Analysis of fumonisins B1 and B2 in spices and aromatic and medicinal herbs by HPLC-FLD with on-line post-column derivatization and positive confirmation by LC-MS/MS

Mycotoxins in raw materials, beverages and supplements of botanicals: A review of occurrence, risk assessment and analytical methodologies

Over recent years, consumer interest in natural products, such as botanicals has increased considerably. One of the factors affecting their quality is the presence of mycotoxins. This review focuses on exploring the mycotoxin occurrence in botanicals (raw material and ready-to-eat forms such as infusions or tablets) and the risk assessment due to their ingestion. Aflatoxins, Ochratoxin A, and Fumonisins are the most commonly studied mycotoxins and data in the literature report levels ranging from traces to 1000 μg/kg in raw materials. In general, the highest contents observed in raw materials decreased to unconcerning levels after the preparation of the infusions, reaching values that generally do not exceed 100 μg/L. Regarding botanical dietary supplements, the levels observed were lower than those reported for other matrices, although higher levels (of up to 1000 μg/kg) have been reported in some cases. Risk assessment studies in botanicals revealed a higher risk when they are consumed as tablets compared to infusions. Analytical methodologies implied in mycotoxin determination have also been contemplated. In this sense, liquid chromatography coupled to fluorescence detection has been the most frequently employed analytical technique, although in recent years tandem mass spectrometry has been widely used.

Simultaneous distribution of aflatoxins B1 and B2, and fumonisin B1 in corn fractions during dry and wet-milling

One of the limitations of the use of corn in the food chain is its contamination with mycotoxins. Reduction in their levels can be achieved by processing the grain, which in the case of corn can be achieved by wet or dry milling. The aim of this study was to compare the distribution of aflatoxins B1 and B2, and fumonisin B1 in corn fractions obtained by dry and wet milling, aiming to identify conditions to mitigate the risk of exposure to these contaminants. Naturally, contaminated corn kernels were subjected to laboratory milling. The wet-milling conditions containing 1% lactic acid in the steeping solution and 18 h of steeping were the most efficient for mycotoxin reduction in the endosperm fraction, reducing aflatoxins B1 and B2 contamination to levels below the limit of quantification. Dry-milling reduced the concentration of these mycotoxins in the endosperm (98-99%). Fumonisin B1 contamination increased in the germ and pericarp fraction by more than three times in both dry and wet milling. Dry-milling reduced fumonisin B1 contamination in the endosperm to levels below the limit of quantitation. Wet and dry milling processes can be an efficient control method to reduce aflatoxins and fumonisin in the corn endosperm fraction.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-022-05373-9.

Rapid determination of fumonisin (FB1) by syringe SPE coupled with solid-phase fluorescence spectrometry

Fumonisin B₁ is the most prevalent member of a family of toxins, known as fumonisins, which occurs mainly in maize, wheat and other cereals. Due to its hepatotoxic and nephrotoxic in all animal species, very strict regulations have been imposed on the levels of fumonisin B₁ in cereal and cereal-based foods worldwide. In this work, a rapid determination method of fumonisin B₁ by membrane solid phase extraction coupled with solid-phase fluorescence analysis is developed. A rhodamine based fluorescent probe was used for derivatization with fumonisin B₁. After derivatization and extraction by nylon membrane, the enriched fumonisin B₁ can be detected directly on the membrane without further elution process that is placed in a designed spectra collection device. The established method showed a linear relationship in concentration range of 0.5-5.0 μg/L, with the R² = 0.991, and a limit of detection of 0.119 μg/L. Method accuracy was further confirmed using LC-MS method by comparing the detection results of 3 corn powder samples spiked with FB₁, that demonstrated equivalent results. The results of this study indicated that the proposed method was simple, sensitive, reliable and suitable for trace fumonisins B₁ quantitation in corn-based feeds.

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.

Multiclass mycotoxins in lotus seeds analysed by an isotope-labelled internal standard-based UPLC-MS/MS

Objectives

This study aimed to explore the residue levels of multiclass mycotoxins in medicinal and edible lotus seeds.

Methods

A rapid and reliable isotope-labelled internal standard-based UPLC-MS/MS method was developed and validated for sensitive and accurate analysis of multiclass mycotoxins including aflatoxins (AFB1, AFB2, AFG1 and AFG2), ochratoxin A (OTA), zearalenone (ZEN), deoxynivalenol (DON), fumonisins (FB1 and FB2), T-2 and HT-2 toxins in lotus seeds. Some critical conditions such as extract solution with the addition of isotope-labelled internal standard, type of mobile phase and the elution condition were scientifically optimized. The 11 mycotoxins obtained satisfactory resolution and sensitive detection in multiple reactions monitoring scanning mode combined with the ion switching technology in positive and negative ion switching mode.

Key findings

The developed isotope-labelled internal standard-based UPLC-MS/MS method exhibited an approving linearity (r ≥ 0.9984), high sensitivity (limit of detection in the range of 0.015–30.05 μg/kg), acceptable precision (RSDs ≤6.3%) and good recovery (76.0–116.0%) for 11 analytes, respectively. Ten batches of real lotus seed samples were tested, and three batches out of which were contaminated with AFB1, FB2, T-2 and ZEN. AFB1 showed the highest occurrence rate (30%) with contents of 10.50 and 8.32 μg/kg in two samples over the official limit (5.0 μg/kg).

Conclusions

The monitoring of multiclass mycotoxins in Chinese herbal medicines is in great urgency to ensure the security of consumers. The proposed method could be further utilized for simple, sensitive and rapid detection of more mycotoxins in other complex matrices to compensate for matrix effects.

An ultrasensitive chemiluminescence immunoassay for fumonisin B1 detection in cereals based on gold-coated magnetic nanoparticles

BACKGROUND

In the present study, a novel highly sensitive magnetic enzyme chemiluminescence immunoassay (MECLIA) was developed to detect fumonisin B₁ (FB₁ ) in cereal samples. The gold-coated magnetic nanoparticles (Fe₃ O₄ @Au, GoldMag) were used as solid phase carrier to develop a competitive CLIA for detecting FB₁ , in which FB₁ in samples would compete with FB₁ -ovalbumin coated on the surface of Fe₃ O₄ @Au nanoparticles for binding with FB₁ antibodies. Successively, horseradish peroxidase labeled goat anti-rabbit IgG (HRP-IgG) was conjugated with FB₁ antibodies on the microplate. In substrate solution containing luminol and H₂ O₂ , HRP-IgG catalyzed luminol oxidation by H₂ O₂ , generating a high chemiluminescence signal. The FB₁ immune GoldMag particles were characterized by Fourier transform infrared spectroscopy, scanning electron microscope and zeta potential analysis, etc. RESULTS: The concentrations and the reaction times of these immunoreagents were optimized to improve the performances of this method. The established method could detect as low as 0.027 ng mL^-1 FB₁ from 0.05 ng mL^-1 to 25 ng mL^-1 , demonstrating little cross-reaction (less than 2.4%) with other structurally related compounds. The average intrassay relative SD (RSD) (n = 6) was 3.4% and the average interassay RSD (n = 6) was 5.4%. This method was successfully applied for the determination of FB₁ in corn and wheat and gave recoveries of between 98-110% and 91-105%, respectively.

CONCLUSION

The results of the present study suggest that the MECLIA approach has potential application for high-throughput fumonisin screening in cereals. © 2018 Society of Chemical Industry.

Detection of Fumonisins in Fresh and Dehydrated Commercial Garlic

An epidemic fungal disease caused by Fusarium proliferatum, responsible for fumonisin production (FB1, FB2, and FB3), has been reported in the main garlic-producing countries in recent years. Fumonisins are a group of structurally related toxic metabolites produced by this pathogen. The aim of this work was to establish an enzyme-linked immunosorbent assay (ELISA) procedure, mostly applied to cereals, that is suitable for fumonisin detection in garlic and compare these results to those obtained by high-performance liquid chromatography (HPLC) and screening of fresh and dehydrated garlic for toxicological risk. The results show good correlation between the two analytical methods. In fresh symptomatic garlic, fumonisin levels were higher in the basal plates than those in the portions with necrotic spots. Among the 56 commercially dehydrated garlic samples screened, three were positive by ELISA test and only one was above the limit of quantitation. The same samples analyzed by HPLC showed the presence of FB1 in trace amounts that was below the limit of quantitation; FB2 and FB3 were absent. The results are reassuring, because no substantial contamination by fumonisins was found in commercial garlic.

Polyphasic Approach Including MALDI-TOF MS/MS Analysis for Identification and Characterisation of Fusarium verticillioides in Brazilian Corn Kernels

Fusarium verticillioides is considered one of the most important global sources of fumonisins contamination in food and feed. Corn is one of the main commodities produced in the Northeastern Region of Brazil. The present study investigated potential mycotoxigenic fungal strains belonging to the F. verticillioides species isolated from corn kernels in 3 different Regions of the Brazilian State of Pernambuco. A polyphasic approach including classical taxonomy, molecular biology, MALDI-TOF MS and MALDI-TOF MS/MS for the identification and characterisation of the F. verticillioides strains was used. Sixty F. verticillioides strains were isolated and successfully identified by classical morphology, proteomic profiles of MALDI-TOF MS, and by molecular biology using the species-specific primers VERT-1 and VERT-2. FUM1 gene was further detected for all the 60 F. verticillioides by using the primers VERTF-1 and VERTF-2 and through the amplification profiles of the ISSR regions using the primers (GTG)₅ and (GACA)₄. Results obtained from molecular analysis shown a low genetic variability among these isolates from the different geographical regions. All of the 60 F. verticillioides isolates assessed by MALDI-TOF MS/MS presented ion peaks with the molecular mass of the fumonisin B1 (721.83 g/mol) and B2 (705.83 g/mol).

Solid-phase extraction using molecularly imprinted polymer for determination of ochratoxin A in human urine

A rapid, selective and reliable sample preparation technique employing solid-phase extraction (SPE) based on molecularly imprinted polymer (MIP) for the determination of ochratoxin A (OTA) in human urine was described. After sample adjustment to pH 2.5 with 0.1 M HCl, the urine sample was loaded onto the MIP-SPE column, and after a wash step, OTA was eluted for measurement by ultra-high performance liquid chromatography coupled with fluorescence detection. Key parameters which affected the MIP-SPE extraction efficiency were optimized as was the detection method. Under the optimised conditions, the limits of detection and quantification for OTA in urine were 0.2 ng/ml and 0.6 ng/ml, respectively. The recoveries for OTA in urine, spiked at the 0.6, 6.0 and 60 ng/ml levels, ranged from 92.0 to 98.9%. Sixty urine samples were analysed, of which four were found to contain OTA at concentrations ranging from 0.022 to 0.083 ng/ml; the positive results were confirmed by liquid chromatography coupled with tandem mass spectrometry. OTA determination in urine is a good indicator for human exposure to the mycotoxin, and this is the first report on OTA contamination in Chinese people.

Occurrence of enniatins and beauvericin in 60 Chinese medicinal herbs

A total of 60 Chinese medicinal herbs were examined for contamination of the emerging Fusarium mycotoxins enniatins (ENNs) A, A1, B, B1 and beauvericin (BEA). The herbs under study are commonly used in China as both medicines and food. The dried samples of herbs were randomly collected from traditional Chinese medicine stores in Zhejiang province, China. Sample preparation was achieved by methanol extraction, followed by a simple membrane filtration step; no tedious clean-ups were involved. ENNs A, A1, B, B1 and BEA were analysed by the recently developed stable isotope dilution assays, using liquid chromatography-tandem mass spectrometry (LC-MS/MS). With limits of detection ranging between 0.8 and 1.2 µg kg(-1) for the analytes under study, 25% of all analysed samples were contaminated with at least one of the ENNs and BEA. BEA was the most frequently detected toxin with a 20% incidence in all samples. The percentages of ENN-positive samples were lower: each single ENN was detected in 6.7-11.7% of all samples. Considering the total amounts of the five mycotoxins in single samples, values between 2.5 and 751 µg kg(-1) were found. The mean total amount in positive samples was 126 µg kg(-1). Regarding ginger, the frequent occurrence of ENNs and BEA in dried ginger could be confirmed in samples from Germany. However, in fresh ginger root the toxins were not detectable. This is the first report on the presence of ENNs and BEA in Chinese medicinal herbs.

Natural occurrence of mycotoxins in medicinal plants: a review

Medicinal plants are widely used as home remedies and raw materials for the pharmaceutical industries. Herbal remedies are used in the prevention, treatment and cure of disorders and diseases since ancient times. However, use of medicinal herbs may not meet the requirements of quality, safety and efficacy. During harvesting, handling, storage and distribution, medicinal plants are subjected to contamination by various fungi, which may be responsible for spoilage and production of mycotoxins. The increasing consumption of medicinal plants has made their use a public health problem due to the lack of effective surveillance of the use, efficacy, toxicity and quality of these natural products. The increase in use of medicinal plants may lead to an increase in the intake of mycotoxins therefore contamination of medicinal plants with mycotoxins can contribute to adverse human health problems and therefore represents a special hazard. Numerous natural occurrences of mycotoxins in medicinal plants and traditional herbal medicines have been reported from various countries including Spain, China, Germany, India, Turkey and from Middle East as well. This review discusses the important mycotoxins and their natural occurrences in medicinal plants and their products.

Developments in mycotoxin analysis: an update for 2011-2012

This review highlights developments in mycotoxin analysis and sampling over a period between mid-2011 and mid- 2012. It covers the major mycotoxins aflatoxins, Alternaria toxins, ergot alkaloids, fumonisins, ochratoxin, patulin, trichothecenes, and zearalenone. A section on mycotoxins in botanicals and spices is also included. Methods for mycotoxin determination continue to be developed using a wide range of analytical systems ranging from rapid immunochemical-based methods to the latest advances in mass spectrometry. This review follows the format of previous reviews in this series (i.e. sections on individual mycotoxins), but due to the rapid spread and developments in the field of multimycotoxin methods by liquid chromatography-tandem mass spectrometry, a separate section has been devoted to advances in this area of research.