Contamination Of Maize Research Articles

Identification and Characterization of an Aspergillus niger Amine Oxidase that Detoxifies Intact Fumonisins.

Fumonisin contamination of maize damaged by Fusarium verticillioides and related species is a major problem when it is grown under warm and dry conditions. Consumption of fumonisin contaminated food and feed is harmful to both humans and livestock. Novel tools for reducing or eliminating fumonisin toxicity may be useful to the agri-feed sector to deal with this worldwide problem. Enzymes capable of catabolizing fumonisins have been identified from microorganisms that utilize fumonisins as an energy source. However, fumonisin detoxifying enzymes produced by the very species that biosynthesize the toxin have yet to be reported. Here we describe the identification and characterization of a novel amine oxidase synthesized by the fumonisin-producing fungus Aspergillus niger. We have recombinantly expressed this A. niger enzyme in E. coli and demonstrated its ability to oxidatively deaminate intact fumonisins without requiring exogenous cofactors. This enzyme, termed AnFAO (A. niger fumonisin amine oxidase), displays robust fumonisin deamination activity across a broad range of conditions, has a high native melting temperature, and can be purified to >95% homogeneity at high yield in a one-step enrichment. AnFAO is a promising tool to remediate fumonisin-contaminated feed including maize destined for ethanol production.

Fungal Mycoflora Associated with Busseola fusca Frass in Maize Plants

Busseola fusca and Fusarium verticillioides are considered the most important pest and pathogen, respectively, of maize in South Africa. Busseola fusca tunnels into stems and ears of maize plants, whereas F. verticillioides causes Fusarium ear rot and deposits fumonisins in maize kernels. Frass (excreta) deposited by B. fusca larvae in maize stems and ears during feeding could potentially be contaminated with pathogens such as F. verticillioides, thereby indirectly and passively contributing to plant diseases. The mycoflora present in frass of B. fusca larvae was thus investigated in this study, and the dissemination of fumonisin-producing Fusarium spp. by B. fusca larvae in maize stems determined. Busseola fusca frass was collected from plants with visible insect damage in three maize-growing districts in South Africa. The mycoflora in the frass was isolated and identified morphologically to genus level, followed by the sequencing of target genes for species identification. Species of Acremonium, Aspergillus, Fusarium, Mucor, Rhizopus and Talaromyces were associated with the B. fusca frass. The role of B. fusca larvae in disseminating fumonisin-producing Fusarium spp. was then determined in greenhouse and field trials. Maize whorls were inoculated with F. verticillioides MRC826 spores 4 weeks after plant emergence, and infested with B. fusca larvae 2 days later. The stems were split open after 3 weeks and frass collected from feeding channels, thereafter, target DNA of fumonisin-producing Fusarium spp. was quantified using real-time PCR. Target DNA of fumonisin-producing Fusarium spp. was significantly higher in frass collected from greenhouse plants inoculated with F. verticillioides than in frass collected from the uninoculated control, indicating that the inoculation was successful in the absence of soil-borne inoculum. Nevertheless, the field trial showed no significant differences in target DNA in frass from inoculated and non-inoculated plants. This is possibly due to natural F. verticillioides infection of maize plants in the field. This study further indicated that B. fusca frass also contained maize pathogens such as Aspergillus spp. and Fusarium spp., which could cause ear rot diseases. The occurrence of Acremonium zeae in frass has potential implications for the biological control of F. verticillioides, as the fungus produces pyrrocidines A and B antibiotics which are known to be antagonistic to F. verticillioides. The occurrence of Aspergillus niger in frass requires further investigation in order to clarify its role in fumonisin contamination of maize in South Africa.

Assessment of the Health Quality Related to the Presence of Ochratoxin A, Fumonisin B1 and Zearalenone in Maize (Zea mays l.) Produced in Côte D’ivoire

Aims : The aim of this work is to take stock of the level of ochratoxin A (OTA), fumonisin B1 (FB1) and zearalenone (ZEA) contamination in maize produced in Cote d'Ivoire in order to help improve its quality.
 Study Design: Maize samples (375) were taken in five producing regions (Poro, Hambol, Gontougo, Gbêkê, Indénié-Djuablin).
 Place and Duration of Study: the collection was carried out on maize in grain, on the cob and in spathe from February 2016 to January 2017. Then, the analyzes were carried out at the Biotechnology Laboratory, Agriculture and Development of Biological Resources of the Félix HOUPHOUËT-BOIGNY University.
 Methodology: The determination of ochratoxin A, fumonisin B1 and zearalenone was carried out according to the methods of regulation No. 401/2006/EC, AFNOR, Miraglia and Brera.
 Results: The results indicate the presence of ochratoxin A, fumonisin B1 and zearalenone in all forms of maize (grains, cob, spathes) and the five regions visited. However, the average concentrations of fumonisin B1 and zearalenone are respectively 27.46 µg/kg-1999.22 µg/kg and 8.48 µg/kg-341.84 µg/kg and are lower than the prescribed reference standards (2000 µg/kg ; 500 µg/kg). For ochratoxin A, the average concentrations vary from 0.83 µg/kg to 14.38 µg/kg ; 1.92 µg/kg to 18.60 µg/kg and 2.21 µg/kg to 134.89 µg/kg respectively for grains, cob and spathes.
 Samples from the Regions of Poro, Gbêkê and Hambol have mean concentrations below the maximum reference limit of 5µg/kg. Thus, variability in the sanitary quality of maize was demonstrated from one region to another, regardless of the form of the maize. Based on the principal component analysis, spathes represent the form of maize most prone to high contamination regardless of mycotoxin and région.
 Conclusion: The searching alternative storage methods and the right form of maize storage could be a solution to the high mycotoxin contamination of marketed maize.

Impact of push–pull cropping system on pest management and occurrence of ear rots and mycotoxin contamination of maize in western Kenya

AbstractPush–pull involves intercropping of cereals with Desmodium as a “push” crop and planting Napier grass/Brachiaria as the “pull” crop at the border. The technology has been reported to effectively control stemborers, striga weed, and fall armyworm (FAW), and to improve soil nutrition, resulting in increased grain yield. This study evaluated the impact of stemborer and FAW management using this technology on incidence of maize ear rots and preharvest contamination of grains with aflatoxin and fumonisin in western Kenya. The study was conducted during three cropping seasons on maize grown under the push–pull system and as a monocrop. Incidence of stemborer and FAW damage was determined as percentage of damaged plants, while incidence of ear rots was determined as percentage of ears with symptoms. At harvest, fungi were isolated from kernels and aflatoxin and fumonisin were quantified using enzyme‐linked immunosorbent assay. Stemborer and FAW damage was significantly (p = .001) reduced by over 50% under the push–pull system. There was also a significant (p < .001) reduction in the incidence of Fusarium verticillioides (60%) and Aspergillus flavus (86%), which was reflected in a reduced incidence of ear rots (50%) with the push–pull system (p = .001). Fumonisin in maize from push‐pull farms was significantly (p = .048) reduced (39%) but the technology had no significant (p > .05) effect on aflatoxin. The study showed that push–pull is an effective strategy for managing maize ear rots and fumonisins, and therefore could play a role in improving food safety among smallholder maize farmers in the region.

Incidence of fungi and aflatoxin contamination of maize in Tolon-Kumbungu district of Ghana

Maize (Zea mays L.) is an important staple food crop and a source of income to farmers, as well as foreign exchange earner in most countries in sub-Saharan Africa. Its production is hampered by fungal diseases, which also cause contamination with mycotoxins, especially aflatoxin and its associated health hazards. This study sought to isolate and identify aflatoxigenic fungi, as well as detect the presence of Aflatoxin B1 (AfB1) in maize samples obtained from farmers in the Tolon-Kumbungu district in the northern region of Ghana. Twenty farming communities were randomly selected for the study in consultation with the district office of the Ministry of Food and Agriculture (MoFA). Samples were collected from 200 randomly selected maize farmers by the composite sampling technique, for isolation of aflatoxigenic fungi by the agar plate method and the detection of aflatoxin. Aflatoxin was detected in maize samples with the Black light, rapid screening and immunoassay methods. Aspergillus flavus had the highest percentage of occurrence (63.7%); followed by A. niger (16.5%), Rhizopus stolonifer (9.3%), Penicillium spp. (6.9%) and Fusarium oxysporum (3.7%). Farm samples had more aflatoxin than those from stores and markets. Samples of maize from farms in Gbirimani community had the highest aflatoxin contamination of +60 ppb. Concentrations of Afb1 at or above +20 ppb were recorded in all the communities, except in Tinguli. Apart from Voggu, all market samples were free from aflatoxin contamination.
 Key words: Aflatoxigenic fungi, postharvest, Zea mays

Assessment of soil and maize contamination by TE near a coal gangue-fired thermal power plant.

Coal preparation by-products, such as coal gangue, are inferior fuels enriched with trace elements (TEs). Owing to the issues surrounding the disposal of coal preparation by-products and energy shortages, Chinese researchers have strongly advocated harvesting energy from by-products. However, the secondary environmental pollution caused by such by-products has been overlooked. In this study, we aimed to assess the contamination of soil and maize (Zea mays L.) near a coal gangue-fired power plant (CGPP) in Liupanshui City, Guizhou Province, China, by TEs. The contents of 11 TEs (Be, Cd, Co, Cr, Cu, Mn, Ni, Pb, Sb, V, and Zn) in soil samples and different maize tissues were measured, and their chemical speciation in soil was also determined. The results showed that the soil in the study area was polluted by the above elements to varying degrees at a very high potential ecological risk. The Cr and Pb levels in niblets of partial samples exceeded the Chinese food safety standards. The TE contents of maize tissues largely depend on the bioavailable fraction of the same elements in the soils, rather than their total contents. Pearson's correlation and hierarchical cluster analyses resulted in three clusters:(1) Pb-Zn-Cd; (2) Co-Cu-Mn-Sb-V-Be; and (3) Cr-Ni. Coal preparation by-products should not be directly combusted without pre-treatment. These results will aid readers and engineers in understanding the adverse effect of CGPPs and provide regulators and policymakers with relevant data to scientifically guide the utilisation of coal preparation by-products.

Identification and distribution of gene clusters required for synthesis of sphingolipid metabolism inhibitors in diverse species of the filamentous fungus Fusarium

BackgroundSphingolipids are structural components and signaling molecules in eukaryotic membranes, and many organisms produce compounds that inhibit sphingolipid metabolism. Some of the inhibitors are structurally similar to the sphingolipid biosynthetic intermediate sphinganine and are referred to as sphinganine-analog metabolites (SAMs). The mycotoxins fumonisins, which are frequent contaminants in maize, are one family of SAMs. Due to food and feed safety concerns, fumonisin biosynthesis has been investigated extensively, including characterization of the fumonisin biosynthetic gene cluster in the agriculturally important fungi Aspergillus and Fusarium. Production of several other SAMs has also been reported in fungi, but there is almost no information on their biosynthesis. There is also little information on how widely SAM production occurs in fungi or on the extent of structural variation of fungal SAMs.ResultsUsing fumonisin biosynthesis as a model, we predicted that SAM biosynthetic gene clusters in fungi should include a polyketide synthase (PKS), an aminotransferase and a dehydrogenase gene. Surveys of genome sequences identified five putative clusters with this three-gene combination in 92 of 186 Fusarium species examined. Collectively, the putative SAM clusters were distributed widely but discontinuously among the species. We propose that the SAM5 cluster confers production of a previously reported Fusarium SAM, 2-amino-14,16-dimethyloctadecan-3-ol (AOD), based on the occurrence of AOD production only in species with the cluster and on deletion analysis of the SAM5 cluster PKS gene. We also identified SAM clusters in 24 species of other fungal genera, and propose that one of the clusters confers production of sphingofungin, a previously reported Aspergillus SAM.ConclusionOur results provide a genomics approach to identify novel SAM biosynthetic gene clusters in fungi, which should in turn contribute to identification of novel SAMs with applications in medicine and other fields. Information about novel SAMs could also provide insights into the role of SAMs in the ecology of fungi. Such insights have potential to contribute to strategies to reduce fumonisin contamination in crops and to control crop diseases caused by SAM-producing fungi.

Antimicrobial, Aflatoxin B1 Inhibitory and Lipid Oxidation Suppressing Potential of Anethole-Based Chitosan Nanoemulsion as Novel Preservative for Protection of Stored Maize

Aflatoxins (AFs) are the most frequent contaminants of maize and maize-based products, and its consumption can cause severe adverse effects to humans and animals. The efficacy of essential oils (EOs) and their bioactive compounds as potential antifungal agents has been well documented against food-borne fungi. This study evaluates the preservative potency of anethole-based chitosan nanoemulsion (Ant-eCsNe) to control deterioration of stored maize samples from fungal infestation, aflatoxin B1 (AFB1) contamination and lipid oxidation. Release study indicated a relatively good sustainable release profile for the encapsulated anethole after 10 days. The Ant-eCsNe showed improved efficacy against A. flavus (AF-LHP-VS8) and other common food-borne moulds and inhibited growth and AFB1 biosynthesis at 0.8 and 0.4 μL/mL, respectively. Ant-eCsNe caused concentration-dependent inhibition of ergosterol content and increased efflux of cellular ions (Ca+2, Mg+2 and K+) and 260 and 280 nm absorbing materials, suggesting damage of fungal plasma membrane. Inhibition of methylglyoxal in fungal cells treated with Ant-eCsNe signifies its novel antiaflatoxigenic mechanism of action. Ant-eCsNe exhibited strong in vitro DPPH• and ABTS+• scavenging activity with IC50 value 89.36 and 45.05 μL/mL, respectively, and inhibited lipid oxidation in stored maize samples. Further, Ant-eCsNe exhibited reasonably strong efficacy in preserving maize samples from fungal and AFB1 contamination during in vivo investigations and did not change the sensory attributes as well. Overall results revealed that Ant-eCsNe holds good potential to be applied as food preservative to reduce fungal and aflatoxin contamination causing deterioration of stored maize.

Postharvest Handling Knowledge and Practices among Food Handlers on Mycotoxigenic Molds Contamination in Maize Based Diets in School Meals Program in Salima District, Malawi

Aims: The aim of the present study was to determine the postharvest handling knowledge and practices among food handlers on mycotoxigenic molds contamination in maize based diets in School Meals Program in Salima District, Malawi.
 Study Design: This was cross-sectional study with qualitative and quantitative component.
 Place and Duration of Study: The study was carried out in Salima district, Central Malawi, between August and November, 2019.
 Methodology: The study used a structured questionnaire which was administered to 124 individual food handlers which were purposively selected from 31 primary schools. The simple random sampling technique was used to select the 31 primary schools among those implementing home-grown school meals program. The food handlers included School Meals Cooks, Food Suppliers, Food Committee members, and Stores Keepers. Data was analyzed using Statistical Package for Social Scientists (version 20.0).
 Results: The results showed that 80% of food handlers had high knowledge of causes of mycotoxigenic molds contamination in maize foods, 47% had moderate knowledge of health effects of mycotoxigenic molds, while 50% had moderate knowledge of control measures of mycotoxigenic molds in maize foods. Eighty-five percent (85%) were not aware of mycotoxins contamination in maize foods. Furthermore, the study revealed that 60% of food handlers practiced poor postharvest handling of maize foods during transporting, storage and processing in schools. There were no significant differences in knowledge of mycotoxigenic molds and postharvest handling practices of maize foods across demographic regions among food handlers (P >0.05).
 Conclusion: The study concluded that majority of food handlers had high knowledge of mycotoxigenic molds in maize foods, however they practiced poor postharvest handling which might influence occurrence of mycotoxigenic molds in maize based diets for school children. There is need to educate all stakeholders involved in School meals Programme on mycotoxins and postharvest handling of maize foods to prevent school children from the risk of mycotoxins exposure.

Influence of temperature and environmental conditions on aflatoxin contamination in maize collected from different regions of Pakistan during 2016–2019

Aspergillus and their associated metabolites like aflatoxins (AFs) are one of the extremely significant contaminants that affect food production around the world. This species decreases yield and grains quality under suitable environmental conditions. AFs were identified in various food commodities, have been recognized as carcinogenic, mutagenic, teratogenic and immunosuppressive. From 2016 to 2019, a total of 324 samples of maize were obtained from diverse areas of Pakistan and examined for AFs level. AFs were determined using an HPLC validated method through post-column derivatization and fluorescence detection. This study also focused on the effect of climatic conditions on AF production. The total AFs (B1+B2+G1+G2) were detected in 267 (82.4%) samples, ranged between 0.69 and 356.7 μg/kg with a mean of 15.27 ± 0.82 μg/kg. A total of 182 (56.2%) and 85 (26.2%) samples had AFs level above the maximum acceptable limit as accepted by European Union (EU) and United States of America (USA), respectively. The outcomes of the existing study indicated that the climatic situations in the examined areas had a great impact on AFs contamination. Significant differences were found between AFs contamination levels in the samples collected in different months (p < 0.05). The most contaminated samples were identified in July, August and September as the climatic conditions favored the AF production. These outcomes suggested that the food commodities must be regularly examined in order to prevent the health of human and animal from the hazardous effects produced by AFs contamination.

Field efficacy of two atoxigenic biocontrol products for mitigation of aflatoxin contamination in maize and groundnut in Ghana

Biological control is one of the recommended methods for aflatoxin mitigation. Biocontrol products must be developed, and their efficacy demonstrated before widespread use. Efficacy of two aflatoxin biocontrol products, Aflasafe GH01 and Aflasafe GH02, were evaluated in 800 maize and groundnut farmers’ fields during 2015 and 2016 in the Ashanti, Brong Ahafo, Northern, Upper East, and Upper West regions of Ghana. Both products were developed after an extensive examination of fungi associated with maize and groundnut in Ghana. Each product contains as active ingredient fungi four Aspergillus flavus isolates belonging to atoxigenic African Aspergillus Vegetative Compatibility Groups (AAVs) widely distributed across Ghana. An untreated field was maintained for each treated field to determine product efficacy. Proportions of atoxigenic AAVs composing each product were assessed in soils before product application, and soils and grains at harvest. Significant (P < 0.05) displacement of toxigenic fungi occurred in both crops during both years, in all five regions. Biocontrol-treated crops consistently had significantly (P < 0.05) less aflatoxins (range = 76% to 100% less; average = 99% less) than untreated crops. Results indicate that both biocontrol products are highly efficient, cost-effective, environmentally safe tools for aflatoxin mitigation. Most crops from treated fields could have been sold in both local and international food and feed premium markets. Adoption and use of biocontrol products have the potential to improve the health of Ghanaians, and both income and trade opportunities of farmers, aggregators, distributors, and traders.

Genomic prediction for resistance to Fusarium ear rot and fumonisin contamination in maize

AbstractFusarium ear rot (FER) disease of maize (Zea mays L.) is caused by Fusarium verticillioides (Sacc.) Nirenberg, which produces fumonisin (FUM), a mycotoxin linked to human and animal health risks. Extensive field trials, laborious inoculations and ear evaluations, and expensive antibody assays are required to reliably assess resistances to FER and FUM contamination in breeding populations. To evaluate the potential utility of genomic selection (GS) to improve FER and FUM in maize, we genotyped 6086 single nucleotide polymorphisms (SNPs) on 449 S0:1 lines from a recurrent selection population. Two different partitions of the S0:1 evaluation data were made to test the ability of models trained on 251 or 201 lines evaluated at three locations in 2014–2015 to predict FER and FUM of 198 or 248 different lines evaluated at three locations in 2016. Single‐stage univariate and multivariate genomic best linear unbiased predictor (GBLUP) models and two‐stage GBLUP, Bayes Cπ, Bayesian LASSO, and extreme gradient boosting models were compared for prediction. Maximum prediction accuracy for untested lines in a new year was 0.46 for FER and 0.67 for FUM. Bayesian models optimized for predicting traits influenced by major‐effect loci were best for FUM in one set, despite no evidence for significant individual SNP–trait associations from genome‐wide association study (GWAS) in the training sets; otherwise, GBLUP models were best. These results suggest that GS can help improve resistance to FER and FUM contamination in an applied breeding program.

Non-destructive classification and prediction of aflatoxin-B1 concentration in maize kernels using Vis-NIR (400-1000nm) hyperspectral imaging.

Aflatoxin-B1 contamination in maize is a major food safety issue across the world. Conventional detection technique of toxins requires highly skilled technicians and is time-consuming. Application of appropriate chemometrics along with hyperspectral imaging (HSI) can identify aflatoxin-B1 infected maize kernels. Present study was undertaken to classify 240 maize kernels inoculated with six different concentrations (25, 40, 70, 200, 300 and 500ppb) of aflatoxin-B1 by using Vis-NIR HSI. The reflectance spectral data were pre-processed (multiplicative scatter correction (MSC), standard normal variate (SNV), Savitsky-Golay smoothing and their combinations) and classified using partial least square discriminant analysis (PLS-DA) and k-nearest neighbour (k-NN). PLS model was also developed to predict the concentration of aflatoxin-B1in naturally contaminated maize kernels inoculated with Aspergillus flavus. The potential wavelength (508nm) was selected based on principal component analysis (PCA) loadings to distinguish between sterile and infected maize kernels. PCA score plots revealed a distinct separation of low contaminated samples (25, 40 and 70ppb) from highly contaminated samples (200, 300 and 500ppb) without any overlapping of data. The maximum classification accuracy of 94.7% was obtained using PLS-DA with SNV pre-processed data. Across all the combinations of pre-processing and classification models, the best efficiency (98.2%) was exhibited by k-NN model with raw data. The developed PLS model depicted good prediction accuracy ( = 0.820, SECV = 79.425, RPDCV = 2.382) during Venetian-blinds cross-validation. The results of pixel-wise classification (k-NN) and concentration distribution maps (PLS with raw spectra) were quite close to the result obtained by reference method (HPLC analysis) of aflatoxin-B1 detection.

Assessment of heavy metal(loid)s contamination risk and grain nutritional quality in organic waste-amended soil

Studies that evaluate the human health risk of heavy metal(loid)s pollution have not been widely performed for organic waste-amended soils on the Loess Plateau of China. With this respect, we conducted a 3-year field trial to estimate the heavy metal(loid)s contamination of soil and maize, the resultant nutritional quality of maize grains and the health risk under treatments of conventional fertilizer (CF), traditional Chinese medicine residue (TCMR) and sheep manure (SM). We found that protein, amino acids and lysine in maize grains were increased by 12.3, 11.3 and 5.88 % under TCMR treatments relative to SM application, respectively. Meanwhile, this treatment reduced the levels of Cr, Pb, Cd, As and Hg in soil and maize grains. All fertilization regimens resulted in greater health risks for children, with HI values ranging from 1.06 to 1.52 and CR levels for Cr and As being ﹥1.0 × 10−4, especially higher in SM treatments. This presented the beneficial effect of TCMR than SM. The further investigated of toxic metal(loid)s level in SM and its application risks, based on meta-analysis and Monte Carlo simulation, indicated Cd, Hg and Pb were the most cautionary heavy metal(loid)s and contamination risk were greater on the southwest regions of China.

Aflatoxin contamination of maize vended in Ondo state, Nigeria, and health risk assessments

Aflatoxin contamination of maize is a serious food safety problem worldwide. Despite the widespread consumption of maize in Nigeria, there is limited data on aflatoxin contents of maize vended in open markets in Ondo state, Nigeria. A total of 140 maize samples randomly purchased from major markets in four locations in Ondo state, were screened for total aflatoxins using an ELISA method. Exposure and health risk assessments were performed for the maize consumers by the deterministic and Margin of exposure (MOE) approaches, respectively. About 99% of the maize were contaminated with total aflatoxins (range: 0.65–265 µg/kg; mean: 125.9 µg/kg). Aflatoxin levels exceeding the 4 µg/kg set by the European Union for total aflatoxins were found in 88% of the maize whilst more than one half contained at least 100 µg/kg aflatoxins. The average probable daily intake values were 830, 332 and 138 ng/kg bw/day for the average children, adolescent and adult populations, respectively. Consequently, MOEs for the respective populations were 0.20, 0.51 and 1.23, suggesting a high level of health risk for consumers of maize vended in open markets in Ondo state due to high aflatoxin levels. Maize farmers and households in Ondo state need urgent aflatoxin mitigation interventions.

Morphological and molecular identification of Fusarium spp. isolated from maize kernels in Java and Lombok, Indonesia

Abstract. Widiastuti A, Karlina ML, Dhanti KR, Chinta YD, Joko T, Suryanti, Wibowo A. 2020. Morphological and molecular identification of Fusarium spp. isolated from maize kernels in Java and Lombok, Indonesia. Biodiversitas 21: 2741-2750. Fungal contamination of maize is a serious problem in Indonesia. Fusarium spp. infect maize in the field will be continuing to contaminate in the post-harvest period even though disease symptoms are not always emerged. Some Fusarium spp. produced mycotoxins which are harmful to human and animal health. Aims of this research were to reveal the presence of Fusarium spp. from both symptomatic and unsymptomatic maize, and to identify them based on morphological characteristics and molecular analysis. Samples of maize were collected from maize cultivation areas in East Java (EJ), Central Java (CJ), West Java (WJ), Yogyakarta Special Province (DIY), and Lombok, West Nusa Tenggara. Fusarium spp. were isolated in a single spore method and cultured in potato dextrose agar (PDA) medium for morphological identification of macro-and microconidia. Molecular identification was conducted by PCR assay using species-specific primers. Furthermore, unidentified species were analyzed by DNA sequence. This research found four species of mycotoxigenic Fusarium isolated from maize-based on molecular identification, which were Fusarium verticillioides (15 isolates), F. proliferatum (6 isolates), F. graminearum (1 isolate) and F. asiaticum (1 isolate). This research showed a novel report of F. asiaticum infection on maize kernel in Indonesia.

Low-cost grain sorting technologies to reduce mycotoxin contamination in maize and groundnut

The widespread contamination of foods by mycotoxins continues to be a public health hazard in sub-Saharan Africa, with maize and groundnut being major sources of contamination. This study was undertaken to assess the hypothesis that grain sorting can be used to reduce mycotoxin contamination in grain lots by removing toxic kernels. We tested a set of sorting principles and methods for reducing mycotoxin levels in maize and groundnut from a variety of genotypes and environments. We found that kernel bulk density (KBD) and 100-kernel weight (HKW) were associated with the levels of aflatoxins (AF) and fumonisins (FUM) in maize grain. A low-cost sorter prototype (the ‘DropSort’ device) that separated maize grain based on KBD and HKW was more effective in reducing FUM than AF. We then evaluated the effectiveness of DropSorting when combined with either size or visual sorting. Size sorting followed by DropSorting was the fastest method for reducing FUM to under 2 ppm, but was not effective in reducing AF levels in maize grain to under 20 ppb, especially for heavily AF-contaminated grain. Analysis of individual kernels showed that high -AF maize kernels had lower weight, volume, density, length, and width and higher sphericity than those with low AF. Single kernel weight was the most significant predictor of AF concentration. The DropSort excluded kernels with lower single kernel weight, volume, width, depth, and sphericity. We also found that visual sorting and bright greenish-yellow fluorescence sorting of maize single kernels were successful in separating kernels based on AF levels. For groundnut, the DropSort grouped grain based on HKW and did not significantly reduce AF concentrations, whereas size sorting and visual sorting were much more effective.

Thiosemicarbazone nano-formulation for the control of Aspergillus flavus.

Nanoparticles are widely studied for applications in medical science. In recent years, they have been developed for agronomical purposes to target microbial pest such as bacteria, fungi, and viruses. Nanoparticles are also proposed to limit the use of pesticides, whose abuse is causing environmental impact and human health concerns. In this study, nanoparticles were obtained by using poly-(ε-caprolactone), a polyester chosen for its biocompatibility and biodegradability properties. Poly-(ε-caprolactone) nanoparticles were formulated by using poly(vinyl alcohol) or Pluronic® F127 as non-ionic surfactants, and then loaded with benzophenone or valerophenone thiosemicarbazone, two compounds that inhibit aflatoxin production by Aspergillus flavus. The different types of nanoparticles were compared in terms of size, polydispersity index, morphology, and drug loading capacity. Finally, their effects were investigated on growth, development, and aflatoxin production in the aflatoxigenic species Aspergillus flavus, a ubiquitous contaminant of maize, cereal crops, and derived commodities. Aflatoxin production was inhibited to various extents, but the best inhibitory effect was obtained with respect to sclerotia production that was most effectively suppressed by both benzophenone and valerophenone thiosemicarbazone-loaded nanoparticles. These data support the idea that it is possible to use such nanoparticles as an alternate to pesticides for the control of mycotoxigenic sclerotia-forming fungi.

Biological Control of Aflatoxin in Maize Grown in Serbia.

Aspergillus flavus is the main producer of aflatoxin B1, one of the most toxic contaminants of food and feed. With global warming, climate conditions have become favourable for aflatoxin contamination of agricultural products in several European countries, including Serbia. The infection of maize with A. flavus, and aflatoxin synthesis can be controlled and reduced by application of a biocontrol product based on non-toxigenic strains of A. flavus. Biological control relies on competition between atoxigenic and toxigenic strains. This is the most commonly used biological control mechanism of aflatoxin contamination in maize in countries where aflatoxins pose a significant threat. Mytoolbox Af01, a native atoxigenic A. flavus strain, was obtained from maize grown in Serbia and used to produce a biocontrol product that was applied in irrigated and non-irrigated Serbian fields during 2016 and 2017. The application of this biocontrol product reduced aflatoxin levels in maize kernels (51–83%). The biocontrol treatment had a highly significant effect of reducing total aflatoxin contamination by 73%. This study showed that aflatoxin contamination control in Serbian maize can be achieved through biological control methods using atoxigenic A. flavus strains.

Functional Biology and Molecular Mechanisms of Host-Pathogen Interactions for Aflatoxin Contamination in Groundnut (Arachis hypogaea L.) and Maize (Zea mays L.).

Aflatoxins are secondary metabolites produced by soilborne saprophytic fungus Aspergillus flavus and closely related species that infect several agricultural commodities including groundnut and maize. The consumption of contaminated commodities adversely affects the health of humans and livestock. Aflatoxin contamination also causes significant economic and financial losses to producers. Research efforts and significant progress have been made in the past three decades to understand the genetic behavior, molecular mechanisms, as well as the detailed biology of host-pathogen interactions. A range of omics approaches have facilitated better understanding of the resistance mechanisms and identified pathways involved during host-pathogen interactions. Most of such studies were however undertaken in groundnut and maize. Current efforts are geared toward harnessing knowledge on host-pathogen interactions and crop resistant factors that control aflatoxin contamination. This study provides a summary of the recent progress made in enhancing the understanding of the functional biology and molecular mechanisms associated with host-pathogen interactions during aflatoxin contamination in groundnut and maize.