Aflatoxin B1 Accumulation Research Articles

Effects of aflatoxin B1 on subacute exposure of hybrid groupers (Epinephelus fuscoguttatus♀ × Epinephelus lanceolatus♂): Growth, liver histology, and integrated liver transcriptome and metabolome analysis

With the increasing incorporation of plant-based ingredients into the grouper diet, the issue of aflatoxin B1 (AFB1) contamination in the diet has become a significant concern. In this study, the negative effects of AFB1 on the growth and liver health of hybrid grouper (Epinephelus fuscoguttatus♀ × Epinephelus lanceolatus♂) were investigated in the context of growth, liver histology, serum biochemical indices, and integrated transcriptomic and metabolomic data. A total of 540 healthy hybrid groupers, initially weighing 11.59 ± 0.03 g, were randomly divided into six groups (three replicates of 30 fish each): the Control group was fed a basal diet, and the experimental groups were supplemented with 7 (AF7), 30 (AF30), 111 (AF111), 445 (AF445) and 2230 μg/kg AFB1 (AF2230) in the basal diet respectively, for 56 days. Groups Control, AF445, and AF2230 were selected for subsequent histological, muscle fatty acid, and transcriptomic and metabolomic analyses based on the results of hybrid grouper growth and serum biochemical indices. Compared to the Control group, both whole-body crude lipid and muscle crude lipid contents showed significant decreases in the AF2230 group (P < 0.05), while only muscle crude lipid content showed a significant decrease in the AF445 group (P = 0.001). Liver damage was seen in the histology of the liver of AF445 and AF2230 groups. Muscle fatty acid results showed that the addition of 445 and 2230 μg/kg AFB1 to the ration increased saturated fatty acids and monounsaturated fatty acids and decreased polyunsaturated fatty acids and highly unsaturated fatty acids in muscle (P < 0.05). Transcriptome analyses revealed multiple metabolic pathways associated with AFB1 metabolism, and metabolomics analyses further confirmed changes in the activity of these pathways. The results of the combined transcriptomic and metabolomic analyses indicated that AFB1 causes liver injury mainly by affecting liver retinol metabolism, metabolism of xenobiotics by cytochromes P450, drug metabolism-cytochromes P450 and biosynthesis of unsaturated fatty acids. In conclusion, dietary AFB1 levels above 445 μg/kg resulted in growth inhibition, liver injury, liver AFB1 accumulation, and reduced muscle polyunsaturated fatty acid content in grouper, thereby affecting muscle quality. This study provides novel insights into the detrimental effects of AFB1 on aquatic species and contributes to the scientific basis for the health and sustainability of aquaculture practices.

A novel biomass carbon dots ratiometric fluorescence probe coupled with molecularly imprinted polymer for selective detection of aflatoxin B1

The accumulation of Aflatoxin B1 (AFB1) in food and crops can pose significant hazards to human health. Consequently, there has been extensive attention paid to the development of a rapid and reliable method for detecting AFB1 in food. In this context, a ratiometric fluorescence probe (DE-MIPs) was prepared using dual-emission fluorescent carbon dots (CDs) coupled with the molecular imprinting technique for visual detection of AFB1. The dual-emission CDs consisted of red fluorescence biomass CDs (R-CDs) wrapped by molecularly imprinted cavities (R-CDs@MIPs), which served as a response signal, and pure blue emission biomass CDs (B-CDs) as a reference signal. Due to the specific quenching effect of AFB1 on red fluorescence while leaving blue fluorescence unaffected, there was a gradual decrease in the fluorescence intensity ratio (I670/I437) and a distinct shift in fluorescence color from red to blue as the concentration of AFB1 increased. The ratiometric probe demonstrated excellent linearity in detecting AFB1 within the concentration range of 0.1–200 ng/mL, with a detection limit (LOD) of 0.05 ng/mL. Furthermore, the practicality of DE-MIPs was validated by successfully detecting AFB1 in vegetable oil, with desirable recoveries from 89.0% to 107.4%. Furthermore, the integration of a smartphone as colorimetric reader enabled rapid AFB1 detection by capturing changes in fluorescence color. Overall, the development of this ratiometric probe offers a novel perspective for the facile and efficient identification of AFB1 in complex food samples.

Curcumin alleviates Aflatoxin B1-triggered chicken liver necroptosis by targeting the LOC769044/miR-1679/STAT1 axis

Aflatoxin B1 (AFB1) is an unavoidable environmental toxin. The accumulation of AFB1 and its metabolites in the liver poses a threat to both human and animal health. Curcumin exhibits anti-oxidative, anti-tumor, and anti-inflammatory properties. There is no report on the mechanism regarding how curcumin relived liver necroptosis in chickens induced by AFB1 based on the regulatory network of ceRNA. To explore this, we performed transmission electron microscopy and sequenced lncRNA and mRNA in chicken livers treated with AFB1 and/or curcumin for 28 d in vivo. We observed substantial alterations in the lncRNA and mRNA expression profiles within the chicken liver, indicating that curcumin can mitigate AFB1-induced necroptosis both in vivo and in vitro. Further analysis, including the establishment of an lncRNA-miRNA-mRNA network and the utilization of a dual luciferase reporter assay, revealed that LOC769044 acts as a competing endogenous RNA (ceRNA) for miR-1679. In addition, STAT1 was identified as a direct target of miR-1679. Modulating miR-1679 levels through overexpression, and silencing LOC769044 and STAT1, effectively reversed the necroptotic effects induced by AFB1, a reversal that was also observed with curcumin supplementation. In conclusion, our data demonstrate that curcumin alleviates AFB1-induced liver necroptosis through the LOC769044/miR-1679/STAT1 signaling axis. This study suggests that LOC769044 may serve as a novel therapeutic target for managing AFB1-mediated liver toxicity.

Dietary garden cress (Lepidium sativum) seeds mitigate the effect of aflatoxin B1 contamination on growth, antioxidant status, AFB1 residues, immune response, and tissue architecture of Oreochromis niloticus

The contamination of fish diets with aflatoxin B1 (AFB1) poses a significant hazard to the aquaculture sector. This study investigates the efficacy of supplementing Nile tilapia (Oreochromis niloticus) diets with garden cress (Lepidium sativum) seeds (GCS) to mitigate the adverse effects of AFB1. For this purpose, a factorial design was utilized, consisting of a 2×3 arrangement of treatments. This included two contamination levels of AFB1: (0 and 2 mg kg−1 diet). Within each contamination level, three dietary levels of GCS were used (0 %, 1 %, and 2 %). The study involved 270 healthy O. niloticus with an average weight of 25.14 ± 0.39 g (45 fish/group and 15 fish/replicate). The duration of the trial was 60 days. The study evaluated growth performance, hematological indices, hepatorenal function, immune and antioxidant indicators, histomorphology of organs, AFB1 residues in muscles, and fish resistance to Aeromonas hydrophila. The results indicated that GCS dietary supplementation significantly counteracted AFB1-induced growth retardation and reduced fish survival. Additionally, GCS effectively reversed the anemia, leukopenia, hypoproteinemia, hypoalbuminemia, and hypoglobulinemia that were produced by AFB1. Moreover, GCS dietary supplementation significantly suppressed the AFB1-induced increase in serum bilirubin, hepatic enzymes, kidney damage products, cortisol, and glucose. Additionally, the inclusion of GCS in the fish's diet effectively eliminated the accumulation of AFB1 in their muscles. Moreover, GCS supplementation demonstrated significant restoration of depleted antioxidant and innate immune components induced by AFB1. Furthermore, GCS significantly reduced the degenerative changes in renal, hepatic, splenic, and small intestine tissues caused by AFB1. Fish fed a GCS-fortified diet and exposed to AFB1 displayed restored disease resistance when challenged with A. hydrophila. In conclusion, supplementing Nile tilapia diets with GCS at 2 %, even in the presence the AFB1 contamination, significantly enhanced the fish growth, improved health, and increased disease resistance while reducing AFB1 residues, thereby benefiting consumer health.

Early contamination warning of Aflatoxin B1 in stored maize based on the dynamic change of catalase activity and data fusion of hyperspectral images

Aflatoxin B1 (AFB1) is a metabolite of mold with high toxicity, the early warning is of significance to prevent stored maize from AFB1 contamination. Catalase (CAT) is a precursor production before the synthesis of AFB1, which has a significant relationship with the accumulation of AFB1. Hence it is possible to assess the risk level of AFB1 contamination in stored maize according to the change rate of CAT activity, so that to help granary managers avoid AFB1 contamination by regulating storage environment. However, the the chemical detection procedure of CAT activity is complicated, a nondestructive and fast determination method of CAT activity would be more convenient for CAT activity detection and then help to provide the early warning of AFB1 contamination in stored maize. This study proposed to evaluate the contamination risk of AFB1 based on the linkage-warning models of CAT-AFB1 and the nondestructive prediction models of CAT activity. In terms of the dynamic response mechanism between CAT activity of mold and the AFB1 accumulation of maize, the effects of moisture content and storage temperature on the CAT activity of mold and AFB1 accumulation under different storage environment were analyzed, the linkage-warning models of CAT-AFB1 showed that CAT activity of mold and AFB1 content of maize increased exponentially with the change of storage time, proving that CAT activity of mold had the early warning ability for AFB1 contamination. In terms of nondestructive detection of CAT activity, the nondestructive prediction models of CAT activity of mold were developed based on the characteristic spectra and texture information using a novel algorithms namely union partial least squares, which achieved satisfying prediction results with RP2 = 0.924, RMSEP = 0.158, and RPD = 3.65 based on the fused characteristic spectra and texture information of visible-shortwave near-infrared region. This result obtained by this study will provides theoretical basis and technical guarantee for safe storage of maize.

Correlation between Aspergillus flavus fungal biomass and aflatoxin contamination in harvested maize: insights from Kenya and Tanzania

Controlling the occurrence of aflatoxins in foods must be accompanied by managing the fungi responsible for their production. The abundance and diversity of aflatoxin-producing Aspergillus flavus are responsible for the accumulation of these toxins in crops, posing a persistent threat to public health and the economy in tropical developing countries. A study was conducted to investigate the occurrence and level of A. flavus and relate them to aflatoxin levels in maize in Kenya and Tanzania. A total of 786 maize samples were collected during harvesting in selected areas of the two countries for analysis. The fungal abundance in the samples was measured as the amount of fungal DNA relative to maize DNA. This was accomplished by quantifying the fungal DNA using qPCR, targeting the internal transcribed spacer (ITS) gene, while the maize DNA was quantified through the alpha-tubulin gene, the two genes known to be conserved. Aflatoxins were quantified using ultra-high performance liquid chromatography, coupled with ultra-high sensitivity, ultra-fast triple quadrupole tandem-mass spectrophotometer. A. flavus was detected in 88.5% of the 786 tested samples, and the average fungal load for these samples (expressed as the log host/pathogen ratio) was 5.53. Aflatoxin occurrence was positive in 31.9% of the samples, with an average level of 2.3 ± 0.643 ppb. The study established a positive relationship between the occurrence and level of aflatoxin B1 and the presence and biomass of A. flavus, which was statistically proven. These findings emphasize the need to place substantial attention on preharvest control of A. flavus in cereal fields as an effort to control the accumulation of aflatoxin B1 in foods.

Immunotoxicity and the mechanisms of aflatoxin B1-induced growth retardation in shrimp and alleviating effects of bile acids

Aflatoxin B1 (AFB1) is one of the most toxic mycotoxins prevalent in the environment and food chain, posing severe health risks to humans and animals. Bile acids are natural detergents synthesized from cholesterol and play a key role in the excretion of toxins in vertebrates. Here, pacific white shrimp (Litopenaeus vannamei) served as an animal model to examine the toxicity mechanisms of AFB1 and assess the potential alleviating effects of bile acids against AFB1. Our results revealed that AFB1 exposure significantly inhibited the growth performance and immune response of shrimp, accompanied by AFB1 accumulation and histological damage. Mechanistically, AFB1-induced DNA damage activated DNA repair mechanisms and induced the arrest of cell cycle via the ATR-cyclin B/cdc2 pathway. Additionally, AFB1 directly suppressed the immune response and growth performance of shrimp by inhibiting Toll and IMD pathways and the secretion of digestive enzymes. Notably, dietary bile acids significantly reduced AFB1 accumulation and alleviated AFB1-induced growth retardation and immunotoxicity in shrimp, and CCKAR, ATR, and Relish may be key mediators of the alleviating effects of bile acids. Our study provided new insights into the toxicity mechanisms of AFB1 in invertebrates and highlighted the potential of bile acids to alleviate AFB1 toxicity.

土壌サンプル中のアフラトキシン産生菌の生残を調査するための寒天培地全量抽出法

In this study, we investigated a method of extracting the whole agar dish culture to assess the existence and survival of producing fungi of aflatoxins (AFs) in field soil samples. In a control experiment using a known aflatoxigenic Aspergillus flavus strain with dichlorvos (DV) - coated agar or DV-free agar, no significant difference on the recovery of colony numbers was observed while DV clearly inhibited AFs accumulation. Therefore, a method of extracting the whole dish culture of DV-free agar followed by aflatoxin B1 (AFB1) analysis was applied to assess the survival of aflatoxigenic fungi in soil samples during storage. Soil samples stored at different temperature (4°C, -20°C, and -80°C) and duration (3-12 months) were cultured and analyzed for the accumulation of AFB1 in triplicate. Each soil sample suspension was cultured on DV-free agar for 7 days at 25°C, and the whole dish culture was extracted by methanol and the amount of AFB1 was measured. AFB1 amounts were drastically decreased after the fourth month of storage at all temperatures tested. After the fifth month, AFB1 amounts of samples stored at 4°C were significantly lower than those stored at -20°C or -80°C, indicating that temperatures below -20°C may be suitable for longer storage of soil samples. This whole dish culture extraction method is easy to handle and will be applicable to estimate the population of aflatoxigenic fungi among various soil samples from different origin or conditions.

Evaluation of Aspergillus flavus Growth and Detection of Aflatoxin B1 Content on Maize Agar Culture Medium Using Vis/NIR Hyperspectral Imaging

The physiological and biochemical processes of Aspergillus flavus (A. flavus) are complex. Monitoring the metabolic evolution of products during the growth of A. flavus is critical to the overall understanding of the fungal and aflatoxin production detection mechanism. The dynamic growth process of A. flavus and the aflatoxin B1 (AFB1) accumulation in culture media was investigated with a visible/near-infrared hyperspectral imaging (Vis/NIR HSI) system in the range of 400 to 1000 nm. First, the growth of A. flavus and the synthesis pattern of AFB1 were monitored on maize agar medium (MAM) culture for 120 h with a 24-h time-lapse imaging interval. Second, to classify the A. flavus growth, a principal component analysis (PCA) was employed, and a support vector machine (SVM) model was established with the PC1–PC3 as inputs. The results suggested that the PCA-SVM method could distinguish the A. flavus growth time with a classification accuracy larger than 0.97, 0.91, and 0.92 for calibration, validation, and cross-validation, respectively. Third, regression models to predict the AFB1 accumulation using hyperspectral images were developed by comparing different pre-processing methods and key wavelengths. The successive projection algorithm (SPA) was adopted to distill the key wavelengths. The experimental results indicated that the standard normal variate transformation (SNV) with the partial least squares regression (PLSR) achieved the optimal regression performance with an RC value of 0.98–0.99 for calibration and RV values of 0.95–0.96 for validation. Finally, a spatial map of the AFB1 concentration was created using the PLSR model. The spatial regularity of the AFB1 concentration was comparable to the measurement performed. The study proved the potential of the Vis/NIR HSI to characterize the A. flavus growth and the concentration of AFB1 on the MAM over time.

Assessment of Maize Hybrids Resistance to Aspergillus Ear Rot and Aflatoxin Production in Environmental Conditions in Serbia.

Aflatoxin, a naturally occurring toxin produced by the fungus Aspergillus flavus, is the most economically important mycotoxin in the world, with harmful effects on human and animal health. Preventive measures such as irrigation and planting dates can minimize aflatoxin contamination most years. However, no control strategy is completely effective when environmental conditions are extremely favorable for growth of the fungus. The most effective control method is growing maize hybrids with genetic resistance to aflatoxin contamination. The aim of this research was to evaluate the sensitivity of different maize hybrids to A. flavus infection and aflatoxin accumulation. Twenty commercial maize hybrids were evaluated in field trials with artificial inoculations using the colonized toothpicks method. The mycotoxin production potential of A. flavus isolates was confirmed by cluster amplification patterns (CAPs) analysis. The results of this research indicated the existence of significant differences in maize hybrids susceptibility to Aspergillus ear rot and aflatoxin B1 accumulation. No hybrid included in this research showed complete resistance in all conditions, but some hybrids showed partial resistance. Different hybrids also responded differently depending on the sowing date. This research showed that infection intensity is not always consistent with aflatoxin levels, and therefore visual evaluation is not enough to assess maize safety.

Inhibitory Mechanism of Pinosylvin Monomethyl Ether against Aspergillus flavus.

Control of Aspergillus flavus is beneficial for the agricultural economy and food safety. Stilbenes exhibit antifungal properties through an unknown mechanism. Here, six stilbenes isolated from Cajanus cajan were screened for anti-A. flavus activity. Among them, pinosylvin monomethyl ether (PME) showed the strongest anti-A. flavus activity and has a broad antifungal spectrum with negligible hemolysis within the concentration range measured. PME inhibited the spore germination of A. flavus and the accumulation of aflatoxin B1. Mechanistic studies showed that PME could bind the cell membrane phospholipids, resulting in increased permeability and decreased fluidity. Further metabolic analysis showed that PME caused the lysis of cell membranes and subsequent collapse of spores, which resulted in a cell wall autolysis-like phenotype. Structure-activity relationship analysis revealed the importance of maintaining amphiphilicity harmony by substituent groups for the antifungal activity of stilbenes. Together, natural stilbenes are promising antifungal lead compounds worthy of further exploration and research for potential application in the food, pharmaceutical, and agricultural industries.

Pre-harvest strategy for reducing aflatoxin accumulation during storage of maize in Argentina

Maize (Zea mays L.) is an important crop in Argentina. Aspergillus flavus may infect this crop at growing stage and the harvested kernels can be contaminated with aflatoxins (AFs), whose levels may increase during storage. In Argentina, silo bags, a hermetic type of storage system, are widely used. Biocontrol based on competitive exclusion by atoxigenic A. flavus strains is a useful tool for AFs management at pre-harvest stage. The aim of the present study was to evaluate the effect of pre-harvest biocontrol treatments on aflatoxin B1 (AFB1) accumulation in maize stored in silo bags during 3 and 6 months. Three bioformulations based on A. flavus AFCHG2 and ARG5/30 strains were applied during field trials as single and mixed inocula. Harvested kernels were stored in non-hermetic and hermetic silo bags. At initial time (t0), 3 and 6 months (t3 and t6) the following parameters were evaluated: percentage of damaged kernels, moisture content, water activity, Aspergillus section Flavi incidence, relative humidity, O2 and CO2 levels into the silo bags, and AFB1 levels. The biocontrol strains included in the 3 bioformulations were able to infect maize kernels during the field trial and displaced native toxigenic isolates. At t0 control plots showed 10.9 ± 0.4 μg/kg of AFB1 while no AFs were detected in all the treatments. Along the storage assay AFB1 levels varied from not detected (<1 μg/kg) to 20.1 ± 0.8 μg/kg. Hermetic bags were better than non-hermetic bags in preventing AFB1 accumulation. Both single and mixed inocula were effective to control AFB1 accumulation in maize kernels during 3 and 6 months. AFB1 was not detected in kernels from the treatment at field stage with AFCHG2 + ARG5/30 after 6 months of storage into hermetic bags. The application of the biocontrol agents at field stage is an appropriate tool to reduce AFB1 accumulation under storage in hermetic silo bags. This is the first report on biocontrol strategy based on native atoxigenic strains applied at pre-harvest stage to reduce AFB1 accumulation during storage in Argentina.

Lactobacillus plantarum T3 as an adsorbent of aflatoxin B1 effectively mitigates the toxic effects on mice

The accumulation of aflatoxin B1 (AFB1) in the body is extremely harmful for host health. Using lactic acid bacteria (LAB) to modulate the adsorption and toxicity of AFB1 is an attractive research field. This paper aims to isolate LAB for AFB1 removal, confirm its action mechanism, investigate factors affecting adsorption, and evaluate its protection against AFB1-induced toxicity. Sixty indigenous LAB strains were evaluated for their ability to remove AFB1 (1 μg/ml) and Lactobacillus plantarum T3 exhibited the highest AFB1 removal rate (68.5%). The removal rates of AFB1 by inactivated L.plantarum T3 cells, peptidoglycan, and cytoderm were 84.0%, 87.8%, and 77.0% respectively, indicating that L.plantarum T3 mainly removes AFB1 by cell adsorption. The stability of L.plantarum T3-AFB1 complex was assessed by determination of AFB1 residues in the artificial gastrointestinal environment after the complex was co-cultured for 1–3 h. The results revealed that the complex remained relatively stable, with an adsorption capacity of >50%. Compared to the mice induced by AFB1, oral intake of live and inactivated L.plantarum T3 can (i) efficiently enhance fecal AFB1 excretion, normalize pathology, and reduce serum levels of ALT, AST and Cr; (ii) ameliorate oxidative stress and immune imbalance by increasing the levels of GSH, IL-4, IgG, IgM, while decreasing MDA and TNF-α; (iii) restore gut homeostasis by maintaining Firmicutes/Bacteroidetes balance and promoting growth of beneficial bacteria. The results suggested that both live and inactivated L.plantarum T3 are promising adsorbents of AFB1 and could be considered as an effective and easy dietary intervention against its toxicity.

Growth and Toxigenicity of A. flavus on Resistant and Susceptible Peanut Genotypes.

Aflatoxin contamination poses serious health concerns to consumers of peanut and peanut products. This study aimed at investigating the response of peanuts to Aspergillus flavus infection and aflatoxin accumulation. Isolates of A. flavus were characterised either as aflatoxigenic or non-aflatoxigenic using multiple cultural techniques. The selected isolates were used in an in vitro seed colonisation (IVSC) experiment on two A. flavus-resistant and susceptible peanut genotypes. Disease incidence, severity, and aflatoxin accumulation were measured. Genotypes differed significantly (p < 0.001) in terms of the incidence and severity of aflatoxigenic and non-aflatoxigenic A. flavus infection with the non-aflatoxigenic isolate having significantly higher incidence and severity values. There was no accumulation of aflatoxins in peanut genotypes inoculated with non-aflatoxigenic isolate, indicating its potential as a biocontrol agent. Inoculations with the aflatoxigenic isolate resulted in the accumulation of aflatoxin B1 and G1 in all the peanut genotypes. Aflatoxin B2 was not detected in ICGV–03401 (resistant genotype), while it was present and higher in Manipinta (susceptible genotype) than L027B (resistant genotype). ICGV–03401 can resist fungal infection and aflatoxin accumulation than L027B and Manipinta. Non-aflatoxigenic isolate detected in this study could further be investigated as a biocontrol agent.

Detection of Aflatoxin B1 in Single Peanut Kernels by Combining Hyperspectral and Microscopic Imaging Technologies.

To study the dynamic changes of nutrient consumption and aflatoxin B1 (AFB1) accumulation in peanut kernels with fungal colonization, macro hyperspectral imaging technology combined with microscopic imaging was investigated. First, regression models to predict AFB1 contents from hyperspectral data ranging from 1000 to 2500 nm were developed and the results were compared before and after data normalization with Box-Cox transformation. The results indicated that the second-order derivative with a support vector regression (SVR) model using competitive adaptive reweighted sampling (CARS) achieved the best performance, with RC2 = 0.95 and RV2 = 0.93. Second, time-lapse microscopic images and spectroscopic data were captured and analyzed with scanning electron microscopy (SEM), transmission electron microscopy (TEM), and synchrotron radiation-Fourier transform infrared (SR-FTIR) microspectroscopy. The time-lapse data revealed the temporal patterns of nutrient loss and aflatoxin accumulation in peanut kernels. The combination of macro and micro imaging technologies proved to be an effective way to detect the interaction mechanism of toxigenic fungus infecting peanuts and to predict the accumulation of AFB1 quantitatively.

Maize Milling and Modifying Atmospheric Conditions Limit Formation of Aflatoxin B1 by Aspergillus Flavus

Occurrence of mycotoxins in foods poses a serious health concern all over the world. Aflatoxin B1 (AFB1) is the most toxic, with widest occurrence in various foods, but mainly in cereals and nuts and its accumulation depends on substrate and environmental factors. This study investigated the how physical status (milling) of maize kernels and atmospheric conditions (aeration, moisture and temperature) affect production of aflatoxin B1 by Aspergillus flavus (ATCC 28862). Intact kernels and flour were incubated for up to 20 days in open and partially sealed petri dishes under controlled temperatures of 25 ºC, 30 ºC and 37 ºC and initial moisture contents of 27%, 22%, 18%, 15% and 12%. It was found that on average, significantly higher (p &lt; 0.05) aflatoxin B1 level was accumulated in intact kernels (145.7 µg/kg) as compared to milled kernels (2.2 µg/kg). Also, none of the samples incubated under partially sealed conditions, compared to up to 100% of the samples incubated in open atmosphere had detectable levels of aflatoxin B1 after 20 days. Fungal growth was not affected by milling or aeration, but sporulation was low at 37 ºC and high at 25 ºC and 30 ºC. The findings of this study provide baseline information on how conditions can be modified to control postharvest accumulation of aflatoxin B1 in cereals.

Effect of exogenous melatonin treatment onAspergillusdecay, aflatoxin B1 accumulation and nutritional quality of fresh “Akbari” pistachio fruit

This study aimed to investigate the mechanisms activated by melatonin treatment for attenuating Aspergillus decay, suppressing aflatoxin B1 (AB1) accumulation, and preserving nutritional quality in fresh pistachio fruits during storage at 25°C for 18 days. At 6-day intervals, samples from each of three replications were selected, and subjected to biochemical analysis. Our results showed that fresh pistachio fruits treated with 1,000 µM melatonin and inoculated with Aspergillus flavus, exhibited lower Aspergillus decay accompanied by lower endogenous AB1 accumulation. Melatonin treated fruit also showed lower H2O2 and malondialdehyde accumulation during storage. Furthermore, higher linolenic acid accumulation accompanied by higher phenols and flavonoids accumulation as well as superior DPPH scavenging capacity in fresh pistachio fruits treated with 1,000 µM melatonin, could be ascribed to lower lipoxygenase and higher phenylalanine ammonia-lyase enzymes activity, respectively, during storage. Besides, melatonin applying at 1,000 µM suppressed spore germination and germ tube elongation in A. flavus. Practical applications Aflatoxin B1 (AB1) accumulation as carcinogenic mycotoxin in pistachio fruits during Aspergillus flavus infection have been considered as a risk for human health. Since ROS generating from kernels could be responsible for triggering A. flavus growth and AB1 biosynthesis. Therefore, alleviating oxidative stress by melatonin treatment not only could be operative for attenuating fungal decay and decreasing AB1 accumulation but also could be favorable for maintaining the quality of fresh pistachio fruits.

AFB1-induced mice liver injury involves mitochondrial dysfunction mediated by mitochondrial biogenesis inhibition

Aflatoxin B1 (AFB1) pollutes foodstuffs and feeds, causing a food safety problem and seriously endangering human and animal health. Liver is the principal organ for AFB1 accumulation and biotransformation, during which AFB1 can cause acute and chronic liver damage, however, the specific mechanism is not completely clear. Mitochondria are the primary organelle of cellular bio-oxidation, providing 95% energy for liver to execute its multiple functions. Therefore, we speculated that mitochondrial dysfunction is involved in AFB1-induced liver injury. To verify the hypothesis, a total of eighty healthy male mice were randomly divided into four groups on average, and exposed with 0, 0.375, 0.75 and 1.5 mg/kg body weight AFB1 by intragastric administration for 30 d. The results displayed that AFB1 triggered liver injury accompanied by oxidative stress. AFB1 exposure also damaged mitochondria structure, decreased mitochondrial membrane potential (MMP), as well as increased cytoplasmic cytochrome c (Cyt-c) protein expression, Bax, p53, Caspase-3/9 protein and/or mRNA expression levels and terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine-5'-triphosphate (dUTP) nick end labeling (TUNEL) staining positive cells in mice liver. Meanwhile, AFB1 exposure elevated pyruvate content, inhibited tricarboxylic acid (TCA) cycle rate-limiting enzymes and electron transport chain (ETC) complexes I-V activities, disturbed ETC complexes I-V subunits mRNA expression levels and reduced adenosine triphosphate (ATP) level in mice liver. These results indicated that AFB1 destroyed mitochondrial structure, activated mitochondrion-dependent apoptosis and induced mitochondrial dysfunction. In addition, AFB1 disrupted mitochondrial biogenesis, presented as the abnormalities of protein and/or gene expression levels of voltage dependent anion channel protein 1 (VDAC1), peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), nuclear respiratory factor 1 (Nrf1) and mitochondrial transcription factor A (Tfam). This may contribute to hepatic and mitochondrial lesions induced by AFB1. These results provide a new perspective for elucidating the mechanisms of AFB1 hepatotoxicity.

Spatiotemporal assessment of post-harvest mycotoxin contamination in rural North Indian food systems

The spatiotemporal trends in aflatoxin B1 (AFB1), fumonisin B1 (FB1), and deoxynivalenol (DON) accumulation were analyzed in a range of food commodities (maize, groundnut, pearl millet, rice, and wheat) in village settings in Unnao, Uttar Pradesh, India. Samples (n = 1549) were collected across six communities and six time points spanning a calendar year and were analyzed for mycotoxins using enzyme-linked immunosorbent assays. AFB1 and FB1 were common across surveyed villages, with moderate to high detection rates (45–75%) observed across commodities. AFB1 levels in maize and groundnuts and FB1 levels in maize and pearl millet frequently exceeded regulatory threshold levels of 15 μg/kg (AFB1) and 2 μg/g (FB1). DON was analyzed in wheat, with 3% of samples yielding detectable levels and none exceeding 1 μg/g. In rice, AFB1 levels were highest in the bran and husk and lower in the kernel. Commodity type significantly influenced AFB1 detection status, while commodity type, season, and visual quality influenced samples’ legal status. Storage characteristics and household socioeconomic status indicators did not have significant effects on contamination. No significant effects of any variables on FB1 detection or legal status were observed. Data on mycotoxin contamination, combined with data on local dietary intake, were used to estimate spatiotemporal mycotoxin exposure profiles. Estimated seasonal per capita exposure levels for AFB1 (5.4–39.3 ng/kg body weight/day) and FB1 (~0–2.4 μg/kg body weight/day) exceeded provisional maximum tolerable daily intake levels (1 ng/kg body weight/day for AFB1 and 2 μg/kg body weight/day for FB1) in some seasons and locations. This study demonstrates substantial dietary mycotoxin exposure risk in Unnao food systems and serves as an evidentiary foundation for participatory food safety intervention in the region.

Unveiling the spatial distribution of aflatoxin B1 and plant defense metabolites in maize using AP-SMALDI mass spectrometry imaging.

In order to cope with the presence of unfavorable compounds, plants can biotransform xenobiotics, translocate both parent compounds and metabolites, and perform compartmentation and segregation at the cellular or tissue level. Such a scenario also applies to mycotoxins, fungal secondary metabolites with a pre-eminent role in plant infection. In this work, we aimed to describe the effect of the interplay between Zea mays (maize) and aflatoxin B1 (AFB1) at the tissue and organ level. To address this challenge, we used atmospheric pressure scanning microprobe matrix-assisted laser desorption/ionization mass spectrometry imaging (AP-SMALDI MSI) to investigate the biotransformation, localization and subsequent effects of AFB1 on primary and secondary metabolism of healthy maize plants, both insitu and from a metabolomics standpoint. High spatial resolution (5µm) provided fine localization of AFB1, which was located within the root intercellular spaces, and co-localized with its phase-I metabolite aflatoxin M2. We provided a parallel visualization of maize metabolic changes, induced in different organs and tissues by an accumulation of AFB1. According to our untargeted metabolomics investigation, anthocyanin biosynthesis and chlorophyll metabolism in roots are most affected. The biosynthesis of these metabolites appears to be inhibited by AFB1 accumulation. On the other hand, metabolites found in above-ground organs suggest that the presence of AFB1 may also activate the biochemical response in the absence of an actual fungal infection; indeed, several plant secondary metabolites known for their antimicrobial or antioxidant activities were localized in the outer tissues, such as phenylpropanoids, benzoxazinoids, phytohormones and lipids.