Management of Mycotoxins in Spices.

Spices are very important for cuisines around the world as well as for health enhancement. The Egyptians, Chinese, and Indians have used spices in medicinal remedies and procedures starting in around 2000 BC. Through the centuries, spices have found use as food ingredients to modify the aroma and taste of the final products; however, some spices are suitable substrates for mold growth and mycotoxin development, which could be detrimental to human and animal health. This report covers regulatory control of mycotoxins in food and spices by means of monitoring and regulatory limits, sampling and analysis, management, and prevention of mycotoxins from plant growth (preharvest) through harvest and postharvest as well as decontamination for mycotoxins when necessary. There is no one single-best strategy that can solve mycotoxin contamination problems, but a well-designed and integrated plan of all these strategies could result in a substantial reduction of mycotoxins in spices to regulation safety levels.

The use of regenerated immunoaffinity columns for aflatoxins B1, B2, G1 and G2 in peanut confection.

The aim of this study was to investigate the feasibility of using multitime-regenerated immunoaffinity column (IAC) for aflatoxins B1, B2, G1 and G2 in peanut confection. After each use, the IAC was washed immediately with phosphate-buffered saline and stored for >12h prior to reuse. The evaluation procedure consisted of using extracts of naturallycontaminated peanut confection (4 replicates), aflatoxin-free peanut confection (duplicates), and aflatoxin-free peanut confection sample spiked with the 4 aflatoxins (AFT) at 3 levels in 4 replicates. Each day, 18 test extracts were analyzed using 18 designated IACs. After each use, the IACs were regenerated and reused for corresponding test extracts on the following day. This procedure was repeated daily over the course of 9days. Analytical steps included passing the test extracts through the IACs, washing the columns with water, and eluting AFT with methanol. The eluates were diluted with water and were subjected to reversed phase LC separation, post-column photochemical derivatization and fluorescence detection. After eluting AFT, IACs were immediately regenerated by washing with phosphate buffer solution and storing overnight at 8°C for re-use the following day. Results were analyzed using ANOVA and Tukey tests. The numbers of reuse varied for each AF: For AFB1 AFB2, AFG1and AFG2 could be reused for 9, 6, 6 and 0 times, respectively. According to AOAC method performance criteria, recoveries ranging from 70% to 125% are considered acceptable at the spiking levels used in this study.

Perspective on Advancing FDA Regulatory Monitoring for Mycotoxins in Foods using Liquid Chromatography and Mass Spectrometry (Review).

The presence of mycotoxins (such as aflatoxins, deoxynivalenol, fumonisins, and patulin) is routinely monitored by the U.S. Food and Drug Administration (FDA) to ensure that their concentrations in food are below the levels requiring regulatory action or advisories. To improve the efficiency of mycotoxin analysis, the researchers at the FDA's Center for Food Safety and Applied Nutrition have been evaluating modern LC-MS technologies. Consequently, a variety of LC-tandem MS and LC-high-resolution MS methods have been developed, which simultaneously identify and quantitate multiple mycotoxins in foods and feeds. Although matrix effects (matrix-induced ion suppression or enhancement) associated with LC-MS-based mycotoxin analysis remain, this review discusses methods for managing these effects and proposes practical solutions for the future implementation of LC-MS-based multimycotoxin analysis.

Multi-mycotoxin Analysis of Finished Grain and Nut Products Using Ultrahigh-Performance Liquid Chromatography and Positive Electrospray Ionization-Quadrupole Orbital Ion Trap High-Resolution Mass Spectrometry.

Ultrahigh-performance liquid chromatography using positive electrospray ionization and quadrupole orbital ion trap high-resolution mass spectrometry was evaluated for analyzing mycotoxins in finished cereal and nut products. Optimizing the orbital ion trap mass analyzer in full-scan mode using mycotoxin-fortified matrix extracts gave mass accuracies, δM, of < ± 2.0 ppm at 70,000 full width at half maximum (FWHM) mass resolution (RFWHM). The limits of quantitation were matrix- and mycotoxin-dependent, ranging from 0.02 to 11.6 µg/kg. Mean recoveries and standard deviations for mycotoxins from acetonitrile/water extraction at their relevant fortification levels were 91 ± 10, 94 ± 10, 98 ± 12, 91 ± 13, 99 ± 15, and 93 ± 17% for corn, rice, wheat, almond, peanut, and pistachio, respectively. Nineteen mycotoxins with concentrations ranging from 0.3 (aflatoxin B1 in peanut and almond) to 1175 µg/kg (fumonisin B1 in corn flour) were found in 35 of the 70 commercial grain and nut samples surveyed. Mycotoxins could be identified at δM < ± 5 ppm by identifying the precursor and product ions in full-scan MS and data-dependent MS/MS modes. This method demonstrates a new analytical approach for monitoring mycotoxins in finished grain and nut products.

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.

Screening multimycotoxins in food-grade gums by stable isotope dilution and liquid chromatography/tandem mass spectrometry.

Stable isotope dilution with LC/MSIMS was used to determine the following 11 mycotoxins in food grade gums: aflatoxins B1, B2, G1, and G2; deoxynivalenol; fumonisins B1, B2, and B3; ochratoxin A; T-2 toxin; and zearalenone. Samples were fortified with 11 [13C]-uniformly labeled internal standard ([13C]-IS) mycotoxins that corresponded to the 11 target mycotoxins and extracted by acetonitrile-water (4 + 1, v/v), followed by LC/MS/MS analysis. Mycotoxins were quantitated with the fortified [13C]-IS in each sample. The average recoveries of aflatoxins B1, B2, G1, and G2 (1, 5, and 25 microg/kg); deoxynivalenol and fumonisins B1, B2, and B3 (25, 100, and 500 microg/kg); and ochratoxin A, T-2 toxin, and zearalenone (10, 50, and 250 microg/kg) ranged from 84 to 117% with RSDs less than 20%. Method-dependent LOQs were from 0.1 (aflatoxin B1) to 25 microg/kg (fumonisin B3). Among 20 market samples, aflatoxin B1 (< LOQ) was detected in a Guar gum and a Tragacanth gum, and zearalenone (6 +/- 0.6 microg/kg) was detected in a Xanthan gum. The detected mycotoxins were further confirmed by comparing their enhanced product ion spectra to those of reference standards. The single laboratory validated stable isotope dilution and LC/MSIMS method provides sufficient selectivity, sensitivity, accuracy, and reproducibility with a simple sample preparation to screen the 11 mycotoxins in gums.

Dopant-assisted atmospheric pressure photoionization of patulin in apple juice and apple-based food with liquid chromatography-tandem mass spectrometry.

A dopant-assisted atmospheric pressure photoionization (APPI) with liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed to determine patulin in apple juice and apple-based food. Different dopants, dopant flow rates, and LC separation conditions were evaluated. Using toluene as the dopant, the LC-APPI-MS/MS method achieved a linear calibration from 12.5 to 2000 µg/L (r(2) > 0.99). Matrix-dependent limits of quantitation (LOQs) were from 8 µg/L (solvent) to 12 µg/L (apple juice). [(13)C]-Patulin-fortified apple juice samples were directly analyzed by the LC-APPI-MS/MS method. Other apple-based food was fortified with [(13)C]-patulin, diluted using water (1% formic acid), centrifuged, and filtered, followed by LC-APPI-MS/MS analysis. In clear apple juice, unfiltered apple cider, applesauce, and apple-based baby food, average recoveries were 101 ± 6% (50 µg/kg), 103 ± 5% (250 µg/kg), and 102 ± 5% (1000 µg/kg) (av ± SD, n = 16). Using the suggested method, patulin was detected in 3 of 30 collected market samples with concentrations ranging from

Determination of aflatoxins B1, B2, G1, and G2 in olive oil, peanut oil, and sesame oil using immunoaffinity column cleanup, postcolumn derivatization, and liquid chromatography with fluorescence detection: first action 2013.05.

A collaborative study of a method for determination of aflatoxins (AFs) B1, B2, G1, and G2 in olive oil, peanut oil, and sesame oil using immunoaffinity column cleanup, postcolumn derivatization, and LC with fluorescence detection, previously published in J. AOAC Int. 95, 1689-1700 (2012), was approved as First Action 2013.05 on March 29, 2013 by the Method-Centric Committee for Aflatoxins in Edible Oils. The method uses methanol for extraction followed by filtration. The extract is applied to an immunoaffinity column with antibodies specific for AFs, which are then eluted from the column with a methanol solution. Determination and quantification occur using RP-LC with fluorescence detection after postcolumn derivatization. The average recovery of AFs in olive, peanut, and sesame oils in spiked samples (levels between 2.0 and 20.0 microg/kg) ranged from 84 to 92%. The recoveries for AFs B1, B2, G1, and G2 were 86-93, 89-95, 85-97, and 76-85%, respectively. Within-laboratory RSD (RSDr) values for AFs ranged from 3.4 to 10.2%. RSDr values forAF B1, B2, G1, and G2 were 3.5-10.9, 3.2-9.5, 6.5-14.9, and 4.8-14.2%, respectively. Between-laboratory RSD (RSDR) values for AFs were 6.1-14.5%. RSD, values for AFs B1, B2, G1, and G2 were 7.5-15.4, 7.1-14.6, 10.8-18.1, and 7.6-23.7%, respectively. Horwitz ratio values were < or =2 for the analytes in the three matrixes.

Determination of mycotoxins in milk-based products and infant formula using stable isotope dilution assay and liquid chromatography tandem mass spectrometry.

A stable isotope dilution assay and liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed and validated for the determination of 12 mycotoxins, aflatoxins B1, B2, G1, G2, and M1, deoxynivalenol, fumonisins B1, B2, and B3, ochratoxin A, T-2 toxin, and zearalenone, in milk-based infant formula and foods. Samples were fortified with 12 ¹³C uniformly labeled mycotoxins ([¹³C]-mycotoxins) that correspond to the 12 target mycotoxins and prepared by dilution and filtration, followed by LC-MS/MS analysis. Quantitation was achieved using the relative response factors of [¹³C]-mycotoxins and target mycotoxins. The average recoveries in fortified milk, milk-based infant formula, milk powder, and baby yogurt of aflatoxins B1, B2, G1, and G2 (2, 10, and 50 µg/kg), aflatoxin M1 (0.5, 2.5, and 12.5 µg/kg), deoxynivalenol, fumonisins B1, B2, and B3 (40, 200, and 1000 µg/kg), ochratoxin A, T-2 toxin, and zearalenone (20, 100, and 500 µg/kg), range from 89 to 126% with RSDs of <20%. The individual recoveries in the four fortified matrices range from 72% (fumonisin B3, 20 µg/kg, milk-based infant formula) to 136% (T-2 toxin, 20 µg/kg, milk powder), with RSDs ranging from 2 to 25%. The limits of quantitation (LOQs) were from 0.01 µg/kg (aflatoxin M1) to 2 (fumonisin B1) µg/kg. Aflatoxin M1 was detected in two European Reference materials at 0.127 ± 0.013 µg/kg (certified value = 0.111 ± 0.018 µg/kg) and 0.46 ± 0.04 µg/kg (certified value = 0.44 ± 0.06 µg/kg), respectively. In 60 local market samples, aflatoxins B1 (1.14 ± 0.10 µg/kg) and B2 (0.20 ± 0.03 µg/kg) were detected in one milk powder sample. Aflatoxin M1 was detected in three imported samples (condensed milk, milk-based infant formula, and table cream), ranging from 0.10 to 0.40 µg/kg. The validated method provides sufficient selectivity, sensitivity, accuracy, and reproducibility to screen for aflatoxin M1 at nanograms per kilogram concentrations and other mycotoxins, without using standard addition or matrix-matched calibration to compensate for matrix effects.

Multi-mycotoxin analysis of finished grain and nut products using high-performance liquid chromatography-triple-quadrupole mass spectrometry.

Mycotoxins in foods have long been recognized as potential health hazards due to their toxic and carcinogenic properties. A simple and rapid method was developed to detect 26 mycotoxins (aflatoxins, ochratoxins, fumonisins, trichothecenes, and ergot alkaloids) in corn, rice, wheat, almond, peanut, and pistachio products using high-performance liquid chromatography-triple-quadrupole mass spectrometry. Test portions of homogenized grain or nut products were extracted with acetonitrile/water (85:15, v/v), followed by high-speed centrifugation and dilution with water. Mean recoveries (± standard deviations) were 84 ± 6, 89 ± 6, 97 ± 9, 87 ± 12, 104 ± 16, and 92 ± 18% from corn, rice, wheat, almond, peanut, and pistachio products, respectively, and the matrix-dependent instrument quantitation limits ranged from 0.2 to 12.8 µg/kg, depending on the mycotoxin. Matrix effects, as measured by the slope ratios of matrix-matched and solvent-only calibration curves, revealed primarily suppression and were more pronounced in nuts than in grains. The measured mycotoxin concentrations in 11 corn and wheat reference materials were not different from the certified concentrations. Nineteen mycotoxins were identified and measured in 35 of 70 commercial grain and nut products, ranging from 0.3 ± 0.1 µg/kg (aflatoxin B1 in peanuts) to 1143 ± 87 µg/kg (fumonisin B1 in corn flour). This rapid and efficient method was shown to be rugged and effective for the multiresidue analysis of mycotoxins in finished grain and nut products.

Determination of aflatoxins B1, B2, G1, and G2 in olive oil, peanut oil, and sesame oil using immunoaffinity column cleanup, postcolumn derivatization, and liquid chromatography/fluorescence detection: collaborative study.

The accuracy, repeatability, and reproducibility characteristics of a method using immunoaffinity column (IAC) cleanup with postcolumn derivatization and LC with a fluorescence detector (FLD) for determination of aflatoxins (AFs; sum of AFs B1, B2, G1, and G2) in olive oil, peanut oil, and sesame oil have been established in a collaborative study involving 15 laboratories from six countries. Blind duplicate samples of blank, spiked at levels ranging from 0.25 to 20.0 microg/kg for AF, were analyzed. A naturally contaminated peanut oil sample was also included. Test samples were extracted with methanol-water (55 + 45, v/v). After shaking and centrifuging, the lower layer was filtered, diluted with water, and filtered through glass microfiber filter paper. The filtrate was then passed through an IAC, and the toxins were eluted with methanol. The toxins were then subjected to RPLC-FLD analysis after postcolumn derivatization. Average recoveries of AFs from olive oil, peanut oil, and sesame oil ranged from 84 to 92% (at spiking levels ranging from 2.0 to 20.0 microg/kg); of AFB1 from 86 to 93% (at spiking levels ranging from 1.0 to 10.0 microg/kg); of AFB2 from 89 to 95% (at spiking levels ranging from 0.25 to 2.5 microg/kg); of AFG1 from 85 to 97% (at spiking levels ranging from 0.5 to 5.0 microg/kg); and of AFG2 from 76 to 85% (at spiking levels ranging from 0.25 to 2.5 microg/kg). RSDs for within-laboratory repeatability (RSD(r)) ranged from 3.4 to 10.2% for AF, from 3.5 to 10.9% for AFB1, from 3.2 to 9.5% for AFB2, from 6.5 to 14.9% for AFG1, and from 4.8 to 14.2% for AFG2. RSDs for between-laboratory reproducibility (RSDR) ranged from 6.1 to 14.5% for AF, from 7.5 to 15.4% for AFB1, from 7.1 to 14.6% for AFB2, from 10.8 to 18.1% for AFG1, and from 7.6 to 23.7% for AFG2. Horwitz ratio values were < or = 2 for the analytes in the three matrixes.

Chromatographic method for the determination of aflatoxin M1 in cheese, yogurt, and dairy beverages.

The aim of this work was to develop and validate a method to determine aflatoxin M1 (AFM1) in cheese, yogurt, and dairy beverages. The method consisted of aqueous methanol extraction, immunoaffinity column purification and isolation, RPLC separation, and fluorescence detection. The four types of cheese samples were classified according to moisture and fat content. The mean recoveries were 71% for cheese at spiked levels from 100 to 517 ng/kg, and 76% for yogurt and dairy beverages spiked at levels from 66 to 260 ng/kg. The mean RSDs were 5.9% for cheese, and 10% for yogurt and dairy beverages. The LOD was 3 ng/kg and the LOQ was 10 ng/kg for all test commodities. To test the applicability of the developed method, a small survey of the presence of AFM1 in cheese, yogurt, and dairy beverages purchased in Ribeirão Preto-SP, Brazil, was conducted. AFM1 was detected (> 3 ng/kg) in all samples. Twenty cheese samples (83%) were contaminated with AFM1 in the range of 13-304 ng/kg. In yogurt and dairy beverages, the contamination was lower (13-22 ng/kg) in five samples (42%). The results indicated that the method is adequate for the determination of AFM1 in these four types of cheese, as well as in yogurt and dairy beverages.

Use of a multifunctional column for the determination of deoxynivalenol in grains, grain products, and processed foods.

Deoxynivalenol (DON), also known as vomitoxin, belongs to a class of naturally occurring mycotoxins produced by Fusarium spp. DON, 12, 13-epoxy-3,7 trihydroxytrichothec-9-en-8-one, is one of the most frequently detected mycotoxins in agricultural commodities worldwide. A method consisting of extraction, filtration, column cleanup, and RP-HPLC-UV separation and quantitation was validated for the determination of DON in grains (rice and barley), grain products (whole wheat flour, white flour, wheat germ, and wheat bran), and processed foods (bread, breakfast cereals, and pretzels). A 25 g test portion was extracted with 100 mL acetonitrile-water (84 + 16, v/v). After blending for 3 min, the supernatant was applied to a multifunctional column (MycoSep 225). The purified filtrate (2 mL) was evaporated to dryness and redissolved in the mobile phase. The toxins were then subjected to RP-HPLC-UV analysis. The accuracy and repeatability characteristics of the method were determined. Recoveries of DON added at levels ranging from 0.5 to 1.5 microg/g for all test matrixes were from 75 to 98%. SD and RSD(r) ranged from 0.7 to 11.6% and 0.9 to 12.7%, respectively. Within-laboratory HorRat values were from 0.1 to 0.7 for all matrixes analyzed. The method was found to meet AOAC method performance criteria for grains, grain products, and processed foods. The identity of DON in naturally contaminated test sample extracts was confirmed by HPLC/MS/MS analysis.

Determination of zearalenone in botanical dietary supplements, soybeans, grains, and grain products by immunoaffinity column cleanup and liquid chromatography: single-laboratory validation.

The accuracy, repeatability, and reproducibility characteristics of a method for measuring levels of zearalenone (ZON) in botanical root products, soybeans, grains, and grain products were determined by an AOAC single-laboratory validation procedure. Replicates of 10 test portions of each powdered root product (black cohosh, ginger, ginseng), brown rice flour, brown rice grain, oat flour, rice bran, soybeans, and wheat flour at each spiking level (ZON at 0, 50, 100, and 200 microg/kg) were analyzed on 3 separate days. Test samples were extracted with methanol-water (75 + 25, v/v). The extracts were centrifuged or filtered, diluted with phosphate-buffered saline (PBS) containing 0.5% Tween 20, and filtered; the filtrates were applied to an immunoaffinity column containing antibodies specific for ZON. After the column was washed with methanol-PBS (15 + 85, v/v) containing 0.5% Tween 20 and then with water, the toxin was eluted from the column with methanol, and the eluate was diluted with water. The eluate containing the toxin was then subjected to RPLC with fluorescence detection. All commodities that were found to contain ZON at < 10 microg/kg were used for the recovery study. The average within-day and between-days recoveries of ZON added at levels of 50-200 microg/kg ranged from 82 to 88% and from 81 to 84%, respectively, for all test commodities. The total average of within- and between-day SD and RSDr values for all test commodities ranged from 2.5 to 7.3 microg/kg and from 4.6 to 6.2%, respectively. HorRat values were <1.3 for all matrixes examined. The tested method was found to be acceptable for the matrixes examined.

Determination of fumonisin B1 in botanical roots by liquid chromatography with fluorescence detection: single-laboratory validation.

The accuracy, repeatability, and reproducibility characteristics of a published method for measuring levels of fumonisin B1 (FB1) in botanical root products were determined by an AOAC single-laboratory validation procedure. Replicates of 10 test portions of each powdered root product (black cohosh, echinacea, ginger, ginseng, valerian, dong quai, and turmeric) at each spiking level (FB1 at 0, 50, 100, and 200 ng/g) were analyzed on 3 separate days. Test samples were extracted with methanol-acetonitrile-water (25 + 25 + 100, v/v/v). The extracts were centrifuged, the supernatants diluted with phosphate-buffered saline (PBS) containing 1% Tween 20 and filtered, and the filtrates applied to an immunoaffinity column containing antibodies specific for fumonisins. After the column was washed sequentially with PBS and water, the toxin was eluted from the column with 80% methanol, and the eluate dried by lyophilization. The residue was reconstituted with 50% acetonitrile. FB1 was derivatized with a mixture of o-phthaldialdehyde and mercaptoethanol by using an LC autoinjector. Separations were performed with an RP-LC column, and the FB1 derivative was quantified by fluorescence detection. All root products were found to contain FB1 at <10 ng/g. Average within- and between-day recoveries of FB1 from the botanical roots ranged from 67 to 95% and from 68 to 100%, respectively. Total RSD values for within- and between-day repeatability ranged from 5.5 to 26.4%. HorRat values were <1.3 for all of the matrixes examined. The method meets the AOAC method performance criteria at levels of >50 ng/g for the seven botanical roots tested.

Determination of deoxynivalenol in processed foods.

Deoxynivalenol (DON), commonly referred to as vomitoxin, belongs to a class of naturally occurring mycotoxins produced by Fusarium fungi. The presence of DON in foods is a human health concern. The frequency of occurrence of DON in wheat is high, although cleaning prior to milling can reduce DON concentration in final products, and food processing can partially degrade the toxin. This paper describes a method for the determination of DON in some major wheat food products, including bread, breakfast cereals, pasta, pretzels, and crackers. Test samples containing 5% polyethylene glycol were extracted with water. After blending and centrifuging, the supernatant was diluted with water and filtered through glass microfiber filter paper. The filtrate was then passed through an immunoaffinity column and the toxins eluted with methanol. The toxins were then subjected to RPLC separation and UV detection. The accuracy and repeatability characteristics of the method were determined. Recoveries of DON spiked at levels from 0.5 to 1.5 microg/g in the five processed foods were >70%. SD and RSD values ranged from 2.0 to 23.5% and from 2.0 to 23.2%, respectively. HorRat values were <2 for all of the matrixes examined. The method was found to be acceptable for the matrixes examined. LC/MS/MS with multiple-reaction monitoring was used to confirm the identity of DON in naturally contaminated test samples.

Determination of aflatoxins B1, B2, G1, and G2 in olive oil, peanut oil, and sesame oil.

Edible oils are consumed directly, and used as ingredients in food, soaps, and skin products. However, oils such as olive oil, peanut oil, and sesame oil could be contaminated with aflatoxins, which are detrimental to human and animal health. A method using immunoaffinity column cleanup with RPLC separation and fluorescence detection (FLD) for determination of aflatoxins (AF) B1, B2, G1, and G2 in olive oil, peanut oil, and sesame oil was developed and validated. Test samples were extracted with methanol-water (55 + 45, v/v). After shaking and centrifuging, the lower layer was filtered, diluted with water, and filtered through glass microfiber filter paper. The filtrate was then passed through an immunoaffinity column, and the toxins were eluted with methanol. The toxins were then subjected to RPLC/FLD analysis after postcolumn UV photochemical derivatization. The accuracy and repeatability characteristics of the method were determined. Recoveries of AFB1 spiked at levels from 1.0 to 10.0 microg/kg in olive oil, peanut oil, and sesame oil ranged from 82.9 to 98.6%. RSDs ranged from 0.6 to 8.9%. HorRat values were < 0.2 for all of the matrixes tested. Recoveries of AF spiked at levels from 2.0 to 20.0 microg/kg ranged from 87.7 to 102.2%. RSDs ranged from 1.3 to 12.6%. HorRat values were < 0.4 for all of the matrixes tested. LC/MS/MS with multiple-reaction monitoring was used to confirm the identities of aflatoxins in a naturally contaminated peanut oil.

Determination of aflatoxins in botanical roots by a modification of AOAC Official Method 991.31: single-laboratory validation.

AOAC Official Method 991.31 for the determination of aflatoxins (AFs; sum of aflatoxins B1, B2, G1, and G2) in corn, raw peanuts, and peanut butter by using immunoaffinity column cleanup with LC has been modified and applied to the determination of AFs in botanical roots. The modifications were necessary to improve the performance of the method for matrixes beyond corn and peanuts. The extraction solvent was changed from a mixture of methanol and water to acetonitrile and water. The accuracy, repeatability, and reproducibility characteristics of this method were determined. Replicates of 10 test portions of each powdered root (black cohosh, echinacea, ginger, ginseng, kava kava, and valerian) at each spiking level (AFs at 0, 2, 4, 8, and 16 ng/g) were analyzed on 3 separate days. Test portions were extracted with acetonitrile-water (84 + 16, v/v), and the extracts were centrifuged, diluted with phosphate-buffered saline, filtered, and applied to an immunoaffinity column containing antibodies specific for AFs. After the column was washed with water, the toxins were eluted from the column with methanol and quantified by HPLC with fluorescence detection. All test materials except kava kava were found to contain AF at < 0.1 ng/g. Kava kava was naturally contaminated with AFs at 0.5 ng/g. Average within-day and between-days recoveries of AFs from botanical roots ranged from 88 to 112 and from 86 to 118%, respectively. Total RSD values for within-day and between-days repeatability ranged from 1.4 to 15.9%. HorRat values were < 0.4 for all of the matrixes examined. The modified AOAC Official Method 991.31 was found to be applicable to an analysis of the six botanical roots.