Nano-adsorbents obtained from walnut and almond shells for the effective removal of aflatoxin B1
In the present study, new nano-adsorbents were prepared from the walnut (WSN) and almond (ASN) shells for the sequestering of aflatoxin B1 (AFB1) contamination. The nano-adsorbents were characterized via SEM, EDS, XRD, and FTIR spectroscopy techniques to discover valuable data about the morphology, surface, and chemical configuration of the nano-adsorbents. The adsorption process was further optimized by altering the biosorbent dosage, AFB1 concentration, pH, time, and temperature. Among the tested biosorbents, the WSN and ANS presented a significant removal of AFB1 compared with the walnut and almond shell powders (WSP and ASP). The maximum removal using WSN and ASN was achieved as 93.70% and 83.81% using 10 mg/mL of nano-adsorbent, pH 5.0 at 45 °C for 45 min. Langmuir was the best fitting model for each adsorption data with adsorption capacities of WSP, ASP, WSN, and ASN were 47.6, 36.1, 176.3, and 161.1 mg/g, respectively, with a leading monolayer form adsorption. Kinetic data followed the pseudo-second-order with fast AFB1 uptake. However, thermodynamics studies indicated the spontaneity and endothermic nature of the adsorption process. Furthermore, no significant decline in AFB1 adsorption was recorded after reusability up to five times. The production of nano-adsorbents in this study offers the possibility of dropping the cost of production, controlling agro-waste, and reducing toxins and other organic materials. Finally, the adsorption presentation confirmed the ability of this novel, cost-effective, environment-friendly, and non-toxic biosorbent to remove AFB1 effectively.
https://doi.org/10.1007/s13399-025-06590-w
Comparative metabolomics analysis reveals secondary cell wall thickening as a barrier to resist Aspergillus flavus infection in groundnut
Aflatoxin contamination caused by Aspergillus flavus significantly threatens food safety and human health. Resistance to aflatoxin is a highly complex and quantitative trait, but the underlying molecular and biochemical mechanisms are poorly understood. The present study aims to identify the resistance-related metabolites in groundnut that influence the defense mechanism against aflatoxin. Here, metabolite profiling of resistant (55–437) and susceptible (TMV-2) groundnut genotypes, which exhibited contrasting levels of resistance to A. flavus growth and aflatoxin accumulation under pathogen- or mock-inoculated treatments, was undertaken using liquid chromatography and high-resolution mass spectrometry (LC-HRMS). Non-targeted metabolomic analysis revealed key resistance-related metabolites belonging to phenylpropanoids, flavonoids, fatty acids, alkaloids, and terpenoid biosynthetic pathways. The phenylpropanoids - hydroxycinnamic acid amides (HCAAs) and lignins were among the most abundantly accumulated metabolites in the resistant genotype compared to the susceptible genotype. HCAAs and lignins are deposited as polymers and conjugated metabolites to strengthen the secondary cell wall, which acts as a barrier to pathogen entry. Further, histochemical staining confirmed the secondary cell wall thickening due to HCAAs and lignin depositions. Quantitative real-time PCR studies revealed higher expressions of phenylalanine ammonia-lyase (PAL), 4-coumarate: CoA ligase (4CL), cinnamoyl CoA reductase (CCR2), cinnamoyl alcohol dehydrogenase (CAD1), agmatine hydroxycinnamoyl transferase (ACT), chalcone synthase (CHS), dihydroflavonol 4-reductase (DFR) and flavonol synthase (FLS) in the pathogen-inoculated resistant genotype than in the susceptible genotype. This study reveals that the resistance to aflatoxin contamination in groundnut genotypes is associated with secondary cell wall thickening due to the deposition of HCAAs and lignins.
https://doi.org/10.1056/NEJMoa2312382
Development of an Antifungal Device Based on Oriental Mustard Flour to Prevent Fungal Growth and Aflatoxin B1 Production in Almonds
The present study describes the manufacture of an antifungal device composed of oriental mustard flour and hydroxyethyl-cellulose (H-OMF) and evaluates its efficacity in inhibiting Aspergillus flavus growth and aflatoxin B1 (AFB1) production in almonds. Additionally, it compares the H-OMF with allyl isothiocyanate (AITC) and a freeze-dried extract of yellow mustard flour (YMF-E); such substances were previously described as antifungal. Minimum inhibitory concentration (MIC), Minimum fungicidal concentration (MFC), the H-OMF in vitro antifungal activity, and the residual fungal population, as well as the production of AFB1 in almonds were determined. AITC and YMF-E showed significant antifungal activity in vitro. Additionally, the in vitro activity of H-OMF avoided mycelial growth by applying 30 mg/L. Almonds treated with AITC (5.07, 10.13, and 20.26 mg/L) and H-OMF (2000 and 4000 mg/L) showed a reduction in the population of A. flavus and the production of AFB1 to values below the limit of detection. YMF-E showed effectiveness by in vitro methodologies (MIC and MFC) but did not show efficacy when applied in almonds. Our findings indicated that the hydroxyethyl-cellulose-based device containing oriental mustard flour might be utilised as a fumigant to increase the safety of almonds and could be extended to other cereals or dry fruits. https://doi.org/10.3390/toxins14010005
Validation of New ELISA Technique for Detection of Aflatoxin B1 Contamination in Food Products versus HPLC and VICAM.
Toxin-contaminated foods and beverages are a major source of illness, may cause death, and have a significant negative economic impact worldwide. Aflatoxin B1 (AFB1) is a potent toxin that may induce cancer after chronic low-level exposure. This study developed a quantitative recombinant AflR gene antiserum ELISA technique for aflatoxin B1 detection in contaminated food products. Aflatoxin B1 residuals from 36 food samples were analyzed with HPLC and VICAM. DNA was extracted from aflatoxin-contaminated samples and the AflR gene amplified using PCR. PCR products were purified and ligated into the pGEM-T vector. Recombinant plasmids were sequenced and transformed into competent E. coli (BL21). Molecular size and B-cell epitope prediction for the recombinant protein were assessed. The purified protein was used to induce the production of IgG antibodies in rabbits. Serum IgG was purified and labeled with alkaline phosphatase. Finally, indirect-ELISA was used to test the effectiveness of polyclonal antibodies for detection of aflatoxin B1 in food samples. https://doi.org/10.3390/toxins13110747
Research Full Papers Effect of food processing on aflatoxin reduction in cereals and nuts: A meta-analysis approach.
Fungal toxins, mycotoxinssuch as aflatoxins, are compounds produced by different fungi during the growth and reproduction period. The most important fungal toxins that jeopardize human health are aflatoxins, which are produced by Aspergillus fungi and can grow in all crops. With toxic and carcinogenic effects of aflatoxins, many studies were performed using different methods to eliminate or reduce the amount of aflatoxin in cereals and nuts. On the contrary, using different methods for reducing aflatoxins in cereals and nuts make it impossible or difficult for researchers who study one or few related articles. This paper was conducted to review, investigate and do a meta-analysis on the results of the studies conducted and aimed to answer this general question as by which method can further reduce the amount of aflatoxin in cereals and nuts. Results showed that the methods of UV-irradiation, Ozone & UV irradiation and citric acid were the most important methods by 0.469, 0.441, and 0.427 of effect size respectively. https://ifstrj.um.ac.ir/article_40402_6a2fe2aebfc01e37e90e12640b28b1f0.pdf
Research advancements in optical imaging and spectroscopic techniques for nondestructive detection of mold infection and mycotoxins in cereal grains and nuts.
Cereal grains and nuts are represented as the economic backbone of many developed and developing countries. Kernels of cereal grains and nuts are prone to mold infection under high relative humidity and suitable temperature conditions in the field as well as storage conditions. Health risks caused by molds and their molecular metabolite mycotoxins are, therefore, important topics to investigate. Strict regulations have been developed by international trade regulatory bodies for the detection of mold growth and mycotoxin contamination across the food chain starting from the harvest to storage and consumption. Molds and aflatoxins are not evenly distributed over the bulk of grains, thus appropriate sampling for detection and quantification is crucial. Existing reference methods for mold and mycotoxin detection are destructive in nature as well as involve skilled labor and hazardous chemicals. Also, these methods cannot be used for inline sorting of the infected kernels. Thus, analytical methods have been extensively researched to develop the one that is more practical to be used in commercial detection and sorting processes. Among various analytical techniques, optical imaging and spectroscopic techniques are attracting growers’ attention for their potential of nondestructive and rapid inline identification and quantification of molds and mycotoxins in various food products. This review summarizes the recent application of rapid and nondestructive optical imaging and spectroscopic techniques, including digital color imaging, X-ray imaging, near-infrared spectroscopy, fluorescent, multispectral, and hyperspectral imaging. Advance chemometric techniques to identify very low-level mold growth and mycotoxin contamination are also discussed. Benefits, limitations, and challenges of deploying these techniques in practice are also presented in this paper. https://doi.org/10.1111/1541-4337.12801
High-throughput Analysis of Aflatoxins in Cereals, Nuts and Processed Products Involving Automated Immunoaffinity Cleanup and Inline HPLC-Fluorescence Detection.
Background: The testing of aflatoxins (AFs) in fresh and processed foods is highly demanded to comply with trade regulations. Consequently, commercial laboratories face huge AF sample loads in food consignments. Worldwide, there is a rising interest to implement automation to increase sample throughput in AF analysis. Objective: This study sought to evaluate the performance of an automated cleanup and HPLC analysis system for determination of regulated AFs (B1, B2, G1, G2) in rice, flattened rice, sorghum, raw and processed peanut, almond, peanut butter, and wheat-based cookies. Methods: The samples were extracted with methanol-water (80:20), diluted with Triton X-100 and subjected to automated analysis, where the cleanup step through immunoaffinity column (IAC) and HPLC-fluorescence analyses [involving post-column bromination-derivatisation] were performed in 10 and 11 min, respectively. The method was validated in all test matrices at the LOQ and higher levels. The method performance was also evaluated against a conventional workflow where cleanup and HPLC analysis were manually performed. Results: The LOQ for peanut, sorghum, rice, and flattened rice was 0.125 ng/g, while it was 0.5 ng/g for peanut butter, almond, and wheat-based cookies. In all matrices, the recoveries at LOQ and higher levels were satisfactory. The double-cartridge exchange system completed the analysis of ∼96 injections in 18 h. Each IAC could be reused for 15-times, without incurring any recovery loss. The automated-system provided a better precision (RSD<9%) than the conventional (RSD=12-15%) workflow. Conclusions: Because of its high-throughput nature, this method is recommended for routine analysis of AFs. Highlights: A high-throughput method is reported where cleanup and HPLC analysis of aflatoxins were automatically performed. Each immunoaffinity column could be used 15-times without any loss in recoveries. The method performance was better than the conventional approach and complied with the analytical quality control guidelines. https://doi.org/10.1093/jaoacint/qsab083
Decontamination of aflatoxin B1 in peanuts using various cooking methods.
Peanut and its processed products are recurrently contaminated with aflatoxins (AFs) which are of potential public health concern. Among the different types of AFs, Aflatoxin B1 (B1) is the most frequently detected in peanuts over the maximum level (ML), and thus has warranted considerable research interest in the domain of food safety. In this study, we investigated the decontamination of B1 in three naturally-incurred lots (4, 12, and 40 µg/kg) of peanuts by a range of cooking treatments, including frying, pressure cooking, and roasting. B1 concentrations were determined by ultra-high performance liquid chromatography- fluorescence detection. The method provided a limit of quantification of 0.25 µg/kg for B1, which was much lower than any of its national and international MLs. The recoveries of B1 in fresh and cooked peanuts (positive-control) were in the range of 90-100%. Overall, all the cooking methods demonstrated a significant reduction in B1 loads. The degree to which the processing methods reduced the B1 content followed the pattern: roasting with a combination of NaCl and citric acid > pressure-cooking with a combination of NaCl and citric acid > frying. As the cooking procedures did not involve any complicated steps or sophisticated equipment, these could be readily adopted for decontamination or reduction in the level of B1 for a safer consumption of peanuts at the household level without affecting the organoleptic properties. https://doi.org/10.1007/s13197-020-04761-3
A simple extraction method with no lipid removal for the determination of aflatoxins in almonds by liquid chromatography tandem-mass spectrometry (LC-MS/MS).
The present study describes a simple and rapid method for the determination of aflatoxins in almonds using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Aflatoxins were extracted using a modified QuEChERS method with little sample preparation, excluding the use of laborious purification procedures. Extracts were frozen overnight to separate the majority of lipids. The method was successfully validated for almonds. Linearity was demonstrated in the range 0.125-20 µg/kg. Limits of quantification (LOQ) ranged from 0.34 to 0.5 μg/kg. Matrix effect was not significant for the aflatoxins. Satisfactory recoveries were obtained at spike levels below 1 μg/kg and between 1 and 10 μg/kg. Relative standard deviations (RSDs) of repeatability and reproducibility were below 15%. The method was successfully tested with two proficiency tests in almond powder and peanut paste, with acceptable z-scores (-2 ≤ z ≤ 2). Only one of 11 local almond samples contained detectable aflatoxins, at concentrations below the maximum permitted level. https://doi.org/10.1080/19440049.2021.1925167
The Existing Methods and Novel Approaches in Mycotoxins’ Detection.
Mycotoxins represent a wide range of secondary, naturally occurring and practically unavoidable fungal metabolites. They contaminate various agricultural commodities like cereals, maize, peanuts, fruits, and feed at any stage in pre- or post-harvest conditions. Consumption of mycotoxin-contaminated food and feed can cause acute or chronic toxicity in human and animals. The risk that is posed to public health have prompted the need to develop methods of analysis and detection of mycotoxins in food products. Mycotoxins wide range of structural diversity, high chemical stability, and low concentrations in tested samples require robust, effective, and comprehensible detection methods. This review summarizes current methods, such as chromatographic and immunochemical techniques, as well as novel, alternative approaches like biosensors, electronic noses, or molecularly imprinted polymers that have been successfully applied in detection and identification of various mycotoxins in food commodities. In order to highlight the significance of sampling and sample treatment in the analytical process, these steps have been comprehensively described. https://doi.org/10.3390/molecules26133981