Development of Three Risk Assessment Models for Deoxynivalenol and Fumonisins B1 ＋ B2 Contents in Maize Kernel

The maximal deoxynivalenol （DON） and fumonisins 131 ＋ B2 （FUM） contents in cereals are dictated by the European regulation 1126/2007. The direct measurement of these mycotoxins is a tedious and expensive process. Our study is based on an alternative tool： near infrared spectroscopy. Different models were developed on 374 maize samples to predict their DON and FUM contents. Several parameters have been determined and used in a multivariate data analysis. Three models were developed： （1） a classification model based on Discriminant Factor Analysis （DFA）, （2） a linear model based on ANalysis of COVAriance （ANCOVA） and （3） a Partial Least Squares Discriminant Analysis model （PLS-DA）. Firstly, the performances of the DFA model for assessing DON and FUM risk were similar： 69 and 72% of the validation samples were respectively well classified. In the second part, the performances of the ANCOVA model for DON were higher than for FUM. The r2 was worth respectively 0.85 and 0.69. In the last part, the performances of the PLS-DA models were better for FUM than for DON. These results show that an evaluation of the mycotoxin risk is possible by analyzing selected kernel parameters measurable by secondary analytical such as near-infrared spectroscopy. Further work is needed to improve the models, adding more samples and using non linear approaches.

Free and Hidden Fumonisins in Hordei Fructus Germinatus and Their Transfer to the Decoction

Objective:This study aimed to determine the free and hidden fumonisins in Hordei Fructus Germinatus samples and to investigate the transfer rates of these mycotoxins from Hordei Fructus Germinatus to its decoction.Materials and Methods:The contamination levels of free and hidden fumonisins in a total of 60 Hordei Fructus Germinatus samples were analyzed using high-performance liquid chromatography coupled to tandem mass spectrometry(LC-MS/MS).The decoction procedure was simulated with a highly contaminated Hordei Fructus Germinatus sample,and fumonisins in the resulting decoction preparation were determined by LC-MS/MS.Results:Among all the samples,8.3%were contaminated with free fumonisins(FB1 and/or FB2)and 13.3%were contaminated with total fumonisins(free+hidden,measured as hydrolyzed fumonisins,i.e.,HFB1 and/or HFB2).The concentrations of FB1 and HFB1 reached up to 83 and 95μg/kg,respectively,whereas FB2 and HFB2 were detected only in traces.The transfer rates of free and total fumonisins from Hordei Fructus Germinatus to the decoction were 71.8%and 83.3%for FB1 and FB2,respectively.In comparison,much lower transfer rates were found for total fumonisins,i.e.,38.2%and 24.7%for HFB1 and HFB2,respectively.Conclusion:The incidence and contamination levels of free and hidden fumonisins in Hordei Fructus Germinatus samples were generally low.Regarding decoction preparation,the transfer rates of free fumonisins into the decoction were high,whereas a large part of hidden fumonisins were retained in Hordei Fructus Germinatus rather than migrating into water.

Occurrence of mycotoxins in food,feed,and milk in two counties from different agro-ecological zones and with historical outbreak of aflatoxins and fumonisins poisonings in Kenya

Aflatoxins and fumonisins contaminate cereals during pre-and post-harvest periods.In this study,household or market maize,sorghum,millet,cow or goat milk,and animal feed samples collected from two counties(Makueni and Nandi)of Kenya and were analyzed for aflatoxins and fumonisins using competitive enzyme-linked immunosorbent assay and confirmation with high performance liquid chromatography.There was a significant difference(P<0.005)in the levels of aflatoxins between the home grown and market-sourced maize,sorghum,and millet samples.In Makueni,24.8%of home maize and 44.6%of the market maize samples exceeded the 10 ppb limit for aflatoxins.In all,93%and 90%of the maize samples were contaminated with fumonisins and 34%and 6%exceeded the 2 ppm limit in Makueni and Nandi,respectively;30%and 37%of homegrown sorghum and millet samples exceeded the 10 ppb limit for aflatoxin in Makueni and Nandi,respectively;and 89%and 81%of homegrown millet samples in Makueni and Nandi,respectively,were positive for fumonisins and 22%and 7%in Makueni and Nandi,respectively,exceeded the 2 ppm fumonisins limit.In total,52%and 87%of the milk samples in Nandi and Makueni,respectively,were contaminated with aflatoxin M1 and 8%of the samples from Makueni exceeded the 50 ppt limit.There is an urgent need to build capacity among the households on cheap,practical,and effective technologies that would reduce the proportions of food samples contaminated with aflatoxins and fumonisins.

Impact of mycotoxins and their metabolites associated with food grains

Mycotoxins are secondary toxic metabolites synthesized by numerous filamentous fungi including members of the genus Fusarium,Penicillium,Drechslera,Aspergillus,Claviceps,Monascum,Alternaria,Cephalosporium,Nigrospora,and Trichoderma.Among them,Aspergillus and Fusarium species are major plant pathogens recognized to induce infection and produce mycotoxins in food crops.More than 400 mycotoxins have been documented and among them,aflatoxin,fumonisins,trichothecenes,zearalenone,ochratoxin A,citrinin,ergot alkaloids,and patulin are the most prominent compounds linked to a variety of human and animal health disorders.Genus Fusarium and Aspergillus belong to a saprophytic group,which can infect and contaminate many crops at pre and post-harvest stages.Mycotoxins can have a variety of negative effects on health in both humans and animals.Mycotoxins and their metabolites can cause severe acute poisoning,which can result in death,as well as long-term negative health effects,such as cancer and immune-suppressive disorders in living beings(animals and humans).Mycotoxin contamination of agricultural goods has gained global significance,due to its toxic effects on living beings,as well as its importance to international trade.Our objective is to provide a consolidated information on the potential mycotixs in food grains and their significant impact on the health of the human beings.

Mango Malformation: I. Toxin Production Associated with Fusarium Pathogens

Eight Fusarium species i.e. F. subglutinans, F. solani, F. oxyspoum, F. sterilihyphosum, F. proliferatum, F. monili-forme, F. avena and F. chlamydspore isolated from mango malformed disease were tested for their ability to cause mango malformation disease and their production of moniliformin and total fumonisins (FB1 + FB2) using HPLC. A evaluated for moniliformin production, seven isolates were toxin producers, the production levels ranging from 0.51 to 8.90 μg/ml. The higher levels were produced by Fusarium subglutinans (8.51 μg/ml). Moderate concentrations of moniliformin was produced by F.moniliforme (6.90 μg/ml), F. oxysporum (6.30 μg/ml), F. proliferatum (4.10 μg/ml) and F. sterilihyphosum (1.10 μg/ml). Separation and identification of Fumonisin that was isolated from the pathogen- causing disease are made by (HPLC). A evaluated for total fumonisin production (FB1 + FB2), seven isolates were toxin producers, the production levels ranging from 0.10 to 8.30 μg/ml. The higher levels were produced by F. monili-forme (8.30 μg/ml. Moderate concentrations of fumonisin was produced by F .proliferatum (0.64 μg/ml) and F. subglutinans (0.50 μg/ml). Strong positive correlations between moniliformin and total fumonisins (FB1 + FB2) activities and malformation disease incidence by F. subglutinans, F. solani, F. oxyspoum, F. sterilihyphosum, F. proliferatum was observed.

The Nature, Sources, Detections and Regulations of Mycotoxins That Contaminate Foods and Feeds Causing Health Hazards for Both Human and Animals

Mycotoxins are toxic secondary metabolites produced by fungus kingdom. Fungi (molds) under aerobic and optimum conditions of humidity and temperature consume nutrients for proliferation and mycotoxin production (secretion). There are seven major groups of mycotoxins produced by different species of toxigenic fungal genus. Mycotoxins production from these toxigenic fungi depends on the surrounding intrinsic and extrinsic environments. These seven mycotoxins groups that contaminate grains, foods and animal feeds are: Aflatoxins, Trichothecene, Ochratoxins, Ergot alkaloid (Ergolin), Fumonisins, Patulin, and Zearalenone. These mycotoxins are capable of causing health hazards and death for both human and animals by effecting mammalian cells, causing a number of problems in normal cell function and a wide variety of clinical symptoms of diseases. These mycotoxins are varied in their toxicity depending on the infected host (human or animal) and the host susceptibility (immunity). The major concern of food and feed industries is the contamination of food products and animal feed supplies by these mycotoxins. Worldwide Health Organization (WHO), and Food and Agriculture Organization (FAO) are responsible to regulate the acceptable (tolerable) levels of these mycotoxins in grains, food and feed supplies to ensure the safety and health for both human and animals. Understanding fungal ecology and factors that affect fungal proliferation and mycotoxins production by these toxigenic fungi in agriculture crops as raw materials for both human food and animal feed products, plus understanding the chemistry and property of these mycotoxins, methods of detection, illness symptoms, and comply with regulatory guidance established by World Health Organization (WHO)/Food and Agriculture Organization (FAO) are key factors to prevent or minimize foods/feeds contamination and the toxicity of these mycotoxins for both human and animals health, plus reducing economical loss.

Aflatoxin and Fumonisin in Corn Production Chain in Bafia, Centre Cameroon： Impact of Processing Techniques

Food safety is to be a vital component of food security, with mycotoxin contamination, a major contributing factor. In linewith this, this study aimed at investigating the effect of maize maturity at harvest, and processing techniques on the aflatoxin andfumonisin levels in maize and maize products. Three maize maturity stages （80, 85, and 90 days after sowing）, two drying processes（sun and barn drying）, three storage periods （one, two and three months） and subsequent maize derivatives under these conditionswere sampled. These were analysed for total aflatoxins and total fumonisins using quantitative ELISA and samples with totalaflatoxins and total fumonisins exceeding regulated levels were analyzed by liquid chromatography-tandem mass spectrometry（LC-MS/MS） to determine the sub-types of toxins present. Results obtained showed that all analyzed samples were contaminatedwith total aflatoxins （range： 0.8 to 20 μg/kg） and total fumonisins （range： 10 to 5990 μg/kg）. Sun or barn drying for one weekfollowed by one month usual storage resulted in significant total fumonisins contamination, emphasizing the need of at least twoweeks of drying maize. It was also observed that processing techniques partly reduced the levels of toxins, mainly in maize productsthat have a sieving step.

Probable Effects of Dual Inoculation of Maize (<i>Zea mays</i>) Stem with <i>Fusarium verticillioides</i>and Certain <i>Trichoderma</i>Species on Fumonisin Content of Maize Seeds

Seeds from maize (Z. mays) plants whose stems received various treatment combinations of pathogen (F. verticillioides) and four antagonists (i.e. Trichoderma harzianum strain 2, T. hamatum, T. pseudokoningii strains 2 and 5) in the field were subjected to fumonisin analysis. Three pairing methods were employed for the inoculation of pathogen and the antagonists into stem of the maize plant, viz., “Pathogen inoculated before Antagonist”, “Antagonist inoculated before Pathogen”, and “Antagonist and Pathogen inoculated simultaneously”. Controls include “Inoculation of pathogen alone”, “Inoculation of antagonist alone”, and “Inoculation of sterile toothpicks”. Inoculation method used was the toothpick method. Seeds were harvested five weeks after inoculation and subjected to fumonisin analysis. Resulting data were subjected to ANOVA using the GLM procedure of SAS. There was a high significance among treatments i.e. there were varying levels of fumonisin occurrence among the treatments and varying Fusarium occurrences within the blocks. Seeds from treatments involving “Inoculating T. pseudokoningii strain 5 alone” and “Inoculating T. harzianum strain 2 alone” had the highest mean fumonisin content (P > 0.01) which were not significantly higher than in control. Seeds from treatments involving “Inoculating T. pseudokoningii strain 5 and pathogen simultaneously” and “Inoculating T. harzianum strain 2 before pathogen” were significantly low in fumonisin content compared to seeds from other treatments. Seeds which received “Inoculation of T. hamatum alone” were also significantly low (P > 0.01) in fumonisin content compared to others. It could thus be said that treatments involving Trichoderma species applied in the maize stem might have an effect on the fumonisin content and hence Fusarium occurrence in the seeds depending on the occurrence pattern of the Trichoderma within the maize stem.

Proximate Composition,Fatty Acid Profile and Mycotoxin Contamination in Several Varieties of Mexican Maize

In Mexico maize (Zea mays L.) is an important cereal due to excellent taste and nutritional value. Nutritional content and fatty acid profile has been reported in white maize, however, there are several genotypes natives (red, yellow, black, blue, pinto), and many improved hybrids maize of which little is known. Fumonisins and aflatoxins are mycotoxins present in 25% of the world’s cereals, mainly in tropical and subtropical regions around the world. This study presents the analysis of proximate composition (ash, protein, lipids), as well as mycotoxins (fumonisins and aflatoxins) and five different fatty acids, two of saturated fatty acids (palmitic and stearic) and three of polyunsaturated fatty acids (oleic, linoleic and linolenic), evaluated by Gas Chromatography and Flame Detector (GC-DF). Thirty varieties of maize (native and hybrid maize) were collected in states of central region. The total fumonisins were determined using the QuickTox TM extraction and quantificated by QuickScan fumonisins;the aflatoxins were analyzed by commercial ELISA kit. The highest protein level was 10.43 g/100g, 5.63 g/100g for fat, 1.62 g/100g for ash in hybrid maize. In native maize, the highest levels of protein and ash were 10.94 g/100g and 1.45 g/100g for pinto maize. The higher value for fat was 5.45 g/100g in yellow maize. The palmitic and stearic acids, in native maize were higher that hybrid maize, for linoleic acid and linoleinic fatty with a significant difference between native corn. Fumonisins and aflatoxins were contaminated in all genotypes of maize, in allow levels. This information obtained may be considered in maize breeding programs, industrialization processes and healthy diets.

Involvement of sphingoid bases in mediating reactive oxygen intermediate production and programmed cell death in Arabidopsis

Sphingolipids have been suggested to act as second messengers for an array of cellular signaling activities in plant cells, including stress responses and programmed cell death （PCD）. However, the mechanisms underpinning these processes are not well understood. Here, we report that an Arabidopsis mutant, fumonisin B1 r_esistant11-1 （/br11-1）, which fails to generate reactive oxygen intermediates （ROIs）, is incapable of initiating PCD when the mutant is challenged by fumonisin B l （FB0, a specific inhibitor of ceramide synthase. Molecular analysis indicated that FBR11 encodes a long-chain base 1 （LCB 1） subunit of serine palmitoyltransferase （SPT）, which catalyzes the first rate-limiting step of de novo sphingolipid synthesis. Mass spectrometric analysis of the sphingolipid concentrations revealed that whereas the fbr11-1 mutation did not affect basal levels of sphingoid bases, the mutant showed attenuated formation of sphingoid bases in response to FBl. By a direct feeding experiment, we show that the free sphingoid bases dihydrosphingosine, phytosphingosine and sphingosine efficiently induce ROI generation followed by cell death. Conversely, ROI generation and cell death induced by dihydrosphingosine were specifically blocked by its phosphorylated form dihydrosphingosine- 1-phosphate in a dosedependent manner, suggesting that the maintenance of homeostasis between a free sphingoid base and its phosphorylated derivative is critical to determining the cell fate. Because alterations of the sphingolipid level occur prior to the ROI production, we propose that the free sphingoid bases are involved in the control of PCD in Arabidopsis, presumably through the regulation of the ROI level upon receiving different developmental or environmental cues.

Evaluation of maize inbred lines for resistance to pre-harvest aflatoxin and fumonisin contamination in the field

Two important mycotoxins, aflatoxin and fumonisin, are among the most potent naturally occurring carcinogens, contaminating maize(Zea mays) and affecting crop yield and quality.Resistance of maize to pre-harvest mycotoxin contamination, specifically aflatoxin produced by Aspergillus flavus and fumonisin produced by Fusarium verticillioides, is a goal in breeding programs that screen for these important traits with the aim of developing resistant commercial hybrids. We conducted two years of field evaluations on 87 inbred lines originating primarily in China and Mexico and not previously screened for resistance.The objectives of our study were to identify resistant germplasm for breeding purposes and to examine possible relationships between resistances to the two mycotoxins. Aflatoxin and fumonisin were present in samples harvested from all lines in both years.Concentrations of total aflatoxin ranged from 52.00 ± 20.00 to 1524.00 ± 396.00 μg kg^(-1),while those of fumonisin ranged from 0.60 ± 0.06 to 124.00 ± 19.50 mg kg^(-1). The inbred lines TUN15, TUN61, TUN37, CY2, and TUN49 showed the lowest aflatoxin accumulation and CN1, GT601, TUN09, TUN61, and MP717 the lowest fumonisin accumulation. TUN61 showed the lowest accumulation of both mycotoxins. This study confirmed previous observations that high levels of aflatoxin can coexist with fumonisin, with 55 maize lines showing a positive correlation coefficient between the concentrations of aflatoxin and fumonisin and 32 lines showing a negative correlation coefficient. These selected lines,particularly TUN61, may provide sources of resistance to mycotoxin contamination in breeding programs. However, the mechanism of resistance in this germplasm remains to be identified. Future research should also address factors that influence the fungus–plant interaction, such as herbivory and environmental stress.

Difference between resistant and susceptible maize to systematic colonization as revealed by DsRed-labeled Fusarium verticillioides

Fusarium verticillioides was labeled with DsRed via Agrobacterium tumefaciens-mediated transformation to examine differences in colonization and reactions of resistant and susceptible inbred lines of maize(Zea mays L.). The extent of systemic colonization of F. verticillioides in roots from maize lines either resistant or susceptible to the fungus was studied by visualizing the red fluorescence produced by the fungus expressing DsRed. The difference in quantities of colony forming units(CFU) in roots and basal stems, production of fumonisin B1, and pH of root were determined. Although F. verticillioides colonized both resistant and susceptible lines, differences were observed in the pattern and extent of fungal colonization in the two types of maize lines. The fungus colonized the susceptible lines producing mosaic patterns by filling the individual root cells with hyphae. Such a pattern of colonization was rarely observed in resistant lines, which were less colonized by the fungus than the susceptible lines in terms of CFUs. The production of mycotoxin fumonisin B1 in roots from different lines was closely correlated with the amount of F. verticillioides colonization, rather than the pH or amylopectin concentrations in the root. The findings from this study contribute to a better understanding of the defense mechanism in resistant maize lines to F. verticillioides.

Effects of Fumonisin B1 on Biomechanics and Cytoskeleton of Human Umbilical Vein Endothelial Cells

Objective Fumonisin B1(FB1)is an important mycotoxin in nature worldwide.The biomechanical properties of cells are closely related to their structure and function,and the cytoskeleton is the structural and functional basis of cells motility,and therefore,from a biomechanical point of view,the purpose of this study is to investigate the effects of FB1 on the biomechanical properties,migration capacity and cytoskeletal structure of human umbilical vein endothelial cells(HUVECs),which may lay an experimental foundation for further exploration of the toxicity mechanism of fumonisin.Methods HUVECs were cultured and treated with different concentrations of FB1.Then,CCK-8 kit was used to detect the effect of FB1 on the survival rate.The osmotic fragility of the cells was measured after treatment with different osmotic pressures for30 min.The cell membrane fluidity was measured by fluorescence polarization method.The cell electrophoretic mobility was measured by cell electrophoretic apparatus.The migration capacity of the cells was observed by scratch repair assay.The changes of reactive oxygen species and cytoskeletal structure were observed by confocal laser scanning microscopy.Finally,the mRNA and protein relative expression levels of cytoskeletal binding proteins were detected by real-time PCR,Western blotting and confocal laser scanning.Results The results of CCK-8 showed that FB1 could significantly inhibit the proliferation of HUVECs in a dose-and time-dependent manner.After treatment of HUVECs with FB1,the hypotonic resistance of the cell,cell surface charge,cell membrane fluidity and migration capacity were all weakened,while reactive oxygen species were significantly increased and the cytoskeletal structure was significantly reorganized.Furthermore,RTPCR results showed that the mRNA relative expression levels of cytoskeletal binding proteins,exception of actin,were down-regulated after treated with FB1.Besides,Western blotting and statistical analysis based on fluorescence intensity of laser confocal microscopy confirmed theses changes in protein level.Conclusions FB1 can significantly affect the biomechanical properties and motility of HUVECs,which may be directly correlated to the remodel of F-actin cytoskeleton,as well as the relative expression changes of cytoskeletal binding proteins.It is significant for further exploring the toxicity mechanism of fumonisin.

The peroxisomal matrix shuttling receptor Pex5 plays a role in FB1 production and virulence in Fusarium verticillioides

The peroxisomal matrix oxidase,catalase and peroxidase are imported peroxisomes through the shuttling receptors,which regulates the cellular oxidative homeostasis and function.Here,we report that PTS1 shuttling receptor FvPex5 is involved in the localization of PTS1,utilization of carbon sources and lipids,elimination ROS,cell wall stress,conidiation,fumonisin B_(1)(FB_(1))production,and virulence in maize pathogen Fusarium verticillioides.Significantly,differential expression of PTS1-,PTS2-,PEX-and FB_(1)toxin-related genes in wild type andΔFvpex5 mutant were examined by RNA-Seq analyses and confirmed by RT-PCR assay.In addition,different expression of PTS1 and PTS2 genes of theΔFvpex5 mutant were enriched in diverse biochemical pathways,such as carbon metabolism,nitrogen metabolism,lipid metabolism and the oxidation balance by combining GO and KEGG annotations.Overall,we showed that FvPex5 is involved in the regulation of genes associated with PTS,thereby affecting the oxidation balance,FB_(1)and virulence in F.verticillioides.The results help to clarify the functional divergence of Pex5 orthologs,and may provide a possible target for controlling F.verticillioides infections and FB_(1)biosynthesis.

Ameliorated effects of Lactobacillus delbrueckii subsp. lactis DSM 20076 and Pediococcus acidilactici NNRL B-5627 on Fumonisin B1-induced Hepatotoxicity and Nephrotoxicity in rats

Oxidative stress has been implicated in a number of human regeneration and disease processes including atherosclerosis, pulmonary fibrosis, cancer, and different neurodegenerative diseases.The aim of this study was to evaluate the protective effects of Lactobacillus delbrueckii subsp. lactis DSM 20076 (LL-DSM) and Pediococcus acidilactici NNRL B-5627 (PA-NNRL) against the hepatic-and nephro-toxicity of fumonisin B1 (FB1) in FB1-treated rats for an experimental period of 4-weeks. Eighty mature male Sprague-Dawley rats were divided to 12 groups: 1 untreated group;3 groups fed by a FB1-contaminated diet (50, 100 and 200 mg FB1/kg diet,respectively);1 group fed orally by LL-DSM(1 ml/d);1 group fed orally by PA-NNRL (1 ml/d);3 groups co-administered by FB1-contaminated diet and LL-DSM (1 ml/d), and 3 groups coadministered by FB1-contaminated diet and PA-NNRL(1 ml/d). Malonaldehyde (MDA) nitric oxide, glutathione content, SOD activity, total antioxidant capacity (TAC), total oxidant status (TOS) and oxidative stress index (OSI) were determined. DPA assay was used to assess apoptosis in liver and kidney tissues.The animals fed with FB1-contaminated diet showed a significant increase in oxidative stress markers and DNA fragmentation accompanied with significant decrease in GSH content, SOD activity, and TAC in liver and kidney tissues, especially at highdosage of FB1 (T200). Probiotics antioxidant strains (LL-DSM and PA-NNRL) relatively succeeded to restore almost all parameters investigated as well as to reduce DNA fragmentation in liver and kidney tissues. As a conclusion, probiotics may induce its protective role via increasing the antioxidant capacity, inhibition of lipid peroxidation, scavenging of free radicals and decreasing DNA lesions in liver and kidney of experimental animals tested.

Effect of Planting Density, Irrigation Regimes, and Maize Hybrids with Varying Ear Size on Yield, and Aflatoxin and Fumonisin Contamination Levels

Corn (maize, Zea mays L.) hybrids expressing the flexibility trait in ear size (number of kernels per ear) are marketed for ability to give higher yields under adverse conditions. Altered kernel number is associated with altered number of silk, a major route for infection of kernels by aflatoxin-producing fungi such as Aspergillus flavus. The effect of plant density and irrigation level on yield and accumulation of aflatoxins and fumonisins in harvested grain was compared in a fixed-ear hybrid (Pioneer 33K81), a semi-flexible ear hybrid (Pioneer 3223) and a flexible ear hybrid (Golden Acres 8460) over a range of seeding densities (49,400, 61,750, 74,700, 86,450, and 98,800 seeds·ha–1) in non-irrigated, moderately-irrigated (6.4 cm soil water deficit) and well-irrigated plots (3.8 cm soil water deficit), during three years with variable rainfall. Irrigation increased yields in all hybrids, but in the absence of irrigation, yields were highest with the semi-flexible ear trait hybrid. In general, the hybrid with the flexible ear trait had lower optimal seeding densities than the other hybrids for each soil water regime. In general, kernel number was least affected by seeding density in the hybrid with fixed-ear trait compared to the semi- and flexible ear hybrids. The lowest levels of aflatoxin and of fumonisin contamination in harvested grain were associated with the flexible ear trait at all rainfall and irrigation levels, but there was no evidence that reducing stress by lowering seeding density reduced mycotoxin contamination. Inoculation with A. flavus resulted in much higher levels of aflatoxin and significantly higher levels of fumonisin contamination in grain of all hybrids under most conditions of rainfall and irrigation, suggesting that factors that promote A. flavus infection can affect production of both mycotoxins.

Maize Storage and Consumption Practices of Farmers in Handeni District, Tanzania: Corollaries for Mycotoxin Contamination

In Tanzania, maize is the main complementary food for infants and primary school children. Dietary exposure to mycotoxins through complementary foods by Tanzanian infants is of concern. The maize storage and consumption practices of farmers in Handeni District, Tanzania and their implications for mycotoxin contamination of maize flour were investigated. A convenient sample of 60 farmers in Seza Kofi and Kwabojo villages in Mgambo and Ndolwa wards were surveyed. The majority of farmers (95%) stored their maize in the house using the roofing and sack methods. Most farmers (67%) did not visually or mechanically sort defective maize kernels before storage. In both villages, the most important storage problems reported by the farmers were rodents and insects. Forty two percent of the farmers surveyed indicated that they consumed dehulled maize, while 35 and 12% consumed non-dehulled and mixed (dehulled and non-dehulled), respectively. The preponderance of storage practices described was unfavorable to mycotoxin reduction in stored maize. It is therefore recommended that appropriate, area-specific farmer training regarding recommended storage practices including storage methods, effective management of storage pests and healthy maize preparation and consumption practices be conducted. Additionally, further research on maize storage and consumption practices for Tanzania is needed.

Fumonisin-Producing Fusarium from Maize Grains in Tretep, Indonesia

Fusarium species commonly occur in maize are fungal pathogen which produce mycotoxins, such as fumonisin, trichothecene and zearalenone. In this study, Fusarium species were isolated from maize kernel from Tretep, maize producer region and were identified based on microscopic- and macroscopic characters as well as molecular characters using PCR assays and the partial sequence of TEF 1-α gene （Translation Elongation Factor 1-α. The fumonisin-producing ability of these Fusarium was determined by growing them in corn medium and analyzed their fumonisin by ELISA （enzyme-linked immuno assay）. Among 9 isolates, three of them were identified as Fusarium verticillioides, two as Fusarium temperatum, two as Fusarium globosum, one as Fusarium proliJeratum and one as Fusarium subglutinans. Fusarium temperatum is similar morphologically to F. subglutinans, however, both of their differences can be found by molecular analysis. Fumonisin-producing abilities of Fusarium were determined in concentrations 20.51 pg/g-1,109.74 pg/g medium with the highest producer was identified as F. globosum.

Investigating Transgenic Corn Hybrids as a Method for Mycotoxin Control

Transgenic Bt corn hybrids have been available for more than 10 years and are known to control specific insects. More recently, so-called “stacked-gene” hybrids, have been released with multiple insect resistance genes and genes for herbicide resistance, resulting in up to 6 traits per plant. Because insect damage can lead to increased levels of mycotoxins, such as aflatoxins and fumonisin, we designed a study to compare ten commercially available corn hybrids, two non-transgenic, four with both herbicide and insect tolerance (stacked-gene) and four with glyphosate tolerance only to determine if any hybrid class had the advantage of reduced mycotoxin contamination. The experiment was carried out in the Mississippi State University Delta Research Extension fields in Stoneville, MS for two years in fine sandy loam and clay soil. Rows were either inoculated at the V10 stage of growth with toxigenic Aspergillus flavus K54 (NRRL 58987, isolated from corn kernels in Mississippi), grown on wheat, and applied at a rate of 22.42 kg/ha or allowed to become naturally infected with disease-producing fungi, including various Fusarium and other Aspergillus spp. Mycotoxin production differed according to the soil type with lower levels detected in the hybrids planted in clay soil vs. sandy soil. However, no significant differences in mycotoxin production were found amongst the hybrid classes. More research is needed to identify conditions under which transgenic hybrids might produce higher yields and lower mycotoxin levels. Presently, selection of transgenic hybrids will not replace integrated strategies of biocontrol, host plant resistance, or good crop management practices for achieving adequate mycotoxin control in corn.

Comparative Analysis of Mycotoxigenic Fungi and Mycotoxins Contaminating Soya Bean Seeds and Processed Soya Bean from Nigerian Markets

Concern for food safety has continued to grow worldwide including the issue of mycotoxin contamination of food products from farm to fork. In this regard, soya bean seeds and processed soya bean powder bought from some Nigerian markets were screened for fungal and mycotoxin contamination. Fungal identification was done by both conventional and molecular methods after samples were cultured on potato dextrose agar (PDA), ohio agricultural experimental station agar (OAESA), malt extract agar (MEA) and czapek yeast agar (CYA). Mycotoxin analysis by thin layer chromatography and high performance liquid chromatography was done after extraction and clean-up by multi-mycotoxin extraction procedure and solid phase extraction (SPE) isolute strong ion exchange (SAX) columns. Results from the analysis showed that soya bean seeds had higher incidences of fungal species such as Alternaria (52.4%) and Aspergillus flavus (42.9%). Mycotoxins detected include aflatoxins, ochratoxin A and fumonisin B with highest concentration of 3.430 μg/g, 0.125 μg/g and 4.286 μg/g respectively, which were below regulatory limits. The study showed that there was co-occurrence of aflatoxins and fumonisin B1 in both sample types and though these values are low, should not be ignored as a result of health risks associated with exposure to these compounds.