Determination of mycotoxins in cereals by liquid chromatography tandem mass spectrometry

A liquid chromatography tandem mass spectrometry (LC–MS/MS) method is described for simultaneous determination of aflatoxins (AFB₁, AFB₂, AFG₁ and AFG₂), ochratoxin A (OTA), zearalenone (ZEA), deoxynivalenol (DON), fumonisins (FB₁ and FB₂), T2 and HT2-toxin in cereals. One-step extraction using solvent mixtures of acetonitrile:water:acetic acid (79:20:1) without any clean-up was employed for extraction of these mycotoxins from cereals. The mean recoveries of mycotoxins in spiked cereals ranged from 76.8% to 108.4%. Limits of detection (LOD) and quantification (LOQ) ranged 0.01–20 and 0.02–40 ng/g, respectively. The developed method has been applied for the determination of mycotoxins in 100 cereal samples collected from Malaysian markets. A total of 77 cereal samples (77%) contaminated with at least one of these mycotoxins. Occurrence of mycotoxins in commercial cereal samples were 70%, 40%, 25%, 36%, 19%, 13%, 16, and 16% for aflatoxins, OTA, ZEA, DON, FB₁, FB₂, T2 and HT2-toxin, respectively. The results demonstrated that the procedure was suitable for the determination of mycotoxins in cereals and could be implemented for the routine analysis.     

Simultaneous detection of 12 mycotoxins in cereals using RP-HPLC-PDA-FLD with PHRED and a post-column derivatization system

A new method for the simultaneous quantification of 12 mycotoxins was developed and optimized using reverse phase high performance liquid chromatography (RP-HPLC) with a photodiode array (PDA) and fluorescence detector (FLD), a photochemical reactor for enhanced detection (PHRED) and post-column derivatization. The mycotoxins included aflatoxins (AFB₁, AFB₂, AFG₁, and AFG₂), ochratoxin A (OTA), zearalenone (ZEA), deoxynivalenol (DON), fumonisins (FB₁, FB₂, and FB₃), T-2 and HT-2 toxins. A double sample extraction with a phosphate-buffered saline solution (PBS) and methanol was used for co-extraction of mycotoxins, and a multifunctional immunoaffinity column was used for cleanup. Optimum conditions for separation of the mycotoxins were obtained to separate 12 mycotoxins in FLD and PDA chromatograms with a high resolution. The method gave recoveries in the range 72–111% when applied to spiked corn samples. The limits of detection (LOD) were 0.025?ng/g for AFB₁ and AFG₁, 0.012?ng/g for AFB₂ and AFG₂, 0.2?ng/g for OTA, 1.5?ng/g for ZEA, 6.2?ng/g for FB₁, FB₃ and HT-2 toxin, 9.4?ng/g for FB₂ and T-2 toxin, and 18.7?ng/g for DON. In addition, the limits of quantification (LOQ) ranged from 0.04?ng/g for AFB₂ and AFG₂ to 62?ng/g for DON. The method was successfully applied to the determination of these mycotoxins in 45 cereal samples obtained from the Malaysian market. The results indicated that the method can be applied for the multi-mycotoxin determination of cereals.     

Occurrence of ochratoxin A,fumonisin B2 and black aspergilli in raisins from Western Greece regions in relation to environmental and geographical factors

The presence of ochratoxin A (OTA), fumonisin B₂ (FB₂) and black aspergilli in raisins from Western Greece regions (Messinia, Corinthia, Achaia, Ilia and Zante Island) was investigated in relation to the different geographic and climatic conditions in the 2011 growing season. The biseriate species Aspergillus niger “aggregate” and A. carbonarius were mainly identified. The population of A. niger “aggregate” species occurred in all raisin samples at colony-forming units (CFU) concentrations significantly higher (mean 2.2 × 10⁵ CFU g^?1 homogenate) than those of A. carbonarius population (mean 4.9 × 10³ CFU g^?1 homogenate), which occurred in 80% of the raisin samples. OTA was found in 73% of the samples at levels ranging from 0.1 µg kg^?1 to 98.2 µg kg^?1, with the highest level occurring in a raisin sample from Ilia that also contained the highest level of A. carbonarius. The European Union legal limit for OTA was exceeded in 15% of the raisin samples. FB₂ was found in 29% of the raisin samples at levels ranging from 7.1 µg kg^?1 to 25.5 µg kg^?1, with 20% of the samples co-occurring with OTA. Principal-component analysis was applied to levels of mycotoxins, fungal contamination, geographical data and environmental conditions recorded in the harvesting (August) or drying (September) period. Principal-component analysis clearly indicated a good direct correlation of rainfall and relative humidity with OTA and A. carbonarius contamination. A lack of clustering was observed when A. niger and FB₂ contamination were considered. This is the first report on the co-occurrence of the mycotoxins OTA and FB₂ in dried vine fruits from Greece.     

Aflatoxin M1 and ochratoxin A in raw bulk milk from French dairy herds

Mycotoxins in milk are a public health concern and have to be regularly monitored. A survey on the presence of aflatoxin M₁ (AFM₁) and ochratoxin A (OTA) in raw bulk milk was conducted in 2003 in the northwest of France, the main French milk-producing basin. Randomly selected farms (n = 132) were characterized by a diet based on corn silage and containing a large proportion of on-farm produced cereals, feeding sources that are frequently contaminated by mycotoxins. Farms were surveyed twice in winter and in summer. At each sampling time, a trained surveyor completed a questionnaire recording farm management procedures and production traits. The AFM₁ was found in 3 out of 264 samples but at levels (26 ng/L or less) that are below the European legislation limit of 50 ng/L. Traces of AFM₁ (less than 8 ng/L) were also found in 6 other samples. The OTA was detected in 3 samples also at low levels, 5 to 8 ng/L. Farms that tested positive to the presence of mycotoxins, 12 in total including 6 farms that had traces of AFM₁, differed from negative farms by a more extensive use of total mixed rations, 58 vs. 27%. In addition, the positive farms tended to have lower milk yields. Although the incidence of milk contamination with AFM₁ and OTA at the farm level was low during the period studied, production and management data from the surveyed farms suggest a link between feeding management practices and mycotoxin contamination.     

Mycoflora and natural occurrence of aflatoxin,cyclopiazonic acid,fumonisin and ochratoxin A in dried figs

Mycoflora, the mycotoxigenic properties of moulds, and natural contamination with mycotoxins such as aflatoxins (AFs), cyclopiazonic acid (CPA), fumonisin B₁ (FB₁) and ochratoxin A (OTA) were investigated in dried figs. Dry fig samples were collected from orchards during the drying stage in the Aegean Region of Turkey. Fungal isolates were identified using morphological, chemical as well as molecular methods. Mycotoxigenic characteristics of moulds were assessed by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). Mycotoxins except CPA (by TLC) were determined by HPLC. All the fig samples were contaminated with moulds and 94.7% contained one or more mycotoxigenic species. The most prevalent moulds present in dried figs belong to the Aspergillus section Nigri members, being 93.9% positive for the samples, followed by Fusarium spp., Aspergillus section Flavi and Penicillium spp. On the other hand, Fusarium spp. had the highest count and the number of fumonisin producing Fusarium was also high. A total of 48% of 115 dried fig samples contained OTA (range?=?0.1–15.3?ng?g^?1), 74.7% of the samples had FB₁ (range?=?0.05–3.65?mg?kg^?1), 10.0% of the samples had aflatoxin (range?=?0.1–763.2?ng?g^?1) and 24.3% of the samples were tentatively identified as being contaminated with CPA (range?=?25–187?ng?g^?1). Dried fig samples were contaminated with one (33.0%), two (47.0%), three (5.2%) and four mycotoxins (3.5%). A total of 11.3% of dried fig samples were not contaminated with any of the four mycotoxins. To the best of our knowledge, CPA and fumonisin have been found for the first time in dried figs.     

Simultaneous determination of multi-mycotoxins in palm kernel cake (PKC) using liquid chromatography-tandem mass spectrometry (LC-MS/MS)

Palm kernel cake (PKC) is a useful source of protein and energy for livestock. Recently, it has been used as an ingredient in poultry feed. Mycotoxin contamination of PKC due to inappropriate handling during production and storage has increased public concern about economic losses and health risks for poultry and humans. This concern has accentuated the need for the evaluation of mycotoxins in PKC. Furthermore, a method for quantifying mycotoxins in PKC has so far not been established. The aims of this study were therefore (1) to develop a method for the simultaneous determination of mycotoxins in PKC and (2) to validate and verify the method. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method using an electrospray ionisation interface (ESI) in both positive- and negative-ion modes was developed for the simultaneous determination of aflatoxins (AFB₁, AFB₂, AFG₁ and AFG₂), ochratoxin A (OTA), zearalenone (ZEA), deoxynivalenol (DON), fumonisins (FB₁ and FB₂), T-2 and HT-2 toxin in PKC. An optimum method using a 0.2 ml min^–1 flow rate, 0.2% formic acid in aqueous phase, 10% organic phase at the beginning and 90% organic phase at the end of the gradient was achieved. The extraction of mycotoxins was performed using a solvent mixture of acetonitrile–water–formic acid (79:20:1, v/v) without further clean-up. The mean recoveries of mycotoxins in spiked PKC samples ranged from 81% to 112%. Limits of detection (LODs) and limits of quantification (LOQs) for mycotoxin standards and PKC samples ranged from 0.02 to 17.5 μg kg^?1 and from 0.06 to 58.0 μg kg^?1, respectively. Finally, the newly developed method was successfully applied to PKC samples. The results illustrated the fact that the method is efficient and accurate for the simultaneous multi-mycotoxin determination in PKC, which can be ideal for routine analysis.     

Occurrence of Aflatoxins and Ochratoxin A in Baby Foods in Portugal

Infants have a more restricted diet and they generally consume more food on a body weight basis than adults. Therefore, the significance and potential health risk of any contaminant in foods consumed by infants is increased and diligent attention must be paid to this particular area. The present study aims to determine the occurrence of aflatoxin M₁ (AFM₁), aflatoxin B₁ (AFB₁) and ochratoxin A (OTA) in processed cereal-based foods (flours) and infant formulae (milk powder) available in the Portuguese market, both sold as conventional and organic origin. Mycotoxin determination was carried out using a method previously applied to duplicate diet samples. This method employed chloroform extraction, liquid–liquid extraction, immunoaffinity column (IAC) cleanup and HPLC analysis with fluorescence detection after post-column derivatisation. Quantification limits were 0.014, 0.004 and 0.028 μg kg⁻¹ for AFM₁, AFB₁ and OTA, respectively. These toxins could only be quantified in 12 of 27 analysed samples (15 positive results): two samples with AFM₁, two samples with AFM₁ and OTA, one sample with AFB₁ and OTA and seven samples with OTA. Positive results concerned four for AFM₁ (26%), one for AFB₁ (7%) and ten for OTA (67%). For these samples, contents ranged between 0.017–0.041 μg AFM₁ kg⁻¹, 0.034–0.212 μg OTA kg⁻¹, and one sample had a value of 0.009 μg AFB₁ kg⁻¹. Considering the presented results, we could provisionally conclude that the presence of these mycotoxins in baby foods does not constitute a public health problem. These are the first results concerning the occurrence of mycotoxins in marketed baby foods in Portugal and this is the first study using the HPLC method, proposed for duplicate diets, in baby food sample analysis.     

Utilising an LC-MS/MS-based multi-biomarker approach to assess mycotoxin exposure in the Bangkok metropolitan area and surrounding provinces

Human exposures to mycotoxins through dietary intake are a major health hazard and may result in various pathophysiological effects. Although Thailand is a country at increased risk due to its climatic conditions, no comprehensive dataset is available to perform proper exposure assessment of its population with regard to mycotoxins. Therefore, this pilot study was conducted to investigate and evaluate the exposure levels of major mycotoxins (aflatoxin B₁, ochratoxin A, fumonisins, zearalenone and trichothecenes). Sixty first-morning urine samples were collected from healthy volunteers who live in the Bangkok metropolitan area and surrounding provinces (Pathumthani, Nonthaburi, Samutprakarn and Samutsakorn). Urine samples were analysed by a LC-MS/MS-based multi-biomarker method following a so-called ‘dilute and shoot’ approach. Results generally indicated low mycotoxin exposures in most individuals through the determination of the four biomarkers that were detected in urine samples, i.e. aflatoxin M₁, ochratoxin A (OTA), as well as the deoxynivalenol (DON) metabolites DON-3-glucuronide and DON-15-glucuronide in 10 of 60 individuals. The maximum concentrations were used to estimate the daily intake confirming that none of the individuals exceeded the tolerable daily intake (TDI) of DON (maximum 26% of TDI) or OTA (maximum 22% of TDI). However, the maximum exposure of aflatoxin B₁, estimated to be 0.91 µg (kg bw)^–1 day^–1, should raise some concerns and suggests further studies utilising a more sensitive method. Low exposure to Fusarium toxins was also confirmed by the absence of zearalenone, α-zearalanol, β-zearalanol and zearalenone-14-glucuronide as well as T-2 toxin, HT-2 toxin, nivalenol and free DON. This is the first multi-mycotoxin biomarker study performed in Southeast Asia.     

A New Extraction Method for the Determination of Oxytocin in Milk by Enzyme Immune Assay or High-Performance Liquid Chromatography: Validation by Liquid Chromatography–Mass Spectrometry

There has been a controversy regarding the use of exogenous oxytocin (OT) in milking cattle which may have toxicological consequences during nonphysiological exposure. In the present study, a new sensitive extraction method for OT was developed followed by enzyme immune assay (EIA) or high-performance liquid chromatography (HPLC) analysis. The extraction of OT in milk involves two steps: (1) TCA precipitation of milk proteins and (2) solid-phase extraction (SPE) cleanup process. Without these steps, analysis of OT in milk was not possible. Utilizing EIA as a quantitative tool the limit of detection (LOD) and limit of quantitation (LOQ) were found to be 7.74 and 10.3 pg?ml^?1, precision in terms of intra- and interday coefficient of variation was below 13 % (%RSD, N?=?8), while percent recoveries were between 85 and 92 %. Utilizing UV-HPLC, the LOD, LOQ, precision, and recovery values were found to be 4.1 ng?ml^?1, 9.8 ng?ml^?1, 2–10 %, and 84–91 %, respectively. OT was found to be stable against adverse temperature (up to 100 °C) and pH (2 to 10) and simulated gastric fluid digestibility assay. Four milk samples collected from the market were analyzed, which showed that TCA precipitation and SPE steps are mandatory and the results were validated by LC-MS showing mass ion peak at 1 kD.     

A promising innovative technique for mycotoxin detoxification from beverages using biofilms of lactic acid bacteria

This study assessed the removal of aflatoxin M₁ (AFM₁) and ochratoxin A (OTA) from artificially contaminated whole UHT milk and red grape juice, respectively, using biofilms from Lactobacillus rhamnosus GG. Using ELISA, the level of AFM₁ and OTA removal from beverages was determined depending on various factors. Biofilms of various ages demonstrated varying degrees of AFM₁ removal capacity from phosphate-buffered saline (PBS). Different levels of AFM₁ contaminated whole UHT milk (0.1, 0.2, and 1 μg/L) and OTA contaminated red grape juice (2 and 4 μg/L) were tested in the detoxification process. The binding ability of mycotoxins was improved by increasing the biofilm surface area up to 70 cm². L. rhamnosus GG biofilm was effective in removing mycotoxins within a short contact time ranging from 1 to 10 min. The proportion of bound AFM₁ and OTA by L. rhamnosus GG biofilm was 64.6 and 98.3% respectively. A new machine has been proposed and used as a trial for detoxication purposes which would be a promising application in liquid food industries.     

Quantification of mycotoxins in vegetable oil by UPLC-MS/MS after magnetic solid-phase extraction

ABSTRACT

The detection of mycotoxin contamination in foodstuffs is highly significant for public health. Herein we report an analytical method based on magnetic solid-phase extraction (MSPE) and UPLC-MS/MS for the simultaneous determination of mycotoxins, including fumonisins B₁ (FB₁), zearalenone (ZON) and ochratoxin A (OTA), in vegetable oil. Magnetic nanoparticles coated with double layers of silicon dioxide were synthesised and found to be an effective MSPE adsorbent for mycotoxins. The proposed MSPE procedure serves not only for sample clean-up but also for mycotoxin enrichment that enhances greatly the assay’s sensitivity. Under the selected MSPE conditions, linear matrix-matched calibration curves were obtained for mycotoxins in a concentration range from 0.178 to 625 μg kg^–1. The limits of detection were 0.210 μg kg^–1 for FB₁, 0.0800 μg kg^–1 for OTA and 1.03 μg kg^–1 for ZON. The proposed MSPE UPLC-MS/MS method was applied for the determination of mycotoxins in vegetable oil samples, including maize oil, rapeseed oil and soybean oil. ZON was detected in a maize oil at 101 μg kg^–1, which is below the European Union limit of 200 μg kg^–1 in foodstuffs.     

Co-occurrence of mycotoxins in maize and maize-derived food in China and estimation of dietary intake

ABSTRACT

A total of 576 samples marketed in China, including maize, maize flour, maize grits and maize meal, was determined for the simultaneous presence of 12 mycotoxins (FB₁, FB₂, FB₃, DON, 3-DON, 15-DON, ZEN, AFB₁, AFB₂, AFG₁, AFG₂ and OTA) using a validated UPLC-MS/MS for multi-mycotoxin method. DON were the most widespread mycotoxins (63%), followed by FB₁ (57%) and ZEN (46%). 78% of the samples was contaminated with at least one of these mycotoxins. Risk assessment indicated that maize and maize-derived food intake does not pose a potential risk for general adult population with respect to individual mycotoxin. However, two or more mycotoxins were detected in 60% of all samples, and a combination of up to seven different mycotoxins was found. A particular attention should be paid to the combined exposure of mycotoxins, in this cases the estimated daily intake might increase greatly due to the high frequency of co-occurrence.     

Determination of aflatoxin M1 in milk by triple quadrupole liquid chromatography-tandem mass spectrometry

A sensitive and reliable method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with an electrospray-positive ionization method was developed for the determination of aflatoxin M₁ in milk. This method includes simple extraction of the sample with acetonitrile by ultrasonic, separation on an MGIII-C₁₈ column using 0.01% formic acid buffer/acetonitrile (60 : 40, v/v) as mobile phase, and MS/MS detection using multiple reaction-monitoring mode. Average recoveries of aflatoxin M₁ from spiked samples at concentrations of 0.02 and 1 ng ml^?1 ranged from 77% to 94%, with a 6% relative standard deviation. The limit of detection and limit of quantification were 0.006 and 0.02 ng ml^?1, respectively. The standard curve was linear between 0.02 and 20.0 ng ml^?1. The recommended method is simple, rapid, specific and reliable for the routine monitoring of aflatoxin M₁ in milk.     

Fluorescence polarization immunoassay based on a monoclonal antibody for the detection of ochratoxin A

A fluorescence polarization immunoassay (FPIA) based on a monoclonal antibody for the determination of ochratoxin A (OTA) was developed. Fluorescein‐labelled OTA derivative (tracer) was synthesized and purified by thin‐layer chromatography. The optimized OTA FPIA had a dynamic range from 5 to 200 ng mL^?1 with IC₅₀ value of 30 ng mL^?1 and a detection limit of 3 ng mL^?1. The method developed was characterized by high specificity and reproducibility. Cross‐reactivity with other mycotoxins (zearalenone, aflatoxins, patulin and T‐2 toxin) was negligible (<0.1%). Methanol extracts of barley samples were used for the analysis. The results of OTA determination in barley were compared with those determined by indirect competitive enzyme‐linked immunosorbent assay (ELISA). Recoveries for the samples spiked at 50, 100 and 500 ng g^?1 levels were 91, 90 and 97%, respectively, for FPIA, and 98, 98 and 102%, for ELISA. Naturally contaminated barley samples were analysed by these methods but some disagreement was observed between the results. The FPIA method can be applied for screening of food samples for OTA residues without a complicated clean‐up.     

Development of rapid immunoassays for the detection of ractopamine in swine urine

The monoclonal antibodies (mAbs) against ractopamine (Rac) were prepared and their properties identified by indirect competitive enzyme-linked immunoabsorbant assay (ELISA). The IC₅₀ of mAbs was 2.7 ng ml^?1 towards Rac or 9.3 ng ml^?1 towards Rac-glucuronides and no cross-reactivity (CR) towards other competitors except dobutamine (CR: 3.76%). Based on the mAbs, the Rac-kit (kit) and Rac-strip (strip) were developed to detect Rac residues in swine urine. The strip and kit assay could be performed within 5–10 min and 2 h, respectively, allowing the analysis of urine samples without the need for sample clean-up. The detection limits were 1 ng ml^?1 for kit and 3 ng ml^?1 with the unaided eye, and 0.2 ng ml^?1 with the Strip Reader for strip. The correlation coefficients (R ²) were 0.988 for kit in the range 0–128.0 ng ml^?1, and 0.987 for strip in the range 0–10.8 ng ml^?1. Comparing the gas chromatography-mass spectrometry (GC-MS) with the kit or strip in swine urine spiked with Rac standards, the differences ranged from 1.4% to 4.5% for kit and 1.0% to 4.7% for strip. However, the differences were greater than 54% for the kit and 55% for the strip test for the analysis of urine from swine treated with Rac. The results obtained from GC-MS using hydrolysed urine samples were generally in good agreement with those obtained from strip or kit using non-hydrolysed urine samples.     

Global occurrence of aflatoxin M1 in milk with particular reference to Iran

Aflatoxin M₁ (AFM₁) is an hydroxylated derivative of aflatoxin B₁ (AFB₁), which occurs in the milk of lactating animals. The aim of the present study was to determine the concentrations of AFM₁ in raw milk samples collected from 18 dairy farms in Qazvin, Iran, over a period of 1 year and compare them with those found in other countries. Samples (30 per farm) were collected in the four seasons, Spring, Summer, Autumn and Winter occurring between April 2009 and March 2010, giving a total of 2160 samples. They were centrifuged and 100 μl of the resulting skimmed milk were tested for AFM₁ contamination by competitive enzyme immunoassay (EIA). All samples (100 %) were contaminated with AFM₁ with concentrations ranging from 0.04 to 148.01 ng.l^?1 and a mean of 38.82 ng.l^?1. Summer samples with a mean of 64.69 ng.l^?1 and autumn samples with a mean of 0.14 ng.l^?1 had the highest and lowest concentrations, respectively, and differed significantly (P?<?0.05). AFM₁ content in 722 samples (33.4 %) was higher than the maximum tolerance limit of 50 ng.l^?1 accepted by the European Union (EU). As contamination of milk with AFM₁ is a potential risk for human health, raw milk should be monitored for its presence.     

NovaSil clay intervention in Ghanaians at high risk for aflatoxicosis: II. Reduction in biomarkers of aflatoxin exposure in blood and urine

The efficacy of NovaSil clay (NS) to reduce aflatoxin (AF) biomarkers of exposure was evaluated in 656 blood samples and 624 urine samples collected from study participants during a 3-month phase IIa clinical intervention trial in Ghana. NS was delivered before meals via capsules. Serum AFB₁–albumin adduct was measured by radioimmunoassay and urinary AFM₁ metabolites were quantified by immunoaffinity-high-performance liquid chromatography (HPLC)-fluorescence methods. Levels of AFB₁–albumin adduct in serum samples collected at baseline and at 1 month were similar (p?=?0.2354 and p?=?0.3645, respectively) among the placebo (PL), low dose (LD, 1.5 g NS day^?1), and high dose (HD, 3.0 g NS day^?1) groups. However, the levels of AFB₁–albumin adduct at 3 months were significantly decreased in both the LD group (p?<?0.0001) and the HD group (p?<?0.0001) compared with levels in the PL group. Levels of AFM₁ in urine samples collected at baseline and at 1 month were not statistically different among the three study groups. However, a significant decrease (up to 58%) in the median level of AFM₁ in samples collected at 3 months was found in the HD group when compared with the median level in the PL group (p?<?0.0391). In addition, significant effects were found for dose, time, and dose–time interaction with serum AFB₁–albumin adduct and dose–time interaction with urinary AFM₁ metabolites. The results suggest that capsules containing NS clay can be used to reduce effectively the bioavailability of dietary AF based on a reduction of AF-specific biomarkers.     

Analysis of some breakfast cereals on the French market for their contents of ochratoxin A,citrinin and fumonisin B1: development of a method for simultaneous extraction of ochratoxin A and citrinin

Crops may be contaminated by mycotoxins which can persist in the final products. Forty-five breakfast cereals were collected in French supermarkets. Ochratoxin A (OTA) and citrinin (CIT) were simultaneously extracted by a new method based on solvent partition validated in-house. The recoveries were over 80% for CIT and OTA. Fumonisin B₁ (FB₁) was analysed by an IUPAC method. The recoveries for FB₁ ranged from 50% to 70%, depending on the matrix. The losses were located at the step of immunoaffinity clean-up.OTA was detected in 69% of the samples; 20% of them were above the EU limit of 3 μg/kg. Twenty percent contained CIT (1.5–42 μg/kg). FBs were detected, not only in cornflakes, but also in products containing oats or rice, in the range 1–1110 μg/kg. Some samples were contaminated by all three mycotoxins.     

Development and Application of a Method for the Analysis of 9 Mycotoxins in Maize by HPLC‐MS/MS

A reliable and sensitive liquid chromatography/tandem mass spectrometry (LC‐MS/MS) method was developed for the simultaneous determination of aflatoxins (AFB₁, AFB₂, AFG₁, and AFG₂), ochratoxin A (OTA), deoxynivalenol (DON), zearalenone (ZEA), fumonisin B₁ (FB₁), and T2‐toxin in maize. The samples were first extracted using acetonitrile: water: acetic acid (79 : 20 : 1), and then further cleaned‐up using OASIS HLB cartridge. Optimum conditions for the extraction and chromatographic separation were investigated. The mean recoveries of mycotoxins in spiked maize ranged from 68.3% to 94.3%. Limits of detection and quantification ranged from 0.01 to 0.64 μg/kg and from 0.03 to 2.12 μg/kg, respectively. The LC‐MS/MS method has also been successfully applied to 60 maize samples, which were collected from Shaanxi Province of China. Twenty‐four of the total 60 samples (40%) were contaminated with at least 1 of these 9 mycotoxins. Occurrence of mycotoxins were 6.7%, 1.7%, 3.3%, 6.7%, 1.7%, 23.3%, and 3.3% for AFB₁, AFB₂, OTA, ZEA, DON, FB₁, and T2‐toxin, respectively. The results demonstrated that the procedure was suitable for the simultaneous determination of these mycotoxins in maize matrix.     

Survey of aflatoxin M1 in cheese from the North-east region of São Paulo,Brazil

In the present study, 24 samples of Minas Frescal cheese and 24 samples of Minas Padrão cheese produced in the North-east region of the state of São Paulo, Brazil, were analysed for aflatoxin M₁ (AFM₁) by high-performance liquid chromatography (HPLC) between March and August 2008. AFM₁ was detected in 13 (27.1%) samples at concentrations ranging from 0.037 to 0.313?ng?g^?1. The mean concentrations of AFM₁ in positive samples of Minas Frescal and Minas Padrão cheese were 0.142?±?0.118 and 0.118?±?0.054?ng?g^?1, respectively. It is concluded that the incidence of AFM₁ in Minas cheese may contribute to an increase in the overall ingestion of aflatoxins in the diet, hence indicating the need for the adoption of a tolerance limit for AFM₁ in cheese in Brazil.