Aflatoxins In Peanuts Research Articles

Kinetics of aflatoxin degradation during peanut roasting

This study investigated aflatoxin degradation during peanut roasting. First, peanuts contaminated with three initial aflatoxin concentrations (35, 332 and 695μg/kg) were roasted at 180°C for up to 20min. The percentage of aflatoxin degradation after 20min were 55, 64 and 81% for peanuts contaminated with aflatoxin at 35, 332 and 695μg/kg, respectively. This difference was statistically significant (p<0.05), showing that initial concentration influences aflatoxin reduction. Thereafter, peanut samples contaminated with an initial aflatoxin concentration of 85μg/kg were roasted at 160, 180 and 200°C for 5, 10, 15, 20 and 25min, then residual concentrations of aflatoxin were determined. Roasting at 160, 180 and 200°C resulted in an aflatoxin reduction of 61.6, 83.6 and 89.7%, respectively. This study has provided quantitative data reinforcing the fact that roasting alone is not enough to control aflatoxins in peanuts.

The biodiversity of Aspergillus section Flavi and aflatoxins in the Brazilian peanut production chain

A total of 119 samples of peanut were collected throughout the peanut production chain in São Paulo State, Brazil. The peanut samples were directly plated for determination of percentages of infection and a polyphasic approach was used to identify Aspergillus section Flavi species. Further, the potential for aflatoxin production by the isolates was tested using the agar plug technique and the presence of aflatoxins in peanuts was assessed using an immunoaffinity column followed by quantification using HPLC with reverse phase column and fluorescence detection. The limit of detection and quantification were 0.05 and 0.17μg/kg for total aflatoxins, respectively. Four species of Aspergillus section Flavi were isolated: A. caelatus (11), A. flavus (515), A. parasiticus (17) and A. tamarii (13). All isolates of A. parasiticus were able to produce aflatoxin B and G whereas aflatoxin B was produced by 50% of A. flavus isolates. Aflatoxins were found in 12 samples at concentrations ranging from 0.3 to 100μg/kg. The data reported in this study add information on the occurrence and biodiversity of fungi in peanuts at several stages of the production chain. The occurrence of aflatoxins is also of major relevance for continuous monitoring and assessment of likely exposure of consumers to aflatoxins through consumption of peanuts.

Characterization of small RNA populations in non-transgenic and aflatoxin-reducing-transformed peanut

Aflatoxin contamination is a major constraint in food production worldwide. In peanut (Arachis hypogaea L.), these toxic and carcinogenic aflatoxins are mainly produced by Aspergillus flavus Link and A. parasiticus Speare. The use of RNA interference (RNAi) is a promising method to reduce or prevent the accumulation of aflatoxin in peanut seed. In this study, we performed high-throughput sequencing of small RNA populations in a control line and in two transformed peanut lines that expressed an inverted repeat targeting five genes involved in the aflatoxin-biosynthesis pathway and that showed up to 100% less aflatoxin B1 than the controls. The objective was to determine the putative involvement of the small RNA populations in aflatoxin reduction. In total, 41 known microRNA (miRNA) families and many novel miRNAs were identified. Among those, 89 known and 10 novel miRNAs were differentially expressed in the transformed lines. We furthermore found two small interfering RNAs derived from the inverted repeat, and 39 sRNAs that mapped without mismatches to the genome of A. flavus and were present only in the transformed lines. This information will increase our understanding of the effectiveness of RNAi and enable the possible improvement of the RNAi technology for the control of aflatoxins.

OPTIMIZATION AND EFFICIENCY IMPROVEMENT OF IN‐HOUSE IMMUNOAFFINITY COLUMN KU-AF02 FOR AFLATOXIN DETECTION

In-house immunoaffinity column for aflatoxins (AFs) detection is firstly developed by Kasetsart University since 2011 i.e. the first IAC prototype, KU-AF01. Detection of aflatoxin B1 (AFB1) up to 200 ng is considered significantly efficient, but the production cost is considered high. The high cost was due to the cost of monoclonal antibody specific to aflatoxin and its supporting materials i.e. CNBr-activated sepharose 4B. Therefore, this study was aimed to improve the efficiency of in-house immunoaffinity colums by replacing CNBr-activated sepharose 4B with other supporting materials and to lower the ratio of antibody to supporting materials.  Response surface methodology (RSM) was applied to determine the optimum alternative supporting materials and the ratio. Results revealed that when compared with CNBr-activated sepharose 4B, all materials tested could recover higher than 80% AFB1, except the activated CH sepharose 4B. Results also indicated that the optimum ratio was 0.4 mg anti-aflatoxin monoclonal antibody to 204 µL CNBr-activated sepharose 4B. CNBr-activated sepharose 4B was considered to provide the best precision in recovering AFB1. KU-AF02 increased the ability to detect AFB1 to 500 ppb. The recovery of AFs in the reference materials using KU-AF02 was more than 96% successful, with HorRat value range of 0.34 – 0.76. The reference materials used were 2 levels of AFs in peanuts, i.e. 47.68 and 72.14 ng/g. In terms of quality control in IAC production, there were no significant differences among the 5 batches produced (p &gt; 0.05). KU-AF02 demonstrated stable and constant percent recovery at 4 oC for up to 12 months (tested with standard 200 ppb AFB1). This study indicated that KU-AF02 could lower the ratio of supporting materials to the antibody and that KU-AF02 has high stability and has good ability for cleaning up AFs. Therefore, KU-AF02 is recommended to be used as an in-house immunoaffinity column for aflatoxin detection in Thailand.

Integrated peanut aflatoxin management for increase income and nutrition in Northern Ghana

Aflatoxins contamination in peanut seeds remains a major challenge in Ghana. This study evaluated aflatoxin levels in peanut samples from farmer storage units, and participatory on-farm research tr...

Peanut trade and aflatoxin standards in Europe: Economic effects on trading countries

The role of aflatoxin contamination in food safety is an important policy issue impacting food industries worldwide. This paper evaluates the economic implications of strict peanut aflatoxin regulation in Europe focusing on price and quantity effects of the policy. Equilibrium displacement modeling is applied on a source-differentiated market. Findings show that regulation tightening leads to price and quantity drop for the United States and other exporters, whereas China benefits owing to its price and quantity gains. Although both peanut exporters and importers share compliance costs from the aflatoxin policy, consumers in Europe pay a greater proportion of the costs.

Estimation of aflatoxins in peanut or maize by enzyme linked immunosorbent assay

&lt;p&gt;Aflatoxin are potentially toxic metabolites produced by microscopic fungi when grow on food. Hence, determining content of mycotoxins such as aflatoxin has significant pharmaceutical value. This study reports step-by-step visual demonstration of determination of aflatoxin contents in peanut and maize (corn)-based food samples through employing enzyme linked immunosorbent assay (ELISA). The method is based on direct competitive ELISA in a micro-well format which allows determination of exact amount of aflatoxin in food samples as parts per billion (ppb), and the results are calculated using Neogen’s Veratox data reduction software that converts the absorbance values into quantities. This visual experiment will certainly contribute knowledge regarding importance and applicability of the ELISA method for determining aflatoxin content in variety of food samples avoided of analytical issues such as sampling, laborious sample preparation, and critical selection of analytical methods.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Video Clip&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;&lt;a href="https://www.youtube.com/v/iWR1gt_u2jo"&gt;Test sample preparation:&lt;/a&gt; 7 min 12 sec&lt;br /&gt;&lt;a href="https://www.youtube.com/v/VY_iwjpXFZI"&gt;Assay procedure:&lt;/a&gt; 5 min 23 sec&lt;br /&gt;&lt;a href="https://www.youtube.com/v/mcdSp9ZRE7Q"&gt;Measurement of absorbance by Tecan ELISA microtiter plate reader:&lt;/a&gt; 2 min 57 sec&lt;/p&gt;&lt;p&gt; &lt;/p&gt;

The Establishment of Real-Time PCR Detection System of Aspergillus Niger in Peanut

In this study, a set of real-time PCR primers for the detection of aflatoxin in peanut was successfully designed according to the AFLR gene of Aspergillus niger. Upstream primer was 5'-AACCTGATGACGACTGATAT-3'; Downstream primer was 5'-AGCACCTTGAGAACGATAA-3'; The real-time PCR detection system established in this study had good specificity, and the sensitivity of DNA detection can reach 3×10-13 ng/ul. The correlation coefficient between the contents of aflatoxin in peanut samples and PCR Ct of Real-time was-0.718, and the correlation coefficient was significantly negative.

Occurrence and factors associated with aflatoxin contamination of raw peanuts from Lusaka district's markets, Zambia

Peanuts, one of the most susceptible crops to aflatoxin (AF) contamination, are widely produced and consumed in Zambia. This cross-sectional study was designed to determine the levels of AFs in raw peanuts sold in Lusaka district's markets as well as identify factors associated with increased AF presence. Raw peanut samples were collected from open markets and supermarkets and analyzed for aflatoxin contamination using high performance liquid chromatography (HPLC). A questionnaire was also administered to the peanut vendors to investigate factors contributing to increased levels of AFs in peanuts. Of the 92 samples, 51 (55.4%; 95% CI: 44.9–65.4) tested positive for presence of AFs. The overall median and geometric mean ± standard deviation (SD) concentration for AF were 0.23 ppb (range: 0.014–48.67 ppb) and 0.43 ± 9.77 ppb, respectively. The association between market types and presence of AFs was not statistically significant (Pearson Χ2 = 0.0587, p = 0.809). Of 51 samples that tested positive to AF, 6.5% and 12% were above the maximum permissible limits (MPLs) set by the Codex Alimentarius Commission and European Union standards, respectively. There was a significant difference in the levels of AF between Chalimbana and Kadononga (p<0.0001), and also Chalimbana and Makulu red (p<0.0001). Chalimbana was the most at risk of AF contamination, when compared to other peanut varieties. The high level of AFs in raw peanuts from both supermarkets and open markets samples constitutes a health hazard for the population of Lusaka district. Therefore, intervention strategies that reduce the levels of AF contamination in peanuts should be given priority.

Aflatoxins in Natural Peanuts (Arachis hypogaea L.) of Mexico: Validation of the Biochemical Methods for Extraction and Quantification

The peanut (Arachis hypogaea L.) is frequently contaminated with aflatoxins (AFs). Aflatoxins are toxic secondary metabolites – bifuran coumarins – produced by the fungi Aspergillus spp. AFs cause damage in animals and humans, including bleeding, vomiting, abortions, malformations, diarrhea and death. AFs can cause chronic liver damage and different cancers, immunosuppression, Reye’s syndrome, kwashiorkor and marasmus. For the present research, 58 samples of peanut were obtained: 48 were purchased from the three major markets of the 16 boroughs of Mexico City, and eight samples from Turkey and two from India were used for comparison. The extraction and quantification methods for AFs in peanut were validated. AFs from 25 g peanut samples were extracted with 100 mL of methanol/water (80:20 v/v) with one gram of salt. The roles of sample origin and types of AF were compared, and their significance was obtained through statistical analysis using the non-parametric Wilcoxon/Kruskal-Wallis tests. The limits of detection of AF (ng g-1) obtained from the calibration curves were AFB1 (0.1), AFB2 (0.01), AFG1 (0.01) and AFG2 (0.05). The results indicated that of the 58 samples, 80% were contaminated with AFB1, and all of them had total aflatoxins (AFt). The statistical analysis revealed a significant difference for AFB1, with the highest concentration of 44 μg kg-1 found in the Gustavo A. Madero Mexican borough. For AFB2, the highest concentration was 80 μg kg-1 from the Benito Juarez Mexican borough. Only traces of AFG1 were detected, with the highest of 0.64 μg kg-1 from the Tlahuac Mexican borough. Only traces of AFG2 were present. All samples had an average AFt of 8.53 μg kg-1.

RNAi-mediated Control of Aflatoxins in Peanut: Method to Analyze Mycotoxin Production and Transgene Expression in the Peanut/Aspergillus Pathosystem.

The Food and Agriculture Organization of the United Nations estimates that 25% of the food crops in the world are contaminated with aflatoxins. That represents 100 million tons of food being destroyed or diverted to non-human consumption each year. Aflatoxins are powerful carcinogens normally accumulated by the fungi Aspergillus flavus and A. parasiticus in cereals, nuts, root crops and other agricultural products. Silencing of five aflatoxin-synthesis genes by RNA interference (RNAi) in peanut plants was used to control aflatoxin accumulation following inoculation with A. flavus. Previously, no method existed to analyze the effectiveness of RNAi in individual peanut transgenic events, as these usually produce few seeds, and traditional methods of large field experiments under aflatoxin-conducive conditions were not an option. In the field, the probability of finding naturally contaminated seeds is often 1/100 to 1/1,000. In addition, aflatoxin contamination is not uniformly distributed. Our method uses few seeds per transgenic event, with small pieces processed for real-time PCR (RT-PCR) or small RNA sequencing, and for analysis of aflatoxin accumulation by ultra-performance liquid chromatography (UPLC). RNAi-expressing peanut lines 288-72 and 288-74, showed up to 100% reduction (p≤0.01) in aflatoxin B1 and B2 compared to the control that accumulated up to 14,000 ng.g-1 of aflatoxin B1 when inoculated with aflatoxigenic A. flavus. As reference, the maximum total of aflatoxins allowable for human consumption in the United States is 20 ng.g-1. This protocol describes the application of RNAi-mediated control of aflatoxins in transgenic peanut seeds and methods for its evaluation. We believe that its application in breeding of peanut and other crops will bring rapid advancement in this important area of science, medicine and human nutrition, and will significantly contribute to the international effort to control aflatoxins, and potentially other mycotoxins in major food crops.

Quantifying aflatoxins in peanuts using fluorescence spectroscopy coupled with multi-way methods: Resurrecting second-order advantage in excitation–emission matrices with rank overlap problem

A rapid, simple and inexpensive method using fluorescence spectroscopy coupled with multi-way methods for the determination of aflatoxins B1 and B2 in peanuts has been developed. In this method, aflatoxins are extracted with a mixture of water and methanol (90:10), and then monitored by fluorescence spectroscopy producing EEMs. Although the combination of EEMs and multi-way methods is commonly used to determine analytes in complex chemical systems with unknown interference(s), rank overlap problem in excitation and emission profiles may restrain the application of this strategy. If there is rank overlap in one mode, there are several three-way algorithms such as PARAFAC under some constraints that can resolve this kind of data successfully. However, the analysis of EEM data is impossible when some species have rank overlap in both modes because the information of the data matrix is equivalent to a zero-order data for that species, which is the case in our study. Aflatoxins B1 and B2 have the same shape of spectral profiles in both excitation and emission modes and we propose creating a third order data for each sample using solvent as a new additional selectivity mode. This third order data, in turn, converted to the second order data by augmentation, a fact which resurrects the second order advantage in original EEMs. The three-way data is constructed by stacking augmented data in the third way, and then analyzed by two powerful second order calibration methods (BLLS–RBL and PARAFAC) to quantify the analytes in four kinds of peanut samples. The results of both methods are in good agreement and reasonable recoveries are obtained.

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Peanut is a cheapest source of protein especially for developing countries communities and mostly it obtained from traditional markets. Earlier studies showed that aflatoxin incidence was relatively less at the farmer/trader levels while it is significantly higher at retail levels especially in traditional markets. Present study was conducted to understand the factors leading to the post-harvest building up of aflatoxin in peanuts sold in traditional market and in supermarket. This study was carried out at Pasuruan regency, East Java Province, Indonesia from March 2005 to June 2006. During study period peanut grains were collected from wholesalers, retailers and supermarkets at three months interval. In each sampling point, 2kg of grains was obtained and then was divided into eight parts for the analysis of parameters namely seed moisture content, physical quality, Aspergillus flavus infection and aflatoxin B1 contamination. The results showed that seed water contents at wholesalers, collectors, and retailers in traditional wet markets were almost lower than 10%. They were thus ‘safe’ from aflatoxin B1 contamination as seed moisture contents were below the aflatoxin risk zone. Time of sampling did not affect the level of aflatoxin B1 contamination. Under controlled condition generated from air-tight container, the influence of seed moisture content and A. flavus infection on aflatoxin production was significant. Agustina A. Rahmianna * and Eriyanto Yusnawan

Marine natural compounds can be efficient toward aflatoxigenic Aspergillus flavus strain

Background The presence of high levels of aflatoxin is a serious problem to the production of raw peanuts and peanut crumbs. The high incidence of aflatoxin in peanuts in our country is mainly due to problems in primary production. High humidity and temperature conditions increase the likelihood of Aspergillus development and aflatoxins production, which is worsened during rainy weather [1]. Aflatoxins may remain in the food after the death of fungus without visible alterations [2]. The effects of aflatoxins on human and animal health, besides resistance of fungi to conventional antifungal agents has motived the search for new inhibitors. The research of marine natural products from sponges has been considered as a promising source for the development of new antifungal agents in order to discover compounds more effective and less toxic [3]. The objective of this study was to evaluate the antifungal activity of 21 marine natural compounds toward an aflatoxigenic A.flavus ATCC strains.

Natural Occurrence of Aflatoxins in Peanuts and Peanut Butter from Bulawayo, Zimbabwe

Mycotoxins are toxic secondary metabolites produced by filamentous fungi that may contaminate food and pose a health risk, especially in developing countries, where there is a lack of food security and quality is subsumed by food insufficiency. Aflatoxins are the most toxic known mycotoxins and are a significant risk factor for liver and kidney cancer, teratogenicity, undernutrition, and micronutrient malabsorption in both humans and animals. The main aim of the study was to determine the extent of fungal and aflatoxin contamination in peanuts and peanut butter being sold in both the formal and informal markets in Bulawayo, Zimbabwe. Eighteen peanut samples and 11 peanut butter samples were purchased from retail shops and the informal market. Fungal contamination was determined using standard mycology culture methods, while aflatoxin contamination was determined using high-performance liquid chromatography-fluorescence detection. Four of the six peanut samples tested for fungal contamination were infected with Aspergillus flavus/parasiticus, ranging from 3 to 20% of the kernels examined, while 27% (3 of 11) of the peanut butter samples were infected with A. flavus/parasiticus. Ninety-one percent (10 of 11) of the peanut butter samples were contaminated with aflatoxins (mean, 75.66 ng/g, and range, 6.1 to 247 ng/g), and aflatoxin B1 was the most prevalent (mean, 51.0 ng/g, and range, 3.7 to 191 ng/g). Three of the 18 peanut samples were contaminated with aflatoxins (range, 6.6 to 622 ng/g). The commercial peanut butter samples had very high aflatoxin levels, and manufacturers should be sensitized to the detrimental effects of aflatoxins and measures to reduce contamination.

Ozone‐Induced Changes in Phenols and Antioxidant Capacities of Peanut Skins

AbstractChanges of total phenols, flavonoids, proanthocyanidins and antioxidant capacities of peanut skins were studied after they were ozonated for different times (0–60 h). The phenols and their oxidation products in peanut skins were identified by High Performance Liquid Chromatography Coupled Quadrupole Time‐of‐Flight Mass Spectrometry (HPLC‐Q‐TOF/MS). Ozone treatment significantly affected total phenolic and proanthocyanidin contents, which were reduced by 48.77 and 47.71% after 24 h of ozone treatment, respectively. Total flavonoids were increased due to new flavonoids formed during ozone treatment. The antioxidant capacities of peanut skin extracts were closely correlated to the total phenolic and proanthocyanidin contents, and the correlation coefficients (R) were 0.9831 and 0.7859, respectively. The decrease of total phenolic and proanthocyanidin contents reduced obviously the antioxidant capacities of peanut skin extracts. Ten phenolic compounds and seven oxidation products were identified by Q‐TOF/MS, and the changes of their peak areas further verified the changes of phenols in peanut skin extracts at different ozonation times.Practical ApplicationsMany studies have proved that ozone can degrade aflatoxins in peanuts. However, ozone treatment can also affect the phenols in peanut skins, and then influence their antioxidant capacities. This study demonstrated the changes of phenols and their antioxidant capacities in the ozonated peanut skins. The phenolic compounds and their oxidation products were identified by TOF/MS. Information on the changes of phenols induced by ozone would help in improving the detoxification technology of peanuts for maintaining more functional components in peanut skins.

Identification of the Oxidative Products and Ozonolysis Pathways of Polyphenols in Peanut Skins

Many studies have proved that ozone can decompose aflatoxins in peanuts, while polyphenols in peanut skins can also be destroyed due to its strong oxidative capacity. The polyphenols and their oxidative products in the peanut skin extracts at different ozonated times were separated and identified by HPLC-Q-TOF/MS. Based on the accurate molecular weight from mass spectrogram, and consulted the reported literatures, nine polyphenols and nine main oxidative products were identified in the peanut skins. According to the oxidative mechanism of phenols and the Criegee mechanism of ozonolysis, the ozonolysis pathways of nine polyphenols were proposed. The structures of oxidative products showed that ozone can destroy the polyphenols, so the effects of ozone treatment on the peanut skins should be considered by processors in the detoxification of aflatoxin-contaminated peanuts.

Statement of Retraction

This article refers to:RETRACTED ARTICLE: Assessment of aflatoxins in peanuts grown in the Pothohar area of Pakistan

Graphene oxide: An adsorbent for the extraction and quantification of aflatoxins in peanuts by high-performance liquid chromatography

In this paper, graphene oxide (GO) was synthesized and specifically selected by centrifugation to extract four aflatoxins (B1, B2, G1, and G2) as an effective adsorbent. Then, the amount of aflatoxins was quantitatively measured by high-performance liquid chromatography (HPLC). The GO was characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), and ultraviolet (UV) spectrophotometer. Several parameters that could affect the extraction efficiency, including the GO amount, methanol concentration in the extraction solvent, spiked amount, extraction time, and elution cycle, were also investigated and optimized in this work. Under optimal conditions, good linear relationships were achieved with the correlation coefficient (r) ranging from 0.99217 to 0.99995. The detection limit of this method for the four aflatoxins ranged from 0.08 to 0.65ng/g. Finally, the proposed method has been successfully applied to determine aflatoxins in peanut samples. The results show that the recoveries of the four aflatoxins range from 85.1% to 100.8% with the relative standard deviations between 2.1% and 7.9%.

Effect of ozone on aflatoxins detoxification and nutritional quality of peanuts

Aflatoxins are a group of secondary metabolites produced by Aspergillus flavus and Aspergillus parasiticus with carcinogenicity, teratogenicity, and mutagenicity. Aflatoxins may be found in a wide range of agri-products, especially in grains, oilseeds, corns, and peanuts. In this study, the conditions for detoxifying peanuts by ozonation were optimised. Aflatoxins in peanuts at moisture content of 5% (w/w) were sensitive to ozone and easily degraded when reacted with 6.0mg/l of ozone for 30min at room temperature. The detoxification rates of the total aflatoxins and aflatoxin B1 (AFB1) were 65.8% and 65.9%, respectively. The quality of peanut samples was also evaluated in this research. No significant differences (P>0.05) were found in the polyphenols, resveratrol, acid value (AV), and peroxide value (PV) between treated and untreated samples. The results suggested that ozonation was a promising method for aflatoxin detoxification in peanuts.