Aflatoxin Contamination In Foods Research Articles

Development and Testing of Small-Scale Flash Dryer for Maize Bran

Sun drying is the most common technique used to dry various food products due to its economic convenience. However, it is not effective owing to its unreliable nature leading to microbial deterioration and aflatoxin contamination of food. In Tanzania, about 1.3 million tonnes of maize bran are at risk of deterioration annually due to improper drying. The aim of this study was to design, fabricate and test an efficient small-scale flash dryer for maize bran. Using principles of material and energy balance, a small-scale flash dryer with a throughput of 500 kg of dry product per hour was designed resulting in a nominal diameter of 387 mm and a drying length of 20 m. Design calculations and drawings were done using MS Excel 2021 and SolidWorks 2018 respectively. Empirical procedures were used to fabricate and test the dryer. The material of construction used in the flash duct was food grade (stainless steel, SS 201). A fuel blend of Waste Engine Oil (WEO) and diesel (85%-15%) was used with a novel heavy oil burner. It was observed that at an inlet air temperature of 150 °C and air velocity of 12 m/s, moist maize bran was dried from 37% to 10% w.b. The fabricated flash dryer's energy efficiency, specific energy consumption, and specific energy utilization are 74%, 3.4 MJ/kg water evaporated, and 1.71 MJ/kg dry maize bran respectively. It was concluded that the fabricated small-scale flash dryer displayed improved energy performance compared to others presented in literature. Better instrumentation was recommended for feedback control on burner operation and process monitoring which further enhances the performance of the fabricated small-scale flash dryer.

Preparation of 3D pomegranate‐like quantum dot nanobeads and its application to highly sensitive detection of aflatoxin B1

Aflatoxin B1 (AFB1) is often used as a major indicator for evaluating aflatoxin contamination in food, and its accurate and sensitive detection is of great significance. Herein, the high-quality CdSe/ZnS fluorescent quantum dot nanobeads (QBs) with 3D pomegranate were prepared by the dual-protecting microemulsion method, which showed excellent stability in different environments. AFB1 were detected by competitive quantum dot-based fluorescence-linked immunosorbent assay (QLISA) using 3D pomegranate-like QBs and single-core silica-encapsulated quantum dots (QD@SiO2). After optimization of the reaction conditions, the quantitative detection range of AFB1 by single-core QD@SiO2 as fluorescent probe was 0–100 ng/mL, with the half maximal inhibitory concentration (IC50) of 3.01 ng/mL and the limit of detection (LOD) of 0.12 ng/mL; whereas the quantitative detection range of AFB1 by fluorescent QBs was 0–100 ng/mL, with the IC50 of 1.76 ng/mL and the LOD of 1.03 pg/mL. Compared to single-core QD@SiO2, the fluorescent QBs was 120-fold more sensitive. The detection of AFB1 was also achieved in negative corn and peanut samples, indicating the possibility of its application to the detection of real food samples. The high performance of competitive QLISA using 3D pomegranate-like QBs as fluorescent probes offer highly sensitive and accurate quantitative detection of analytes in food safety monitoring.

Aflatoxins in food: Prevalence, health effects, and emerging trends in its mitigation—An updated review

AbstractMycotoxins are secondary metabolites produced by a variety of fungal and mold species. One of the mycotoxin families that is often regarded as the most concerned one in human and animal feeds, is aflatoxin. Aflatoxins produced by Aspergillus species are very toxic and cause significant contamination of food supplies, resulting in serious health repercussions including carcinogenicity. To date, several regulations on aflatoxin permissible level limits have been established in a number of nations. Based on government guidelines and restrictions, consumers and food producers anticipate that aflatoxin contamination in food should not negatively impact human and animal health. Aflatoxin contamination of food commodities poses a consequential risk to humans and is also associated with substantial financial losses. Conventional mycotoxin reduction strategies involve both preventative and decontamination approaches. The present review gives an update on recent research on conventional approaches, including pre‐ and post‐harvest procedures that could potentially be used to decontaminate aflatoxin. Additionally, the current study delves into the source of contamination, global occurrence, impact on human health, and management strategies to assure food security and safety.

Consumer’s Awareness and Willingness to Pay for Aflatoxin-Free Sunflower Oil from Four Selected Regions in Tanzania

This study aimed to answer two objectives: assessing consumer awareness of aflatoxin contamination in food and their willingness to pay (WTP) for aflatoxin-free sunflower oil, and investigating the factors influencing consumers’ WTP a premium price for aflatoxin-free sunflower oil. A total of 480 consumers were randomly selected from four towns, and the towns were selected based on the level of aflatoxin contamination incidences: Dodoma (low awareness) and Iringa (high awareness) (towns with high contamination), and Dar es Salaam (low awareness) and Morogoro (high awareness) (towns with low incidence). To elicit consumers’ willingness to pay for aflatoxin-free food, we used the multiple price list technique (MPL) to assess WTP for sunflower oil which is aflatoxin-free and sunflower oil which has not been tested to be aflatoxin-free. Furthermore, an interval regression model was used to estimate WTP and factors influencing WTP a premium price for aflatoxin-free sunflower oil. We found that consumers were willing to pay a premium price for aflatoxin-free sunflower oil. Consumers had a WTP for a premium of up to 1043 TZS for 1 L of aflatoxin-free sunflower oil. However, the premium varies in the different regions. Consumers from towns with a high incidence of aflatoxin contamination have a WTP of up to 357 TZS, while those from towns with a low incidence of aflatoxin contamination but high awareness have a WTP of up to 1043 TZS. Furthermore, the study finds that education, age, gender, and consumer awareness of aflatoxin contamination have a significant influence on the WTP for sunflower oil free of aflatoxin contamination. This study sheds light to stakeholders involved in the production, marketing, and monitoring of food safety and standards. For the public sector, to maximize consumer welfare, policies to ensure the delivery of safe and healthy food are important, while for the private sector, there is an opportunity to tap into the gap for supplying food with private food safety standards.

A functional intact SUMOylation machinery in Aspergillus flavus contributes to fungal and aflatoxin contamination of food

SUMO adducts occur in Aspergillus flavus, and are implicated in fungal biology, while the underlying mechanism and the SUMOylation apparatus components in this saprophytic food spoilage mould, remain undefined. Herein, genes encoding SUMOylation cascade enzymes in A. flavus, including two heterodimeric SUMO E1 activating enzymes, a unique SUMO E2 conjugating enzyme, and one of SUMO E3 ligases, were identified and functionally analyzed. Global SUMO adducts immunoassay, multiple morphological comparison, aflatoxin attributes test, fungal infection and transcriptomic analyses collectively revealed that: E1 and E2 were essential for intracellular SUMOylation, and contributed to both stress response and fungal virulence-related events, including sporulation, colonization, aflatoxins biosynthesis; the primary E3 in this fungus, AfSizA, might serve as the molecular linkage of SUMOylation pathway to fungal virulence rather than SUMOylation-mediated stress adaptation. These findings demonstrated that SUMOylation machinery in A. flavus was functionally intact and contributed to multiple pathobiological processes, hence offering ideas and targets to control food contamination by this mycotoxigenic fungus.

Aflatoxin Contamination, Exposure among Rural Smallholder Farming Tanzanian Mothers and Associations with Growth among Their Children

Recently, aflatoxin exposure especially through maize and groundnuts has been associated with growth impairment in children. Infants and children are considered to be more susceptible to toxins because of their lower body weight, higher metabolic rate, and lower ability to detoxify. On the other hand, for women of reproductive age, aflatoxin exposure may not only affect their health but also that of their foetus in the case of pregnancy. This study focused on investigating AFB1 contamination in maize and groundnut from respondent households, exposure among women of reproductive age and associations of aflatoxin contamination with growth retardation among children in Mtwara region, Tanzania. The highest maximum AFB1 contamination levels from all samples obtained were in maize grain (2351.5 μg/kg). From a total of 217 maize samples collected, aflatoxins were above European Union (EU) and East African Community (EAC) tolerable limits in 76.0% and 64.5% of all samples. Specifically, maize grain had the highest proportion of samples contaminated above tolerable limits (80.3% and 71.1% for EU and EAC limits). Groundnut had 54.0% and 37.9% of samples above EU and EAC maximum tolerable limits. The lowest proportion of contaminated samples on the other hand was for bambara nut (37.5% and 29.2% for EU and EAC limits, respectively). Aflatoxin exposure in our surveyed population was much higher than previous observations made in Tanzania and also higher than those observed in Western countries such as Australia and the USA. Among children, AFB1 concentration was associated with lower weight for height z scores and weight for age z scores in the univariate model (p < 0.05). In summary, these results indicate the seriousness of aflatoxin contamination in foods commonly consumed in the vulnerable population assessed. Strategies both from the health, trade, and nutrition sectors should therefore be designed and implemented to address aflatoxin and mycotoxin contamination in diets.

Aflatoxin B1 Induced Oxidative Stress and Gut Microbiota Disorder to Increase the Infection of Cyprinid Herpesvirus 2 in Gibel Carp (Carassius auratus gibelio).

Aflatoxin contamination of food and water is a serious problem worldwide. This study investigated the defensive ability of gibel carp exposed to aflatoxin B1 (AFB1) by challenging it with cyprinid herpesvirus 2 (CyHV-2) infection. The data showed that AFB1 exposure significantly increased the mortality of CyHV-2-infected gibel carp, and enhanced the viral load in the fish liver, kidney, and spleen. The oxidative-antioxidant balance suggested that AFB1 induced severe oxidative stress, including increased reactive oxygen species (ROS) and malondialdehyde (MDA) levels in the AFB1 exposed group, and the reduced activity of superoxide dismutase (SOD), glutathione-S-transferase (GST) and catalase (CAT) in the AFB1 exposed group. Meanwhile, the related expression of nuclear factor erythroid 2-related factor 2 (Nrf2), interferon regulatory factor 3 (IRF3) and the type 1 interferon (IFN1) were noticeably down-regulated, but caspase-1 was up-regulated, after exposure to AFB1, demonstrating that fish are unable to avoid the virus infection. It should be noted that the intestinal microbiota diversity and richness were lower in the AFB1 exposed group, and the composition of intestinal microbiota was affected by AFB1, resulting in the higher abundance of bacteria (such as Aeromonas and Bacteroides) and the lower abundance of potentially beneficial bacteria (such as Cetobacterium and Clostridium) in the AFB1 exposed group. This research provides insight into the possibility that AFB1 may increase the susceptibility of C. gibelio to CyHV-2 infection, and thus amplify the viral outbreak to endanger ecological safety in aquatic environment.

Aflatoxin Occurrence, Food Regulations, Dietary Exposure, and Risk Assessment: A Mini Review from the Malaysian Perspective

Aflatoxins are ubiquitous and occur in food. Exposure to aflatoxins seriously impact the health of human and animal. It is concerning especially when aflatoxins are odourless, colourless, and tasteless that hardly be detected through naked eyes. Ingestion of aflatoxin-contaminated food contributes the major route of exposure. The present review is an update on the aflatoxin occurrence in food, aflatoxin regulations in food, and recent risk assessment of aflatoxin exposure in Malaysia. Peanuts and chili were more prone to aflatoxin contamination in Malaysia. The extreme weather experienced in Malaysia and global climatic change may worsen the aflatoxin contamination in food. The regulatory standards for aflatoxins imposed by Malaysia are less stringent than developed countries. The dietary exposure of aflatoxins among Malaysian was relatively high as compared with other Asia countries, ranging from 0.002 to 34.00 ng/kg body weight/day. Nonetheless, Malaysian population had low risk of aflatoxin-related liver cancer, with an estimated liver cancer risk of &lt;1 cancer case/100,000 population/year.

Exposure assessment and risk characterization of aflatoxins intake through consumption of maize (Zea mays) in different age populations in the Volta Region of Ghana

Aflatoxin contamination in foods is a vital health challenge for low and middle-income countries in subtropical regions. Maize (Zea mays L.), a staple food most widely grown in Africa including Ghana, and extensively consumed as much as three times per day, is a source of aflatoxin contamination owing to its susceptibility to fungal infection. Aflatoxin levels were checked against international (European Commission, EC) and local (Ghana Standards Authority, GSA) standards, and health risks associated with maize sampled from the Volta Region (Hohoe, Ho, Battor Dugame, and Keta) of Ghana were determined. Total aflatoxins (totalAFs) and the constituent aflatoxins (AFB1, AFB2, AFG1, and AFG2) were measured with High-Performance Liquid Chromatography (HPLC) with a Fluorescence Detector (FLD). Intake and Risk assessments were also conducted using deterministic models prescribed by the Joint FAO/WHO Expert Committee on Additives (JECFA). The degree of occurrence of aflatoxins was observed to be in decreasing order of AFG2 < AFG1 < AFB2 < AFB1 and were within the ranges of 0.78 ± 0.04 - 234.73 ± 3.8 µg/kg, 0.47 ± 0.03 - 21.6 ± 0.33 µg/kg, 1.01 ± 0.05 - 13.75 ± 1.2 µg/kg and 0.66 ± 0.06 - 5.51 ± 0.26 µg/kg respectively. Out of the 100 samples analyzed for total aflatoxins (totalAFs), 68 (68%) exceeded the limits of EC and were of range 4.98 ± 0.6 - 445.01 ± 8.9 µg/kg whereas 58 (58%) and ranged between 12.12 ± 1.4 - 445.01 ± 8.9 µg/kg exceeded GSA limits. Intake and risk assessments of total aflatoxins (totalAFs) for infants, toddlers, children, adolescents, and adults in the Volta Region were; 0.037–1.14 µg/kg bw/day, 0.35–10.81, and 1.47 -45.14 cases/10,000 person/yr respectively for Estimated Daily Intake (EDI), Margin of Exposure (MOE), and Cancer Risks. It was inferred that the consumption of maize posed potential adverse health effects on all age categories studied because all calculated MOE values were less than 10,000.

Inhibition of Essential Oils on Growth of Aspergillus flavus and Aflatoxin B1 Production in Broth and Poultry Feed.

Aflatoxin B1 (AFB1), a common contaminant in food and feed during storage, does great harm to human and animal health. Five essential oils (thymol, carvacrol, cinnamaldehyde, eugenol, and citral) were tested for their inhibition effect against Aspergillus flavus (A. flavus) in broth and feed. Cinnamaldehyde and citral were proven to be most effective against A. flavus compared to others and have a synergistic effect when used simultaneously. The broth supplemented with cinnamaldehyde and citral was inoculated with A. flavus (106 CFU/mL) by using the checkerboard method, and mold counts and AFB1 production were tested on days 0, 1, 3, and 5. Similarly, 100 g poultry feed supplemented with the mixture of cinnamaldehyde and citral at the ratio 1:1 was also inoculated with A. flavus, and the same parameters were tested on days 0, 7, 14, and 21. In poultry feed, cinnamaldehyde and citral significantly reduced mold counts and AFB1 concentrations (p < 0.05). Results showed that cinnamaldehyde and citral have a positive synergy effect and could both inhibit at least 90% the fungal growth and aflatoxin B1 production at 40 μg/mL in broth and poultry feed, and could be an alternative to control aflatoxin contamination in food and feed in future.

Plant-based natural flavonoids show strong inhibition of aflatoxin production and related gene expressions correlated with chemical structure

Aflatoxins are strong carcinogenic and mutagenic fungal metabolites, and aflatoxin contamination is a critical issue in agriculture and food production. Natural flavonoids can suppress aflatoxin biosynthesis; however, the structure–activity relationship remains unclear. In the present study, a total of 36 structurally related natural flavonoids were tested against the aflatoxigenic Aspergillus flavus, both in-vitro and in-situ (on maize kernels), to investigate their structure–activity relationship and biological activity. Aflatoxin production (IC50 values: 10.85–20.09 μg/mL) and the expression of related genes (aflD, aflK, aflQ, and aflR) were found to be strongly inhibited. Structure–activity relationship studies revealed that the [–OH] or [–O–CH3] groups at position 6 of ring A and position 4′ of ring B were closely associated with antifungal and antiaflatoxigenic activities. These findings provide valuable information for the development of clean and safe methods to prevent aflatoxin contamination in food.

Volatiles of antagonistic soil yeasts inhibit growth and aflatoxin production of Aspergillus flavus

Minimizing Aspergillus flavus growth is an effective strategy to mitigate aflatoxin contamination in food and agricultural products. In the present investigation, we attempted to utilize soil-associated yeasts from the Western and Eastern Ghats of India against A. flavus to reduce aflatoxin contamination. Forty-five yeast isolates were screened against A. flavus using overlay and dual plate assays. Among them, 12 isolates effectively inhibited the growth of A. flavus. The 18S rDNA gene sequence analysis identified the twelve antagonistic isolates as belonging to Saccharomyces cerevisiae, Suhomyces xylopsoci, Pichia kudriavzevii, and Candida tropicalis. From the isolated yeasts, S. cerevisiae strains were selected for further evaluation based on the potential antagonistic activity. Volatiles of S. cerevisiae effectively suppressed the mycelial growth of A. flavus (P < 0.05) up to 92.1 % at 7 DAI. Scanning electron microscopic images of the fungus exposed to volatiles showed hyphal deformity and mycelial damage. Aflatoxin B1 (AFB1) production was drastically reduced up to 99.0 % in the volatile-exposed fungus compared to the control. The yeast strain YKK1 showed consistent Aspergillus flavus growth inhibition (80.7 %) and AFB1 production (98.1 %) for 14 days. Gas chromatography-mass spectrophotometry analysis of the yeast volatiles revealed the presence of antimicrobial compounds, including 1-pentanol, 1-propanol, ethyl hexanol, ethanol, 2-methyl-1-butanol, ethyl acetate, dimethyl trisulfide, p-xylene, styrene, and 1,4-pentadiene. The evaluated compounds of yeast volatiles, including ethyl acetate, hexanal, 1-propanol, 1-heptanol, 1-butanol, and benzothiazole, inhibited the fungal growth and AFB1 production of Aspergillus flavus when applied as pure chemicals. Benzothiazole at 5 mM was responsible for a high level of growth inhibition (23.6 %) and reduction of AFB1 synthesis (93.5 %). Hence, volatile compounds produced by soil yeast strains could be a potential biocontrol mechanism against aflatoxin contamination.

The influence of ultraviolet radiation on aflatoxin producing Aspergillus species' isolated from Iranian rice

Cereal grains are a favorable habitat for aflatoxin- producing fungus to develop. the current investigation was carried out to evaluate the quantity and kind of contaminated imported grains and rice generated in the province of Shiraz, Iran. A total of 60 random rice samples were taken from paddy fields in October and November 2020. Aspergillus genera were detected using PCR. HPLC was used to determine the quantity and type of aflatoxin and mycotoxins in samples collected. Irradiation studies were carried out utilizing a collimated beam system with wavelengths ranging from 200 to 360 nm. The quality of rice was assessed using UV light therapy on some of the changed factors, such as amylose content, aroma, and brightness [P < 0.05]. Aspergillus genera were found in 33.3% [20 samples of 60] of rice samples after morphological and molecular analysis of the ITS gene. According to the sequencing experiment, 12 strains [60%] were identified as Aspergillus flavus, whereas 8 strains [40%] were identified as Aspergillus parasiticus. Ver-1 and afl-R genes were positive in 12/12 [100%] Aspergillus flavus and 87.5% in Aspergillus parasiticus. According to the HPLC findings, three Aspergillus parasiticus strains [37.5%] were able to create all four types of aflatoxins, and aflatoxins B1, B2, G1, G2 were produced by 16.6% of Aspergillus flavus strains. Aflatoxin-1 (AFG1) was lowered to 35.1, 48.2, 59.9, and 65.2%, significantly, at doses of 1.22, 2.44, 3.66, and 4.88 Jcm−2 [P < 0.01]. Furthermore, at doses of 1.22, 2.44, 3.66, and 4.88 Jcm−2, AFB2 and AFG2 was shown to be reduced by 13.1%, 11.7%, 30.3%, and 28.9%. [P < 0.05]. At a maximum dose of 4.88 Jcm−2, AFB1 was shown to be extremely susceptible to UV irradiation, with a > 70% decrease seen [P < 0.001]. Our findings imply that UV irradiation with lower energy and lower danger can help minimize aflatoxin contamination in food.

An in Vitro Antifungal and Antiaflatoxigenic Properties of Commiphora myrrha and Prunus mahaleb

Aflatoxins and especially aflatoxin B, are the devastating contaminant of food and feed products with hazardous effects to mankind and his domestic animals. These investigations were set to evaluate the effect of various levels of Commiphora myrrha resin (1.0, 1.25, 2.25, and 3.25 g/100 ml) and Prunus mahaleb seed extract (0.75, 1.5, 2.5, and 3.5 g/100 ml) on the growth and aflatoxin secretion by two aflatoxigenic strains of Aspergillus flavus and A. parasiticus. The two plant extracts significantly (p&amp;lt;0.05) decreased aflatoxin secretion, and inhibited the fungal growth. Resin of C. myrrha displayed 51.9-95.7% reduction in total aflatoxin secretion by A. flavus, and 46.9-92% for A. parasiticus, and Seed extract of P. mahaleb decreased aflatoxin up to 53.7-95.8% and 40-94.7%, respectively. The inhibition of aflatoxin B (B1 and B2) by myrrh resin and seed extract of mahaleb ranged between 51.7-93.5, 50-93.6% (A. flavus) and 39.5-89.7%, 37.9-93% (A. parasiticus). The mycelial dry weight of A. flavus and A. parasiticus ws decreased up to 46.1-58.7%, 28.9-51.3% (Myrrh resin), and between 45-56.9%, 33.3-55.9% (Mahaleb seed extract). Nonetheless, the two plant extracts did not detoxify aflatoxin B1. Therefore, it apparent that the resin of C. myrrha and seed extract of P. mahaleb affected the biosynthesis pathway of aflatoxins. Thus, they can be recommended as effective natural plant biopreservative against aflatoxin contamination of food and feed products.

Characteristics, Occurrence, Detection and Detoxification of Aflatoxins in Foods and Feeds.

Mycotoxin contamination continues to be a food safety concern globally, with the most toxic being aflatoxins. On-farm aflatoxins, during food transit or storage, directly or indirectly result in the contamination of foods, which affects the liver, immune system and reproduction after infiltration into human beings and animals. There are numerous reports on aflatoxins focusing on achieving appropriate methods for quantification, precise detection and control in order to ensure consumer safety. In 2012, the International Agency for Research on Cancer (IARC) classified aflatoxins B1, B2, G1, G2, M1 and M2 as group 1 carcinogenic substances, which are a global human health concern. Consequently, this review article addresses aflatoxin chemical properties and biosynthetic processes; aflatoxin contamination in foods and feeds; health effects in human beings and animals due to aflatoxin exposure, as well as aflatoxin detection and detoxification methods.

The MAP kinase AflSlt2 modulates aflatoxin biosynthesis and peanut infection in the fungus Aspergillus flavus

Aflatoxin contamination in food and feed products has been brought into sharp focus over the last few decades in the world. However, there is no effective strategy for solving the problem thus far. Therefore, basic research on the aflatoxin-producer Aspergillus flavus is an urgent need. The vital role of mitogen-activated protein kinases (MAPKs) in signal transduction has been documented in various pathogenic fungi, but their functions in A. flavus have rarely been investigated. Herein, we characterized the detailed function of one of these MAPKs, AflSlt2. Targeted deletion of AflSlt2 gene indicates that this kinase is required for vegetative growth, conidia generation, and sclerotium formation. The analysis of AflSlt2 deletion mutant revealed hypersensitivity to cell wall-damaging chemicals and resistance against hydrogen peroxide. Interestingly, the ability of the ΔAflSlt2 mutant to generate aflatoxins in medium was significantly increased compared to wild type. However, a pathogenicity assay indicated that the ΔAflSlt2 mutant was deficient in peanut infection. Site-directed mutation study uncovered that the function of AflSlt2 was dependent on the phosphorylated residues (Thr-186 and Tyr-188) within the activation loop and the phosphotransfer residue (Lys-52) within the subdomain II. Interestingly, an autophosphorylation mutant of AflSlt2 (AflSlt2R66S) displayed wild type-like phenotypes. Bringing these observations together, we propose that Slt2-MAPK pathway is involved in development, stress response, aflatoxin biosynthesis, and pathogenicity in A. flavus. This study may be useful to unveil the regulation mechanism of aflatoxin biosynthesis and provide strategy to control A. flavus contamination.

Effects of zinc chelating nutrients on Aflatoxin production in Aspergillus flavus

Aflatoxins are carcinogenic metabolites produced by Aspergillus and Penicillium spp. Aflatoxin contamination of food is a serious health hazard. Some metal ions (such as Zn2+) affect Aspergillus growth and aflatoxin biosynthesis. Presence of zinc in the growth medium incites aflatoxin production. This study investigates the effect of zinc binding amino acids and peptides on aflatoxin synthesis in indigenous toxigenic Aspergillus species isolated from agro-ecological zones in Northern Iran. Zinc (II) chelating nutrients (such as Histidine (His), Cysteine (Cys), Histidine-Cysteine (His-Cys), and triple peptide (Asn-Cys-Ser) were added to the growth medium of toxigenic Aspergillus isolates and incubated at temperature range of 25–40 °C. Aflatoxin production on different culture media was tested using ELISA. Addition of cysteine to Sabouraud dextrose broth (SDB) medium significantly reduced aflatoxin production, which could be related to its zinc chelating property. Aflatoxin production was drastically restrained at high concentration of His, especially in combination with Cys, at high pH values and incubation temperature (pH = 7.5, temperature = 40 °C). Aflatoxin production was low in presence of triple peptide (Asn-Cys-Ser) at concentration of 500 mg/L. From the application perspective, natural zinc chelators can be used as harmless aflatoxin-production inhibitors.

Spectral-Based Screening Approach Evaluating Two Specific Maize Lines With Divergent Resistance to Invasion by Aflatoxigenic Fungi.

In an effort to control aflatoxin contamination in food and/or feed grains, a segment of research has focused on host resistance to eliminate aflatoxin from susceptible crops, including maize. To this end, screening tools are key to identifying resistant maize genotypes. The traditional field screening techniques, the kernel screening laboratory assay (KSA), and analytical methods (e.g., ELISA) used for evaluating corn lines for resistance to fungal invasion, all ultimately require sample destruction. A technological advancement on the basic BGYF presumptive screening test, fluorescence hyperspectral imaging offers an option for non-destructive and rapid image-based screening. The present study aimed to differentiate fluorescence spectral signatures of representative resistant and susceptible corn hybrids infected by a toxigenic (SRRC-AF13) and an atoxigenic (SRRC-AF36) strain of Aspergillus flavus, at several time points (5, 7, 10, and 14 days), in order to evaluate fluorescence hyperspectral imaging as a viable technique for early, non-invasive aflatoxin screening in resistant and susceptible corn lines. The study utilized the KSA to promote fungal growth and aflatoxin production in corn kernels inoculated under laboratory conditions and to provide actual aflatoxin values to relate with the imaging data. Each time point consisted of 78 kernels divided into four groups (30-susceptible, 30-resistant, 9-susceptible control, and 9-resistant control), per inoculum. On specified days, kernels were removed from the incubator and dried at 60°C to terminate fungal growth. Dry kernels were imaged with a VNIR hyperspectral sensor (image spectral range of 400–1000 nm), under UV excitation centered at 365 nm. Following imaging, kernels were submitted for the chemical AflaTest assay (VICAM). Fluorescence emissions were compared for all samples over 14 days. Analysis of strain differences separating the fluorescence emission peaks of resistant from the susceptible strain indicated that the emission peaks of the resistant strain and the susceptible strains differed significantly (p < 0.01) from each other, and there was a significant difference in fluorescence intensity between the treated and control kernels of both strains. These results indicate a viable role of fluorescence hyperspectral imaging for non-invasive screening of maize lines with divergent resistance to invasion by aflatoxigenic fungi.

Histological and ultrastructural study of AflatoxinB1 induced neurotoxicity in Sciatic nerve of adult male Albino rats

ABSTRACT Aflatoxins are mycotoxins produced by Aspergillus spp. which is a common contaminant of food items such as corn, spices, rice, nuts, and flour. Aflatoxin contamination of foods is a worldwide problem. Chronic aflatoxin exposure is found to be associated with Sciatic nerve damage. In vivo study was carried out to evaluate the toxic effect of aflatoxin B1 (AFB1) on the Sciatic nerve. Twenty-one adult male rats were included and divided equally into 3 groups (7 rats each): Group I (control group), group II (olive oil group) and group III: (AflatoxinB1 group). The rats received AFB1 (250 μg/kg B.W./day) orally by gastric tube 5 days/week for 4 weeks. Sciatic nerve specimens were prepared, and semi-thin sections were stained with Toluidine blue, examined by light microscope and photographed. Ultrathin sections (50–80 nm) from selected areas of the trimmed blocks were made, examined and photographed by transmission electron microscopy (JEOL-JSM-1011) in King Saud University Electron Microscopy Unit. The findings indicate that the administration of AFB1 to rats’ results in degeneration in the sciatic nerve in the form of Wallerian degeneration in the myelin sheath. Macrophages appear to engulf the degenerated myelin and neutrophils.

ANTIFUNGAL ACTIVITY OF KEBAR GRASS (BIOPHYTUM PETERSIANUM KLOTSZCH) STEM ETHANOL EXTRACT ON THE GROWTH OF AFLATOXIGENIC ASPERGILLUS FLAVUS IN CORN AND PEANUT-BASED MEDIA

Cereals and legumes are very easily damaged by fungi, including toxigenic fungi species such as Aspergillus flavus which can produce aflatoxins. Various methods have been carried out to reduce aflatoxin contamination in foods, including the use of plant extracts based antimicrobial compounds. One of indigenous herbs in Papua that has potency as natural antimicrobial is Kebar grass (Biophytum petersianum Klotszch). The aims of this study were to investigate the chemical composition and the effect of kebar grass stem ethanol extract on the growth of toxigenic A. flavus. Kebar grass stem ethanol extract at concentrations of 5, 10, 15, 20, 25, and 30 mg mL-1 was tested on the growth of A. flavus in two types media i.e. corn based-medium and peanut based-medium. The result showed that kebar grass stem ethanol extract at concentration of 15 mg ml-1 in corn based-medium and peanut based-medium caused 100% growth inhibition of A. flavus. The major compounds in kebar grass stem ethanol extract were: Pyrocatechol, Methylhydrazine hydrochloride, 2-Fluoropropane, Isobutyric acid, 2,6-Dimethoxyphenol. The results obtained from this study suggested that the ethanol extract of the kebar grass stem can be used as a natural antifungal agent to inhibit the growth of aflatoxigenic A. flavus.