.

Rapid and Simultaneous Detection of Aflatoxin B1, Zearalenone, and T-2 Toxin in Medicinal and Edible Food Using Gold Immunochromatographic Test Strip

(1) Background: Medicinal and edible food and traditional Chinese medicine have been used to treat various diseases. However, their safety has not been thoroughly assessed. (2) Methods: An immunochromatographic test strip (ICS) was used for the first time to screen some mycotoxins, including aflatoxin B1 (AFB₁), zearalenone (ZEN), and T-2 toxin, in medicinal and edible food and traditional Chinese medicine. Antibody/nano-gold particle coupling was used with the prepared ICS, and the pH, monoclonal antibody concentration, and antigen amount were optimized. The extraction sample solution was diluted 10 times with phosphate-buffered saline containing 0.5% Tween-20 and 0.05% sodium dodecyl sulfate to remove the complex matrix in medicinal and edible food. (3) Results: Under optimal conditions, the sensitivities of the developed ICS for AFB₁, ZEN, and T-2 were 0.5, 5.0, and 5.0 ng/mL, respectively. Among the 30 medicinal and edible food samples tested, two samples (both of sand jujube kernels) were positive, and the results were verified by high-performance liquid chromatography and enzyme-linked immunosorbent assay and were consistent with the ICS test results. (4) Conclusions: The ICS could be used for rapid screening and simultaneous detection of mycotoxins at medicinal and edible food storage facilities.

Volatiles from Pseudomonas palleroniana Strain B-BH16-1 Suppress Aflatoxin Production and Growth of Aspergillus flavus on Coix lacryma-jobi during Storage

Semen coicis is not only a traditional Chinese medicine (TCM), but also a typical food in China, with significant medical and healthcare value. Because semen coicis is rich in starch and oil, it can be easily contaminated with Aspergillus flavus and its aflatoxins (AFs). Preventing and controlling the contamination of semen coicis with Aspergillus flavus and its aflatoxins is vital to ensuring its safety as a drug and as a food. In this study, the endosphere bacteria Pseudomonas&nbsp;palleroniana strain B-BH16-1 produced volatiles that strongly inhibited the mycelial growth and spore formation activity of A. flavus. Gas chromatography-mass spectrometry profiling revealed three volatiles emitted from B-BH16-1, of which 1-undecene was the most abundant. We obtained authentic reference standards for these three volatiles; these significantly reduced mycelial growth and sporulation in Aspergillus, with dimethyl disulfide showing the most robust inhibitory activity. Strain B-BH16-1 was able to completely inhibit the biosynthesis of aflatoxins in semen coicis samples during storage by emitting volatile bioactive components. The microscope revealed severely damaged mycelia and a complete lack of sporulation. This newly identified plant endophyte bacterium was able to strongly inhibit the sporulation and growth of Aspergillus and the synthesis of associated mycotoxins, thus not only providing valuable information regarding an efficient potential strategy for the prevention of A. flavus contamination in TCM and food, but potentially also serving as a reference in the control of toxic fungi.

Chemical analysis of the Chinese herbal medicine licorice (Gan-Cao): An update review

ETHNOPHARMACOLOGICAL RELEVANCE

Licorice, called Gan-Cao in China, is one of the most popular traditional herbal medicines. It is derived from the dried roots and rhizomes of Glycyrrhiza uralensis, G. glabra, and G. inflata. Licorice is recorded in the pharmacopoeias of China, Japan, US, and Europe.

AIM

This review updates research progress of licorice from the perspectives of chemical analysis, quality evaluation, drug metabolism, and pharmacokinetic studies from 2009 to April 2022.

MATERIALS AND METHODS

Both English and Chinese literatures were collected from databases including PubMed, Elsevier, Web of Science, and CNKI (Chinese). Licorice, extraction, structural characterization/identification, quality control, metabolism, and pharmacokinetics were used as keywords.

RESULTS

Newly developed analytical methods, including LC/UV, 2DLC, LC/MS, GC/MS, and mass spectrometry imaging (MSI) for chemical analysis of licorice were summarized.

CONCLUSION

This review provides a comprehensive summary on chemical analysis of licorice.

Advances in the Application of Liquid Chromatography in the Detection of Pollutants

Food is easy to be contaminated because of its complex composition. Therefore, in order to protect people from potential food contaminants, it is very necessary to test for various contaminants in food. Liquid chromatography is widely used in the field of food safety detection. In addition, with the development of liquid chromatography technology, more and more new instruments are combined with liquid chromatography. Compared with traditional liquid chromatography, combined liquid chromatography has great advantages in efficiency and operation. Therefore, it is rapidly promoted in the field of food safety testing. In this paper, the results of the determination of three kinds of food pollutants by different liquid chromatography methods are reviewed, and the indexes are compared and analyzed.

A colorimetric aptasensor based on gold nanoparticles for detection of microbial toxins: an alternative approach to conventional methods

Frequent contamination of foods with microbial toxins produced by microorganisms such as bacteria, fungi, and algae represents an increasing public health problem that requires the development of quick and easy tools to detect them at trace levels. Recently, it has been found that colorimetric detection methods may replace traditional methods in the field because of their ease of use, quick response, ease of manufacture, low cost, and naked-eye visibility. Therefore, it is suitable for fieldwork, especially for work in remote areas of the world. However, the development of colorimetric detection methods with low detection limits is a challenge that limits their wide applicability in the detection of food contaminants. To address these challenges, nanomaterial-based transduction systems are used to construct colorimetric biosensors. For example, gold nanoparticles (AuNPs) provide an excellent platform for the development of colorimetric biosensors because they offer the advantages of easy synthesis, biocompatibility, advanced surface functionality, and adjustable physicochemical properties. The selectivity of the colorimetric biosensor can be achieved by the combination of aptamers and gold nanoparticles, which provides an unprecedented opportunity to detect microbial toxins. Compared to antibodies, aptamers have significant advantages in the analysis of microbial toxins due to their smaller size, higher binding affinity, reproducible chemical synthesis and modification, stability, and specificity. Two colorimetric mechanisms for the detection of microbial toxins based on AuNPs have been described. First, sensors that use the localized surface plasmon resonance (LSPR) phenomenon of gold nanoparticles can exhibit very strong colors in the visible range because of changes caused by aggregation or disaggregation. Second, the detection mechanism of AuNPs is based on their enzyme mimetic properties and it is possible to construct a colorimetric biosensor based on the 3,3',5,5'-tetramethylbenzidine/Hydrogen peroxide, TMB/H₂O₂ reaction to detect microbial toxins. Therefore, this review summarizes the recent applications of AuNP-based colorimetric aptasensors for detecting microbial toxins, including bacterial toxins, fungal toxins, and algal toxins focusing on selectivity, sensitivity, and practicality. Finally, the most important current challenges in this field and future research opportunities are discussed.

Analysis of Fungal Microbiomes in Edible Medicinal Morindae Officinalis Radix and Alpiniae Oxyphyllae Fructus Using DNA Metabarcoding

Morindae Officinalis Radix (MOR) and Alpiniae Oxyphyllae Fructus (AOF) have been widely used as dietary supplements and traditional herbal medicines for centuries. Fungal and mycotoxin contamination in MOR and AOF has been reported recently. In this study, fungi in MOR and AOF are first investigated using DNA metabarcoding, and the differences in fungal microbiome between moldy and non−moldy samples are analyzed. The results show that Ascomycota is the most prevailing fungus at the phylum level in MOR and AOF with relative abundances of 49.53–94.32% and 14.81–81.85%, respectively. Penicillium (1.86–76.14%), Cladosporium (1.82–56.65%), and Trichoderma (0.12–19.71%) are the dominant genera in MOR. Penicillium (0.27–56.06%), Papiliotrema (0.04–51.71%), and Cladosporium (3.08–44.41%) are the dominant genera in AOF. Two potential toxigenic fungi were detected, namely, Trichoderma atroviride and Fusarium equiseti. Moreover, the differences in fungal communities between moldy and non−moldy samples were monitored. In conclusion, DNA metabarcoding can be used to assess the fungal microbiome in edible medicinal herbs, thereby providing a basis for ensuring food safety and drug efficacy.

Monitoring of Aflatoxin M1 in Various Origins Greek Milk Samples Using Liquid Chromatography Tandem Mass Spectrometry

Aflatoxin M1(AFM1), a major metabolite of Aflatoxin B1(AFB1), has been identified as a potential contaminant in dairy products. Because of its possible carcinogenicity, the legislation limits as set by Commission Regulation (EC) No. 1881/2006 are very strict, namely 0.050 μg kg−1 in milk and 0.025 μg kg−1 in infant formulas. To meet these requirements, a sensitive and accurate method was developed, employing liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Ιmmunoaffinity columns (R-Biopharm) were used for sample purification and preconcentration of the analyte of interest. The quantification of AFM1 was conducted using fortified milk samples, while Aflatoxin B2 (AFB2) was used as an internal standard (IS). The method was validated in terms of linearity, precision, trueness, limits of detection and quantification and uncertainty. The performance criteria for the method were evaluated based on European Commission Regulation (EC) No. 401/2006 and its most recent amendment, as well as the suggested criteria for revision by the EU Reference Laboratory for Mycotoxins and Plant Toxins. The recovery was in the range of 77.9–81.0% for all fortification levels (0.025–0.050–0.075 μg kg−1), with RSDR values (Relative Standard Deviation of intermediate precision) ranging from 6.1% to 12%. The method’s detection and quantification limits were 0.0027 μg kg−1 and 0.0089 μg kg−1, respectively. The occurrence of AFM1 was investigated in 40 samples of different animal origin (cow, goat and sheep milk) provided by Greek producers.

Visual detection of aflatoxin B1 and zearalenone via activating a new catalytic reaction of “naked” DNAzyme

It was found for the first time that the catalytic activity of “naked” DNAzyme can be modulated by aflatoxins and zearalenone to generate different color changes, which could be applied to the visual detection for the above two analytes.

Adsorption of aflatoxins and ochratoxins in edible vegetable oils with dopamine-coated magnetic multi-walled carbon nanotubes

A new, green, and cost-effective magnetic solid-phase extraction of aflatoxins and ochratoxins from edible vegetable oils samples was developed using polydopamine-coated magnetic multi-walled carbon nanotubes (PDA@Fe₃O₄-MWCNTs) as the absorbent. PDA@Fe₃O₄-MWCNTs nanomaterials were prepared by chemical co-precipitation and in situ oxidation and self-polymerization of dopamine and was characterized. Factors affecting MSPE and the adsorption behavior of the adsorbent to mycotoxins were studied, and the optimal extraction conditions of MSPE and the complexity of the adsorption process were determined. Based on this, the magnetic solid-phase extraction-high-performance liquid chromatography-fluorescence detection method (MSPE-HPLC-FLD) was established for determining six mycotoxins [aflatoxin B₁ (AFB₁), AFB₂, AFG₁, and AFG₂, and ochratoxin A (OTA) and OTB)] in vegetable oils. The recovery was 70.15%~89.25%, and RSD was ≤6.4%. PDA@Fe₃O₄-MWCNTs showed a high affinity toward aflatoxins and ochratoxins, allowing selective extraction and quantification of aflatoxins and ochratoxins from complex sample matrices.

Reliable and disposable quantum dot-based electrochemical immunosensor for aflatoxin B1 simplified analysis with automated magneto-controlled pretreatment system

An integrated aflatoxin B₁ (AFB₁) detection platform with quantum dot (QD)-based electrochemical immunosensor and an automated magneto-controlled pretreatment system was successfully developed. The automated pretreatment system adopts the immunoaffinity magnetic beads (IMB) as the capture probe of AFB₁ and QD-labeled AFB₁ complete antigen (AFB₁-BSA-QDs) as the signal probe. AFB₁-BSA-QDs can be easily converted into corresponding metallic cations through acidic treatment, which can be detected electrochemically via anode stripping voltammetry (ASV). Moreover, a disposable screen-printed electrode (SPE) without requiring any further modification is used in the novel electrochemical immunosensor' making routine testing feasible. Under optimal conditions, the detectable concentration range of AFB₁ was 0.08-800 μg/kg. The metal ion signal associated linearly with the logarithm of AFB₁ concentration within the range of 5-240 μg/kg, with a detection limit of 0.05 μg/kg. The spiked recoveries of three different concentrations in four different matrixes ranged from 83.9 to 118.0%, and inter-day relative standard deviations were below 10%. Furthermore, the methodology was validated by analyzing naturally contaminated samples, and results of the novel immunosensor were in good agreement with those of LC-MS/MS, demonstrating the potentiality of the developed method for the monitor of AFB₁ in cereals and oils.

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.

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.

Occurrence and analysis of mycotoxins in domestic Chinese herbal medicines

For time immemorial, Chinese herbal medicines (CHMs) have been widely used in China for disease treatment and promotion of general well-being. However, in recent years, many studies have shown that mycotoxins produced by fungi could contaminate CHMs due to unfavourable pre- or post-harvest conditions, raising major concern for consumer safety. At present, there is a significant focus on developing novel mycotoxin detection methods for analysing CHMs, and numerous studies have aimed to determine which kinds of raw herbal materials are most susceptible to mycotoxin contamination. In this review, we focus on recent advances in understanding and detection of mycotoxins in domestic raw herbal materials and related products from 2000 to 2018. Aspects of mycotoxin contamination of CHMs covered in this review include common mycotoxin contaminants in CHMs, maximum mycotoxin residue limits, analytical methods for mycotoxin detection and their applications and limitations, as well as a brief discussion of the trends in ongoing research.

Safety evaluation of Semen Sojae Preparatum based on simultaneous LC-ESI-MS/MS quantification of aflatoxin B1 , B2 , G1 , G2 and M1

Semen Sojae Preparatum (SSP) is one of the most widely used traditional Chinese medicines, and is also a functional food. However, contamination with aflatoxins may occur in the fermentation process. To evaluate its safety, an accurate and rapid LC-ESI-MS/MS analytical method was developed and validated for the simultaneous determination of AFB₁ , AFB₂ , AFG₁ , AFG₂ and AFM₁ in SSP. After a simple ultrasonic extraction of SSP samples, chromatographic separation was achieved on an Agilent Zorbax SB-C₁₈ column (2.1 × 50 mm, 3.5 μm) with a flow rate of 0.50 mL/min. The gradient elution program was performed using a mobile phase consisting of water and acetonitrile, both containing 0.1% formic acid. Detection of five aflatoxins was based on triple quadrupole mass spectrometry using a multiple reaction monitoring mode with an electrospray ionization source. SSP is likely to be contaminated by aflatoxins in the processes of fermentation, storage, transportation and usage, and it is necessary to strictly monitor it. Artemisia annua L. and Morus alba L. may inhibit the production and growth of AFB₁ - and AFB₂ -producing fungi, which has a certain detoxification effect on contamination with aflatoxins in SSP.

Binding-Induced DNA Dissociation Assay for Small Molecules: Sensing Aflatoxin B1

We describe a new fluorescence turn-on sensor for homogeneous detection of aflatoxin B1 (AFB1), a potent low molecular weight mycotoxin. A key innovation is the binding-induced intramolecular interaction involving the following two sets of probes: (1) a gold nanoparticle (AuNP) immobilized with hundreds of assistant oligonucleotides (AO) and dozens of anti-AFB1 monoclonal antibodies, and (2) the AFB1-BSA (BSA = bovine serum albumin) antigen conjugated with fluorophore-labeled signal oligonucleotides (SO) that contained a short sequence complementary to AO. Specific binding of AFB1-BSA to the antibody brought the fluorophore very close to the surface of the AuNP through a stable intramolecular hybridization between AO and SO, resulting in efficient quenching of fluorescence. The improved fluorescence quenching substantially reduced the background, due to the binding-induced intramolecular hybridization, and improved the signal-to-background ratio by 390%. In the presence of AFB1 in a sample, competitive binding of AFB1 in the sample to the antibodies immobilized on the AuNP caused the release of the fluorophore-labeled AFB1-BSA from the AuNP, turning on fluorescence. A detection limit of 2.3 nM was achieved, which meets the requirement for AFB1 detection at regulatory levels. Analyses of rice samples using this assay showed recoveries of 86-102%. Incorporating appropriate antibody probes could extend the assay to the detection of other small molecules.

Analysis of the Fungal Community in Ziziphi Spinosae Semen through High-Throughput Sequencing

Ziziphi Spinosae Semen (ZSS) has been widely used in traditional Chinese medicine system for decades. Under proper humidity and temperature, ZSS is easily contaminated by fungi and mycotoxins during harvest, storage, and transport, thereby posing a considerable threat to consumer health. In this study, we first used the Illumina MiSeq PE250 platform and targeted the internal transcribed spacer 2 sequences to investigate the presence of fungi in moldy and normal ZSS samples collected from five producing areas in China. Results showed that all 14 samples tested were contaminated by fungi. Ascomycota was the dominant fungus at the phylum level, accounting for 64.36⁻99.74% of the fungal reads. At the genus level, Aspergillus, Candida, and Wallemia were the most predominant genera, with the relative abundances of 13.52⁻87.87%, 0.42⁻64.56%, and 0.06⁻34.31%, respectively. Meanwhile, 70 fungal taxa were identified at the species level. Among these taxa, three potential mycotoxin-producing fungi, namely, Aspergillusflavus, A. fumigatus, and Penicillium citrinum that account for 0.30⁻36.29%, 0.04⁻7.37%, and 0.01⁻0.80% of the fungal reads, respectively, were detected in all ZSS samples. Moreover, significant differences in fungal communities were observed in the moldy and normal ZSS samples. In conclusion, our results indicated that amplicon sequencing is feasible for the detection and analysis of the fungal community in the ZSS samples. This study used a new approach to survey the fungal contamination in herbal materials. This new approach can provide early warning for mycotoxin contamination in herbal materials, thereby ensuring drug efficacy and safety.

A test strip for ochratoxin A based on the use of aptamer-modified fluorescence upconversion nanoparticles

An aptamer-based test strip is described for visual and instrumental determination of the mycotoxin ochratoxin A (OTA). It is based on the use of NaYF₄:Yb,Er upconversion nanoparticles (UCNPs) as a label for the aptamer and on the competition between OTA and its complementary sequence for an OTA-specific aptamer. To improve the analytical performance, the optical properties of the UCNPs, the fluidity of the UCNP-aptamer conjugate, and the migration rate on the nitrocellulose membranes were investigated. Under the optimal experimental conditions and by using a 980-nm laser, the relative fluorescence intensity (test line value/control line value) is proportional to the logarithm of the OTA concentration over a range from 5 to 100 ng·mL^-1 (R² = 0.9955). The limit of the detection is 1.86 ng·mL^-1. This aptamer based flow assay can be performed within 15 min and has no serious cross-sensitivity to potentially interfering species. It was successfully applied to the determination of OTA in spiked wheat and beer samples. Graphical abstract An aptamer-based upconversion fluorescent strip based on the use of NaYF₄:Yb,Er nanoparticles was developed for sensitive detection of Ochratoxin A. The limit of the detection was determined as 1.86 ng·mL^-1. The assay can be performed within 15 min, indicating its great potential in point-of-care testing.

Occurrence of multi-class mycotoxins in Menthae haplocalycis analyzed by ultra-fast liquid chromatography coupled with tandem mass spectrometry

To determine the presence of multi-class mycotoxins in Menthae haplocalycis, a sample processing procedure based on a modified quick, easy, effective, rugged, and safe method, and a rapid and accurate testing method using ultra-fast performance liquid chromatography coupled with tandem mass spectrometry, was developed and validated. We systematically evaluated the methodology for multi-mycotoxin analysis in the Menthae haplocalycis samples, and chose matrix-matched calibration curves as a reference to calculate the recoveries. Overall, the average recoveries varied between 67.1 and 103%, with relative standard deviations ranging from 0.34 to 10.3%. The optimized and validated method was applied to detect the presence of the target mycotoxins in 40 batches of Menthae haplocalycis samples. Results showed that the levels of mycotoxins varied among the samples. The most prevalent mycotoxin was tentoxin, followed by alternariol, alternariol monomethyl ether, zearalenone, fumonisin B₂ , fumonisin B₁ , ochratoxin A, aflatoxin B₁ , aflatoxin B₂ , aflatoxin G₁ , and T-2 toxin. The analytical method developed herein could be applied for the routine monitoring of multi-mycotoxins in Menthae haplocalycis.

Simultaneous determination of trace Aflatoxin B1 and Ochratoxin A by aptamer-based microchip capillary electrophoresis in food samples

An aptamer-based microchip capillary electrophoresis coupled with laser induced fluorescence (MCE-LIF) detection method for fast determination of Aflatoxin B₁ (AFB₁) and Ochratoxin A (OTA) was developed. Aptamers that are specific to these two mycotoxins were first hybridized with their aptamer complementary oligonucleotides. The double strand DNA that comes in contact with mycotoxin-containing environment would be unwound into separate aptamer-mycotoxin complex and aptamer complementary single strand. Different types of oligonucleotides can be separated in MCE and detected under the aid of fluorescent dye SYBR gold in LIF detection unit. Under the optimal conditions, on-chip aptamer-mycotoxin conjugates analysis was achieved within 3 min with extremely low LODs (0.026 ng/mL for AFB₁ and 0.021 ng/mL for OTA). Specificity study indicated that other major mycotoxins would not cross-react with these two aptamers, demonstrating the good selectivity of the proposed method. Quantification of trace AFB₁ and OTA in real food samples was carried out and satisfactory recoveries were obtained. It is demonstrated that this method is fast, facile and specific for Simultaneous determination of trace AFB₁ and OTA from foodstuffs.

A Review of Current Methods for Analysis of Mycotoxins in Herbal Medicines

The presence of mycotoxins in herbal medicines is an established problem throughout the entire world. The sensitive and accurate analysis of mycotoxin in complicated matrices (e.g., herbs) typically involves challenging sample pretreatment procedures and an efficient detection instrument. However, although numerous reviews have been published regarding the occurrence of mycotoxins in herbal medicines, few of them provided a detailed summary of related analytical methods for mycotoxin determination. This review focuses on analytical techniques including sampling, extraction, cleanup, and detection for mycotoxin determination in herbal medicines established within the past ten years. Dedicated sections of this article address the significant developments in sample preparation, and highlight the importance of this procedure in the analytical technology. This review also summarizes conventional chromatographic techniques for mycotoxin qualification or quantitation, as well as recent studies regarding the development and application of screening assays such as enzyme-linked immunosorbent assays, lateral flow immunoassays, aptamer-based lateral flow assays, and cytometric bead arrays. The present work provides a good insight regarding the advanced research that has been done and closes with an indication of future demand for the emerging technologies.

Large-Scale Membrane- and Lignin-Modified Adsorbent-Assisted Extraction and Preconcentration of Triazine Analogs and Aflatoxins

The large-scale simultaneous extraction and concentration of aqueous solutions of triazine analogs, and aflatoxins, through a hydrocarbon-based membrane (e.g., polyethylene, polyethylene/polypropylene copolymer) under ambient temperature and atmospheric pressure is reported. The subsequent adsorption of analyte in the extraction chamber over the lignin-modified silica gel facilitates the process by reducing the operating time. The maximum adsorption capacity values for triazine analogs and aflatoxins are mainly adsorption mechanism-dependent and were calculated to be 0.432 and 0.297 mg/10 mg, respectively. The permeation, and therefore the percentage of analyte extracted, ranges from 1% to almost 100%, and varies among the solvents examined. It is considered to be vapor pressure- and chemical polarity-dependent, and is thus highly affected by the nature and thickness of the membrane, the discrepancy in the solubility values of the analyte between the two liquid phases, and the amount of adsorbent used in the process. A dependence on the size of the analyte was observed in the adsorption capacity measurement, but not in the extraction process. The theoretical interaction simulation and FTIR data show that the planar aflatoxin molecule releases much more energy when facing toward the membrane molecule when approaching it, and the mechanism leading to the adsorption.

High enrichment and ultra-trace analysis of aflatoxins in edible oils by a modified hollow-fiber liquid-phase microextraction technique

An improved hollow-fiber liquid-phase microextraction approach with excellent purification and enrichment capabilities enabled the method have good potential for future ultra-trace analysis of AFTs.

Simultaneous determination of aflatoxins B1, B2, G1, G2, and M1 in dairy products by high-performance liquid chromatography/fluorescence

A fast and reliable method was established for the simultaneous detection of aflatoxins in dairy products by HPLC–FLD coupled with the optimized chromatographic conditions.

Quantitative Scrutinization of Aflatoxins in Different Spices from Pakistan

The current research work aimed to access the contamination level of aflatoxins B1, B2, G1, and G2 in the household spices that are widely consumed in huge amounts. 200 different spice samples, 100 packed and 100 unpacked, were analyzed for the aflatoxins profile by HPLC with an incidence of 61.5% contamination out of which 53.66% samples exceed the EU limit. The results disclosed that the unpacked samples are more contaminated as compared to the packed samples except for white cumin seeds. Among packed and unpacked samples of spices, the maximum value of aflatoxins was detected in fennel, that is, 27.93 μg/kg and 67.04 μg/kg, respectively. The lowest concentration of aflatoxin was detected in cinnamon in packed form (0.79 μg/kg) and in the unpacked samples of white cumin seeds which is 1.75 μg/kg. Caraway seeds and coriander in its unpacked form showed positive results whereas black pepper (packed and unpacked) was found free from aflatoxins. This is the first report on the occurrence of aflatoxins in packed and unpacked samples of spices from Pakistan. To ensure safe consumption of spices, there should be constant monitoring of aflatoxin and more studies need to be executed with the intention of preventing mycotoxin accretion in this commodity.

Simultaneous determination of aflatoxin B1 and M1 in milk, fresh milk and milk powder by LC-MS/MS utilising online turbulent flow chromatography

A novel, fully automated method based on dual-column switching using online turbulent flow chromatography followed by LC-MS/MS was developed for the determination of aflatoxin B1 and M1 in milk, fresh milk and milk powder samples. After ultrasound-assisted extraction, samples were directly injected into the chromatographic system and the analytes were concentrated on the clean-up loading column. Through purge switch, analytes were transferred to the analytical column for subsequent detection by mass spectrometry. Different types of TurboFlow(TM) columns, transfer flow rates and transfer times were optimised. Method limits of detection obtained for AFB1 and AFM1 were 0.05 μg kg(-1), and limits of quantification were 0.1 μg kg(-1). Recoveries of aflatoxin B1 and M1 were in range of 81.1-102.1% for all samples. Matrix effects of aflatoxin B1 and M1 were in range of 63.1-94.3%. The developed method was successfully used for the analysis of aflatoxin B1 and M1 in real samples.

Recent mycotoxin survey data and advanced mycotoxin detection techniques reported from China: a review

Mycotoxin contamination in agro-food systems has been a serious concern over the last few decades in China, where the Ministry of Health has set maximum limits for mycotoxins in different agro-products. Overall survey data show that aflatoxin contamination in infant cereals, edible oils, raw milk, ginger and its related products are far below Chinese regulatory limits. The absence of aflatoxin M1 contamination in infant milk powders indicates a high standard of control. Aflatoxins in liquorice roots and lotus seeds have been reported for the first time. For deoxynivalenol, high levels were found in wheat grown in the Yangtze Delta region, which is more prone to rainfall, supporting Fusarium infection. The emerging mycotoxins beauvericins and enniatins have been reported in the medicinal herbs in China. Ochratoxin A in wine was below the European Union regulatory limits, but fumonisins in maize need to be monitored and future regulatory control considered. Overall from all the survey data analysed in this review, it can be concluded that 92% of the samples analysed had mycotoxin levels below the Chinese regulatory limits. In terms of detection techniques in recent years, immuno-based assays have been developed largely due to their excellent sensitivity and ease of use. Assays targeting multiple mycotoxins like aflatoxins, ochratoxin A, zearalenone and deoxynivalenol have been reported using microarrays and suspension arrays targeting in particular maize, rice and peanuts. Aptamer-based assays against ochratoxin A and aflatoxins B1 and B2 have been developed involving fluorescence detection; and surface plasmon resonance immunosensors have been developed targeting wine, maize, wheat, wild rye, hay and peanut oil with high sensitivity (> 0.025 ng l(-1)). Commercialisation of these technologies is much needed for wider usage in the coming years.

Safety issues and new rapid detection methods in traditional Chinese medicinal materials

The safety of traditional Chinese medicine (TCM) is a major strategic issue that involves human health. With the continuous improvement in disease prevention and treatment, the export of TCM and its related products has increased dramatically in China. However, the frequent safety issues of Chinese medicine have become the 'bottleneck' impeding the modernization of TCM. It was proved that mycotoxins seriously affect TCM safety; the pesticide residues of TCM are a key problem in TCM international trade; adulterants have also been detected, which is related to market circulation. These three factors have greatly affected TCM safety. In this study, fast, highly effective, economically-feasible and accurate detection methods concerning TCM safety issues were reviewed, especially on the authenticity, mycotoxins and pesticide residues of medicinal materials.

Developments in mycotoxin analysis: an update for 2012-2013

This review highlights developments in mycotoxin analysis and sampling over a period between mid-2012 and mid-2013. It covers the major mycotoxins: aflatoxins, Alternaria toxins, ergot alkaloids, fumonisins, ochratoxins, patulin, trichothecenes and zearalenone. A wide range of analytical methods for mycotoxin determination in food and feed were developed last year, in particular immunochemical methods and liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS)-based methods. After a section on sampling and sample preparation, due to the rapid spread and developments in the field of LC-MS/MS multimycotoxin methods, a separate section has been devoted to this area of research. It is followed by a section on mycotoxins in botanicals and spices, before continuing with the format of previous reviews in this series with dedicated sections on method developments for the individual mycotoxins.