Evaluation of fumonisin exposure by determination of fumonisin B1 in human hair and in Brazilian corn products

The aim of this study was to evaluate the dietary exposure to fumonisin B₁ (FB₁) through determination of residual FB₁ in hair and corn products consumed by 56 volunteers from Pirassununga and Erval Velho, Brazil. Data from FB₁ analyses in corn products and a Food Frequency Questionnaire (FFQ) were used for estimating the mean probable daily intake (PDI_M) for FB₁. FB₁ was detected in 4 human hair samples (7.2%), at a mean level of 21.3 ± 12.1 ng g⁻¹. The mean FB₁ level found in corn products was 360.4 ± 555.1 μg kg⁻¹. The PDI_M value of FB₁ in volunteers was 159 ± 47 ng kg⁻¹ body weight day⁻¹ which represents 7.9% of the provisional maximum tolerable daily intake (PMTDI) recommended for fumonisins. The FB₁ levels found in human hair samples from each volunteer were associated with their individual PDI of FB₁, indicating that exposure to FB₁ in the sample studied do not represent a health concern. This is the first report on the incidence of FB₁ in individual human hair in Brazil.     

Degradation of fumonisin B1 by cinnamon essential oil

Fumonisins are group of mycotoxins produced mainly by Fusarium verticillioides and Fusarium proliferatum. They frequently contaminate corn and corn based products, and cause several diseases in humans and animals. Fumonisin B₁ (FB₁) is the most prevalent fumonisin and is highly toxic to human and animal. The essential oils from plants offer a hope in the prevention and detoxification of these mycotoxins. The present study investigates the degradation effect of cinnamon, citral, Litsea cubeba, clove, eucalyptus, anise, spearmint and camphor oils on FB₁. The degradation level of FB₁ was determined by ELISA. Cinnamon oil proves to be effective essential oil in reducing FB₁, followed by citral, eugenol oil, eucalyptus oil, anise oil and camphor oil. The effects of incubation time, and temperature with respect to the concentration of cinnamon oil on their degradation effect on FB₁ by cinnamon oil were investigated. Results showed that at 120 h time with the 280 μg/ml concentration of cinnamon oil, under 30 °C is optimal for FB₁ reduction. Under optimal condition, FB₁ was reduced from 15.03 to 0.89 μg/ml (94.06%). Cinnamon oil could be a promising candidate in the detoxification and control of FB₁ in corn based products.     

Determination of fumonisin B1 in bovine milk by LC–MS/MS

The aim of the present work was to develop a sensitive and selective method for identification and quantification of fumonisin B1 (FB1) in bovine milk. FB1 was isolated by immunoaffinity column and was detected using liquid chromatography coupled with tandem mass spectrometry in positive electrospray ionization (ESI+).The LOQ of the method was 0.1 μg/kg that was lower than the others reported in the literature. The high coefficient of determination (R² > 0.99) obtained in the range of 0.1–10.0 μg/kg, the good recovery (84%) and relative standard deviation (7%) of the proposed method ensure correct fumonisin detection in milk even at relatively low concentrations.The developed method was applied on different commercial samples in order to test its efficacy. FB1 was found above the LOQ in eight out of 10 samples analysed and the average level of contamination found was 0.26 μg/kg.     

Thermal treatments and their effects on the fumonisin B1 level in rice

The objective of this study was to evaluate the effects of dry and hydrothermal treatment on FB₁ level in polished, parboiled and whole grain rice collected in Brazilian market. The effect of thermal treatment on FB₁ level was carry out by applying conventional cooking, autoclaving and dry heat treatment. Conventional hydrothermal treatment (cooking) reduced the initial natural contamination by 80%. However, no significant reduction was obtained by autoclaving. Dry heat treatment produced the reduction (70%), at temperatures range from 150 to 200 °C.     

An immunomagnetic-bead-based enzyme-linked immunosorbent assay for sensitive quantification of fumonisin B1

A sensitive enzyme-linked immunosorbent assay (ELISA) based on immunomagnetic beads (IMB-ELISA) was established using a magnetic-bead signal-enrichment system. The immunomagnetic beads were coated with polyclonal antibody directed against keyhole limpet hemocyanin (KLH), which were then coupled with a KLH–fumonisin B1 (FB1) conjugate. Anti-FB1 monoclonal antibody and sample extract were mixed and added to the immunomagnetic-bead solution. After the addition of horseradish peroxidase (HRP)-labeled goat anti-mouse antibody and the substrate solution, stop solution was added and the optical density of the reaction mixture was determined. To improve the performance of this method, the dilution of the immunomagnetic beads, the concentrations of the monoclonal antibody and HRP-labeled goat anti-mouse antibody, and the incubation time for the competition reaction were optimized. Based on the optimum conditions, the regression equation for this IMB-ELISA in quantifying FB1 was y = −0.3538x + 0.703 (R² = 0.9988). The detection limit and IC₅₀ were 0.24 ng/mL and 3.17 ng/mL, respectively. The working range was 0.54–26.3 ng/mL. The recovery rates were 80.4–114.7%, when the spiked concentrations ranged from 19.5 to 156.3 μg/kg. This IMB-ELISA is accurate and more sensitive and less time-consuming than the conventional ELISA.     

An ultrasensitive gray-imaging-based quantitative immunochromatographic detection method for fumonisin B1 in agricultural products

Fumonisins (FBs) are widely found in rice, maize, peanut, wheat, and other agricultural products. These have been detected using a chromatography technique, whereas the rapid assay by a highly sensitive monoclonal antibody is minimally reported. Herein, a highly sensitive monoclonal antibody (7A11) was successfully developed by hybridoma technique. The 50% inhibition concentration (IC₅₀) of 7A11 monoclonal antibody was 0.32 ng/mL in an optimized buffer. The cross-reactivity between fumonisin B₁ and fumonisin B₂, B₃ was 4.3% and 12.8%, respectively. Based on the newly developed 7A11 antibody, a high sensitivity indirect competitive enzyme-linked immunosorbent assay (icELISA) and gold nanoparticles-based gray imaging quantification immunoassay (GNPs-GI) were established. The analytical range of icELISA was 0.08–1.38 ng/mL and that for GNPs-GI was 0.24–15 ng/mL. Both the methods showed adequate recoveries (80.0–105.8% for icELISA and 78.5–115.2% for GNPs-GI) in spiked samples. Compared to high-performance liquid chromatography (HPLC), icELISA and GNPs-GI indicated reliability that could be used for further detection of fumonisin B₁ in agricultural products.     

Gold nanoparticles-based lateral flow immunoassay with silver staining for simultaneous detection of fumonisin B1 and deoxynivalenol

A lateral flow immunoassay with silver staining for the simultaneous detection of fumonisin B₁ (FB₁) and deoxynivalenol (DON) in maize samples was reported. The assay was based on the competition between target mycotoxins and corresponding coating antigens immobilized on test lines for binding to limited gold nanoparticles (AuNPs)-labeled antibodies. The detection signal was further amplified by employment of silver staining on AuNPs. In the process, silver ions were catalyzed by AuNPs into metal silver that deposited on the surface of AuNPs, allowing not only the enlargement of particle dimensions of AuNPs but also a more distinguishable black coloration on the test zone. Under optimized conditions, the cut-off values of silver staining lateral flow immunoassay were 2.0 ng mL⁻¹ for FB₁ and 40 ng mL⁻¹ for DON in buffer, which was improved at least 2 times in comparison to those of AuNPs-based method. The assay was further applied to detect FB₁ and DON in naturally contaminated maize samples and a good agreement was found with the data obtained from HPLC-MS/MS.     

Fungal contamination and aflatoxin B1 of ‘egusi’ melon seeds in Nigeria

One hundred and thirty seven samples of melon seeds (Colocynthis citrullus L.) from randomly selected farmers’ stores in the humid forest and Northern Guinea savanna of Nigeria were analysed for the incidence of diseased seeds, moisture content, associated moulds and levels of aflatoxin B₁ contamination. The proportion of diseased seeds ranged from 2.5 to 37.3% in the forest and 2.1 to 17.9% in the savanna, while the seed moisture content varied from 5.3 to 10.4%, and 4.6 to 9.5% respectively. All the samples contained moulds, with the two genera, Aspergillus and Penicillium predominating, while A. flavus had the highest species count. The other common fungal isolates in order of decreasing incidence were A. niger, P. citrinum, Botryodiplodia theobromae, Cladosporium sp and A. clavatus. Thin layer chromatography analysis showed that 32% in the forest and 21% samples in the savanna contained aflatoxin B₁ with mean levels of 14.8 μg/kg in the forest and 11.3 μg/kg in the savanna respectively. Significant positive correlations were found between number of aflatoxin B₁ positive samples and the percentage of A. flavus infected samples and between the levels of diseased seeds and the levels of aflatoxin B₁ contamination.     

In-house method validation,estimating measurement uncertainty and the occurrence of fumonisin B1 in samples of Brazilian commercial rice

Fumonisin B₁ was investigated in samples of rice intended for human consumption, including polished parboiled rice, whole grain rice and whole grain parboiled rice. Until the present, no studies on the occurrence of fumonisin B₁ have been performed on these types of rice that are commercially available in the south-eastern region of Brazil. A careful intralaboratory validation was carried out to demonstrate the fitness-of-purpose of the applied method for determining fumonisin B₁ in the three studied rice types. The performance criteria – selectivity, reliable limits of detection (50 μg kg⁻¹) and quantification (100 μg kg⁻¹), linearity (range 100–2500 μg kg⁻¹), precision (RSD values ≤ 17.0%) and recovery (71.7–112.0 %) were evaluated, and the expanded measurement uncertainty was estimated by using the data obtained from precision and recovery experiments. Matrix-matched calibration standards were employed to quantify the mycotoxin levels in the rice samples, in which the residual normality, homoscedasticity and independence were confirmed. In addition, the measurement uncertainty values are consistent with the maximum acceptable uncertainty established by European Union regulation for analytical methods for controlling mycotoxins in foodstuffs. Among the thirty-one commercial samples of rice analysed in the present study, five samples presented detectable levels of the mycotoxin, and these levels ranged from 64.8 to 163.0 μg kg⁻¹.     

Curcuma longa L. essential oil composition,antioxidant effect,and effect on Fusarium verticillioides and fumonisin production

Essential oils may be an alternative to the use of synthetic fungicides for the control of fungi involved in agricultural product deterioration. The aim of the present study was to evaluate the composition and antioxidant effect of turmeric essential oil and its antifungal and antimycotoxigenic action on Fusarium verticillioides (Sacc.) Nirenberg. The essential oil major components were α-turmerone (42.6%), β-turmerone (16.0%) and ar-turmerone (12.9%). The half-maximal inhibitory concentration (IC₅₀) for the radical scavenging capacities of 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) were 0.54 and 10.03 mg/ml, respectively, indicating good antioxidant activity. The application of 17.9 and 294.9 μg/ml of turmeric essential oil decreased the development of F. verticillioides by 56.0 and 79.3%, respectively, when compared with the fungal control. The scanning electron microscopy demonstrated that the oil decreased the thickness and the length of the microconidia. Ergosterol production significantly decreased (p < 0.05) in groups treated with the essential oil relative to the control, indicating an effect of the oil on fungal biomass. The production of B₁ and B₂ fumonisins was significantly inhibited (p < 0.05) in groups treated with the essential oil. The results suggest that turmeric essential oil has antioxidant, antifungal and antimycotoxigenic activities.     

Further data on the occurrence of Fusarium emerging mycotoxins enniatins (A,A1, B,B1), fusaproliferin and beauvericin in raw cereals commercialized in Morocco

In this study, 64 samples of raw cereals (wheat, maize and barley) purchased from local markets in Rabat–Salé area from Morocco were analyzed for the occurrence of six emerging mycotoxins: four enniatins ENs (ENA, ENA1, ENB and ENB1), beauvericin (BEA) and fusaproliferin (FUS). Samples were extracted with a mixture of water/acetonitrile (85/15, v/v) by using an Ultra-turrax homogenizer. Mycotoxins were then identified and quantified with a liquid chromatography (LC) with diode array detector (DAD). Positive samples were confirmed with an LC–MS/MS. Analytical results showed that the frequencies of contamination of total samples with ENs, BEA and FUS were 50, 26.5 and 7.8%, respectively. ENA1 was the most common EN found with a percentage of contamination of 39%, levels ranged between 14 and 445 mg/kg. ENB contaminated 14 samples (21.8%) and levels ranged from 5 to 100 mg/kg. ENB1 was present in four samples (6.2%) and levels varied from 8 to 32 mg/kg. ENA was detected in only one sample with 34 mg/kg. BEA levels ranged from 1 to 59 mg/kg and FUS levels varied from 0.6 to 2 mg/kg. The present report is the first one ever drafted on the presence of emerging Fusarium mycotoxins in raw cereals available in Morocco.     

Development and validation of an accurate and rapid LC-ESI-MS/MS method for the simultaneous quantification of aflatoxin B1, B2, G1 and G2 in lotus seeds

An accurate and rapid LC-ESI-MS/MS analytical method was developed and validated for the simultaneous determination of aflatoxin B₁, B₂, G₁ and G₂ in lotus seeds. The samples were firstly extracted with methanol-water solution (80:20, v/v), and then cleaned up by immunoaffinity columns. The mass spectrometer was operated in the positive ionization electrospray (ESI+) mode using multiple reaction monitoring (MRM) for analysis of four aflatoxins. The transitions of m/z 313 → 285 (AFB₁, CE 33 eV), m/z 315 → 259 (AFB₂, CE 37 eV), m/z 329 → 243 (AFG₁, CE 37 eV) and m/z 331 → 257 (AFG₂, CE 37 eV) were used to quantify these four aflatoxins, respectively. The limits of detection (LODs) of aflatoxin B₁, B₂, G₁ and G₂ were 0.007, 0.005, 0.003 and 0.005 μg kg^?1 based on a signal-to-noise ratio of 3:1, respectively. The limits of quantification (LOQs) of aflatoxin B₁, B₂, G₁ and G₂ were 0.02, 0.015, 0.01 and 0.015 μg kg^?1 based on a signal-to-noise ratio of 10:1, respectively. Recoveries for samples of spiked lotus seeds were all above 66% with relative standard deviation all below 15% for all compounds. Nineteen out of twenty batches of lotus seeds collected from different drug stores or markets in China were found to be contaminated with aflatoxins at different levels ranging from 0.02 to 688.4 μg kg^?1.     

First report on the presence of emerging Fusarium mycotoxins enniatins (A,A1, B,B1), beauvericin and fusaproliferin in rice on the Moroccan retail markets

Seventy samples of rice purchased from local markets in six cities from Morocco (Rabat, Casablanca, Kénitra, Mohammadia, Tanger and Errachidia) were analyzed for the presence of six emerging mycotoxins: four enniatins ENs (ENA, ENA₁, ENB and ENB₁), beauvericin (BEA) and fusaproliferin (FUS). Samples were extracted with a mixture of acetonitrile/water (85/15, v/v) by using an ultra-turrax homogenizer. Mycotoxins were then identified and quantified with liquid chromatography (LC) coupled to diode array detector (DAD). Positive samples were confirmed with an LC-MS/MS. Analytical results showed that BEA was present in 75.7% of total analyzed samples. BEA levels varied between 3.8 and 26.3 mg/kg. The frequencies of contamination of samples with total ENs and FUS were 50% and 4.3%, respectively. Among the ENs, ENB was the mycotoxin much more found (30% of total samples), while ENB₁, ENA and ENA₁ were found in 24.6%, 22.8% and 5.7% of total samples, respectively. The high ENs value was registered in a rice sample from kénitra (448.7 mg/kg of ENA₁). This is the first study that describes the presence of emerging Fusarium mycotoxins in rice available in Morocco.     

Bioaccessibility and bioavailability of fumonisin B2 and its reaction products with isothiocyanates through a simulated gastrointestinal digestion system

Fumonisins (FBs) are toxins produced mainly by the molds Fusarium verticillioides (also known as Fusarium moniliforme) and Fusarium proliferatum. These mycotoxins are contaminants of wheat, maize, maize-based foods and other grains worldwide. Isothiocyanates (ITCs) are natural compounds produced by the enzymatic hydrolysis of glucosinolates, which are found in plants of the Brassicaceae family. The use of ITCs as food preservatives has been extensively researched. In this study, allyl (AITC), phenyl (PITC) and benzyl isothiocyanates (BITC) fumigation systems (500 μL/L) were employed to reduce FB₂ levels naturally produced in bread by Gibberella moniliformis CECT 2987. Reaction products formed between FB₂ and ITCs, their bioaccessibility and bioavailability were examined. Reduction of FB₂ in bread ranged from 90 to 99%, whereas its bioaccessibility ranged from 57 to 65%. The bioaccessibility found for the FB₂-ITCs conjugates ranged from 33 to 71%, whereas the bioavailability of the FB₂ and of the FB₂-ITCs adducts ranged from 0.6 to 3.0%.     

Occurrence and diversity of Bacillus cereus and moulds in spices and herbs

Spices and herbs can contain toxin-producing bacteria and moulds, which can cause health problems for consumers and contribute to food spoilage and shelf-life reduction. The aims of the present work were (i) to determine the occurence and levels of B. cereus and moulds; (ii) to charactize the incidence and diversity of B. cereus emetic toxin (ces, CER), and diarrhoeal toxin-encoding genes (entFM, nheA, hblC, cytK) and toxigenic potential of Hbl toxin-producing B. cereus strains. Black ground pepper samples showed the most contamination with the highest concentration of B. cereus 2.49 log₁₀ CFU/g. Moreover, cumin contained the most prominent mould concentration level of 3.6 log₁₀ CFU/g. The most common moulds were Aspergillus and Penicillium spp. Compared to packaging type, all products acquired from the local market, except curry for B. cereus, exchibited high concentrations of B. cereus and moulds. Four genes were identified – 96% of B. cereus strains contained entFM, 94% nheA, 56% hblC, 42% cytK. None of the samples contained emetic toxin-encoding genes (ces, CER). Toxigenic potential of Hbl toxin was found in 72% of B. cereus strains. Different temperature, moisture levels and hygiene practices were observed at places of sale in local markets thus facilitating contamination and development of moulds. Moreover, the presence of B. cereus and its ability to produce toxins in spices and herbs, may suggest the need to establish microbiological criteria for mould and spore-forming bacteria in spices and herbs.     

Biocontrol of dairy moulds by antagonistic dairy yeast Debaryomyces hansenii in yoghurt and cheese at elevated temperatures

Some strains of the yeast Debaryomyces hansenii are known to be antagonistic toward moulds. In this study, we describe the inhibitory effects of a dairy strain of D. hansenii as a biocontrol agent against a number of dairy moulds in plain yoghurt and cheese under non-refrigerated conditions. This antagonistic yeast showed inhibition of growth of the following dairy moulds: Aspergillus sp., Byssochlamys fulva, Byssochlamys nivea, Cladosporium sp., Eurotium chevalieri, Penicillium candidum and Penicillium roqueforti. However, the inhibitory effect of this antagonistic yeast against dairy moulds is dependent upon the concentration of the moulds: the lower the concentration, the more effective the yeast. The findings of this study have implications for both cheese maturation and dairy biopreservation. Good manufacturing practice and hygiene to keep the contaminant load down is essential for the prevention of dairy spoilage.     

Multilayer perceptron neural networks and radial-basis function networks as tools to forecast accumulation of deoxynivalenol in barley seeds contaminated with Fusarium culmorum

The capacity of multi-layer perceptron artificial neural networks (MLP-ANN) and radial-basis function networks (RBFNs) to predict deoxynivalenol (DON) accumulation in barley seeds contaminated with Fusarium culmorum under different conditions has been assessed. Temperature (20–28 °C), water activity (0.94–0.98), inoculum size (7–15 mm diameter), and time were the inputs while DON concentration was the output. The dataset was used to train, validate and test many ANNs. Minimizing the mean-square error (MSE) was used to choose the optimal network. Single-layer perceptrons with low number of hidden nodes proved better than double-layer perceptrons, but the performance depended on the training algorithm. The RBFN reached lower errors and better generalization than MLP-ANN but they required a high number of hidden nodes. Accurate prediction of DON accumulation in barley seeds by F. culmorum was possible using MLP-ANNs or RBFNs.     

Influence of gamma-radiation on mycotoxin producing moulds and mycotoxins in fruits

One hundred random fruit samples were collected and analyzed for mycotoxins and the effect of gamma-irradiation on the production of mycotoxins in fruits was studied. Analysis of fruits revealed the occurrence of penicillic acid, patulin, cyclopiazonic acid (CPA), citrinin, ochratoxin A and aflatoxin B₁. Of the 100 samples examined, 60 were positive for one or more mycotoxin. Irradiation of fruits at dose of 1.5 and 3.5 kGy decreased significantly the total fungal counts compared with unirradiated controls. After 28 days of storage at refrigeration temperature, the unirradiated fruits were contaminated with high concentrations of mycotoxins as compared with irradiated 3.5 kGy samples. Mycotoxins production in fruits decreased with increasing irradiation dose and were not detected at 5.0 kGy.     

Aflatoxin and fumonisin contamination of yam flour from markets in Nigeria

The natural occurrence of aflatoxins (AFs) and fumonisins (FBs) in yam flour samples (n = 100) obtained in south-western Nigeria was evaluated. AFs were determined by HPLC with fluorescence detection and FBs by HPLC coupled with mass spectrometry. Aflatoxin B₁ (AFB₁) and aflatoxin G₁ (AFG₁) were found in 57% and 21% of flours from white yam with concentrations ranging from <0.02 (limit of detection, LOD) to 3.2 μg kg⁻¹ (mean = 0.4 μg kg⁻¹) and from <0.05 to 3.5 μg kg⁻¹, respectively. AFB₁ was the only aflatoxin detected in samples from water yam, contaminating 32% of the samples with values ranging from <LOD to 0.6 μg kg⁻¹ (mean = 0.1 μg kg⁻¹). Fumonisin B₁ was found in 32% of the white yam samples (<0.5 (LOD) to 91 μg kg⁻¹; mean = 5 μg kg⁻¹) and in 5% of water yam samples (<LOD to 2 μg kg⁻¹). AFs and FBs were significantly higher (P < 0.05) in white yam flours compared to water yam flours. Preparation of amala from naturally-contaminated yam flour resulted in reduction of AFB₁ and AFG₁ by 44% and 51% respectively. From this study, only 7% of the samples contained AFs above the European standard limits for cereals intended for direct human consumption, while all the FBs-positive samples were well below the limits. The occurrence of ochratoxin A, zearalenone and deoxynivalenol was also evaluated in 20 samples; these mycotoxins were never detected.