Simultaneous determination of aflatoxins and ochratoxin A in baby foods and paprika by HPLC with fluorescence detection: A single-laboratory validation study

Simultaneous detection of multiple mycotoxins using MXene-based electrochemical aptasensor array and a self-developed multi-channel portable device

In response to the pressing need for highly efficient simultaneous detection of multiple mycotoxins, which are often found co-occurring in food raw materials and feed, an MXene-based electrochemical aptasensor array (MBEAA) was developed. This aptasensor array utilizes high-specificity aptamers as recognition elements, enabling the capture of electrical signal changes in the presence of target mycotoxins. Based on this platform, a multi-channel portable electrochemical device, enabling rapid, cost-effective, and simultaneous detection of aflatoxin B1 (AFB1), ochratoxin A (OTA), and zealenone (ZEN) was further developed. The developed system boasts a wide detection range of 1.0 × 10-1 to 10.0 ng mL-1, with remarkable performance characterized by ultra-low detection limits of 41.2 pg mL-1, 27.6 pg mL-1, and 33.0 pg mL-1 for AFB1, OTA, and ZEN, respectively. Successfully applied in corn samples, this method offers a portable, easy-to-operate, and cost-effective solution for simultaneous multi-mycotoxin detection. Moreover, the application of the self-developed detection system could be expanded for simultaneous detection of many different targets when their specific aptamers or antibodies were available.

Microfluidic paper analytic device (μPAD) technology for food safety applications

Foodborne pathogens, food adulterants, allergens, and toxic chemicals in food can cause major health hazards to humans and animals. Stringent quality control measures at all stages of food processing are required to ensure food safety. There is, therefore, a global need for affordable, reliable, and rapid tests that can be conducted at different process steps and processing sites, spanning the range from the sourcing of food to the end-product acquired by the consumer. Current laboratory-based food quality control tests are well established, but many are not suitable for rapid on-site investigations and are costly. Microfluidic paper analytical devices (μPADs) are a fast-growing field in medical diagnostics that can fill these gaps. In this review, we describe the latest developments in the applications of microfluidic paper analytic device (μPAD) technology in the food safety sector. State-of-the-art μPAD designs and fabrication methods, microfluidic assay principles, and various types of μPAD devices with food-specific applications are discussed. We have identified the prominent research and development trends and future directions for maximizing the value of microfluidic technology in the food sector and have highlighted key areas for improvement. We conclude that the μPAD technology is promising in food safety applications by using novel materials and improved methods to enhance the sensitivity and specificity of the assays, with low cost.

A portable paper-based aptasensor for simultaneous visual detection of two mycotoxins in corn flour using dual-color upconversion nanoparticles and Cu-TCPP nanosheets

A portable paper-based microfluidic aptasensor is established to simultaneously and visually detect zearalenone (ZEN) and ochratoxin A (OTA). The targets at the sample zone can migrate to two detection zones through dual-channels and result in green and blue fluorescence recovery. This is due to the specific recognition by a respective aptamer that destroys fluorescence resonance energy transfer (FRET) from dual-color upconversion nanoparticles (UCNPs) to Cu-TCPP nanosheets. By capturing fluorescent images and analyzing the corresponding RGB value via a smartphone, ZEN and OTA can be analyzed with limits of detection down to 0.44 ng/mL and 0.098 ng/mL in the linear ranges of 0.5-100 ng/mL and 0.1-50 ng/mL, respectively. Satisfactory recoveries are also obtained for ZEN (94.5-103.7 %) and OTA (92.2-106.8 %) in corn flour. With the advantages of simple operation, low sample consumption, and broad adaptability, this promising platform allows for the on-site detection of multiple hazards in food.

Simultaneous Detection of Ochratoxin A and Aflatoxins in Industrial and Traditional Red and isot Pepper Flakes along with Dietary Exposure Risk Assessment

This study focused on the co-occurrence of aflatoxins (AFs) and ochratoxin A (OTA) in traditionally and industrially dried red pepper flakes (DRPFs) and isot pepper flakes (IPFs). Following the multitoxin immunoaffinity column (IAC) clean-up, high-performance liquid chromatography coupled with fluorescence detection (HPLC-FLD) was used to quantify AFs and OTA. The limit of detection (LOD) and limit of quantification (LOQ) values were 0.11 and 0.18 μg kg-1 (AFB1), 0.04 and 0.08 μg kg-1 (AFB2), 0.13 and 0.18 μg kg-1 (AFG1), 0.04 and 0.11 μg kg-1 (AFG2), and 0.10 and 0.21 μg kg-1 (OTA), respectively. AFB1, AFB2, AFG1, and OTA were found to be positive in 93, 74, 17, and 94% of all samples, respectively. The contamination levels in positive samples ranged from 0.23 to 38.69, 0.04 to 2.14, 0.13 to 0.88, and 0.18 to 52.19 μg kg-1 for AFB1, AFB2, AFG1, and OTA, respectively, while no AFG2 was found above the detection limit (0.04 μg kg-1). None of the industrial isot peppers exceeded the European Union limits, while the levels of AFB1 (5 μg kg-1), total AFs (10 μg kg-1), and OTA (20 μg kg-1) of the traditional peppers were above the limit by 30% (16/54), 26% (14/54), and 4% (2/54), respectively. Co-occurrence of AFB1-AFB2-OTA was the most frequent, accounting for 54% (29/54) of all samples. At the upper bound (UB), estimated average exposure to AFB1, total AFs, and OTA was determined to be 0.175, 0.189, and 0.124 ng kg-1 bw day-1 in all samples, respectively. The margin of exposure (MoE) value of AFB1 and total AFs was found to be 977 and 909, indicating high health concerns compared to OTA (MoE >10,000). AFB1 and total AFs may result in 0.0058 and 0.0062 liver cancer cases/100,000 person/year at UB, respectively, and weekly OTA exposure was 0.868 ng kg-1 bw, well below the provisional tolerable weekly intake, hence not of health concern. AFs exposure could endanger health, whereas OTA posed no toxicological concerns through dried red pepper consumption.

Analysis of aflatoxins and ochratoxin a in chilli powder using ultrahigh performance liquid chromatography with fluorescence detection and tandem mass spectrometry

Chilli powder, a popular spice, is predominantly contaminated with aflatoxins (AFs) and ochratoxin A (OTA), posing a menace to public health. As no validated method exists for the simultaneous and direct analysis of AFs and OTA in chilli powder, it was imperative to develop one to ensure their effective monitoring and promote trade. In this research, we developed and validated a multi-mycotoxin analysis method that allows the simultaneous determination of AFs (AFB₁, AFB₂, AFG₁ and AFG₂) and OTA in chilli powder with high sensitivity, accuracy and precision. The optimised sample preparation workflow started with the extraction of chilli powder (25 g) with methanol-water (100 mL, 80:20). An aliquot (3 mL) was cleaned on a multi-mycotoxin, immunoaffinity column (AFLAOCHRA PREP^®) and analysed using ultrahigh performance liquid chromatography with fluorescence (UHPLC-FLD) and tandem mass spectrometric (LC-MS/MS) detection in a single chromatographic run. The method performance was evaluated through intra- and inter-laboratory validation (ILV) studies, and also by analysing a certified reference material. A direct analysis using UHPLC-FLD (without derivatisation) provided the limits of quantification (LOQ) of 0.25 and 1 ng/g for AFs and OTA, respectively, while the LOQ for all these mycotoxins in LC-MS/MS was 0.5 ng/g. These LOQs are much lower than the maximum levels (MLs) specified by the European Commission. The recoveries of these analytes at LOQ and higher levels were above 75% (RSD_r < 12%). The ILV study demonstrated satisfactory method-reproducibility (RSD_R < 25%). The analysis of the certified reference material provided accuracies of AFs and OTA in the range of 83-101%. The analysis by UHPLC-FLD and LC-MS/MS provided very similar results. The incurred levels of B1 in market samples were estimated with a precision-RSD of < 6%. Considering its efficiency and alignment with the regulatory requirements, this method can be implemented for the routine analysis of AFs and OTA in chilli powder.

Metabolomic Analysis Reveals the Mechanisms of Hepatotoxicity Induced by Aflatoxin M1 and Ochratoxin A

Aflatoxin M1 (AFM1) is the only toxin with the maximum residue limit in milk, and ochratoxin A (OTA) represents a common toxin in cereals foods. It is common to find the co-occurrence of these two toxins in the environment. However, the interactive effect of these toxins on hepatoxicity and underlying mechanisms is still unclear. The liver and serum metabolomics in mice exposed to individual AFM1 at 3.5 mg/kg b.w., OTA at 3.5 mg/kg b.w., and their combination for 35 days were conducted based on the UPLC-MS method in the present study. Subsequent metabolome on human hepatocellular liver carcinoma (Hep G2) cells was conducted to narrow down the key metabolites. The phenotypic results on liver weight and serum indicators, such as total bilirubin and glutamyltransferase, showed that the combined toxins had more serious adverse effects than an individual one, indicating that the combined AFM1 and OTA displayed synergistic effects on liver damage. Through the metabolic analysis in liver and serum, we found that (i) a synergistic effect was exerted in the combined toxins, because the number of differentially expressed metabolites on combination treatment was higher than the individual toxins, (ii) OTA played a dominant role in the hepatoxicity induced by the combination of AFM1, and OTA and (iii) lysophosphatidylcholines (LysoPCs), more especially, LysoPC (16:1), were identified as the metabolites most affected by AFM1 and OTA. These findings provided a new insight for identifying the potential biomarkers for the hepatoxicity of AFM1 and OTA.

Multiple fluorescence immunoassay for the simultaneous detection of Zearalenone and Ochratoxin A

A sensitive and accurate multiple fluorescence immunoassay for the simultaneous quantitative detection of Zearalenone (ZEN) and Ochratoxin A (OTA) in single spot based on multicolor quantum dots (QDs) labeling was developed for the first time. Two kinds of ZnCdSe/ZnS (core/shell) QDs with maximum emission wavelengths at 520 nm (green) and 610 nm (orange-red) were selected as marking materials, respectively. The anti-ZEN-mAb-QDs and anti-OTA-mAb-QDs were designed as the immune fluorescent probes. Fluorescence was measured at the same excitation wavelength and two different emission wavelengths to determine each target. The procedure for QDs-based multiple fluorescence labeled immunosorbent assay (M-FLISA) was developed. The 50% inhibition concentrations (IC₅₀) of ZEN and OTA were 0.034 and 1.175 ng/mL. Moreover, the limits of detection (LOD) for the simultaneous determination were 0.0239 and 2.339 ng/g for ZEN and OTA in maize, respectively. In addition, the recoveries ranged from 93.15 to 101.90% for ZEN and from 95.29 to 102.43% for OTA, with the coefficient variation (CV) of 2.70-8.86% and 3.51-6.22% respectively. There was good consistency between the M-FLISA and high performance liquid chromatography (HPLC) results, which confirmed that the M-FLISA was suitable for the simultaneous quantitative detection of various mycotoxins.

Metabolomics analysis underlay mechanisms in the renal impairment of mice caused by combination of aflatoxin M1 and ochratoxin A

Aflatoxin M1 (AFM1) and ochratoxin A (OTA) are pernicious mycotoxins widely co-existing in the environment. However, nephrotoxicity and underlying mechanism induced by AFM1 coupled with OTA still remain to be explored. In this study, CD-1 mice were treated with 3.5 mg/kg b.w. AFM1, OTA, and AFM1 + OTA for 35 days, and UPLC-MS-based metabolomics method was effectuated to investigate metabolomic profiles of mice kidney. Subsequent experiments on human renal proximal tubular (HK-2) cells were performed to dig out the causal connections between distinguished differential metabolites and nephrotoxicity. Compared with DMSO vehicle group, all three toxin treatments (AFM1 and OTA alone, and in combination) significantly reduced final body weight, and remarkably elevated the concentration of serum creatinine (SCr) and caused abnormal histological phenotypes (shown by histopathological slices). OTA, AFM1 + OTA but not AFM1 reduced the relative weight index of kidney. These phenotypic results indicated that AFM1 and OTA were both toxic to the body, and it seemed that OTA exhibited a notable impairment to kidney while AFM1 had similar but limited effect compared with OTA. Further metabolomics analysis showed that when AFM1 and OTA were combined together, OTA exerted dominant effect on the alteration of metabolic processes. There were few differences in the number of changed metabolites between OTA and AFM1 + OTA group. Among the differentially expressed metabolites affected by OTA, and AFM1 + OTA, lysophosphatidylcholines (LysoPCs) were identified as the main type with significant upregulation, in which LysoPC (16:0) accounted for the most prime proportion. Western blotting results of HK-2 cells showed that single OTA and AFM1 + OTA increased the apoptotic protein expressions of Bax, caspase 3 and PARP, and decreased the expression of Bcl-2; while AFM1 only raised the expression of caspase 3. LysoPC (16:0) but not LysoPC (18:1) lifted the protein level of caspase 3 and PARP in HK-2 cells, and reduced the level of Bcl-2. Taken together, this study is the first effort trying to assess nephrotoxicity of AFM1 with OTA, and we guessed that OTA had a more pronounced toxicity to kidney in contrast to AFM1. No obvious synergism between AFM1 and OTA was found to contribute to the occurrence or development of nephropathy. LysoPC (16:0) might be the pivotal metabolite in response to single OTA and combined AFM1 + OTA engendering renal injury.

The role of band structure in Co- and Fe-co-doped Ba0.5Sr0.5Zr0.1Y0.1O3-δ perovskite semiconductor to design an electrochemical aptasensing platform: application in label-free detection of ochratoxin A using voltammetry

Nanocomposites can offer a platform to conjugate biorecognition features of aptamer with unique size-dependent properties of a given material, which can autoprobe the binding event based on their electroactive characteristics. Herein, we design electroactive switchable aptamer probes based on co-doped single-phase semiconducting materials employing the cyclic voltammetry method to record the current signal at each step of electrochemical characterization. To do so, we utilized a facile hydrothermal method assisted by co-precipitation method such as Co-Fe-co-doped Ba_0.5Sr_0.5Zr_0.1Y_0.1O_3-δ (CF-BSZY) and tuned the alignment of the energy band structure of the material to amplify the output of the electrochemical signal. At various steps, changes occurred in the electrochemical properties at the surface of CF-BSZY. The binding of the ssDNA with prepared materials enhances the current signal by the interaction with the target (ochratoxin A (OTA)) depressing the current signal and facilitating the construction of a novel design of electrochemical aptasensor. As a proof of concept, an electrochemical aptasensor for the detection of ochratoxin A (OTA) in rice samples has been developed. The electrochemical aptasensor provides a limit of detection (LOD) of 0.00012 μM (0.12 nM), with a linear range from 0.000247 to 0.74 μM and sound OTA recovery in real samples. The developed aptasensor is simply designed and is free of oligonucleotide labeling or decorative nanoparticle modifications. The proposed mechanism is generic in principle with the potential to translate any type of aptamer and target binding event into a detectable signal; hence, it can be largely applied to various bioreceptor recognition phenomena for subsequent applications.

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.

Occurrence and Safety Evaluation of Ochratoxin A in Cereal-based Baby Foods Collected from Iranian Retail Market

Contamination of agricultural commodities with ochratoxin A (OTA) is a worldwide concern in recent decades. Consumption of OTA-contaminated baby foods exerts health implications especially in children as the most vulnerable subpopulations. In the current study, for the first time in Iran, 64 baby foods (rice, wheat, and multigrain) samples from five different brands available in the Iranian market were analyzed to determine OTA level, using a HPLC with fluorescence detector. Overall, OTA was observed in 41% of analyzed samples with a mean and maximum level of 0.42 ± 0.27 and 1.1 μg/kg, respectively. OTA levels in five of 64 samples (7.8 %) were higher than the permissible limit recommended by European Commission (permissible limit: 0.5 μg/kg) and OTA levels in two of 64 samples (3.1%) were higher than the standard set by Iranian standard organization (1 μg/kg). The highest OTA contamination was observed in rice-based baby food cereals (1.1 μg/kg; 57% of the samples), followed by wheat-based (23%) and multigrain (20%) samples. OTA intake in infants (≥9 months old) was more than established provisional tolerable weekly intake by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) and the European Food Safety Authority (EFSA) (100 and 120 ng OTA per kg of body weight, respectively). OTA content in baby food and cereals, as well as other raw foodstuff should be investigated comprehensively to reduce the exposure rate of young children to OTA.

Improved Quantitation of Gluten in Wheat Starch for Celiac Disease Patients by Gel-Permeation High-Performance Liquid Chromatography with Fluorescence Detection (GP-HPLC-FLD)

Purified wheat starch (WSt) is commonly used in gluten-free products for celiac disease (CD) patients. It is mostly well-tolerated, but doubts about its safety for CD patients persist. One reason may be that most ELISA kits primarily recognize the alcohol-soluble gliadin fraction of gluten, but insufficiently target the alcohol-insoluble glutenin fraction. To address this problem, a new sensitive method based on the sequential extraction of gliadins, glutenins, and gluten from WSt followed by gel-permeation high-performance liquid chromatography with fluorescence detection (GP-HPLC-FLD) was developed. It revealed that considerable amounts of glutenins were present in most WSt. The gluten contents quantitated by GP-HPLC-FLD as sum of gliadins and glutenins were higher than those by R5 ELISA (gluten as gliadin content multiplied by a factor of 2) in 19 out of 26 WSt. Despite its limited selectivity, GP-HPLC-FLD may be applied as confirmatory method to ELISA to quantitate gluten in WSt.

Advances in Mycotoxin Research: Public Health Perspectives

Aflatoxins, ochratoxins, fumonisins, deoxynivalenol, and zearalenone are of significant public health concern as they can cause serious adverse effects in different organs including the liver, kidney, and immune system in humans. These toxic secondary metabolites are produced by filamentous fungi mainly in the genus Aspergillus, Penicillium, and Fusarium. It is challenging to control the formation of mycotoxins due to the worldwide occurrence of these fungi in food and the environment. In addition to raw agricultural commodities, mycotoxins tend to remain in finished food products as they may not be destroyed by conventional processing techniques. Hence, much of our concern is directed to chronic health effects through long-term exposure to one or multiple mycotoxins from contaminated foods. Ideally risk assessment requires a comprehensive data, including toxicological and epidemiological studies as well as surveillance and exposure assessment. Setting of regulatory limits for mycotoxins is considered necessary to protect human health from mycotoxin exposure. Although advances in analytical techniques provide basic yet critical tool in regulation as well as all aspects of scientific research, it has been acknowledged that different forms of mycotoxins such as analogs and conjugated mycotoxins may constitute a significant source of dietary exposure. Further studies should be warranted to correlate mycotoxin exposure and human health possibly via identification and validation of suitable biomarkers.

Aflatoxin B1 in eggs and chicken livers by dispersive liquid-liquid microextraction and HPLC

A rapid, low-cost and simple technique has been developed for the determination of aflatoxin B1 (AFB1) in eggs and livers using high-performance liquid chromatography (HPLC) with UV detection. In this study, the presence of AFB1 was investigated in 150 eggs and 50 chicken livers from the local market of Tabriz, Iran. AFB1 was extracted with a mixture of acetonitrile:water (80:20) and cleaned up by dispersive liquid-liquid microextraction which is a very economical, fast and sensitive method. AFB1 was quantified by HPLC-UV without need for any complex derivatisation in samples to enhance the detection. The results showed that 72% of the liver and 58% of the egg samples were contaminated with AFB1 ranging from 0.30 to 16.36 µg kg (̶1). limit of detection and limit of quantification for AFB1 were 0.08 and 0.28 µg kg (̶ 1), respectively. The proposed method is suitable for fast analysing of AFB1 in egg and liver samples.

A label free aptasensor for Ochratoxin A detection in cocoa beans: An application to chocolate industries

Contamination of food by mycotoxin occurs in minute/trace quantities. Nearly 92.5% of the cocoa samples present Ochratoxin A (OTA) levels at trace quantity. Hence, there is a necessity for a highly sensitive and selective device that can detect and quantify these organic toxins in various matrices such as cocoa beans. This work reports for the first time, a facile and label-free electrochemical impedimetric aptasensor for rapid detection and quantitation of OTA in cocoa beans. The developed aptasensor was constructed based on the diazonium-coupling reaction mechanism for the immobilization of anti-OTA-aptamer on screen printed carbon electrodes (SPCEs). The aptasensor exhibited a very good limit of detection (LOD) as low as 0.15 ng/mL, with added advantages of good selectivity and reproducibility. The increase in electron transfer resistance was linearly proportional to the OTA concentration in the range 0.15-2.5 ng/mL, with an acceptable recovery percentage (91-95%, RSD = 4.8%) obtained in cocoa samples. This work can facilitate a general model for the detection of OTA in cocoa beans based on the impedimetric aptasensor. The analysis can be performed onsite with pre-constructed and aptamer modified electrodes employing a portable EIS set up.

Sensitive quantitation of Ochratoxin A in cocoa beans using differential pulse voltammetry based aptasensor

In this work, we propose for the first time a sensitive Ochratoxin A (OTA) detection in cocoa beans using competitive aptasensor by differential pulse voltammetry (DPV). In the proposed method, biotin labeled and free OTA competed to bind with immobilized aptamer onto the surface of a screen printed carbon electrode (SPCE), and percentage binding was calculated. The detection was performed after adding avidin-ALP to perform avidin-biotin reaction; the signal was generated through a suitable substrate 1-naphthyl phosphate (1-NP), for alkaline phosphatase (ALP). The cocoa samples were extracted and purified using molecular imprinted polymer (MIP) columns specifically designed for OTA. The developed aptasensor showed a good linearity in the range 0.15-5 ng/mL with the limit of detection (LOD) 0.07 ng/mL and 3.7% relative standard deviation (RSD). The aptasensor displayed good recovery values in the range 82.1-85% with 3.87% RSD, thus, demonstrated the efficiency of proposed aptasensor for such matrices.

Simultaneous determination of three banned psychiatric drugs in pig feed and tissue using solid-phase reactor on-line oxidizing and HPLC-fluorescence detection

The banned addition of psychiatric drugs such as phenothiazines to animal feed and foodstuffs increases the risk of human organ lesion. Phenothiazines usually exhibit weak native fluorescence and can be oxidized to strongly fluorescent compounds. In this study, a novel, sensitive and convenient method of HPLC-fluorescence detection based on post-column on-line oxidizing with lead dioxide solid-phase reactor has been developed for simultaneous determination of three banned psychotropic drugs, promethazine, chlorpromazine and thioridazine. Three compounds were successfully separated on an Agilent TC-C18 column with mobile phase of acetonitrile (A) and water (B), both containing 0.5% (v/v) formic acid. A gradient elution was programmed and fluorimetric detection was performed at λex /λem of 332/373 nm for promethazine, 340/380 nm for chlorpromazine and 352/432 nm for thioridazine. The calibration graphs gave good linearity over the concentration ranges of 30.0-4976.4 µg/L for promethazine, 2.0-2153.2 µg/L for chlorpromazine, and 15.0-3088.0 µg/L for thioridazine, and correlation coefficients (r) were ≥0.995. The method was applied to the determination of phenothiazines in pig feed and pig tissue, and the average spiked recoveries were in the range 69.1-115.4%.

Determining mycotoxins in baby foods and animal feeds using stable isotope dilution and liquid chromatography tandem mass spectrometry

We developed a stable isotope dilution assay with liquid chromatography tandem mass spectrometry (LC-MS/MS) to determine multiple mycotoxins in baby foods and animal feeds. Samples were fortified with [(13)C]-uniformly labeled mycotoxins as internal standards ([(13)C]-IS) and prepared by solvent extraction (50% acetonitrile in water) and filtration, followed by LC-MS/MS analysis. Mycotoxins in each sample were quantitated with the corresponding [(13)C]-IS. In general, recoveries of aflatoxins (2-100 ng/g), deoxynivalenol, fumonisins (50-2000 ng/g), ochratoxin A (20-1000 ng/kg), T-2 toxin, and zearalenone (40-2000 ng/g) in tested matrices (grain/rice/oatmeal-based formula, animal feed, dry cat/dog food) ranged from 70 to 120% with relative standard deviations (RSDs) <20%. The method provides sufficient selectivity, sensitivity, accuracy, and reproducibility to screen for aflatoxins at ng/g concentrations and deoxynivalenol and fumonisins at low μg/g concentrations in baby foods and animal feeds, without using conventional standard addition or matrix-matched calibration standards to correct for matrix effects.

Natural occurrence, analysis, and prevention of mycotoxins in fruits and their processed products

Mycotoxins are small toxic chemical products formed as the secondary metabolites by fungi that readily contaminate foods with toxins in the field or after harvest. The presence of mycotoxins, such as aflatoxins, ochratoxin A, and patulin, in fruits and their processed products is of high concern for human health due to their properties to induce severe acute and chronic toxicity at low-dose levels. Currently, a broad range of detection techniques used for practical analysis and detection of a wide spectrum of mycotoxins are available. Many analytical methods have been developed for the determination of each group of these mycotoxins in different food matrices, but new methods are still required to achieve higher sensitivity and address other challenges that are posed by these mycotoxins. Effective technologies are needed to reduce or even eliminate the presence of the mycotoxins in fruits and their processed products. Preventive measures aimed at the inhibition of mycotoxin formation in fruits and their processed products are the most effective approach. Detoxification of mycotoxins by different physical, chemical, and biological methods are less effective and sometimes restricted because of concerns of safety, possible losses in nutritional quality of the treated commodities and cost implications. This article reviewed the available information on the major mycotoxins found in foods and feeds, with an emphasis of fruits and their processed products, and the analytical methods used for their determination. Based on the current knowledge, the major strategies to prevent or even eliminate the presence of the mycotoxins in fruits and their processed products were proposed.

Effect of Aspergillus flavus contamination on the inherent quality of Glycyrrhiza uralensis

Glycyrrhiza uralensis is a common edible plant of the Chinese Materia Medica (CMM). Such a herb might be naturally contaminated with toxicogenic fungi producing various mycotoxins that can cause serious harm to humans. So far, studies have focused mainly on mycotoxin detection in CMM, but the effect of mycotoxin production on the inherent quality of CMM has not been investigated and elucidated. In the present study, sterilised G. uralensis was inoculated and incubated with Aspergillus flavus for several days to investigate the effect of aflatoxins accumulation on the inherent quality of G. uralensis. Changes in content of aflatoxin B1, B2, G1 and G2, and the herb's four bioactive components, i.e. glycyrrhizic acid, liquiritin apioside, liquiritin and liquiritigenin, were detected using ultra performance liquid chromatography coupled with fluorescence and photodiode array detection, respectively. The results showed that incubation of G. uralensis with A. flavus for 10 days resulted in the accumulation of aflatoxins, especially aflatoxin B1 and B2, and the reduction of the four bioactive components. From the negative correlation between the content of aflatoxins and bioactive components, it can be concluded that fungal contamination does not only result in harmful mycotoxins in CMM, but also influences its inherent quality.

Multi-mycotoxin determination in baby foods and in vitro combined cytotoxic effects of aflatoxin M1 and ochratoxin A

The co-occurrence of mycotoxins in baby foods, including aflatoxin M1 (AFM1) and ochratoxin A (OTA), has been reported in previous studies, but data on their potential combined toxic effects are still missing. The present work aimed at (1) validating an in-house multi-mycotoxin high performance liquid chromatography with fluorescence detection (HPLC-FLD) method for AFM1, total aflatoxins (aflatoxin B1 (AFB1), aflatoxin B2 (AFB2), aflatoxin G1 (AFG1), aflatoxin G2 (AFG2)) and OTA in infant formulae (milk powders) and cereal baby foods (flours), and (2) assessing the combined cytotoxic effects of AFM1 and OTA in an intestine-derived cell line. The HPLC-FLD method, which included a chloroform extraction, liquid-liquid extraction, immunoaffinity column clean-up and fluorescence detection after post-column derivatisation with electrochemically generated bromine, was adequate for the analysis of baby foods and met the requirements of validation and quality control for the studied working ranges. The limits of quantification for AFM1, AFB1, AFB2, AFG1, AFG2 and OTA were 0.069, 0.032, 0.020, 0.047, 0.020 and 0.244 μg/kg, respectively. The mean recovery values were 96, 114, 112, 107, 101 and 87%, respectively. A dose-dependent cytotoxicity was observed for individual and combined AFM1 and OTA using the Caco-2 cell line, which represents a site of contact of both mycotoxins in the body, after oral exposure. Interactions between both mycotoxins were disclosed by application of the concentration addition (CA) and independent action (IA) models, revealing the predominance of an antagonistic pattern. In conclusion, this study proposes a HPLC-FLD method for multi-mycotoxin monitoring in baby foods and provides evidence for the interaction between AFM1 and OTA, and for the applicability of CA/IA models to predict the effect of mycotoxins mixtures, further contributing to the prevention of mycotoxins-associated adverse health effects.

Fluorimetric immunoassay for multianalysis of aflatoxins

A sensitive fluorimetric ELISA was developed for the analysis of aflatoxins. The assay was performed in a 384 microwell plate, wherein high specificity monoclonal antibody against AFM1 (mAb-AFM1) was used as capture antibody and FITC conjugated secondary antibody was used for detection and quantification of the analyte. The linear range of the immunoassay was found to be 6.25-50 pg/mL. AFM1 as low as 1 pg/mL was detected by this method with assay volume 40  μ L. The multi-analysis of different aflatoxins was also investigated in the microwell plate, based on the cross-reactivity (CR) approach. Real milk samples were tested along with certified reference material by standard addition method and recovery analysis was done. The mAb-AFM1 showed 23.2% CR with AFB1, 50% CR with respect to AFM2, and least CR towards AFG1 (<1%). Furthermore, mixture analysis of AFM2 and AFB1 was carried out at specific concentrations of AFM1. The advantages of this developed immunoassay are high sensitivity, high throughput, multianalyte detection, versatility, and ease of handling.

Developments in mycotoxin analysis: an update for 2010-2011

This review highlights developments in mycotoxin analysis and sampling over a period between mid-2010 and mid-2011. It covers the major mycotoxins: aflatoxins, Alternaria toxins, ergot alkaloids, fumonisins, ochratoxin, patulin, trichothecenes, and zearalenone. Analytical methods for mycotoxins continue to be developed and published. Despite much interest in immunochemical methods and in the rapid development of LC-MS methodology, more conventional methods, sometimes linked to novel clean-up protocols, have also been the subject of research publications over the above period. Occurrence of mycotoxins falls outside the main focus of this review; however, where relevant to analytical method development, this has been mentioned.