Exposure Biomarkers and Histopathological Analysis in Pig Liver After Exposure to Mycotoxins Under Field Conditions: Special Report on Fumonisin B1.

Liver samples from finisher pigs were collected at the slaughterhouses for the analysis of zearalenone (ZEA), alfa-/beta-zearalenone (α-ZE, ß-ZE), zearalanone (ZA), alfa-/beta-ZA (α-ZA, ß-ZA), aflatoxin B1 (AFB1) and aflatoxin M1, fumonisin B1 (FB1), ochratoxin A (OTA) and ochratoxin B, deoxynivalenol and deepoxi-deoxynivalenol (DOM-1). For the analysis liquid chromatography-triple quadrupole coupled with mass spectrometry was applied. Liver samples with detected FB1 were further histopathologically evaluated after hematoxylin and eosin staining. Various levels of liver mycotoxins were detected in all farms. Pig livers with 2.91-8.30 µg/kg of FB1 were detected in three farms, estimate of 850-2400 µg/kg of FB1 intake, whereas 0.54 µg/kg of OTA was detected in one farm, estimate of 75 µg/kg of OTA intake. Moreover, pig livers with 0.30 µg/kg of ZEA, 1.87 µg/kg of α-ZE, and 0.63 µg/kg of ß-ZE were detected in one farm, estimate with of 300 µg/kg of ZEA intake. The histopathological analysis revealed that the lesions' grading and necrosis grading were analogously increased when FB1 concentration increased from 2.91 to 4.36-8.30 µg/kg. The severity of megalocytosis was analogously increased with FB1 detection levels and particularly in levels of 4.36-8.3 µg/kg. However, the increased FB1 detection levels did not show analogous behavior with the severity of hepatic cell vacuolization. Results showed that FB1 remained the most critical risk factor in the Greek pig industry, whereas ZEA and AFB1 were also prevalent. The OTA contamination in pig farms raised a high risk for animal and human health.

Analysis of multiple mycotoxins-contaminated wheat by a smart analysis platform.

This study describes a smart analysis platform capable of quantitative measurements using a multiplex lateral flow strip. Using the multi-mycotoxin strip, five fungal toxins were simultaneously and quantitatively detected in naturally contaminated wheat. First, a matrix-based standard curve was established for the detection of aflatoxin B1 (AFB1), fumonisin B1 (FB1), T-2, deoxynivalenol (DON), and zearalenone (ZEN). Established on an open android system, the platform is able to read 6 lines on the strip simultaneously. The platform is equipped with a Quick Response code scanning model, which reads the established standard curves, and then rapidly quantify mycotoxins in naturally contaminated wheat. All the data and sample information are stored on a central server through the platform which is linked to the cloud. The limits of detection (LOD) for AFB1, FB1, T-2, DON, and ZEN in wheat were 4, 20, 10, 200, and 40 µg/kg and the visual cut off values was 20, 1000, 200, 4000, and 400 µg/kg, separately. To validate the platform and the multi-mycotoxin detection method, 10 wheat samples were analyzed and the results were in a good agreement with those obtained by LC-MS/MS. The platform will be a powerful tool for crop monitoring services.

Preparative isolation and purification of B-type fumonisins by using macroporous resin column and high-speed countercurrent chromatography.

B-type fumonisins (FBs) are water-soluble mycotoxins produced by Fusarium species, which are mainly found in maize products and threaten food safety. Toxicological studies and quantitative determinations of fumonisins require large amounts of pure toxins, and their high prices limit progress in FBs research. In this study, we used a macroporous resin column combined with high-speed countercurrent chromatography to separate large quantities of FBs. A fermented rice culture was extracted with 75% methanol. The dynamic adsorption capacity of FBs on XAD-2 resin was 27.5 mg/g resin at 25°C, pH 4.0, and then the FBs were desorbed with 60% methanol. The crude FBs were further purified using a biphasic system consisting of n-heptane/n-butanol/methanol/water (2:4:1:4, v/v/v/v). The method yielded 1.55 g of FB1 and 0.55 g of FB3 with purities of 96.8% and 95.6%, respectively, from 1 kg of rice culture, and the final overall yield of FBs was 74.8%.

Molecularly imprinted photoelectrochemical sensor for fumonisin B1 based on GO-CdS heterojunction.

A rapid and ultrasensitive molecularly imprinted photoelectrochemical (MIP-PEC) sensing platform based on ITO electrode modified with GO-CdS heterojunction was prepared for ultrasensitive measure of fumonisin B1 (FB1). CdS quantum dots (QDs) were combined with a suitable amount of graphene oxide (GO) to form a heterojunction to enhance signal response with accurately calculating energy levels (VB/CB or HOMO/LUMO). The MIP-PEC sensor was successful fabricated after MIP was immobilized on the electrode with the basis of these results. In the phosphate buffer solution (PBS), it was clearly observed that the non-elution MIP-PEC sensor had almost no photocurrent response, which was due to the slower electron transfer speed. When the MIP-PEC sensor is eluted in ethanol, its photocurrent response was significantly restored, that was because the fact that the template molecules were washed away, and electron donors entered the holes and accelerated the electron transfer. Its photocurrent response was reduced because of holes blocked when the MIP-PEC sensor was hatched in the template molecules culture fluid. This phenomenon fully showed that the MIP-PEC sensor can specifically detect the target. Thus, The work has a linear range from 0.01 to 1000 ng mL-1 with a detection limit of 4.7 pg mL-1 for FB1. Furthermore, the fabricated MIP-PEC sensor will confirm the actual application.

A comparison of mycotoxin contamination of premium and grocery brands of pelleted cat food in South Africa.

Contamination with mycotoxins is of concern to pet owners and veterinary practitioners owing to their ability to cause disease and exacerbate the pathological changes associated with other diseases. Currently, there is a lack of information regarding the mycotoxin content of common premium brand (PB) and grocery brand (GB) cat feeds. Therefore, we undertook to determine the mycobiota content of feed samples, from both categories (n = 6 each), and measured the levels of aflatoxin (AF), fumonisin (FB), ochratoxin A (OTA) and zearalenone (ZEA) by high performance liquid chromatographic analysis. There were high concentrations of mycotoxins in both categories of feed, regardless of the notion that PBs are of a higher quality. The concentration of these toxins may contribute to the development of related pathologies in felines.

The use of innovative and efficient nanocomposite (magnetic graphene oxide) for the reduction on of Fusarium mycotoxins in palm kernel cake.

Adsorption plays an important role in the removal of mycotoxins from feedstuffs. The main objective of this study was to investigate the efficacy of using magnetic graphene oxide nanocomposites (MGO) as an adsorbent for the reduction of Fusarium mycotoxins in naturally contaminated palm kernel cake (PKC). Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to assess the mycotoxins in animal feed. Target mycotoxins included the zearalenone (ZEA), the fumonisins (FB1 and FB2) and trichothecenes (deoxynivalenol (DON), HT-2 and T-2 toxin). Response surface methodology (RSM) was applied to investigate the effects of time (3-7 h), temperature (30-50 °C) and pH (3-7) on the reduction. The response surface models with (R2 = 0.94-0.99) were significantly fitted to predict mycotoxins in contaminated PKC. Furthermore, the method ensured a satisfactory adjustment of the polynomial regression models with the experimental data except for fumonisin B1 and B2, which decrease the adsorption of magnetic graphene oxide (MGO). The optimum reduction was performed at pH 6.2 for 5.2 h at of 40.6 °C. Under these optimum conditions, reduced levels of 69.57, 67.28, 57.40 and 37.17%, were achieved for DON, ZEA, HT-2, and T-2, respectively.

HPLC-HRMS Quantification of the Ichthyotoxin Karmitoxin from Karlodinium armiger.

Being able to quantify ichthyotoxic metabolites from microalgae allows for the determination of ecologically-relevant concentrations that can be simulated in laboratory experiments, as well as to investigate bioaccumulation and degradation. Here, the ichthyotoxin karmitoxin, produced by Karlodinium armiger, was quantified in laboratory-grown cultures using high-performance liquid chromatography (HPLC) coupled to electrospray ionisation high-resolution time-of-flight mass spectrometry (HRMS). Prior to the quantification of karmitoxin, a standard of karmitoxin was purified from K. armiger cultures (80 L). The standard was quantified by fluorescent derivatisation using Waters AccQ-Fluor reagent and derivatised fumonisin B1 and fumonisin B2 as standards, as each contain a primary amine. Various sample preparation methods for whole culture samples were assessed, including six different solid phase extraction substrates. During analysis of culture samples, MS source conditions were monitored with chloramphenicol and valinomycin as external standards over prolonged injection sequences (>12 h) and karmitoxin concentrations were determined using the response factor of a closely eluting iturin A2 internal standard. Using this method the limit of quantification was 0.11 µg·mL-1, and the limit of detection was found to be 0.03 µg·mL-1. Matrix effects were determined with the use of K. armiger cultures grown with 13C-labelled bicarbonate as the primary carbon source.

Removal of fumonisin B1 and B2 from model solutions and red wine using polymeric substances.

Fumonisins are a group of mycotoxins found in various foods whose consumption is known to be harmful for human health. In this study, we evaluated the ability of three polymers (Polyvinylpolypyrrolidone, PVPP; a resin of N-vinyl-2-pyrrolidinone with ethylene glycol dimethacrylate and triallyl isocyanurate, PVP-DEGMA-TAIC; and poly(acrylamide-co-ethylene glycol-dimethacrylate), PA-EGDMA) to remove fumonisin B1 (FB1) and fumonisin B2 (FB2) from model solutions and red wine. Various polymer concentrations (1, 5 and 10mgmL-1) and contact times (2, 8 and 24h) were tested, with all polymers exhibiting fumonisin removal capacities (monitored by LC-MS). The impact of all polymers on polyphenol removal was also assessed. PA-EGDMA showed to be the most promising polymer, removing 71% and 95% of FB1, and FB2, respectively, with only a 22.2% reduction in total phenolics.

The mechanism of Lactobacillus strains for their ability to remove fumonisins B1 and B2.

Two Lactobacillus strains, L. plantarum B7 and L. pentosus X8, exhibited high efficiency in removing fumonisins (FB1 and FB2) from aqueous medium. 52.9% FB1 and 85.2% FB2 were bound by L. plantarum B7, and 58.0% FB1 and 86.5% FB2 by L. pentosus X8, respectively. Temperature, incubation time, and pH affected the binding ability of two strains. Cell viability was not necessary for the binding ability. The various components of cell wall were determined for their ability to absorb FBS. The results revealed that the intact peptidoglycans exhibited the greatest capacity in binding FBs. Especially the better structural integrity of the peptidoglycans the more FBs was bound. Thus, the absorption of two bacterial cells to FBs is proposed to be a physical process, and peptidoglycans should be the main binding site. Additionally, Caco-2 cell lines were used to evaluate the ability of the two strains to reduce the damage of FBs in vitro. Caco-2 cell's death was reduced after the cell lines were subjected to both viable and non-viable L. pentosus X8, respectively. The two Lactobacillus strains might be used as a biological detoxification for the removal of FBs from diet and feed in the future.

A universal multi-wavelength fluorescence polarization immunoassay for multiplexed detection of mycotoxins in maize.

Multi-analyte immunoassays have attracted increasing attention due to their short assay times, low sample consumption, and reduced detection costs per assay. In this work, we describe a homologous and high-throughput multi-wavelength fluorescence polarization immunoassay (MWFPIA) for the multiplexed detection of mycotoxins. Three typical Fusarium mycotoxins, deoxynivalenol (DON), T-2 toxin and fumonisin B1 (FB1), were labeled with different dyes. Tracers and specific monoclonal antibodies (mAbs) were employed in the MWFPIA to simultaneously detect the three mycotoxins. Under optimal conditions, the limits of detection using MWFPIA were 242.0 µg kg(-1) for DON, 17.8 µg kg(-1) for T-2 toxin and 331.5 µg kg(-1) for FB1, providing sufficient sensitivity to meet the action levels of these three contaminants in maize as set by the European Union. The use of a methanol/water (2:3, v/v) mixture for sample pretreatment allowed recoveries ranging from 76.5-106.3%, with coefficients of variation less than 21.7%. The total time of analysis, including sample preparation, was less than 30 min. Twenty naturally contaminated maize samples were tested using MWFPIA and HPLC-MS/MS, with correlation coefficients (R(2)) of 0.97 for DON and 0.99 for FB1. By changing the targets of interest, homologous MWFPIA, a method with high sensitivity, a simple procedure and a short analysis time, can easily be extended to other chemical contaminants. Thus, MWFPIA represents a versatile strategy for food safety analysis.

Factores extrínsecos e intrínsecos asociados a poblaciones fúngicas micotoxigénicas de granos de maíz (Zea mays L) almacenados en silos bolsa en Argentina / Extrinsic and intrinsic factors associated with mycotoxigenic fungi populations of maize grains (Zea mays L.) stored in silobags in Argentina

Con el objeto de caracterizar las poblaciones fúngicas, en particular las especies potencialmente micotoxigénicas, que pueden contaminar los granos de maíz almacenados en silos bolsa con un contenido de humedad superior al recomendado como seguro, se evaluaron 270 muestras extraídas al inicio, a los 90 días y al final de un período de almacenamiento de 5 meses. En dichas muestras se cuantificó e identificó la biota fúngica y se determinó la contaminación con fumonisinas y aflatoxinas. Asimismo, se evaluó el efecto de factores extrínsecos (ambiente), intrínsecos (granos) y tecnológicos (ubicación de los granos en el perfil del silo bolsa) sobre las poblaciones totales y micotoxigénicas. El pH de los granos y el nivel de O2 se redujeron significativamente a los 5 meses, mientras que la concentración de CO2 se incrementó en igual período. Los recuentos totales de la micobiota fueron significativamente mayores en los granos ubicados en el estrato superior del silo bolsa. Se identificaron especies micotoxigénicas de Fusarium, Aspergillus, Penicillium y Eurotium. La frecuencia de aislamiento de Fusarium verticillioides se redujo al final del almacenamiento y Aspergillus flavus solo se aisló en el inicio del almacenamiento. Los recuentos de Penicillium spp. y Eurotium spp. se incrementaron al final del almacenamiento. El 100 % de las muestras presentaron contaminación con fumonisinas, con niveles máximos de 5,707 mg/kg, mientras que las aflatoxinas contaminaron el 40 % de las muestras con niveles máximos de 0,0008 mg/kg. Las condiciones ambientales y de sustrato generadas durante el almacenamiento produjeron cambios en la composición de las poblaciones fúngicas y limitaron el desarrollo de hongos micotoxigénicos y la producción de micotoxinas.

In order to determine the behavior of mycotoxin-producing fungal populations linked with silobags stored corn grains with a moisture content greater at the recommended as safe, 270 samples taken in three times (beginning, 90 days, final) over a five month period of storage were evaluated. The fungal biota was quantified and identified and the contamination with fumonisin and aflatoxin was determined. Extrinsic factors (environment), intrinsic factors (grains) and technological factors (location of the grains in the profile of silobag) were taken into account to evaluate the presence and quantity of total and mycotoxigenic fungal populations. The pH of grains and O2 levels were significantly reduced after five months, while CO2 concentration increased in the same period. The total counts of mycobiota were significantly higher in grains located in the top layer of silobag. Mycotoxigenic species of Fusarium, Aspergillus, Penicillium and Eurotium were identified. The frequency of isolation of Fusarium verticillioides decreased at the end of storage and Aspergillus flavus was isolated only at the beginning of storage. The counts of the Penicillium spp. and Eurotium spp. were increased at the end of storage. Fumonisin contamination was found in all the samples (100 %) with maximum levels of 5.707 mg/kg whereas aflatoxin contaminated only 40 % with maximum levels of 0.0008 mg/kg. The environmental and substrate conditions generated during the storage limited the development of mycotoxigenic fungi and mycotoxin production.

Rapid detection of fumonisin B1 using a colloidal gold immunoassay strip test in corn samples.

Fumonisin B1 (FB1) is the most common and highest toxic of fumonisins species, exists frequently in corn and corn-based foods, leading to several animal and human diseases. Furthermore, FB1 was reported that it was associated with the human esophageal cancer. In view of the harmful of FB1, it is urgent to develop a feasible and accuracy method for rapid detection of FB1. In this study, a competitive immunoassay for FB1 detection was developed based on colloidal gold-antibody conjugate. The FB1-keyhole limpet hemoeyanin (FB1-KLH) conjugate was embedded in the test line, and goat anti-mouse IgG antibody embedded in the control line. The color density of the test line correlated with the concentration of FB1 in the range from 2.5 to 10 ng/mL, and the visual limit detection of test for FB1 was 2.5 ng/mL. The results indicated that the test strip is specific for FB1, and no cross-reactivity to other toxins. The quantitative detection for FB1 was simple, only needing one step without complicated assay performance and expensive equipment, and the total time of visual evaluation was less than 5 min. Hence, the developed colloidal gold-antibody assay can be used as a feasible method for FB1 rapid and quantitative detection in corn samples.

Detection of N-(1-deoxy-D-fructos-1-yl) Fumonisins B2 and B3 in Corn by High-Resolution LC-Orbitrap MS.

The existence of glucose conjugates of fumonisin B2 (FB2) and fumonisin B3 (FB3) in corn powder was confirmed for the first time. These "bound-fumonisins" (FB2 and FB3 bound to glucose) were identified as N-(1-deoxy-D-fructos-1-yl) fumonisin B2 (NDfrc-FB2) and N-(1-deoxy-D-fructos-1-yl) fumonisin B3 (NDfrc-FB3) respectively, based on the accurate mass measurements of characteristic ions and fragmentation patterns using high-resolution liquid chromatography-Orbitrap mass spectrometry (LC-Orbitrap MS) analysis. Treatment on NDfrc-FB2 and NDfrc-FB3 with the o-phthalaldehyde (OPA) reagent also supported that D-glucose binding to FB2 and FB3 molecules occurred to their primary amine residues.

Nanomaterial-based biosensors for food toxin detection.

There is an increased interest toward the development of bioelectronic devices for food toxin (mycotoxins) detection. Mycotoxins are highly toxic secondary metabolites produced by fungi like Fusarium, Aspergillus, and Penicillium that are frequently found in crops or during storage of food including cereals, nuts, fruits, etc. The contamination of food by mycotoxins has become a matter of increasing concern. High levels of mycotoxins in the diet can cause adverse, acute, and chronic effects on human health and a variety of animal species. Side effects may particularly affect the liver, kidney, nervous system, endocrine system, and immune system. Among 300 mycotoxins known till date, there are a few that are considered to play an important part in food safety, and for these, a range of analytical methods have been developed. Some of the important mycotoxins include aflatoxins, ochratoxins, fumonisins, citreoviridin, patulin, citrinin, and zearalenon. The conventional methods of analysis of mycotoxins normally require sophisticated instrumentation, e.g., liquid chromatography with fluorescence or mass detectors, combined with extraction procedures for sample preparation. Hence, new analysis tools are necessary to attain more sensitive, specific, rapid, and reliable information about the desired toxin. For the last about two decades, the research and development of simpler and faster analytical procedures based on affinity biosensors has aroused much interest due to their simplicity and sensitivity. The nanomaterials have recently had a great impact on the development of biosensors. The functionalized nanomaterials are used as catalytic tools, immobilization platforms, or as optical or electroactive labels to improve the biosensing performance to obtain higher sensitivity, stability, and selectivity. Nanomaterials, such as carbon nanomaterials (carbon nanotubes and graphene), metal nanoparticles, nanowires, nanocomposites, and nanostructured metal oxide nanoparticles are playing an increasing role in the design of sensing and biosensing systems for mycotoxin determination. Furthermore, these nanobiosystems are also bringing advantages in terms of the design of novel food toxin detection strategies. We will focus on some of the recent results related to fabrication of nanomaterial-based biosensors for food toxin detection obtained in our laboratories.

Use of liquid chromatography-high-resolution mass spectrometry for isolation and characterization of hydrolyzed fumonisins and relevant analysis in maize-based products.

The synthesis of partially hydrolyzed fumonisins (PHFB1 and PHFB2) and hydrolyzed fumonisins (HFB1 and HFB2) by chemical hydrolysis of pure fumonisins (FB1 and FB2) is reported together with the isolation and characterization by liquid chromatography-high-resolution mass spectrometry (LC-HRMS). Two structural isomers of partially hydrolyzed forms of FB1 and FB2 were identified, namely PHFB(1a) and PHFB(1b) and PHFB(2a) and PHFB(2b). Reaction yields were 21% for PHFB1 (sum of the two isomers), 52% for HFB1, 31% for PHFB2 (sum of the two isomers) and 30% for HFB2. Purity of each isolated compound was >98%. An LC-HRMS method for the simultaneous determination of fumonisins and their partially and totally hydrolyzed derivatives was applied to 24 naturally contaminated samples of maize and maize-based products. The majority of samples (18 out of 24) were contaminated with fumonisins B1 and B2. Fumonisins co-occurred with both partially hydrolyzed and hydrolyzed fumonisins in four nixtamalized samples (three masa flours and one tortilla chips). Co-occurrence of fumonisins with partially hydrolyzed fumonisins was also recorded in one sample of maize kernels and four samples of maize-based products (i.e. maize meal, cous-cous, corn-cakes and cornflakes). Mycotoxins levels ranged from 60 to 5700 µg/kg for fumonisins (sum of FB1 and FB2), from 10 to 210 µg/kg for partially hydrolyzed fumonisins (sum of PHFB1 and PHFB2) and from 30 to 200 µg/kg for hydrolyzed fumonisins (sum of HFB1 and HFB2). This is the first report of the isolation of PHFB2 and the co-occurrence of FB1, FB2, PHFB1, PHFB2, HFB1 and HFB2 in maize products. Considering the growing use of nixtamalized and maize-based products, the monitoring of fumonisins and their partially and totally hydrolyzed forms in these products may represent an important contributing factor in evaluating the relevant human risk exposure.

Reliable and simple detection of ochratoxin and fumonisin production in black Aspergillus.

To date, edible fungi such as black Aspergillus (Aspergillus niger aggregates) have been considered as safe. However, it has recently been reported that some strains have a mycotoxin biosynthetic capability, and this capability must be evaluated to determine the safety of edible fungi. In this study, we assessed the ability of mycotoxin production in A. niger aggregates isolated from various Korean foods using multiplex PCR and high-performance liquid chromatography (HPLC) analyses. Multiplex PCR and HPLC analyses of 32 A. niger aggregates showed that ochratoxin and fumonisin were produced only by strains exhibiting positive PCR patterns with ochratoxin and fumonisin biosynthesis genes. However, several strains did not produce mycotoxins, even though they contained mycotoxin biosynthesis genes. Using multiplex PCR pattern and HPLC analyses, we selected Aspergillus strains that do not produce mycotoxins, which will contribute to the development of safer fermented foods.

Preparation and identification of monoclonal antibody against fumonisin B(1) and development of detection by Ic-ELISA.

Fumonisin B(1) (FB(1)) is one of the mycotoxins produced by Fusarium verticillioides, which was mainly found in corn and related products. FB(1) was small molecule with no immunogenicity, so it should be conjugated to carrier proteins such as BSA (bovine serum albumin) or KLH (keyhole limpet hemocyanin) to generate immunogenicity. In this study, conjugate FB(1)-BSA was used to immunize Balb/c mice, and one hybrid cell line 4G5 excreting monoclonal antibody against FB(1) was obtained by fusing mouse Sp2/0 myeloma cells with spleen cells from the immunized mouse. Hybridoma 4G5 was injected into the abdomen of Balb/c mice, and the anti-FB(1) mcAb was harvested from ascites and the titer reached 6.4 × 10(4) after purification with caprylic/ammonium sulfate precipitation (CA-AS) method. The cross-reactivity results showed that anti-FB(1) mcAb was highly specific to fumonisin B(1), and the affinity was 2.1 × 10(8) L/M. Indirect competitive ELISA (ic-ELISA) indicated that the linear range to detect FB(1) was 1-800 ng/mL with IC50 of 32 ng/mL. The detection limit was 1.0 ng/mL, and the recovery average was 93.75 ± 6.90%. Therefore, the anti-FB(1) mcAb excreted by 4G5 can be used to detect fumonisin B(1) in corn and related samples.

Assessment of multi-mycotoxin adsorption efficacy of grape pomace.

Grape pomace (pulp and skins) was investigated as a new biosorbent for removing mycotoxins from liquid media. In vitro adsorption experiments showed that the pomace obtained from Primitivo grapes is able to sequester rapidly and simultaneously different mycotoxins. Aflatoxin B1 (AFB1) was the most adsorbed mycotoxin followed by zearalenone (ZEA), ochratoxin A (OTA), and fumonisin B1 (FB1), whereas the adsorption of deoxynivalenol (DON) was negligible. AFB1 and ZEA adsorptions were not affected by changing pH values in the pH 3-8 range, whereas OTA and FB1 adsorptions were significantly affected by pH. Equilibrium adsorption isotherms obtained at different temperatures (5-70 °C) and pH values (3 and 7) were modeled and evaluated using the Freundlich, Langmuir, Sips, and Hill models. The goodness of the fits and the parameters involved in the adsorption mechanism were calculated by the nonlinear regression analysis method. The best-fitting models to describe AFB1, ZEA, and OTA adsorption by grape pomace were the Sips, Langmuir, and Freundlich models, respectively. The Langmuir and Sips models were the best models for FB1 adsorption at pH 7 and 3, respectively. The theoretical maximum adsorption capacities (mmol/kg dried pomace) calculated at pH 7 and 3 decreased in the following order: AFB1 (15.0 and 15.1) > ZEA (8.6 and 8.3) > OTA (6.3-6.9) > FB1 (2.2 and 0.4). Single- and multi-mycotoxin adsorption isotherms showed that toxin adsorption is not affected by the simultaneous presence of different mycotoxins in the liquid medium. The profiles of adsorption isotherms obtained at different temperatures and pH and the thermodynamic parameters (ΔG°, ΔH°, ΔS°) suggest that mycotoxin adsorption is an exothermic and spontaneous process, which involves physisorption weak associations. Hydrophobic interactions may be associated with AFB1 and ZEA adsorption, whereas polar noncovalent interactions may be associated with OTA and FB1 adsorption. In conclusion, this study suggests that biosorption of mycotoxins onto grape pomace may be a reasonably low-cost decontamination method.

Characterization and validation of sampling and analytical methods for mycotoxins in workplace air.

Mycotoxins are produced by certain plant or foodstuff moulds under growing, transport or storage conditions. They are toxic for humans and animals, some are carcinogenic. Methods to monitor occupational exposure to seven of the most frequently occurring airborne mycotoxins have been characterized and validated. Experimental aerosols have been generated from naturally contaminated particles for sampler evaluation. Air samples were collected on foam pads, using the CIP 10 personal aerosol sampler with its inhalable health-related aerosol fraction selector. The samples were subsequently solvent extracted from the sampling media, cleaned using immunoaffinity (IA) columns and analyzed by liquid chromatography with fluorescence detection. Ochratoxin A (OTA) or fumonisin and aflatoxin derivatives were detected and quantified. The quantification limits were 0.015 ng m(-3) OTA, 1 ng m(-3) fumonisins or 0.5 pg m(-3) aflatoxins, with a minimum dust concentration level of 1 mg m(-3) and a 4800 L air volume sampling. The methods were successfully applied to field measurements, which confirmed that workers could be exposed when handling contaminated materials. It was observed that airborne particles may be more contaminated than the bulk material itself. The validated methods have measuring ranges fully adapted to the concentrations found in the workplace. Their performance meets the general requirements laid down for chemical agent measurement procedures, with an expanded uncertainty less than 50% for most mycotoxins. The analytical uncertainty, comprised between 14 and 24%, was quite satisfactory given the low mycotoxin amounts, when compared to the food benchmarks. The methods are now user-friendly enough to be adopted for personal workplace sampling. They will later allow for mycotoxin occupational risk assessment, as only very few quantitative data have been available till now.