Ng Ochratoxin A Research Articles

A label-free, direct solid-phase fluorimetric analysis of ochratoxin A in agricultural products with monoclonal antibody-immobilized monolith

We established a method for directly measuring mycotoxin ochratoxin A (OTA) in foods by solid-phase fluorescence of monolith-immobilized antibodies. The antibody was introduced onto only one side of an 8 mm-diameter, 3 mm-thick monolith via covalently immobilized protein G. 4 μg (2.7 × 10−11 mol) of antibody was immobilized per one monolith. A maximum of 10 μg (2.4 × 10−11 mol) OTA adsorbed to the activated side of each monolith. The amount of OTA adsorbed and the fluorescence intensity showed good linearity in the range of 0.5–3 ng OTA. Loading the sample solution onto the non-antibody side on the monolith blocked the hydrophobic fluorescent matrices from reaching the immobilized surface of the antibody. The proposed method was able to detect 1 ng OTA/g in solid samples with complex matrices. Mean recoveries obtained at spiked concentration of 3 ng g−1 OTA/g were 78–90% with relative standard deviations of <7.9%.

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 1.1μg/kg, respectively. OTA levels in five of 64 samples (7.8 %) were higher than the permissible limit recommended by European Commission (permissible limit: 0.5μg/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.

Oxidative Stress of in-Ovo Ochratoxin A Administered during Chick Embryonic Development

ABSTRACT The present work was carried out to study the effect of in-ovo injection of ochratoxin A (OTA) as an oxidative stress and its consequences on hepatic and kidney functions, thyroid activity, and histological examination of brain and liver in chicken embryos and subsequently in the hatching chicks. On the 10th day of incubation, one hundred and sixty-two fertile eggs were randomly divided into two equal treatments. Control treatment, (injected by 50 µl sodium carbonate) and OTA treatment (injected by 12.5 ng OTA dissolved in 50 µl sodium carbonate). OTA treatement group significantly reduced glutathione (GSH) and significantly increased thiobarbituric acid reactive substances production (TBARS) in embryonic and hatched chicks regarding livers, spleen, bursa of Fabricius, heart, and brain as an indicator of oxidative stress. OTA injection increased TBARS and decreased GSH levels in both allantoic and amniotic fluids. On the 14th and 16th days of incubation and at the hatch, a significant lower concentration in cholesterol and higher concentrations of alanine amino transferase, aspartate amino transferase, alkaline phosphatase, gamma glutamyl transferase, acid phosphatase enzymes activities and triglycerides in the hepatic tissues of the OTA group were observed. Histological examination of OTA group of brain and liver tissues showed some degenerative changes through the experimental period. In conclusion, in-ovo OTA treated had teratogenic and embryotoxic effects.

A reproductive and developmental screening study of the fungal toxin ochratoxin A in Fischer rats.

The presence of the mycotoxin ochratoxin A (OTA) in cereal grains is due to the growth of toxigenic Penicillium mold on stored crops. Human exposure to OTA is higher in infants, toddlers, and children than in adolescents and adults, based on exposure assessments of ng OTA consumed/kg body weight/day. Ochratoxin A is nephrotoxic and teratogenic in animals, but its effects on juveniles exposed during the reproduction and development period have not been studied. To address this, Fischer rats were exposed to 0, 0.16, 0.4, 1.0, or 2.5mg OTA/kg diet throughout breeding, gestation, and lactation and its adverse effects were assessed in adult rats and their offspring on postnatal day (PND) 21. There were no effects on implantation but post-implantation fetotoxicity was observed in the 2.5mg/kg dose group, corresponding to a calculated dose of 167.0μg/kg bw/day in dams. Adverse effects on body and kidney weights and on clinical parameters indicative of renal toxicity were significant in adult rats exposed to 1.0mg OTA/kg diet (55.2 and 73.3μg/kg bw/day in adult males and females, respectively) and in PND21 rats at the 0.4mg/kg dose (33.9μg/kg bw/day in dams), suggesting that weanling rats were more sensitive to OTA than adults. Overall, nephrotoxicity was the primary effect of OTA in weanling rats exposed throughout gestation and lactation at sub-fetotoxic concentrations in diet.

Toxic Effects of Ochratoxin A on Calcium Metabolism during Chick Embryo Developmentand in Hatched Chicks

The present study was carried out to study the effect of in-ovo ochratoxin A (OTA) injection in Highline layer eggs on calcium metabolism and blood biochemical parameters of embryos and after the hatch. At day 10 of embryonic development, one hundred and sixty-two fertile eggs were individually weighed and divided into two equal treatments. The first treatment (control) consisted of the individual injection of fertile eggs with 50 µL sodium carbonate. In the second treatment (OTA), fertile eggs were individually injected with 12.5 ng OTA dissolved in 50 µL sodium carbonate. On days 12, 14, and 16 of incubation and at the hatch, serum calcium and inorganic phosphorus concentrations were lower (p<0.05), while sodium, alkaline phosphatase and triiodothyronine concentrations were higher (p<0.05) in the OTA-injected eggs compared with the controls. Serum potassium concentration was not affected (p<0.05) by OTA treatment. Lower calcium and phosphorus levels were determined (p<0.05) in the allantoic fluid of OTA-injected eggs compared with the controls. On days 12, 14, and 16 of incubation and at the hatch, lower whole body and yolk calcium and phosphorus, but not sodium levels, were measured (p<0.05) in the OTA treatment compared with the controls. In conclusion, the injection of eggs with OTA reduced blood calcium and phosphorus levels, which were associated with reduced whole body and yolk content from these electrolytes. Therefore, ochratoxin A had a negative effect on calcium metabolism.

Gamma radiation inhibits the production of Ochratoxin A by Aspergillus carbonarius. Development of a method for OTA determination in raisins

Ochratoxin A (OTA) is a mycotoxin of great interest to humans for its nephrotoxic effects. The development and validation of an OTA method determination in raisins is described by using High Pressure Liquid Chromatography (HPLC) with Fluorescence Detector (FD). The recovery of the method was 104% while the detection limit (DL) and quantification limit were 0.26 and 0.51 ng g−1, respectively. The effect of gamma irradiation at dose of 10 kGy on the production of OTA by Aspergillus carbonarius in raisins (Vitis vinifera L.) and on OTA in contaminated samples, was investigated. The OTA which was produced by A. carbonarius on the 12th day of incubation, after irradiation, showed that at dose level of 10 kGy, OTA production was not detectable (below the detection limit of the method) compared with the non-irradiated the same day. A dose of 10-kGy gamma radiation applied on 100 ng of OTA, in raisins reduced OTA contamination ~88%. According to the risk assessment analysis the Provisional Maximum Tolerable Daily Intake (PMTDI) of 5.8 ng OTA kg−1 bw, indicates that adult consumers are less exposed, 31.4–78.4 fold lower to OTA by the irradiated raisins.

Composting coffee wastes, a potential source of ochratoxigenic fungi and ochratoxin A contamination

Ochratoxin A (OTA) has been extensively documented as a global contaminant of a wide variety of food commodities including the green coffee bean, but there is no clear information available on the spread of Aspergillus ochraceus in the coffee production chain. In this study, the growth of A. ochraceus and the fate of OTA during composting of solid coffee wastes, i.e. pulp and husk, were investigated. A trial was set up with pulp and husk alone or in combination, naturally and artificially contaminated with A. ochraceus. OTA was detected at levels up to 2.6 and 6.2 ng/g in naturally and artificially contaminated pulp, respectively. At the end of the composting process, 8.4 and 14.2 ng OTA per g were measured in naturally and artificially contaminated husk, respectively. Throughout the composting process, A. ochraceus counts did not show any clear increasing or decreasing trend.

Ochratoxin A in wines from 2002 to 2008 harvest marketed in Rio de Janeiro, Brazil

The occurrence of ochratoxin A (OTA) in wine from 2002 to 2008 harvest, traded in Rio de Janeiro State, was evaluated by analysing 43 national and 37 imported wines from Argentina (32) and Chile (5), adding up to 80 samples in total. OTA determination was performed using immunoaffinity columns and high-performance liquid chromatography. In 80 wine samples analysed, 25 (31.3%) were positive, presenting levels greater than 0.020 ng OTA mL−1. It was not detected in imported wines. Within national wines, 58.1% of the samples were contaminated, with levels ranging from 0.020 to 0.050 ng mL−1. The toxin was detected in 18 (69.2%) of 26 samples analysed of red table wine. Wines from 2008 harvest presented 84.6% of samples contaminated in 13 samples analysed. Despite the levels found in this study, they are below Brazilian tolerance limits. Nevertheless, the presence of OTA as found contributes to the human exposure to this toxin.

Competitive direct ELISA based on a monoclonal antibody for detection of Ochratoxin A in dried fig samples

A monoclonal antibody (MAb) generated against Ochratoxin A (OTA) has been used in a competitive direct enzyme linked immunosorbent assay (cdELISA) for the detection of OTA in dried figs obtained from the Spanish retail market. Fifty per cent inhibition of the maximum binding was obtained with an OTA concentration of 2 ng/mL, and the detection limit for OTA in solution was 0.18 ng/mL, corresponding to 3.15 ng OTA per gram of sample. OTA was detected in 19 (54.3%) out of 35 samples of dried figs analysed, with concentrations that ranged from 3.15 to 277 ng/g. Five samples contained OTA concentrations above the tolerable level set by EC regulations for dried vine fruits (10 ng/g). The MAb-based cdELISA assay developed in this work could be effectively applied for OTA screening in dried figs.

Health risk assessment of ochratoxin A for all age-sex strata in a market economy

In order to manage risk of ochratoxin A (OTA) in foods, we re-evaluated the tolerable daily intake (TDI), derived the negligible cancer risk intake (NCRI), and conducted a probabilistic risk assessment. A new approach was developed to derive ‘usual’ probabilistic exposure in the presence of highly variable occurrence data, such as encountered with low levels of OTA. Canadian occurrence data were used for various raw food commodities or finished foods and were combined with US Department of Agriculture (USDA) food consumption data, which included data on infants and young children. Both variability and uncertainty in input data were considered in the resulting exposure estimates for various age/sex strata. Most people were exposed to OTA on a daily basis. Mean adjusted exposures for all age–sex groups were generally below the NCRI of 4 ng OTA kg bw−1, except for 1–4-year-olds as a result of their lower body weight. For children, the major contributors of OTA were wheat-based foods followed by oats, rice, and raisins. Beer, coffee, and wine also contributed to total OTA exposure in older individuals. Predicted exposure to OTA decreased when European Commission maximum limits were applied to the occurrence data. The impact on risk for regular eaters of specific commodities was also examined.

Reduction of Ochratoxin A Levels in White Wine by Yeast Treatments

This paper describes the abilities of 21 yeast strains isolated from six different wine-grapes of Turkey to bind ochratoxin A (OTA). Viable (108 CFU/mL) and heat-treated yeast cells were incubated both in phosphate-buffered saline (PBS) and white wine containing 10 ng OTA per mL for 4 h at 25°C. After centrifugation, the concentration of OTA was measured in the supernatant fraction using a high-performance liquid chromatography system coupled with fluorescence detector. The adsorption abilities of OTA by viable yeast strains within 4 h ranged from 1.96 to 26.11% in PBS. On the other hand, a slight decrease was observed in the percentage of OTA removal by yeast strains in white wine when compared to their activity in PBS. The addition of yeasts at 108 CFU/mL resulted in a reduction to a maximum of 21.40% in white wine, with respect to the control. Among the yeasts, Candida famata D7 was found to be the most efficient binder to OTA both in spiked white wine and PBS. In addition, dead yeast cells can potentially be used for removing OTA (a maximum of 30.45%) from white wine.

Study of the Ochratoxin A effect on Aspergillus parasiticus growth and aflatoxin B 1 production

Aflatoxin B 1 (AFB 1) is a carcinogenic metabolite produced by certain Aspergillus species. Ochratoxin A (OTA) is a metabolite of Aspergillus ochraceus and Penicillium verrucosum. AFB 1 and OTA are amongst the most frequent combinations of mycotoxins found in plant products. Thus, synergistic effects or interactions between the two mycotoxins could be taking place. The aim of the present study was to investigate the effect of OTA on Aspergillus parasiticus growth and AFB 1 production in yeast extract sucrose (YES) medium at concentrations of 0.16, 1.6 and 16 ng OTA flask −1. The AFB 1 extracted from cultures and purified with immunoaffinity columns was then quantitated by HPLC. The recovery and detection limit of the method were 95.3% and 0.02 ng AFB 1 mL −1, respectively. Maximum AFB 1 productions in cultures with OTA were observed from 9 to 12 days (76.09–82.52 ng AFB 1 flask −1) while in control cultures (without OTA) maximum production (197.2 ng AFB 1 flask −1) was observed on 14th day. Maximum AFB 1 levels in cultures with OTA were reduced by a percentage of 58–61% compared to control cultures. Furthermore AFB 1 levels in cultures with OTA were practically (92%) degraded after 18 days of incubation. Conclusively when OTA is present the production of AFB 1 by A. parasiticus in YES medium is inhibited.

Simultaneous detection of airborne Aflatoxin, Ochratoxin and Zearalenone in a poultry house by immunoaffinity clean-up and high-performance liquid chromatography

An AOZ method, based on high-performance liquid chromatography (HPLC), was optimized on HPLC condition such as mobile phase and wavelength to simultaneously quantify six kinds of mycotoxins [four aflatoxins (AFs), ochratoxin A (OTA) and zearalenone (ZEA)]. Conditions for immunoaffinity clean-up, HPLC and photo-derivatization were optimized in this study and successfully applied in assessment of airborne mycotoxins from a poultry house in Dalian, China. Fifty-two air samples were collected with AGI-30 air samplers using pure water as collection media. Twenty air samples (20/52, 38.46%) were positive for four toxins. Among the positive samples, airborne mycotoxin concentrations (mean±S.D.) for AFG 2, AFB 1, and ZEA were 0.189±0.024 ( n=9), 0.080±0.003 ( n=11) and 2.363±0.030 ( n=5) ng/m 3 air, while the concentration for OTA was 8.530 ( n=1) ng/m 3. No positive sample was found for either AFG 1 or AFB 2. A chicken may inhale 0.019–0.057 ng AFG 2, 0.013–0.019 ng AFB 1, 0.436–0.513 ng ZEA, and 1.706 ng OTA, respectively, in a day. A poultry worker may inhale 0.504–1.512 ng AFB 1, 0.752–2.28 ng AFG 2, 68.240 ng OTA, and 17.432–20.512 ng ZEA in a working day. This is the first report on airborne mycotoxins in poultry house. These data may have importance in animal and public health implications.

A survey on the occurrence of ochratoxin A in feeds and sera collected in conventional and organic poultry farms in Northern Italy

A survey has been conducted on conventional and organic poultry farms located in northern Italy in order to investigate the occurrence of ochratoxin A (OTA) in feeds and sera in 2006. Ten poultry farms were monitored by taking 20 samples of feed and 94 samples of blood. OTA was assessed through immunoaffinity column purification and HPLC analysis. For in-house validation, recovery experiments, carried out on the spiked samples in the range of 1.0-10.0 μg OTA kg-1 and 0.3-3.0 ng OTA ml-1 for the feed and serum samples, respectively, led to overall recovery averages of 80.6% (RDS=7.3%, n=9) and 83.3% (RDS=3.1%, n=9), respectively. All the feed samples were contaminated by OTA with values ranging from 0.04 to 6.50 μg kg-1. Fiftythree percent of the sera samples were positive, with values ranging from 0.003-0.165 ng ml-1. None of the feed samples was above the limits set by the European Union on OTA contamination in poultry feeds. No statistically significant differences in OTA contamination of feed or sera were observed either between the organic vs conventional group or between the laying hens vs broiler group.

Guttation droplets of Penicillium nordicum and Penicillium verrucosum contain high concentrations of the mycotoxins ochratoxin A and B

Eight of eleven ochratoxigenic isolates of Penicillium nordicum and Penicillium verrucosum produced guttation droplets when grown on Czapek yeast extract (CYA) agar for 10-14 days at 25 degrees C. Parallel cultivation of one strain each of P. nordicum and P. verrucosum on malt extract agar demonstrated that higher volumes of exudate are produced on this agar. However, HPLC analyses revealed higher concentrations of ochratoxin A (OTA) and B (OTB) in droplets originating from cultures on CYA. For quantitative determination of the mycotoxin contents, triplicates of three isolates each of P. nordicum and P. verrucosum were grown as single spot cultures on CYA for up to 14 days at 25 degrees C. Guttation droplets were carefully collected between day 11 and 14 with a microliter syringe from each culture. Extracts from exudates and corresponding mycelia as well as fungal free agar were analyzed by HPLC for the occurrence of ochratoxin A (OTA) and B (OTB). Mean concentrations ranging between 92.7-8667.0 ng OTA and 159.7-2943.3 ng OTB per ml were detected in the guttation fluids. Considerably lower toxin levels were found in corresponding samples of the underlying mycelia (9.0-819.3 ng OTA and 4.5-409.7 ng OTB/g) and fungal free agar (15.3-417.0 ng OTA and 12.7-151.3 ng OTB/g). This is the first report which shows that high amounts of mycotoxins could be excreted from toxigenic Penicillium isolates into guttation droplets.

Study of aflatoxin B 1 and ochratoxin A production by natural microflora and Aspergillus parasiticus in black and green olives of Greek origin

Aflatoxin B 1 (AFB 1) is a carcinogenic metabolite produced by certain Aspergillus species. Ochratoxin A (OTA) is classified as “possible carcinogen” and it is a metabolite of Aspergillus ochraceus and Penicillium verrucosum. Fungi contaminate natural and processed olives which support AFB 1 and OTA production. The aim of this study was to compare and investigate AFB 1 and OTA production in three different varieties of damaged olives. For each variety two different treatments were applied: (1) olives with natural microflora and (2) olives inoculated with A. parasiticus after natural microflora elimination. AFB 1 and OTA have been extracted simultaneously from olives, purified with immunoaffinity columns and quantitated by HPLC using fluorescence detector. The recoveries and detection limits of AFB 1 and OTA were 94% and 0.15 ng AFB 1 g −1 and 102.7%, 0.41 ng OTA g −1 respectively. Results showed that, meanwhile OTA was not found in any olive sample, AFB 1 production within the three varieties of olives with natural microflora was significantly ( P ⩽ 0.05 ) different regarding their substrate and time of incubation (18 days). AFB 1 production in two different varieties of black olives after inoculation by A. parasiticus was not significantly higher compared with control samples. On the contrary, AFB 1 production in green olives was stimulated after the 12th day. Additionally, investigation on the occurrence of AFB 1 and OTA in 30 samples of olives and olive pasta from Athens market showed OTA's presence in two samples of olives contaminated at the levels of 1.18 and 1.86 ng OTA g −1. Aflatoxin B 1 was found at levels 0.15–1.13 ng AFB 1 g −1 in all samples tested.

Molecularly-imprinted polypyrrole-modified stainless steel frits for selective solid phase preconcentration of ochratoxin A

A molecularly-imprinted polymer (MIP) was prepared by electropolymerization of pyrrole (Py) onto a stainless steel frit, using ochratoxin A (OTA) as the template, in order to make a micro solid phase preconcentration (microSPP) device. The OTA template was removed with 1% triethylamine (TEA) in methanol. Compared to non-imprinted polypyrrole (PPy), the molecularly-imprinted polypyrrole (MIPPy) enhanced the selective binding of OTA. The percentage recovery improved from 0 to 40% when the OTA sample solution was acidified with 1 M HCl (1% by volume). At a flow rate of 0.2 mL/min, maximum OTA binding was reached in 6 min after a total loading of 3.2 ng OTA. Final elution of the OTA was analyzed by high performance liquid chromatography (HPLC) with fluorescence detection, using 20:80 v/v acetonitrile-ammonia buffer (NH4Cl/NH3, 20 mM, pH 9.2) as the mobile phase. The MIPPy-microSPP-HPLC results clearly demonstrated that the MIPPy-microSPP device afforded selective preconcentration of OTA from red wine samples, at OTA concentration levels as low as 0.05 ppb, prior to HPLC analysis.

Penicillium verrucosum occurrence and Ochratoxin A contents in organically cultivated grain with special reference to ancient wheat types and drying practice

This study addresses the relationship between the ochratoxigenic strains of Penicillium verrucosum and ochratoxin A (OTA) contents in organically cultivated grain. It included 37 combined, non-dried grain samples from farmers with no drying facilities as well as 19 non-dried and 22 dried samples from six farms with on-farm drying facilities (Case studies 1-6). The study focused on the ancient wheat type spelt but also included samples of wheat, rye, barley, oats, triticale, emmer, and einkorn. All 78 samples were analysed for moisture content (MC) and occurrence of P. verrucosum. The latter was assessed by plating non-disinfected kernels on DYSG agar and counting those contaminated by the fungus. Fifty-five samples were analysed for OTA. Most of the combine harvested samples (82%) were contaminated with P. verrucosum prior to drying. This was ascribed to difficult harvest conditions and many samples of spelt, which was significantly more contaminated by P. verrucosum than oats, wheat and barley. Though not statistically significant, the results also indicated that spelt was more contaminated than rye, which is usually regarded the most sensitive small grain cereal. No correlation was found between number of kernels contaminated by P. verrucosum and OTA content. Despite many non-dried samples being contaminated by P. verrucosum, only two exceeded the EU maximum limit for grain (5 ng OTA g(-1)), both being spring spelt with 18 and 92 ng g(-1), respectively. The problems were most likely correlated to a late harvest and high MC of the grain. The case studies showed exceedings of the maximum limit in a batch of dried oats and spring wheat, respectively, probably to be explained by insufficient drying of late harvested grain with high MC. Furthermore, our results clearly indicate that OTA is not produced in significant amounts in samples with MCs below 17%. All dried samples with MCs above 18% exceeded the 5 ng OTA g(-1) limit in grain. However, no correlation between MC and the amount of OTA produced was found.

Polypyrrole modified stainless steel frits for on-line micro solid phase extraction of ochratoxin A

Polypyrrole (PPy) was electrochemically synthesized on stainless steel frits as a sorbent for the micro solid phase extraction (muSPE) of ochratoxin A (OTA). Using 20 microl of standard solution under a fast flow rate of 0.5 ml/min, 80% recovery of OTA was achieved in the concentration range from 0.1-10 pg/mul. This good recovery was achieved within a short residence time of 1.2 s. A binding capacity of 1 ng OTA was estimated for each PPy-modified frit, or 2 ng OTA for two frits in series. The bound OTA could be pulsed eluted (PE) with 20 microl of 1% triethylamine in acetonitrile. On-line coupling of this PPy-on-a-frit and PE technique to high performance liquid chromatography (HPLC) was straightforward. On-line muSPE-PE-HPLC results clearly demonstrated the capability of PPy-on-a-frit to bind OTA in the presence of red wine, beer, and orange juice components.

Analysis of wheat extracts for ochratoxin A by molecularly imprinted solid-phase extraction and pulsed elution.

A molecularly imprinted solid-phase extraction (MISPE) method has been developed for the rapid analysis of wheat extracts for ochratoxin A (OTA). Molecularly imprinted polymer (MIP) particles were synthesized from N-phenylacrylamide (PAM) and slurry-packed into a micro-column for selective solid-phase extraction (SPE) of OTA. With water flowing at 0.5 mL min(-1), a total binding capacity of 30 ng OTA was determined for the 20 mg of MIP particles. MISPE conditions were optimized using OTA in methanol/acetic acid (99:1 v/v). Nearly 100% binding could be achieved from one 20-microL injection of sample containing up to 30 ng of OTA. Pulsed elution (PE) using methanol/triethylamine (99:1 v/v) was good for the quantitative desorption of OTA. The MISPE-PE method, with fluorescence detection at lambda(ex)=385 nm and lambda(em)=445 nm, afforded a detection limit of 5.0 ng mL(-1) (or 0.1 ng in 20 microL of sample injected) for OTA. Recovery of OTA from wheat extracts was 103+/-3%. Each MISPE-PE analysis required less than 5 min to complete.