Banana peel: an effective biosorbent for aflatoxins

This work reports the application of banana peel as a novel bioadsorbent for in vitro removal of five mycotoxins (aflatoxins (AFB1, AFB2, AFG1, AFG2) and ochratoxin A). The effect of operational parameters including initial pH, adsorbent dose, contact time and temperature were studied in batch adsorption experiments. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and point of zero charge (pH_pzc) analysis were used to characterise the adsorbent material. Aflatoxins’ adsorption equilibrium was achieved in 15 min, with highest adsorption at alkaline pH (6–8), while ochratoxin has not shown any significant adsorption due to surface charge repulsion. The experimental equilibrium data were tested by Langmuir, Freundlich and Hill isotherms. The Langmuir isotherm was found to be the best fitted model for aflatoxins, and the maximum monolayer coverage (Q₀) was determined to be 8.4, 9.5, 0.4 and 1.1 ng mg^?1 for AFB1, AFB2, AFG1 and AFG2 respectively. Thermodynamic parameters including changes in free energy (ΔG), enthalpy (ΔH) and entropy (ΔS) were determined for the four aflatoxins. Free energy change and enthalpy change demonstrated that the adsorption process was exothermic and spontaneous. Adsorption and desorption study at different pH further demonstrated that the sorption of toxins was strong enough to sustain pH changes that would be experienced in the gastrointestinal tract. This study suggests that biosorption of aflatoxins by dried banana peel may be an effective low-cost decontamination method for incorporation in animal feed diets.     

Simultaneous Determination of Aflatoxins and Ochratoxin A in Bee Pollen by Low-Temperature Fat Precipitation and Immunoaffinity Column Cleanup Coupled with LC-MS/MS

A simple and sensitive method has been developed for simultaneous determination of aflatoxins (AFB1, AFB2, AFG1, and AFG2) and ochratoxin A (OTA) in bee pollen. The analytes in the sample were extracted with a mixture of acetonitrile/water (60:40, v/v), using low temperature for fat precipitation, followed by immunoaffinity column cleanup of extracts. The mycotoxins were quantified using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) with an electrospray ionization (ESI) and a triple quadrupole (QqQ) analyzer. Matrix effect, accuracy, and precision were evaluated and achieved good results calculated by matrix-matched calibration standards which reduced the influence of matrix effect. Recoveries at three levels were in the range of 74.3–96.5 % with RSD less than 10.0 %. The correlation coefficients (r ²) of the five mycotoxins were higher than 0.997. The method showed high sensitivity with LOD below 0.05 μg/kg.     

Aspergillus section Flavi and aflatoxins in dried figs and nuts in Algeria

The presence of Aspergillus section Flavi and aflatoxin (AF) contamination was investigated in 112 samples of peanuts, almonds and dried figs collected in Algeria. The occurrence of aflatoxin B1 (AFB1), B2 (AFB2), G1 (AFG1) and G2 (AFG2) in different commodities has been determined with a sensitive method based on high performance liquid chromatography (HPLC) coupled with fluorescence detection with post-column photochemical derivatisation. Analytical results indicated that 28 samples of peanuts, 16 samples of almonds and 26 samples of dried figs contained detectable levels of AFs. A total of 69 samples (61.6%) were contaminated with AFB1 ranging from the limit of quantification to 174 µg kg^?1. AFB2 was found in 12 samples (10.7%) and varied from 0.18 to 193 µg kg^?1. Seven samples revealed AF concentrations lower than the limit of quantification. Eleven peanut and fourteen dried fig samples exceeded the European maximum limits for AFB1.     

Distribution of aflatoxins in shelling and milling fractions of naturally contaminated rice

The objective of this study was to determine the distribution of an economically important class of mycotoxins, the aflatoxins, in rice milling fractions. Rice plants grown under field production conditions are frequently infected with types of pathogenic fungi that produce toxic metabolites (mycotoxins). Paddy (seeds) rice from healthy plants in the field was collected and stored on a farm under humid, poorly ventilated conditions. Samples were milled into four fractions (hulls, brown rice, bran and white rice) and analysed for aflatoxins (B(1), B(2), G(1) and G(2)) using a validated method. Rice fractions from healthy plants, which contained low levels of aflatoxins (less than 1?μg?kg(-1)), were used to determine the efficiency of the extraction method. Seeds stored under poor conditions were found to be contaminated with aflatoxins B(1) and B(2) as were the fractions. The sums of AFB(1) and AFB(2) in stored paddy rice, hulls, brown rice, bran and white rice were 141, 39, 158, 367 and 56?μg?kg(-1), respectively. The ratio of aflatoxin B(1) and B(2) was about 10?:?1. AFG(1) and AFG(2) were less than 1?μg?kg(-1). Thus, brown rice contained 92.9% of the aflatoxins in paddy rice, whereas white rice contained only 27.9%.     

Dietary mycotoxins binders: a strategy to reduce aflatoxin m1 residues and improve milk quality of lactating Beetal goats

Aflatoxin M1 (AFM1) is a metabolite of aflatoxin B1 (AFB1) and secreted in milk of animals that are kept on a moldy diet. AFB1 is produced by several toxigenic species of fungi. In this study, the comparative efficacy of two mycotoxin binders was evaluated in terms of reducing excretion of AFM1, total viable bacterial count and somatic cell count in milk obtained from goats fed with AFB1 contaminated diet. A total of 32 lactating Beetal goats were reared and divided into 4 equal groups: Animals of group A were kept as control, while those in groups B, C, and D were individually fed with AFB1 at 40 µg alone, 40 µg AFB1 along with mycotoxin binder Toxfin^® at 3 g kg^?1 of cotton seed cake, and 40 µg AFB1 along with mycotoxin binder Elitox^® at a dose rate of 1 g kg^?1 of cotton seed cake, respectively. Toxfin^® significantly decreased the excretion of AFM1 in goats’ milk by 49.57 % while Elitox^® non-significantly reduced the excretion of AFM1 in goats’ milk by 19.49 %. Total viable bacterial count in milk samples of group C and D, and somatic cell count in milk samples of group C did not reduce significantly. However, somatic cell count in milk samples of group D reduced significantly. We conclude that the addition of Toxfin^® in the moldy diet significantly reduce the excretion of AFM1 in animals’ milk and minimize the risk of mycotoxin toxicity to public health.     

Simultaneous evaluation of neonicotinoids in cotton seed cake using reverse phase high‐performance liquid chromatography

BACKGROUND: The cotton crop accounts for more than 52% of total insecticide usage in India. Neonicotinoids, being newer insecticides, have found greater use in the northern region. In this study a rapid and sensitive high‐performance liquid chromatography method was developed for measuring neonicotinoid residues in cotton seed cake (CSC). The method involves the extraction of three neonicotinoids from CSC with acetonitrile/water (80:20 v/v), followed by liquid–liquid partitioning and column clean‐up prior to injection. RESULTS: Recoveries at 0.5–2 µg g^?1 spiking levels varied from 95.60 to 79.50% for imidacloprid, from 92.89 to 84.00% for acetamiprid and from 96.96 to 88.36% for thiacloprid. Minimum detectable levels using this method were 5, 10 and 20 ng g^?1 for imidacloprid, acetamiprid and thiacloprid respectively. CONCLUSION: The method developed in this study allows rapid and reliable measurement of the insecticides imidacloprid, acetamiprid and thiacloprid in CSC. Copyright © 2009 Society of Chemical Industry     

Aspergillus and aflatoxin in groundnut (Arachis hypogaea L.) and groundnut cake in Eastern Ethiopia

This study was conducted to assess major Aspergillus species and aflatoxins associated with groundnut seeds and cake in Eastern Ethiopia and evaluate growers’ management practices. A total of 160 groundnut seed samples from farmers’ stores and 50 groundnut cake samples from cafe and restaurants were collected. Fungal isolation was done from groundnut seed samples. Aspergillus flavus was the dominant species followed by Aspergillus parasiticus. Aflatoxin analyses of groundnut seed samples were performed using ultra performance liquid chromatography; 22.5% and 41.3% of samples were positive, with total aflatoxin concentrations of 786 and 3135 ng g^?1 from 2013/2014 and 2014/2015 samples, respectively. The level of specific aflatoxin concentration varied between 0.1 and 2526 ng g^?1 for B₂ and B₁, respectively. Among contaminated samples of groundnut cake, 68% exhibited aflatoxin concentration below 20 ng g^?1, while as high as 158 ng g^?1 aflatoxin B₁ was recorded. The study confirms high contamination of groundnut products in East Ethiopia.     

Determination of mycotoxins in biscuits,dried fruits and fruit jams: an assessment of human exposure

ABSTRACT

A reliable, fast and simple method using UHPLC-MS/MS was developed for the determination of aflatoxins B₁ (AFB1), G₁ (AFG1), B₂ (AFB2) and G₂ (AFG2), ochratoxin A (OTA), deoxynivalenol (DON), zearalenone (ZEA), HT-2 toxin and T-2 toxin in crude extracts of biscuits with fruit filling, cookies, dried fruits and fruit jams. The method was successfully demonstrated on 39 samples of biscuits with fruit filling, 34 cookies, 14 dried fruits and 10 fruit jams. The mycotoxins detected in biscuits samples were ZEA, OTA, T-2 and AFB1 with an average concentrations of positive samples of 2.64, 4.10, 8.13 and 1.32 µg kg^?1, respectively; while the mycotoxins detected in jam samples were AFB1, OTA, T-2 and AFB2 with an average concentrations of positive samples of 2.00, 17.7, 4.37 and 1.15 µg kg^?1, respectively. The results showed that the majority of samples were in compliance with relevant regulations. However in eight samples of biscuits and three samples of fig jam the contents of OTA were higher than the existing OTA limits. The combined dietary exposure of selected mycotoxins was estimated for the first time for children, adolescents and adults. The estimated combined dietary exposures were all lower than the proposed value assumed to predict a possible risk scenario.     

Occurrence of aflatoxins in selected spices in Poland

The aim of this study was to determine the contamination of aflatoxins B₁, B₂, G₁, G₂ in some selected spices (n = 84) in the Kuyavian-Pomeranian province of Poland. Aflatoxins were found in 63.1 % of the analysed samples. The presence of these compounds was confirmed in all the samples of pepper, nutmeg and turmeric. The maximum content for the sum of aflatoxins B₁, B₂, G₁, G₁ exceeding the acceptable level (10 μg/kg) was 16.91 μg/kg in one sample of nutmeg and 12.1 μg/kg in one sample of pepper, whereas in one sample of nutmeg the maximum content was equal to the regulatory limit. The lowest degree of contamination was found in black pepper.     

Aflatoxins and ochratoxin A and their Aspergillus causal species in Tunisian cereals

ABSTRACT

Occurrence of aflatoxins (AFs) AFB1, AFB2, AFG1, AFG2 and ochra toxin A (OTA) was studied in 65 samples of stored and freshly harvested wheat, barley and maize collected in Tunisia. The mycotoxins were simultaneously extracted and quantified by high performance liquid chromatography. Determination of AF-producing (section Flavi) and OTA-producing Aspergillus species (sections Nigri and Circumdati) was conducted in these samples by species-specific polymerase chain reaction (PCR). Results showed that most of maize samples were contaminated with AFs, data after storage showing lower values than those collected at harvest. All contaminated maize samples contained AFG1 and AFG2, among which 27.78% also had AFB1 and AFB2. This AFs pattern was consistent with the A. parasiticus toxin profile. A. flavus however showed the highest frequency in maize but was also found in barley and wheat where no AFs were detected. In contrast, OTA was neither found in maize nor in barley and only one wheat sample contained OTA. A. niger was the only OTA-producing species detected.     

Survey of aflatoxins in retail samples of whole and ground black and white peppercorns

A total of 126 local and imported samples of commercial white and black pepper in Malaysia were analysed for aflatoxins B₁, B₂, G₁ and G₂ (AFB1, AFB2, AFG1, AFG2) content using high-performance liquid chromatography (HPLC) with a fluorescence detector (FD). An acetonitrile–methanol–water (17 : 29 : 54; v/v) mixture was used as a mobile phase and clean-up was using an immunoaffinity column (IAC). Seventy out of 126 (55.5%) samples were contaminated with total aflatoxins, although only low levels of aflatoxins were found ranging from 0.1 to 4.9 ng g^?1. Aflatoxin B₁ showed the highest incidence of contamination and was found in all contaminated samples. There was a significant difference between type of samples and different brands (p < 0.05). The results showed black peppers were more contaminated than white peppers.     

Validation of a confirmatory analytical method for the determination of aflatoxins B₁, B₂, G₁ and G₂ in foods and feed materials by HPLC with on-line photochemical derivatization and fluorescence detection

A sensitive and selective analytical method for the simultaneous separation and quantitative determination of aflatoxins B1, B2, G1 and G2 in foodstuffs and materials for feed has been validated. The method is based on high performance liquid chromatography with on-line post-column photochemical derivatization and fluorescence detection. The chromatographic separation of aflatoxins was accomplished using a C18 column eluted with an isocratic mobile phase consisting of water, methanol and acetonitrile. The sample preparation required a simple extraction of aflatoxins with MeOH/H2O (80:20, v/v) and a purification step by immunoaffinity column cleanup. The total analysis time, including sample preparation and chromatographic separation, did not exceed 40 min with a run time of 10 min. The on-line photochemical derivatization ensures better results in terms of simplicity, sensitivity and reproducibility with respect to chemical derivatization techniques, and provides an increase of the peak resolution and an extent of automation in comparison with the electrochemical ones. The procedure for the determination of aflatoxins in food samples and cereals for animal consumption was extensively validated following Regulation (EC) No. 882/2004. Detection limits in wheat bran samples of 0.08 μg kg1 for AFB1, 0.02 μg kg1 for AFB2, 0.16 μg kg1 for AFG1 and 0.04 μg kg1 for AFG2 were attained. The method allows high recovery with mean values ranging from 72 to 94% and it satisfies the necessary requirements for sensitivity, linearity, selectivity, precision and ruggedness, demonstrating the conformity of the method with provisions of Regulation (EC) No. 401/2006.     

Time-resolved fluorescent immunochromatographic assay-based on three antibody labels for the simultaneous detection of aflatoxin B1 and zearalenone in Chinese herbal medicines

ABSTRACT

A time-resolved fluorescent immunochromatographic assay (TRFICA) was successfully developed for the sensitive, simultaneous, and quantitative detection of aflatoxin B₁ (AFB1) and zearalenone (ZEN) in Chinese herbal medicines. Eu-nanospheres (EuNPs) with unique optical properties increased the stability and sensitivity of the immunochromatographic assay. To obtain stable quantitative results, we applied a three-label system in which monoclonal antibodies for AFB1 and ZEN were conjugated to the EuNPs as detection probes on the test line (T line), and EuNP-labelled chicken IgY conjugates acted as the reference on the control line (C line). The fluorescence intensities of the T and C lines were recorded, and the T/C ratio was employed as the quantitative signal for the elimination of strip variation and matrix effects. The parameters that affected the TRFICA were optimised. Under optimal conditions, the established TRFICA gave good linear ranges from 0.60 μg/kg to 3.92 μg/kg for AFB1 and from 0.40 μg/kg to 1.28 μg/kg for ZEN. The limits of detection for AFB1 and ZEN were as low as 0.60 and 0.40 μg/kg, respectively, in Chinese herbal medicines Semen coicis, Rhizoma dioscoreae, and Platycodon grandiflorus, respectively. The average recoveries of the spiked samples were 73%–95% for AFB1 and 75.83%–90% for ZEN, both with a relative standard deviation of < 9.08%. The results of 15 actual samples detected by the developed TRFICA showed a satisfactory correlation with those of ultra-performance liquid chromatography tandem mass spectrometry. Therefore, the TRFICA is a simple, rapid, and sensitive approach to quantitatively detect mycotoxins in Chinese herbal medicines.     

Natural co-occurrence of aflatoxin and cyclopiazonic acid in peanuts grown in Argentina

Natural occurrence of aflatoxins and cyclopiazonic acid (CPA) contamination in peanuts was investigated. Co-occurrence of CPA and aflatoxins was detected in two of 50 samples analysed. The levels of these toxins found in positive samples were 4300 and 493 μg kg -1 for CPA, 625 and 435 μg kg -1 for aflatoxin B (AFB 1 ), and 625 and 83 μg kg -1 for aflatoxin G (AFG 1 ), respectively. Levels of CPA contamination in the positive samples were similar to those registered in other substrates. This is the first report of natural co-occurrence of CPA and aflatoxins in Argentina.     

Aflatoxins and ochratoxin A in flour: a survey of the Serbian retail market

This report presents data on the occurrence of aflatoxins (AF) and ochratoxin A in different types of flour marketed in Serbia. A total of 114 samples of wheat, buckwheat, rye, oat, barley, rice, millet and corn flour were collected in the period 2012–2016 and analysed using high performance liquid chromatography with fluorescence detection. Among flours other than corn, AFB1 was quantified only in rice, while ochratoxin A (OTA) was found in 29% of the samples. In corn flours the percentage of positive samples varied greatly over the years: AFB1 7.1–80.0%, OTA 30.0–40.6%, with a co-occurrence of 7.1–34.4%. Overall 5.2% of flours other than corn and 10.7% of corn flours exceeded the maximum levels (MLs) for AFB1 and/or OTA. The highest recorded levels were 8.80 μg kg^?1 of AFB1 (corn) and 23.04 μg kg^?1 of OTA (rye). Overall mean contamination levels of corn flours were 0.53 μg kg^?1 of AFB1 and 0.46 μg kg^?1 of OTA.     

Aflatoxins contamination of maize in Serbia: the impact of weather conditions in 2015

ABSTRACT

In recent years climate changes recorded in temperate regions of Europe have led to aflatoxin (AF) contamination of maize. Thus, the aim of this study was to investigate the influence of weather conditions on levels of aflatoxin B₁ (AFB1), aflatoxin B₂ (AFB2), aflatoxin G₁ (AFG1) and aflatoxin G₂ (AFG2) in 180 maize samples collected from the main maize-growing regions (Western Ba?ka, North Banat, South Banat and Central Serbia) in Serbia after harvest in 2015. The concentrations of AFs were determined by a validated HPLC method with post-column derivatisation and fluorescence detection (HPLC-FLD). The presence of AFB1, AFB2, AFG1 and AFG2 was detected in 57.2%, 13.9%, 5.6% and 2.8% of maize samples in the concentration ranges of 1.3–88.8 µg kg^–1, 0.60–2.8 µg kg^–1, 1.8–28.5 µg kg^–1 and 2.1–7.5 µg kg^–1 respectively. The recorded smaller amount of precipitation and especially higher air temperatures during the summer of 2015 were favourable for AF production, which resulted in 32.2% and 21.1% of samples being unsuitable for human consumption, since AFB1 and the sum of AFs concentrations were above 5.0 and 10.0 µg kg^–1 respectively. Furthermore, the findings in this study indicate that the microclimate conditions in the investigated regions had a great influence on the contamination frequency of maize with AFs. The highest percentage of samples unsuitable for human consumption, considering both AFB1 and total AFs content were 72.5% and 51.5% respectively from Central Serbia, whilst the lowest percentages of 15.6% and 6.2% respectively were found in Western Ba?ka. These findings confirmed that maize should be continuously monitored in order to protect human and animal health from the harmful effects caused by AFs contamination.     

西南地区辣椒干制品中黄曲霉毒素污染状况及风险评估

为分析来自西南地区（四川、重庆和云南）辣椒干制品中黄曲霉毒素（AFB1、AFB2、AFG1和AFG2）的污染情况和暴露风险,购自西南地区的超市、农贸市场和零售店的干辣椒和辣椒粉样品经研碎、过筛、提取、衍生等前处理后,采用高效液相色谱（HPLC）法测定黄曲霉毒素含量。结果表明,该方法的精密度及准确度较好,AFB1、AFG1的检出限和定量限均分别为0.05 ng/mL、0.15 ng/mL;AFB2、AFG2的检出限和定量限均分别为0.03 ng/m L、0.10 ng/mL。四川、重庆和云南地区辣椒干制品中黄曲霉毒素的阳性率分别为15%、10%和5%;干辣椒和辣椒粉中黄曲霉毒素的阳性率均分别为6.67%和13.33%;来自农贸市场和零售店的辣椒干制品阳性率（分别为15%、10%）比超市（5%）高。样品中黄曲霉毒素的膳食暴露量为0.001 455 ng/（kg体质量·d）,西南地区人群暴露率为0.15%,表明存在一定的暴露风险。     

高效液相色谱法同时检测粮谷中的黄曲霉毒素和赭曲霉毒素

建立粮谷类食品中黄曲霉毒素(B1、B2、G1 和G2)和赭曲霉毒素A 的同时检测方法。样品经过甲醇- 水(80:20,V/V)提取,液液萃取净化和富集后,三氟乙酸衍生,采用Agilent ZORBAX SB-C18 色谱柱(4.6mm ×250mm),以乙腈和体积分数2% 冰醋酸溶液为流动相梯度洗脱,在线变换波长荧光检测。根据3 倍信噪比的峰 响应值,确定黄曲霉毒素(B1、B2、G1 和G2)和赭曲霉毒素A 检出限分别为0.06、0.03、0.18、0.05μg/kg 和0.51μg/kg,上述5 种毒素分别在质量浓度0.05～100、0.125～25.00、0.05～100、0.125～25.00μg/L 和0.05～50.00μg/L 范围内呈线性相关,相关系数r 分别为0.9998、0.9998、0.9998、0.9996 和0.9998;在玉米、大米、小麦3 类样品中加标回收率平均为71.73%～115.37%,相对标准偏差为3.00%～9.88%,方法学验证结果表明,黄曲霉毒素和赭曲霉毒素A 5 种毒素同时检测结果与现行国标的单独检测方法检测结果无显著性差异(P ＞ 0.05)。     

Survey of roasted street-vended nuts in Sierra Leone for toxic metabolites of fungal origin

Consumption of mycotoxin contaminated foodstuffs is common in regions where foods are not adequately controlled and routinely monitored, and this could have adverse effects on the health of consumers. In this study, 100 samples of roasted nuts (50 cashew nuts and 50 peanuts) vended within two cities of Sierra Leone were analysed for mycotoxins and other microbial metabolites by a LC-MS/MS method. The peanut samples contained detectable levels of 17 microbial metabolites, including aflatoxins B₁, B₂, G₁ and G₂ and alternariol, while none of these metabolites were found in the cashew samples. Aflatoxins (max: 5,729 μg/kg; mean: 487.8 μg/kg) and alternariol (3 μg/kg) were found in 24% and 2% of the peanut samples, respectively. One-third of the aflatoxin-contaminated peanut samples contained aflatoxins at levels exceeding the total aflatoxin limit of 4 μg/kg set by the European Union. Aflatoxin contamination of Sierra Leonean peanuts is high and requires urgent intervention to reduce consequent exposure.     

Aflatoxins,ochratoxins and zearalenone in sorghum and sorghum products in Sudan

This survey examined 60 samples of sorghum and 30 samples of sorghum products from three states (Khartoum, Kordofan and Gadarif) of Sudan for aflatoxin B1, B2, G1 and G2 (AFB1, AFB2, AFG1, AFG2), ochratoxin A and B (OTA, OTB) and zearalenone (ZEN), using high performance liquid chromatography with fluorescence detection. The limits of detection and limits of quantification were in the range 0.01–0.6 µg kg^–1 and 0.03–2.0 µg kg^?1, respectively. The frequency of contaminated samples with AFB1 from Khartoum, Gadarif and Kordofan state was 38.1%, 22.2% and 23.8%, respectively. Only two samples of sorghum from Khartoum state were contaminated with OTA (3.3%). Concentrations of OTA and OTB were low and may not cause problems. No sample of sorghum or sorghum products was contaminated with ZEN. Some sorghum samples contained AFB1 concentrations above the European Union regulatory limits. The highest contaminated samples were found in Khartoum state.