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
Aflatoxins and Ochratoxin A in dried fruits from Morocco: Monitoring, regulatory aspects, and exposure assessment.
The present study aims to investigate the presence of Aflatoxins (AF) in 180 samples dried fruits and Ochratoxin A (OTA) in 210 samples dried fruits and grape juices collected in Morocco. Mycotoxins were analyzed by high performance liquid chromatography (HPLC) coupled to fluorescence detection and immunoaffinity columns (IAC) cleanup. Contamination levels were compared with the maximum regulatory limits (MRL) recently adopted in the country, and mycotoxin exposure of adult consumers was assessed. Results showed that 13.8% of samples were contaminated with AF, with incidences of 23.3, 23.3, 20, 13.8, and 3.3%, in raisins, figs, nuts, peanuts and pistachio, respectively. There were 12 samples (6.6%) that exceeded the MRL of 2-12 ng/g set for aflatoxin B1 (AFB1). While OTA was detected in 17.1% of samples, with incidences of 3.3, 3.3, 30, 30, and 53.3% in walnuts, pistachios, peanuts, raisins and figs, respectively, and a maximum value of 99.1 in dried raisins, that exceeded the MRL (10 ng/g) set for OTA. The co-occurrence of OTA and AF was observed in 4.7% of total samples. Dietary intake showed that the OTA exposure level was lower than safety guidelines set by The Joint FAO/WHO Expert Committee on Food Additives (JECFA) at 100 ng/kg b.w./week. https://doi.org/10.1016/j.yrtph.2023.105503
Computer vision-assisted smartphone microscope imaging digital immunosensor based on click chemistry-mediated microsphere counting technology for the detection of aflatoxin B1 in peanuts
Aflatoxin B1 is a carcinogenic contaminant in food or feed, and it poses a serious health risk to humans. Herein, a computer vision-assisted smartphone microscope imaging digital (SMID) immunosensor based on the click chemistry-mediated microsphere counting technology was designed for the detection of aflatoxin B1 in peanuts. In this SMID immunosensor, the modified polystyrene (PS) microspheres were used as the signal probes and were recorded by a smartphone microscopic imaging system after immunoreaction and click chemistry reaction. The number of PS probes is adjusted by aflatoxin B1. The customized computer vision procedure was used to efficiently identify and count the obtained PS probes. This SMID immunosensor enables sensitive detection of aflatoxin B1 with a linear range from 0.001 ng/mL to 500 ng/mL, providing a simple, sensitive, and portable tool for food safety supervision. https://doi.org/10.1016/j.aca.2023.341687