Determination of four Alternaria alternata mycotoxins by QuEChERS approach coupled with liquid chromatography-tandem mass spectrometry in tomato-based and fruit-based products

High-throughput extraction and automatic purification of alternariol from edible and medicinal herbs based on aptamer-functionalized magnetic nanoparticles

Mycotoxin contamination is widespread in plants and herbs, posing serious threats to the consumer and human health. Of them, alternariol (AOH) has attracted great attention as an "emerging" mycotoxin in medicinal herbs. However, a specific and high-throughput extraction method for AOH is currently lacking. Thus, developing an efficient pre-treatment technique for AOH detection is extremely vital. Here, a novel automated magnetic solid-phase extraction method was proposed for the highly efficient extraction of AOH. Combining the aptamer-functionalized magnetic nanoparticles (AMNPs) and the automatic purification instrument, AOH could be extracted in medicinal herbs in high throughput (20 samples) and a short time (30 min). The main parameters affecting extraction were optimized, and the method was finally carried out by incubation AMNPs with 3 mL of sample solution for 10 min, and then desorption in 75% methanol for liquid-phase detection. Under optimal conditions, good reproducibility, stability, and selectivity were realized with an adsorption capacity of 550.84 ng/mg. AOH extraction in three edible herbs showed good resistance to matrix interference with recovery rates from 86% to 111%. In combination with AMNPs and the automatic purification instrument, high-throughput and labor-free extraction of AOH in different complex matrices was achieved, which could be extended in other complex matrices.

Profiling of Volatile Compounds in 'Muscat Hamburg' Contaminated with Aspergillus carbonarius before OTA Biosynthesis Based on HS-SPME-GC-MS and DLLME-GC-MS

Aspergillus carbonarius is known to produce the carcinogenic ochratoxin A (OTA) in grapes. The metabolism process before OTA biosynthesis influences the content and composition of the volatile compounds in grapes. In this study, a self-established method based on QuEChERS coupled with high-performance liquid chromatography-fluorescence detection (HPLC-FLD) was used to determine the OTA levels during a seven-day contamination period. The results showed that OTA was detected on the second day after contamination with A. carbonarius. Thus, the first day was considered as the critical sampling timepoint for analyzing the volatiles in grapes before OTA biosynthesis. Additionally, the volatile compounds in grapes were analyzed using headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) and dispersive liquid-liquid microextraction gas chromatography-mass spectrometry (DLLME-GC-MS). The corresponding data were evaluated via multivariate data analysis using projection methods, including PCA and OPLS-DA. The results indicated significant differences in the nine volatile compounds in grapes contaminated with A. carbonarius before OTA biosynthesis. The results of the Pearson correlation analysis showed positive correlations between ethyl acetate, styrene, 1-hexanol and OTA; (E)-2-hexenal and nerolic acid were negatively correlated with OTA. Overall, these findings provide a theoretical basis for the early prediction of OTA formation in grape and grape products using GC-MS technology.

The fate of mycotoxins in oranges during storage and processing

To evaluate the safety of orange consumption induced by mycotoxins, 'Newhall' navel oranges were artificially inoculated with P. expansum and A. tenuissima, followed by an evaluation of the distribution and migration patterns of corresponding mycotoxins (patulin [PAT], tentoxin [Ten], altenuene [ALT], alternariol monomethyl ether [AME], alternariol [AOH] and tenuazonic acid [TeA]) during orange storage and processing. The concentration of mycotoxins decreased as the increase of distance from the lesion, and mycotoxins could be detected throughout the orange when the lesion extended to 8 mm in diameter. AOH and AME pose the primary source of dietary risk with high concentrations and low thresholds of toxicological concern. Orange juice and pectin processing could remove 43.4-98.7% of mycotoxins, while tangerine peelprocessing might lead to significant enrichment of mycotoxins with the processing factors (PFs) of 2.8-3.5. The findings may offer scientific insights into mitigating the dietary risk of mycotoxin exposure from oranges and their derivatives.

Scope of Onsite, Portable Prevention Diagnostic Strategies for Alternaria Infections in Medicinal Plants

Medicinal plants are constantly challenged by different biotic inconveniences, which not only cause yield and economic losses but also affect the quality of products derived from them. Among them, Alternaria pathogens are one of the harmful fungal pathogens in medicinal plants across the globe. Therefore, a fast and accurate detection method in the early stage is needed to avoid significant economic losses. Although traditional methods are available to detect Alternaria, they are more time-consuming and costly and need good expertise. Nevertheless, numerous biochemical- and molecular-based techniques are available for the detection of plant diseases, but their efficacy is constrained by differences in their accuracy, specificity, sensitivity, dependability, and speed in addition to being unsuitable for direct on-field studies. Considering the effect of Alternaria on medicinal plants, the development of novel and early detection measures is required to detect causal Alternaria species accurately, sensitively, and rapidly that can be further applied in fields to speed up the advancement process in detection strategies. In this regard, nanotechnology can be employed to develop portable biosensors suitable for early and correct pathogenic disease detection on the field. It also provides an efficient future scope to convert innovative nanoparticle-derived fabricated biomolecules and biosensor approaches in the diagnostics of disease-causing pathogens in important medicinal plants. In this review, we summarize the traditional methods, including immunological and molecular methods, utilized in plant-disease diagnostics. We also brief advanced automobile and efficient sensing technologies for diagnostics. Here we are proposing an idea with a focus on the development of electrochemical and/or colorimetric properties-based nano-biosensors that could be useful in the early detection of Alternaria and other plant pathogens in important medicinal plants. In addition, we discuss challenges faced during the fabrication of biosensors and new capabilities of the technology that provide information regarding disease management strategies.

Evaluation of the efficacy of ozonated olive oil for controlling the growth of Alternaria alternata and its toxins

Toxigenic fungi infect fruits and vegetables either during harvest or storage and create mycotoxins as secondary metabolites, which pose a serious threat to human and animal health throughout the food chain. Therefore, the objective of this study was to determine the inhibitory effect of OZO against the growth and spore germination of the Alternaria alternata fungal strain. Additionally, evaluation of the synthesis inhibition of Alternaria toxins (ATs), among which are alternariol (AOH), alternariol-9-methyl ether (AME), and tenuazonic acid (TeA) in the potato dextrose broth (PDB) medium and orange fruit after harvest. The results indicated that the inhibition zone was 29.0 ± 1.2 mm at 20 mg/L of OZO. The MIC and MFC values were recorded at 0.186 and 1.57 mg/mL, respectively. In this regard, OZO prevented conidia germination at 98.8% with the treatment of 5 mg/mL. OZO at 20 mg/mL was efficacious in producing a high loss in ATs production in the PDB medium, reaching 73.4, 76, and 67.1% for AOH, AME, and TeA, respectively. In addition, OZO prevents the biosynthesis of AOH and AME during the storage of orange fruits compared with the positive control sample. In contrast, 20 mg/mL reduced TeA accumulation and the appearance of Alternaria brown spot (ABS) in orange. To the best of our knowledge, this is the first report that studies OZO to control ATs in vitro in orange fruits.

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

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

Development of Acid Hydrolysis-Based UPLC–MS/MS Method for Determination of Alternaria Toxins and Its Application in the Occurrence Assessment in Solanaceous Vegetables and Their Products

In this work, we proposed an acid hydrolysis-based analytical method for the detection of Alternaria toxins (ATs) in solanaceous vegetables and their products with solid-phase extraction (SPE) and ultrahigh-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS). This study was the first to reveal that some compounds in the eggplant matrix bind to altenusin (ALS). Validation under optimal sample preparation conditions showed that the method met the EU criteria, exhibiting good linearity (R2 > 0.99), matrix effects (−66.6–−20.5%), satisfying recovery (72.0–107.4%), acceptable precision (1.5–15.5%), and satisfactory sensitivity (0.05–2 µg/kg for limit of detection, 2–5 µg/kg for limit of quantification). Out of 393 marketed samples, only 47 samples were detected, ranging from 0.54–806 μg/kg. Though the occurrence ratio (2.72%) in solanaceous vegetables could be negligible, the pollution status in solanaceous vegetable products was much more serious, and the incidences were 41.1%. In the 47 contaminated samples, the incidences were 4.26% for alternariol monomethyl ether (AME), 6.38% for alternariol (AOH) and altenuene (ALT), 42.6% for tentoxin (TEN), and 55.3% for tenuazonic acid (TeA).

Simultaneous Rapid Determination of Seven Alternaria Toxins in Tuberous Crops during Storage Using QuEChERS Coupled with Ultrahigh-Performance Liquid Chromatography-Tandem Mass Spectrometry

Robust and sensitive ultrahigh-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) combined with the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method was applied for the detection of seven Alternaria toxins (ATs) in tuberous crops. The influence of tuber conditions (fresh, germinated, and moldy) during storage on the concentration of the seven ATs is also investigated. ATs were extracted with acetonitrile under acidic conditions and purified with a C₁₈ adsorbent. ATs were scanned with electrospray ionization (positive/negative ion) dynamic switching and detected in MRM mode. Calibration curve analysis results reveal good linear relationships in all toxin concentration ranges (R² > 0.99). The limit of detection and limit of quantification were 0.25-0.70 and 0.83-2.31 μg/kg, respectively. The average recoveries of the seven ATs were 83.2-104% with intra-/inter-day precision at 3.52-6.55% and 4.02-7.26%, respectively. The developed method provided adequate selectivity, sensitivity, and precision in detecting the seven ATs at trace levels, and dispensed with standard addition or matrix-matched calibration to compensate for matrix effects. ATs in the fresh, germinated, and moldy samples of tuberous crops in storage (taro, potato, sweet potato, yam, cassava) were analyzed with this method, and the concentrations were 2.01-14.51 μg/kg and significantly increased with storage duration. ALS was detected in most samples, whereas no quantities of ALT and ATX-I were detected. AME was often detected in combination with AOH in sweet potatoes. TeA and Ten were mostly detected in taro, potato, and yam. The established method could be used for the simultaneous detection and quantification of multicomponent toxins in elaborate matrices.

Mycotoxin Monitoring, Regulation and Analysis in India: A Success Story

Mycotoxins are deleterious fungal secondary metabolites that contaminate food and feed, thereby creating concerns regarding food safety. Common fungal genera can easily proliferate in Indian tropical and sub-tropical conditions, and scientific attention is warranted to curb their growth. To address this, two nodal governmental agencies, namely the Agricultural and Processed Food Products Export Development Authority (APEDA) and the Food Safety and Standards Authority of India (FSSAI), have developed and implemented analytical methods and quality control procedures to monitor mycotoxin levels in a range of food matrices and assess risks to human health over the last two decades. However, comprehensive information on such advancements in mycotoxin testing and issues in implementing these regulations has been inadequately covered in the recent literature. The aim of this review is thus to uphold a systematic picture of the role played by the FSSAI and APEDA for mycotoxin control at the domestic level and for the promotion of international trade, along with certain challenges in dealing with mycotoxin monitoring. Additionally, it unfolds various regulatory concerns regarding mycotoxin mitigation in India. Overall, it provides valuable insights for the Indian farming community, food supply chain stakeholders and researchers about India's success story in arresting mycotoxins throughout the food supply chain.

Fe3O4@COF(TAPT-DHTA) Nanocomposites as Magnetic Solid-Phase Extraction Adsorbents for Simultaneous Determination of 9 Mycotoxins in Fruits by UHPLC-MS/MS

In this study, a simple and efficient magnetic solid-phase extraction (MSPE) strategy was developed to simultaneously purify and enrich nine mycotoxins in fruits, with the magnetic covalent organic framework nanomaterial Fe₃O₄@COF(TAPT-DHTA) as an adsorbent. The Fe₃O₄@COF(TAPT-DHTA) was prepared by a simple template precipitation polymerization method, using Fe₃O₄ as magnetic core, and 1,3,5-tris-(4-aminophenyl) triazine (TAPT) and 2,5-dihydroxy terephthalaldehyde (DHTA) as two building units. Fe₃O₄@COF(TAPT-DHTA) could effectively capture the targeted mycotoxins by virtue of its abundant hydroxyl groups and aromatic rings. Several key parameters affecting the performance of the MSPE method were studied, including the adsorption solution, adsorption time, elution solvent, volume and time, and the amount of Fe₃O₄@COF(TAPT-DHTA) nanomaterial. Under optimized MSPE conditions, followed by analysis with UHPLC-MS/MS, a wide linear range (0.05-200 μg kg^-1), low limits of detection (0.01-0.5 μg kg^-1) and satisfactory recovery (74.25-111.75%) were achieved for the nine targeted mycotoxins. The established method was further successfully validated in different kinds of fruit samples.

Simultaneous determination of twelve mycotoxins in edible oil, soy sauce and bean sauce by PRiME HLB solid phase extraction combined with HPLC-Orbitrap HRMS

A solid phase extraction-high-performance liquid chromatography-tandem Orbitrap high resolution mass spectrometry (HPLC-Orbitrap HRMS) method was established for the determination of 12 mycotoxins (ochratoxin A, ochratoxin B, aflatoxin B1, aflatoxin B2, aflatoxin G1, aflatoxin G2, HT-2 toxin, sterigmatocystin, diacetoxysciroenol, penicillic acid, mycophenolic acid, and citreoviridin) in edible oil, soy sauce, and bean sauce. Samples were extracted by 80:20 (v:v) acetonitrile-water solution, purified by PRiME HLB column, separated by aQ C18 column with mobile phase consisting of 0.5 mmol/L ammonium acetate-0.1% formic acid aqueous solution and methanol. The results showed that the limits of detection (LODs) and limits of quantification (LOQs) of 12 mycotoxins were 0.12–1.2 μg/L and 0.40–4.0 μg/L, respectively. The determination coefficients of 12 mycotoxins in the range of 0.20–100 μg/L were > 0.998. The average recoveries in soy sauce and bean sauce were 78.4–106.8%, and the relative standard deviations (RSDs) were 1.2–9.7% under three levels, including LOQ, 2× LOQ and 10 × LOQ. The average recoveries in edible oil were 78.3–115.6%, and the precision RSD (n = 6) was 0.9–8.6%. A total of 24 edible oils, soy sauce and bean sauce samples were analyzed by this method. AFB1, AFB2, sterigmatocystin and mycophenolic acid were detected in several samples at concentrations ranging from 1.0 to 22.1 μg/kg. The method is simple, sensitive, and rapid and can be used for screening and quantitative analysis of mycotoxin contamination in edible oil, soy sauce, and bean sauce.

Detection of seven Alternaria toxins in edible and medicinal herbs using ultra-high performance liquid chromatography-tandem mass spectrometry

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A modified QuEChERS-UPLC-MS/MS method was established to investigate alternaria mycotoxins.

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The method was applied to 260 edible and medicinal herb samples.

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28.46% of samples were contaminated by at least one toxin.

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AME with a high occurrence in analyzed herbs.

Alternaria mycotoxins are ubiquitous mycotoxins that contaminate food and animal feed. Here, an UPLC-MS/MS was developed and used for the detection of seven Alternaria mycotoxins in 19 different edible and medicinal herbs. Extensive optimization resulted in a simple and convenient sample preparation procedure with satisfactory extraction and a lower matrix effect. LOQs ranged from 0.01 to 2.0 ng/mL. Recoveries varied between 71.44% and 112.65%, with RSD less than 12%. The method was successfully applied for use in the mycotoxin analysis of 260 samples. A high percentage (28.46%) of samples were contaminated by 1–5 mycotoxins. Alternariol mono methylether was the predominant mycotoxin with high percentage of positive samples (37.5%), followed by alternariol (22.5%), alternariol (17.5%), tentoxin (10.83%), altertoxin Ⅰ (7.5%), and altenusin (4.17%). Collectively, the natural incidence data obtained from this study will help with better, validated risk assessments and efforts towards more comprehensive, future regulation.

Determination of Alternaria Toxins in Food by SPE and LC-IDMS: Development and In-House Validation of a Candidate Method for Standardisation

Alternaria toxins (ATs) are frequently found contaminants in foodstuffs (e.g., alternariol), often reaching high concentrations (e.g., tenuazonic acid). They can spoil a wide variety of food categories (e.g., cereals, vegetables, seeds and drinks) and storage at fridge temperatures does not prevent the growth of Alternaria fungi. Therefore, reliable and validated analytical methods are needed to protect human health and to ensure a transparent and fair trade. This paper describes new technical features that improved a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the analysis of ATs in tomato, wheat and sunflower seeds. This analytical method should be simple to implement in different laboratories across the EU and thus be an attractive candidate for standardisation. The major element for improvement was the use of isotopically labelled internal standards, only recently commercially available, thereby reducing the sample handling and improving the accuracy of the results. In addition, the sample extraction and the solid-phase extraction (SPE) enrichment/clean-up were fine-tuned, whereas a more suitable analytical column (XSelect HSS T3) with improved selectivity was also employed. Overall, this method shows adequate precision (repeatability < 5.7% RSD; intermediate precision < 7.0% RSD) and trueness (recoveries ranging from 74% to 112%). The limits of quantification in wheat (the most analytically demanding matrix) vary between 0.19 and 1.40 µg/kg. These figures were deemed satisfactory by the European Committee for Standardization (CEN) and have formed the basis for a subsequent interlaboratory validation study. The corresponding standard was published by CEN in 2021.

Monitoring Alternaria toxins in Italian food to support upcoming regulation

The collection of occurrence data on Alternaria toxins in food and feed across the European countries is required since 2012 by the European Commission, endorsing the relevant scientific opinion by the EFSA CONTAM Panel. Within this framework, occurrence data for Alternaria toxins (Alternariol, Alternariol monomethyl ether, Tenuazonic acid, Tentoxin, and Altenuene) in 97 samples of cereal foods, tomato products, and sunflower seeds have been provided as requested by the Italian national monitoring programme (years 2017-2020). To this purpose, an LC-MS/MS method was set up and validated, obtaining fit for purpose sensitivity, recoveries (70-120%), repeatability (≤20%) and within laboratory reproducibility (≤26%). Occurrence data showed that oilseeds were the most contaminated food group with levels of Tenuazonic acid up to 16752 µg/kg and Tentoxin up to 570 µg/kg, whereas for the other mycotoxin/commodities combinations, the percentage of left censored data (below the limit of quantification) ranged from 74 to 100%.

Review of occurrence of mycotoxins in Serbian food items in the period from 2005 to 2022

This paper aimed to review the publications on mycotoxins' presence in cereals and foodstuffs originated from the Serbian market covering the period from 2005 to 2022. The review covers all the important steps in mycotoxins analysis including sampling, sample preparation, instrumental analysis, and concentration ranges in which the mycotoxins were found. Also, the results were interpreted from the European Union regulation point of view. The review emphasizes the importance of multi-mycotoxins analysis for determining the simultaneous presence of mycotoxins that can negatively affect the Serbian human population. The most frequently used instrumental technique in the mycotoxin analysis of Serbian products was the Enzyme-Linked Immunosorbent Assay followed by the Ultra-High Performance Liquid Chromatography coupled with triple quadrupole mass spectrometry. Most of the studies undertaken in Serbia until now investigated a few groups of matrices such as wheat, maize, milk, and dairy products. Only a few studies involved specific matrices such as nuts, dried fruits, biscuits, cookies, and spices. The review showed that contamination of milk and dairy products with aflatoxin M1 (AFM1), occurred at the very beginning of 2013, was the major health issue related to the population health. The contamination of milk and dairy products with the AFM1 was a consequence of maize contamination with aflatoxins which occurred in the year 2012, characterized by drought conditions. The studies dealing with the analysis of masked and emerging mycotoxins are rare and more attention should be paid to monitoring the presence of these types of mycotoxins in foodstuffs from Serbia.

Review of occurrence of mycotoxins in Serbian food items in the period from 2005 to 2022

This paper aimed to review the publications on mycotoxins' presence in cereals and foodstuffs originated from the Serbian market covering the period from 2005 to 2022. The review covers all the important steps in mycotoxins analysis including sampling, sample preparation, instrumental analysis, and concentration ranges in which the mycotoxins were found. Also, the results were interpreted from the European Union regulation point of view. The review emphasizes the importance of multi-mycotoxins analysis for determining the simultaneous presence of mycotoxins that can negatively affect the Serbian human population. The most frequently used instrumental technique in the mycotoxin analysis of Serbian products was the Enzyme-Linked Immunosorbent Assay followed by the Ultra-High Performance Liquid Chromatography coupled with triple quadrupole mass spectrometry. Most of the studies undertaken in Serbia until now investigated a few groups of matrices such as wheat, maize, milk, and dairy products. Only a few studies involved specific matrices such as nuts, dried fruits, biscuits, cookies, and spices. The review showed that contamination of milk and dairy products with aflatoxin M1 (AFM1), occurred at the very beginning of 2013, was the major health issue related to the population health. The contamination of milk and dairy products with the AFM1 was a consequence of maize contamination with aflatoxins which occurred in the year 2012, characterized by drought conditions. The studies dealing with the analysis of masked and emerging mycotoxins are rare and more attention should be paid to monitoring the presence of these types of mycotoxins in foodstuffs from Serbia.

Quechers approach to the Alternaria mycotoxins detection in wheat: The recovery study

The performance of the QuEChERS extraction followed by the LC-MS/ MS analytical method was evaluated in terms of Alternaria mycotoxins recovery from the wheat. The alternariol (AOH), tentoxin (TEN) and alternariol monomethyl ether (AME) were analyzed using the ESI+ (electrospray positive ionization) by multiple reactions mon?itoring mode (MRM). In order to determine the recovery, the blank wheat samples were spiked at two spiking levels (0.01 and 0.1 mg/kg) in six replicates. The obtained average recoveries and precisions (expressed as the RSDr, %) were as follows: 107.6% (RSDr of 6.84%) for alternariol, 108.0% (RSDr of 6.78%) for tentoxin and 110.1% (RSDr of 6.50%) for alternariol monomethyl ether. The results of this study were in accordance with the Commission Decision 2002/657/EC and Commission Regulation (EC) No 401/2006.

Simultaneous Detection of Seven Alternaria Toxins in Mixed Fruit Puree by Ultra-High-Performance Liquid Chromatography-Tandem Mass Spectrometry Coupled with a Modified QuEChERS

The presence of Alternaria toxins (ATs) in fruit purees may cause potential harm to the life and health of consumers. As time passes, ATs have become the key detection objects in this kind of food. Based on this, a novel and rapid method was established in this paper for the simultaneous detection of seven ATS (tenuazonic acid, alternariol, alternariol monomethyl ether, altenuene, tentoxin, altenusin, and altertoxin I) in mixed fruit purees using ultra-high performance liquid chromatography-tandem mass spectrometry. The sample was prepared using the modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) method to complete the extraction and clean-up steps in one procedure. In this QuEChERS method, sample was extracted with water and acetonitrile (1.5% formic acid), then salted out with NaCl, separated on an ACQUITY UPLC BEH C₁₈ with gradient elution by using acetonitrile and 0.1% formic acid aqueous as eluent, and detected by UPLC-MS/MS under positive (ESI⁺) and negative (ESI⁻) electrospray ionization and MRM models. Results showed that the seven ATs exhibited a good linearity in the concentration range of 0.5–200 ng/mL with R² > 0.9925, and the limits of detection (LODs) of the instrument were in the range of 0.18–0.53 μg/kg. The average recoveries ranged from 79.5% to 106.7%, with the relative standard deviations (RSDs) no more than 9.78% at spiked levels of 5, 10, and 20 μg/kg for seven ATs. The established method was applied to the determination and analysis of the seven ATs in 80 mixed fruit puree samples. The results showed that ATs were detected in 31 of the 80 samples, and the content of ATs ranged from 1.32 μg/kg to 54.89 μg/kg. Moreover, the content of TeA was the highest in the detected samples (23.32–54.89 μg/kg), while the detection rate of Ten (24/31 samples) was higher than the other ATs. Furthermore, the other five ATs had similar and lower levels of contamination. The method established in this paper is accurate, rapid, simple, sensitive, repeatable, and stable, and can be used for the practical determination of seven ATs in fruit puree or other similar samples. Moreover, this method could provide theory foundation for the establishment of limit standard of ATs and provide a reference for the development of similar detection standard methods in the future.

Production of Alternaria Toxins in Yellow Peach (Amygdalus persica) upon Artificial Inoculation with Alternaria alternate

The yellow peach (Amygdalus persica), an important fruit in China, is highly susceptible to infection by Alternaria sp., leading to potential health risks and economic losses. In the current study, firstly, yellow peaches were artificially inoculated with Alternariaalternate. Then, the fruits were stored at 4 °C and 28 °C to simulate the current storage conditions that consumers use, and the Alternaria toxins (ATs) contents from different parts of the fruits were analyzed via ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The results showed that the growth of A. alternate and the ATs production were dramatically affected by the storage temperature. At 28 °C, the fungi grew rapidly and the lesion diameter reached about 4.0 cm within 15 days of inoculation, while, at 4 °C, the fungal growth was noticeably inhibited, with no significant change in the lesion diameter. To our surprise, high contents of ATs were produced under both storage conditions even though the fungal growth was suppressed. With an increase in the incubation time, the amounts of ATs showed a steady tendency to increase in most cases. Remarkably, alternariol monomethyl ether (AME), alternariol (AOH), and tenuazonic acid (TeA) were detected in the rotten tissue and also in the surrounding tissue, while a large amount of TeA could also be found in the healthy tissue. To the best of our knowledge, this is the first report regarding the production of ATs by the infection of Alternaria sp. in yellow peach fruits via artificial inoculation under regulated conditions, and, based on the evidence herein, it is recommended that ATs be included in monitoring and control programs of yellow peach management and food safety administration.

Alternaria Mycotoxins: An Overview of Toxicity, Metabolism, and Analysis in Food

The genus Alternaria is widely distributed in the environment. Numerous species of the genus Alternaria can produce a variety of toxic secondary metabolites, called Alternaria mycotoxins. In this review, natural occurrence, toxicity, metabolism, and analytical methods are introduced. The contamination of these toxins in foodstuffs is ubiquitous, and most of these metabolites present genotoxic and cytotoxic effects. Moreover, Alternaria toxins are mainly hydroxylated to catechol metabolites and combined with sulfate and glucuronic acid in in vitro arrays. A more detailed summary of the metabolism of Alternaria toxins is presented in this work. To effectively detect and determine the mycotoxins in food, analytical methods with high sensitivity and good accuracy are also reviewed. This review will guide the formulation of maximum residue limit standards in the future, covering both toxicity and metabolic mechanism of Alternaria toxins.

Data-dependent acquisition based high-resolution mass spectrum for trace Alternaria mycotoxin analysis and sulfated metabolites identification

Alternaria mycotoxins are food-related compounds that are mainly produced by Alternaria fungi species. However, it's difficult for Alternaria mycotoxins analysis, especially for conjugated metabolites in food safety surveillance. In this work, a novel data-dependent acquisition (DDA) full mass scan and products scan protocol was proposed for qualitative and quantitative analysis of five target mycotoxins in tomato samples using ultra-high-performance liquid chromatography coupled with quadrupole Orbitrap high-resolution mass spectrometry (UHPLC-Q-Orbitrap). In total, 24 sulfated metabolites were detected with post-data analysis techniques, and two sulfated metabolites (AME-sulfated and AOH-sulfated) were identified in Alternaria fungi -inoculated tomatoes. In addition, a custom database was established, and it was successfully applied for Alternaria mycotoxins and sulfated metabolites screening in tomatoes. With the improvement in high-resolution mass spectrometry (HRMS) as well as post-data analysis techniques, DDA based HRMS method could be widely applied for compound analysis, identification, and screening in quantitative field.

Alternaria toxins in tomato products in Northern Italy in the period 2017-2019

The occurrence of tenuazonic acid (TeA), alternariol, alternariol monomethyl and tentoxin in tomato-based products was surveyed over the years 2017-2019. A total of 120 samples were collected from retail outlets and tomato-based food producers located in Northern Italy. After extraction and purification through prepacked columns, the mycotoxins were analysed using LC-MS/MS. A widespread contamination of TeA was found in tomato-based products, particularly in concentrated tomato paste. Other Alternaria toxins were not detected. The incidence of TeA was 78.5%, 47.4%, 55.5%, and 76.9% in concentrated tomato paste (maximum value 5955 µg kg^-1), tomato sauce, tomato pulp, and ketchup, respectively. The mean level was 243 ± 725 µg kg^-1 in concentrated tomato paste and below 30 µg kg^-1 in the other tomato products. The contamination varied from year to year. Alternaria spp strains isolated from fresh tomatoes produced mainly TeA. This study provides further Alternaria toxins occurrence data, useful for future risk assessments.

Development of a chemiluminescence immunoassay for detection of tenuazonic acid mycotoxin in fruit juices with a specific camel polyclonal antibody

The natural mycotoxin tenuazonic acid (TeA) in foods is identified as the most toxic mycotoxin among the over 70 kinds of secondary toxic metabolites produced by Alternaria alternata. Some hapten-antibody-mediated immunoassays have been developed for TeA detection in food samples, but these methods show unsatisfactory sensitivity and specificity. In this study, a rationally designed hapten for TeA mycotoxin generated with computer-assisted modeling was prepared to produce a highly specific camel polyclonal antibody, and an indirect competitive chemiluminescence enzyme immunoassay (icCLEIA) was established with a limit of detection of 0.2 ng mL-1 under optimized conditions. The cross-reactivity results showed that several analogs and some common mycotoxins had negligible recognition by the anti-TeA polyclonal antibody. The average recoveries spiked in fruit juices were determined to be 92.7% with an acceptable coefficient of variation, and good correlations between icCLEIA and liquid chromatography tandem mass spectrometry (LC-MS/MS) results were obtained in spiked samples. This developed icCLEIA for TeA detection with significantly improved sensitivity and satisfactory specificity is a promising alternative for environmental monitoring and food safety.

Recent Advances in Mycotoxin Analysis and Detection of Mycotoxigenic Fungi in Grapes and Derived Products

Mycotoxins are secondary metabolites of filamentous fungi that can cause toxic effects in human and animal health. Most of the filamentous fungi that produce these mycotoxins belong to four genera, namely, Aspergillus, Penicillium, Fusarium, and Alternaria. Mycotoxigenic fungi, along with mycotoxins, create a constant and serious economic threat for agriculture in many terms, counting product losses due to crop contamination and food spoilage, as well malnutrition when considering nutritional quality degradation. Given the importance of robust and precise diagnostics of mycotoxins and the related producing fungi in the grape food chain, one of the most important agricultural sectors worldwide, the present review initially delivers a comprehensive presentation of mycotoxin reports on grape and derived products, including a wide range of commodities such as fresh grapes, raisins, wine, juices, and other processed products. Next, based on worldwide regulations’ requirements for mycotoxins, and referring to the relative literature, this work presents methodological approaches for mycotoxin determination, and stresses major methods for the detection of fungal species responsible for mycotoxin production. The principle of function and basic technical background on the available analytical and molecular biology techniques developed—including chromatography, mass spectrometry, immunochemical-based assays, biosensors, and molecular assays—is briefly given, and references for their application to grape and derived product testing are highlighted.

A Dilute and Shoot Strategy for Determining Alternaria Toxins in Tomato-Based Samples and in Different Flours Using LC-IDMS Separation

Alternaria toxins are emerging mycotoxins whose regulation and standardization are in progress by the European Commission and the European Committee for Standardization. This paper describes a dilute and shoot approach to determine five Alternaria toxins in selected food samples using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The strategy involves sample extraction with acidified aqueous methanol, followed by a solvent change accomplished via sample evaporation and reconstitution. The quantification is based on isotope dilution, applying all corresponding isotopically labeled internal standards to compensate possible matrix effects of the analysis. The main advantages of the present method over other existing methods includes simple and effective sample preparation, as well as detection with high sensitivity. The five-fold sample dilution can decrease matrix effects, which were evaluated with both external and internal standard methods. The results demonstrated a limit of quantification lower than 1.0 µg/kg for all five analytes for the first time. The newly presented method showed acceptable accuracy (52.7-111%) when analyzing naturally contaminated and spiked standard samples at the described levels. The method was validated for tomato-based and flour samples (wheat, rye, and maize). The absolute recovery ranged from 66.7% to 91.6% (RSD < 10%). The developed method could be an alternative approach for those laboratories that exclude sample cleanup and pre-concentration of state-of-the-art instruments with enhanced sensitivity.

Microfiltration results in the loss of analytes and affects the in vitro genotoxicity of a complex mixture of Alternaria toxins

Alternaria molds produce a variety of chemically diverse secondary metabolites with potentially adverse effects on human health. However, data on occurrence in food and human exposure is inconsistent for some of these mycotoxins. Membrane filtration is a frequent step in many sample preparation procedures for LC-MS-based methods analyzing food contaminants. Yet, little is known about the possibility of adsorptive phenomena that might result in analyte losses. Thus, we treated a complex extract of Alternaria toxins with several types of syringe filters and unraveled the impact on its chemical composition by LC-MS/MS. We observed significant, and in some cases complete, losses of compounds due to filtration. Particularly, two key Alternaria toxins, alternariol (AOH) and its monomethyl ether (AME), were heavily affected. As a comparison with published food surveys indicating a correlation of the type of filtration used with lower incidence reports in food, our results point at a possible underestimation of AME in past exposure assessment. Also, perylene quinones were greatly affected by filtration, underlining the importance to take this into consideration during analytical method development. Furthermore, we applied the comet assay in HT-29 cells to elucidate the impact of filtration on the genotoxicity of the extract. We observed strong coincidences with the loss of epoxide-carrying metabolites and also an intriguing induction of oxidative DNA damage by yet toxicologically uncharacterized Alternaria toxins. In conclusion, we highlight potential issues with sample filtration and call for a critical re-evaluation of previous food occurrence data in the light of the results at hand.

Levels of Alternaria Toxins in Selected Food Commodities Including Green Coffee

Alternaria toxins are emerging mycotoxins, candidates for regulation by European Authorities. Therefore, highly sensitive, confirmatory, and reliable analytical methodologies are required for their monitoring in food. In that context, an isotope dilution LC-MS/MS method was developed for the analysis of five Alternaria toxins (Altenuene, Alternariol, Alternariol monomethylether, Tentoxin, and Tenuazonic Acid) in a broad range of commodities including cereals and cereal-based products, tomato-based products, tree nuts, vegetable oils, dried fruits, cocoa, green coffee, spices, herbs, and tea. Validation data collected in two different laboratories demonstrated the robustness of the method. Underestimation of Tenuazonic Acid level in dry samples such as cereals was reported when inappropriate extraction solvent mixtures were used as currently done in several published methodologies. An investigation survey performed on 216 food items evidenced large variations of Alternaria toxins levels, in line with data reported in the last EFSA safety assessment. The analysis of 78 green coffee samples collected from 21 producing countries demonstrated that coffee is a negligible source of exposure to Alternaria toxins. Its wide scope of application, adequate sample throughput, and high sensitivity make this method fit for purpose for the regular monitoring of Alternaria toxins in foods.

A magnetic fluorinated multi-walled carbon nanotubes-based QuEChERS method for organophosphorus pesticide residues analysis in Lycium ruthenicum Murr

In order to meet the requirements of pesticide residues' detection in complex matrix samples, the magnetic fluorinated multi-wall carbon nanotubes (M-F-MWCNTs) were prepared and applied as new QuEChERS clean-up materials. Combined with GC-MS, an improved QuEChERS method was successfully developed for the detection of organophosphorus pesticide residues. The results showed that the M-F-MWCNTs could effectively remove the interfering substances in Lycium ruthenicum Murr. (L. ruthenicum) samples. The recoveries of 10 tested targets were 74.9% to 113.5% with the relative standard deviations (RSDs) of 3.9-14.7%. The experiment results pointed out that the M-F-MWCNTs were qualified as QuEChERS clean-up materials and expected to be applied to other complex matrix samples and pesticide targets.

Determination of Alternaria Toxins in Sunflower Oil by Liquid Chromatography Isotope Dilution Tandem Mass Spectrometry

Alternaria toxins have gained attention as a potential health risk and can be classified as emerging mycotoxins. As a result, they are candidates to be regulated by the European Commission. This paper describes a liquid chromatography tandem mass spectrometric (LC-MS/MS) method for analyzing five Alternaria toxins in sunflower oil, which is a rather different type of sample to those matrices investigated in earlier published papers. An optimal sample preparation condition was achieved when samples were dissolved in n-hexane and extracted with methanol/water mixture, followed by sample pre-concentration with solvent evaporation. This study is the first focusing only on this lipophilic matrix and in using all corresponding isotopically labeled internal standards (ISTD) to compensate the matrix effect that strongly influences the LC-MS/MS analysis of toxins. Target compounds were separated on Zorbax Extend C-18 column enabling the analysis at alkaline pH of 8.8 that was necessary to obtain appropriate peak shape of tenuazonic acid and to separate the analytes at baseline. The method was validated according to the EU 2002/657/EC Decision and all the analytical performance characteristics met the requirements. The recovery was between 74% and 122% in fortified sunflower oil samples and the precision varied from 9% to 22%. The method was successfully demonstrated for sunflower seed quality check (QC) samples. Finally, 16 different sunflower oil samples were measured; and tenuazonic acid and tentoxin toxins were detected at levels close to LOQ concentrations.

Developments in mycotoxin analysis: an update for 2018-19

This review summarises developments on the analysis of various matrices for mycotoxins that have been published in the period from mid-2018 to mid-2019. Analytical methods to determine aflatoxins, Alternaria toxins, ergot alkaloids, fumonisins, ochratoxins, patulin, trichothecenes, and zearalenone are covered in individual sections. Advances in sampling strategies are also discussed in a dedicated section. In addition, developments in multi-mycotoxin methods – including comprehensive mass spectrometric-based methods as well as simple immunoassays – are also reviewed. This critical review aims to briefly present the most important recent developments and trends in mycotoxin determination as well as to address limitations of the presented methodologies.

Development of Sensitive and Reliable UPLC-MS/MS Methods for Food Analysis of Emerging Mycotoxins in China Total Diet Study

With the climatic changes that have taken place during the last decade, the spectrum of fungal pathogens as well as mycotoxins has considerably changed. As a result, some emerging mycotoxins have been shown to occur frequently in agricultural products. In this study, a sensitive and reliable method for the determination of 10 emerging mycotoxins (beauvericin, enniatin A, enniatin A1, enniatin B, enniatin B1, alternariol, alternariol monomethyl ether, altenuene, tentoxin, and tenuazonic acid) in 12 different food matrices (cereals, legumes, potatoes, meats, eggs, aquatic foods, dairy products, vegetables, fruits, sugars, beverages, and alcohol beverages) was developed and validated. After a simple extraction, a one-step sample clean-up by a HLB solid phase extraction (SPE) column was sufficient for all 12 food matrices prior to analysis with ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS). Isotope internal standards ¹³C-TeA, TEN-d₃, and ¹³C-AFB2 were used for accurate quantification. Validation in terms of linearity, selectivity, sensitivity, accuracy, and precision (intra and inter-day variability) were evaluated for the 10 mycotoxins in all selected matrices. The sensitivity varied from 0.0004 to 0.3 ng mL^-1 (limits of detection) and from 0.002 to 0.9 ng mL^-1 (limits of quantitation). The recoveries of 10 mycotoxins in fortified samples were from 60.6% to 164% including very low spiking levels in all 12 food matrices, with relative standard deviations (RSDs) less than 12%. The proposed methodology was applied to the analysis of 60 samples collected from five provinces within the 6^th China Total Diet Study with the results discussed in detail. The advantages of sensitivity, accuracy, and robustness made it a powerful tool for emerging mycotoxin monitoring and dietary exposure assessment.

A magnetic nanoparticle based immunoassay for alternariol monomethyl ether using hydrogen peroxide-mediated fluorescence quenching of CdTe quantum dots

The authors describe a fluorometric immunoassay for alternariol monomethyl ether (AME). It is making use of magnetic nanoparticles and quenching of the fluorescence of mercaptopropionic acid-capped CdTe quantum dots (MPA-CdTe QDs) by H₂O₂. Catalase (CAT) was labeled with AME as a competitive antigen to competitively bind to magnetic nanoparticles carrying monoclonal antibodies (mAbs) with free AME in samples. The effects of the concentration and pH value of buffer, the concentrations of H₂O₂ and CAT-AME, and the incubation time of H₂O₂ and MPA-CdTe QDs were optimized. Under optimal conditions and in combination with magnetic separation, the quenching of the fluorescence of the MPA-CdTe QDs (excitation at 310 nm, emission at 599 nm) can be used to quantify AME with a detection limit of 0.25 pg·mL^-1 and the linear range from 0.25 to 7.5 pg·mL^-1. The immunoassay also has a lower cross-reactivity to AME analogues. It was evaluated by analyzing fruit samples spiked with AME. The recoveries from spiked fruits ranged from 87.2% to 92.0%. Graphical abstract Schematic presentation of a fluorometric immunoassay for alternariol monomethyl ether (AME) using magnetic nanoparticles (MNPs) for the rapid separation and purification. The method is based on quenching of the fluorescence of mercaptopropionic acid-capped CdTe quantum dots (MPA-CdTe QDs) by H₂O₂ for the fluorescence signal output, and on the use of catalase (CAT) with its high catalytic activity.

QuEChERS - Fundamentals, relevant improvements, applications and future trends

The Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method is a simple and straightforward extraction technique involving an initial partitioning followed by an extract clean-up using dispersive solid-phase extraction (d-SPE). Originally, the QuEChERS approach was developed for recovering pesticide residues from fruits and vegetables, but rapidly gained popularity in the comprehensive isolation of analytes from different matrices. According to PubMed, since its development in 2003 up to November 2018, about 1360 papers have been published reporting QuEChERS as extraction method. Several papers have reported different improvements and modifications to the original QuEChERS protocol to ensure more efficient extractions of pH-dependent analytes and to minimize the degradation of labile analytes. This analytical approach shows several advantages over traditional extraction techniques, requiring low sample and solvent volumes, as well as less time for sample preparation. Furthermore, most of the published studies show that the QuEChERS protocol provides higher recovery rate and a better analytical performance than conventional extraction procedures. This review proposes an updated overview of the most recent developments and applications of QuEChERS beyond its original application to pesticides, mycotoxins, veterinary drugs and pharmaceuticals, forensic analysis, drugs of abuse and environmental contaminants. Their pros and cons will be discussed, considering the factors influencing the extraction efficiency. Whenever possible, the performance of the QuEChERS is compared to other extraction approaches. In addition to the evolution of this technique, changes and improvements to the original method are discussed.

Quantitation of Six Alternaria Toxins in Infant Foods Applying Stable Isotope Labeled Standards

Alternaria fungi are widely distributed saprophytes and plant pathogens. As pathogens, Alternaria fungi infect crops and vegetables and cause losses in the fields and during postharvest storage. While farmers suffer from declining yields, consumers are endangered by the formation of secondary metabolites, because some of these exhibit a pronounced toxicological potential. The evaluation of the toxicological capabilities is still ongoing and will contribute to a valid risk assessment. Additionally, data on the incidence and the quantity of Alternaria mycotoxins found in food products is necessary for dietary exposure evaluations. A sensitive LC-MS/MS method for the determination of the Alternaria mycotoxins alternariol (AOH), alternariol monomethylether (AME), tentoxin (TEN), altertoxin I (ATX I), alterperylenol (ALTP), and tenuazonic acid (TA) was developed. AOH, AME, and TA were quantified using stable-isotopically labeled standards. TEN, ATX I, and ALTP were determined using matrix matched calibration. The developed method was validated by using starch and fresh tomato matrix and resulted in limits of detection ranging from 0.05 to 1.25 μg/kg for starch (as a model for cereals) and from 0.01 to 1.36 μg/kg for fresh tomatoes. Limits of quantification were determined between 0.16 and 4.13 μg/kg for starch and between 0.02 and 5.56 μg/kg for tomatoes. Recoveries varied between 83 and 108% for starch and between 95 and 111% for tomatoes. Intra-day precisions were below 4% and inter-day precisions varied from 3 to 8% in both matrices. Various cereal based infant foods, jars containing vegetables and fruits as well as tomato products for infants were analyzed for Alternaria mycotoxin contamination (n = 25). TA was the most frequently determined mycotoxin and was detected in much higher contents than the other toxins. AME and TEN were quantified in many samples, but in low concentrations, whereas AOH, ATX I, and ALTP were determined rarely, among which AOH had higher concentration. Some infant food products were highly contaminated with Alternaria mycotoxins and the consumption of these individual products might pose a risk to the health of infants. However, when the mean or median is considered, no toxicological risk was obvious.

Assessment of Detoxification Efficacy of Irradiation on Zearalenone Mycotoxin in Various Fruit Juices by Response Surface Methodology and Elucidation of Its in-vitro Toxicity

Fruits are vital portion of healthy diet owed to rich source of vitamins, minerals, and dietary fibers, which are highly favorable in keeping individual fit. Unfortunately, these days, one-third of fruits were infested with fungi and their toxic metabolites called mycotoxins, which is most annoying and pose significant health risk. Therefore, there is a need to suggest appropriate mitigation strategies to overcome the mycotoxins contamination in fruits. In the present study, detoxification efficiency of irradiation on zearalenone (ZEA) mycotoxin was investigated in distilled water and fruit juices (orange, pineapple, and tomato) applying statistical program response surface methodology (RSM). The independent factors were distinct doses of irradiation and ZEA, and response factor was a percentage of ZEA reduction in content. A central composite design (CCD) consists of 13 experiments were planned applying software program Design expert with distinct doses of irradiation (up to 10 kGy) and ZEA (1-5 μg). The results revealed that independent factors had a positive significant effect on the response factor. The analysis of variance (ANOVA) was followed to fit a proper statistical model and suggested that quadratic model was appropriate. The optimized model concluded that doses of irradiation and ZEA were the determinant factors for detoxification of ZEA in fruit juices. Further, toxicological safety of irradiation mediated detoxified ZEA was assessed in the cell line model by determining the cell viability (MTT and live/dead cell assays), intracellular reactive oxygen species (ROS), mitochondrial membrane potential (MMP), nuclear damage, and caspase-3 activity. The higher level of live cells and MMP, lower extent of intracellular ROS molecules and caspase-3, and intact nuclear material were noticed in cells treated with irradiation mediated detoxified ZEA related to non-detoxified ZEA. The results confirmed that toxicity of ZEA was decreased with irradiation treatment and detoxification of ZEA by irradiation is safe. The study concluded that irradiation could be a potential post-harvest food processing technique for detoxification of ZEA mycotoxin in fruit juices. However, irradiation of fruit juices with high dose of 10 kGy has minimally altered the quality of fruit juices.

Development and Application of a QuEChERS-Based Liquid Chromatography Tandem Mass Spectrometry Method to Quantitate Multi-Component Alternaria Toxins in Jujube

A simple, rapid and efficient methodology was developed and validated for the analysis of four Alternaria toxins in jujube: Tenuazonic acid, alternariol, alternariol monomethyl ether, and tentoxin. Under the optimized extraction procedure, chromatographic conditions, and instrumental parameters, the four toxins were effectively extracted via a quick, easy, cheap, effective, rugged, and safe (QuEChERS) method, and quantified by ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS). Matrix-matched calibrations ranging from 0.01 to 0.5 μg mL⁻¹ were conducted for the quantification due to the matrix effect. A blank jujube sample was spiked at 40, 80 and 160 μg kg⁻¹, obtaining recoveries in the range of 83.5–109.6%. Limits of detection and limits of quantification were in the range of 0.14–0.26 and 0.47–0.87 μg kg⁻¹, respectively. Finally, the developed method was applied for the quantification of the four toxins in 14 jujube samples, including black spot-infected and uninfected samples. Results showed that the predominant toxin detected in all the samples was tenuazonic acid, the content of which was associated with the infection level; alternariol, alternariol monomethyl ether, and tentoxin were detected in all the infected samples and some of the uninfected samples with rather low contents.

Development and comparison of single-step solid phase extraction and QuEChERS clean-up for the analysis of 7 mycotoxins in fruits and vegetables during storage by UHPLC-MS/MS

A robust and sensitive UHPLC-MS/MS method was developed for the analysis of seven mycotoxins in fruits and vegetables. The variations of seven mycotoxins concentrations during storage were also determined for the first time. Solid phase extraction (SPE) and QuEChERS clean-up were compared, and extraction was finally performed with acetonitrile under acidic conditions followed by HLB SPE purification. Seven mycotoxins were separated on a C18 column by gradient elution, scanned by ESI⁺ and ESI^- dynamic switching and detected with MRM mode. LOD and LOQ, matrix effect, accuracy and precision of the developed method were investigated. Results were linear in their concentration ranges for all mycotoxins with R² being greater than 0.999. LODs and LOQs were ranged from 0.05 to 3.0 μg/kg and 0.2 to 10.0 μg/kg, respectively. Average recoveries were between 81.1% and 116% with intraday- and interday-precision being in the ranges of 3.0-6.2% and 4.2-6.1%, respectively. The validated method provides sufficient selectivity, sensitivity and accuracy to screen for seven mycotoxins at trace levels, without using standard addition or matrix-matched calibration to compensate for matrix effects. The method was successfully applied for mycotoxins analysis in fruits and vegetables. None were detected in fresh samples, but AOH and AME were detected in strawberry, and TeA was detected in tomato fruits during long-term storage. Their concentrations were in the range of 3.6-165.3 μg/kg from 3 days to 60 days and significantly increased along with storage time.