Occurrence of fumonisins in foods

Interaction of Fumonisin B1, N-Palmitoyl-Fumonisin B1, 5-O-Palmitoyl-Fumonisin B1, and Fumonisin B4 Mycotoxins with Human Serum Albumin and Their Toxic Impacts on Zebrafish Embryos

Fumonisins are frequent food contaminants. The high exposure to fumonisins can cause harmful effects in humans and animals. Fumonisin B1 (FB1) is the most typical member of this group; however, the occurrence of several other derivatives has been reported. Acylated metabolites of FB1 have also been described as possible food contaminants, and the very limited data available suggest their significantly higher toxicity compared to FB1. Furthermore, the physicochemical and toxicokinetic properties (e.g., albumin binding) of acyl-FB1 derivatives may show large differences compared to the parent mycotoxin. Therefore, we tested the interactions of FB1, N-palmitoyl-FB1 (N-pal-FB1), 5-O-palmitoyl-FB1 (5-O-pal-FB1), and fumonisin B4 (FB4) with human serum albumin as well as the toxic effects of these mycotoxins on zebrafish embryos were examined. Based on our results, the most important observations and conclusions are the following: (1) FB1 and FB4 bind to albumin with low affinity, while palmitoyl-FB1 derivatives form highly stable complexes with the protein. (2) N-pal-FB1 and 5-O-pal-FB1 likely occupy more high-affinity binding sites on albumin. (3) Among the mycotoxins tested, N-pal-FB1 showed the most toxic effects on zebrafish, followed by 5-O-pal-FB1, FB4, and FB1. (4) Our study provides the first in vivo toxicity data regarding N-pal-FB1, 5-O-pal-FB1, and FB4.

Well-oriented immobilized immunoaffinity magnetic beads for detection of fumonisins in grains and feeds via pre-column automatic derivatization of high-performance liquid chromatography

In this study, based on the high-throughput automatic sample pretreatment with immunoaffinity magnetic beads with oriented immobilized antibodies, grain and feed fumonisin (FB) content was detected using pre-column automatic derivatization of high-performance liquid chromatography (HPLC). The FB capacity of well-oriented antibody immunoaffinity magnetic beads was 1.5-1.8 times that of magnetic beads with randomly fixed antibody. This pre-column automatic derivatization method using an autosampler can reduce error from manual injection and improve detection efficiency. The spiked recoveries for three different concentrations in maize, husked rice, and pig feed under optimized conditions were 84.6-104.0% (RSD < 9.3%). Our novel method was also applied to the analysis of FBs in 63 maize samples collected from the main maize-production regions in China. The results showed that as latitude increased, the contamination level of FBs tended to decrease. High temperature and high humidity are also more favorable for FB growth.

Preparation of 3-O-, 5-O- and N-palmitoyl derivatives of fumonisin B1 toxin and their characterisation with NMR and LC-HRMS methods

We have previously published six esterified O-acyl (EFB1) and three N-acyl fumonisin B₁ derivatives extracted from rice cultures inoculated with Fusarium verticillioides, amongst these the identification of N-palmitoyl-FB1 has been clearly established in a spiking experiment. At that time, it was assumed that as in the case of O-acyl-FB1 derivatives, linoleic-, oleic- or palmitic acid esterify through the OH group on the 3C or 5C atom of the carbon chain of the fumonisins. In our most recent experiments, we have synthetically acylated the FB1 toxin and subsequently purified 3-O-palmitoyl- and 5-O-palmitoyl-FB1 toxins in addition to the N-palmitoyl-FB1 toxin. They were identified and characterised using ¹H and ¹³C NMR as well as LC-HRMS. Our aim was the identification of the previously detected O-acyl-FB1 derivatives over the course of a spiking experiment, which were obtained through the solid-phase fermentation of Fusarium verticillioides. By spiking the three synthesized and identified components one-by-one into the fungal culture extract and analysing these cultures using LC-MS, it was clearly demonstrated that the F. verticillioides strain produced both the 5-O-palmitoyl-FB1 and N-palmitoyl-FB1 toxins, but did not produce 3-O-palmitoyl-FB1. Thus, it is highly probable that the components thought to be 3-O-acyl-(linoleoyl-, oleoyl-, palmitoyl-) FB1 derivatives in our previous communication are presumably 10-O-acyl-FB1 derivatives. Since these acylated FB1 derivatives can occur naturally in e.g. maize, the use of these synthesized components as reference materials is of great importance in order to obtain accurate qualitative and quantitative data on the occurrence of acylated fumonisins in different matrices including maize based feed samples. The production of these substances has also made it possible to test their toxicity in cell culture and small animal experiments.

Fusarium Mycotoxins, Their Metabolites (Free, Emerging, and Masked), Food Safety Concerns, and Health Impacts

The genus Fusarium produces a number of mycotoxins of diverse chemical structures. Fusariotoxins are secondary metabolites produced by toxigenic fungi of the genus Fusarium. The important and commonly encountered fusariotoxins are trichothecenes, fumonisins, and zearalenone. Fusarium mycotoxins pose varying toxicities to humans and/or animals after consumption of contaminated grain. They can cause acute or chronic illness and, in some cases, death. For instance, a range of Fusarium mycotoxins can alter different intestinal defense mechanisms, such as the epithelial integrity, cell proliferation, mucus layer, immunoglobulins, and cytokine production. Of recent concern is the occurrence of emerging and masked Fusarium mycotoxins in agricultural commodities, which may contribute to toxic health effects, although the metabolic fate of masked mycotoxins still remains a matter of scientific discussion. These mycotoxins have attracted attention worldwide because of their impact on human and animal health, animal productivity, and the associated economic losses. In this paper, we review Fusarium mycotoxins and their metabolites with the aim of summarizing the baseline information on the types, occurrence, and health impacts of these mycotoxins in order to encourage much-needed research on integrated management of this unavoidable food contaminant as concerns for food safety continues to grow worldwide.

Prevalence and concentration of fumonisins in cereal-based foods: a global systematic review and meta-analysis study

Cereal-based foods are utilized as an essential food segment worldwide. Nevertheless, their contamination by mycotoxins, also fumonisins, could pose a critical health risk. The present research provides the first systematic review regarding the prevalence and concentration of fumonisins in cereal-based food with the aid of a meta-analysis. In this regard, some international databases PubMed, Web of Science, Google Scholar, and Scopus were explored during the last 30 years. Among 9729 screened articles, 73 articles (which meet the proposed inclusion criteria), including 11,132 data, were incorporated in the performed meta-analysis. The overall rank order regarding the concentration of fumonisins in cereal-based foods was corn-based foods > wheat-based foods > other cereal foods > barley-based foods > rice-based foods > oat-based foods. Based on the prevalence of fumonisins, the overall rank order was other cereal foods > corn-based foods > rice-based foods > wheat-based foods > oat-based foods > barley-based food. The present meta-analysis results can be a beneficial database for risk assessment model progress, which can help industries and organizations decrease the presence of fumonisins in cereal-based food.

Cold Plasma Affects Germination and Fungal Community Structure of Buckwheat Seeds

Crop seeds are frequently colonised by fungi from the field or storage places. Some fungi can cause plant diseases or produce mycotoxins, compromising the use of seeds as seeding material, food or feed. We have investigated the effects of cold plasma (CP) on seed germination and diversity of seed-borne fungi in common and Tartary buckwheat. The seeds were treated with CP for 15, 30, 45, 60, 90, and 120 s in a low-pressure radiofrequency system using oxygen as the feed gas. The fungi from the seed surface and fungal endophytes were isolated using potato dextrose agar plates. After identification by molecular methods, the frequency and diversity of fungal strains were compared between CP treated and chemically surface-sterilised (30% of H2O2) seeds. CP treatments above 60 s negatively affected the germination of both buckwheat species. A significant reduction in fungal frequency and diversity was observed after 90 s and 120 s in common and Tartary buckwheat, respectively. The filamentous fungi of genera Alternaria and Epicoccum proved to be the most resistant to CP. The results of our study indicate that CP treatment used in our study may be applicable in postharvest and food production, but not for further seed sowing.

Variation of Deoxynivalenol Levels in Corn and Its Products Available in Retail Markets of Punjab, Pakistan, and Estimation of Risk Assessment

This study investigated the natural incidence of deoxynivalenol (DON) in corn and corn products from corn-producing districts of Punjab, Pakistan. The analysis was carried out using high performance liquid chromatography (HPLC) with UV detector and immunoaffinity cleanup columns. The detection limit (LOD) and limit of quantification were 25 and 50 µg/kg, respectively. A total of 1220 samples of corn and corn products were analyzed to detect DON, and 539 (44.2%) samples were observed to be contaminated with DON (n ≥ LOD). Furthermore, 92 (7.5%) samples of corn and corn products had DON levels that were higher than the proposed limits of the EU. The data are significantly different from a normal distribution of DON in samples of corn and corn products from different locations (p < 0.05) for Shapiro-Wilk and Kolmogorov-Smirnov values. However, a significant difference in DON levels was found between corn and corn-derived products (p ≤ 0.05). The lowest and highest exposures, and hazard quotient (HQ) values of 0.92 and 9.68 µg/kg bw/day, were documented in corn flour samples.

Contamination of Wheat, Barley, and Maize Seeds with Toxigenic Fusarium Species and Their Mycotoxins in Tunisia

Background

Fusarium is a worldwide distributed fungal genus. It includes different species pathogenic to cereals among others crops. Some of these species can also produce toxic compounds toward animals and humans.

Objective

In this work, occurrence of fumonisins B1+B2, zearalenone, type A trichothecenes (T-2 and HT-2 toxins), and type B trichothecenes (deoxynivalenol[DON] and nivalenol[NIV]) was studied in 65 samples of stored and freshly harvested wheat, barley, and maize collected in Tunisia.

Methods

Mycotoxins analyses were performed by using gas chromatography for type B trichothecenes and HPLC for other mycotoxins. Obtained results were compared with the presence of mycotoxigenic species considered responsible for their synthesis by using species-specific polymerase chain reaction (PCR).

Results

Fumonisins occurred in 20.83% of wheat, 40% of barley, and 57.14% of maize samples, at levels exceeding European limits and suggesting a risk in Tunisian cereals, especially maize. Zearalenone, DON, NIV, and T-2+HT-2 toxins were detected at lower values in only wheat and barley samples. PCR protocols showed the predominance of F. verticillioides especially in maize, and occurrence of F. equiseti and F. graminearum in wheat and barley, and F. proliferatum in only two maize samples. A very consistent correlation was found between the detection of F. verticillioides and the contamination by fumonisins, as well as between the presence of F. graminearum and the contamination by zearalenone, DON, and NIV in the analyzed cereals.

Conclusions

Consequently, the detection of Fusarium species with the current PCR assays strategy in wheat, barley, and maize grains may be considered predictive of their potential mycotoxin risk in these matrices.

Highlights

This work is the first to report information on the occurrence of fumonisins, trichothecene, and ZEN, together with their potentially producing Fusarium species in wheat, barley, and maize in Tunisia. The high level of fumonisins in cereals, especially maize, stresses the importance of the control and the regularization of these mycotoxins for food safety.

Exposure Assessment of Multiple Mycotoxins and Cumulative Health Risk Assessment: A Biomonitoring-Based Study in the Yangtze River Delta, China

The extensive exposure to multiple mycotoxins has been demonstrated in many countries; however, realistic assessments of the risks related to cumulative exposure are limited. This biomonitoring study was conducted to investigate exposure to 23 mycotoxins/metabolites and their determinants in 227 adults (aged 20-88 years) in the Yangtze River Delta, China. Eight mycotoxins were detected in 110 urine samples, and multiple mycotoxins co-occurred in 51/227 (22.47%) of urine samples, with deoxynivalenol (DON), fumonisin B1 (FB1), and zearalenone (ZEN) being the most frequently occurring. For single mycotoxin risk assessment, FB1, ZEN, aflatoxin B1 (AFB1), and ochratoxin A (OTA) all showed potential adverse effects. However, for the 12 samples containing DON and ZEN, in which none had a hazard risk, the combination of both mycotoxins in two samples was considered to pose potential endocrine disrupting risks to humans by hazard index (HI) method. The combined margin of exposure (MOET) for AFB1 and FB1 could constitute a potential health concern, and AFB1 was the main contributor. Our approach provides a blueprint for evaluating the cumulative risks related to different types of mycotoxins and opens a new horizon for the accurate interpretation of epidemiological health outcomes related to multi-mycotoxin exposure.

The Role of Saccharides in the Mechanisms of Pathogenicity of Fusarium oxysporum f. sp. lupini in Yellow Lupine (Lupinus luteus L.)

The primary aim of this study was to determine the relationship between soluble sugar levels (sucrose, glucose, or fructose) in yellow lupine embryo axes and the pathogenicity of the hemibiotrophic fungus Fusarium oxysporum f. sp. Schlecht lupini. The first step of this study was to determine the effect of exogenous saccharides on the growth and sporulation of F. oxysporum. The second one focused on estimating the levels of ergosterol as a fungal growth indicator in infected embryo axes cultured in vitro on sugar containing-medium or without it. The third aim of this study was to record the levels of the mycotoxin moniliformin as the most characteristic secondary metabolite of F. oxysporum in the infected embryo axes with the high sugar medium and without it. Additionally, morphometric measurements, i.e., the length and fresh weight of embryo axes, were done. The levels of ergosterol were the highest in infected embryo axes with a sugar deficit. At the same time, significant accumulation of the mycotoxin moniliformin was recorded in those tissues. Furthermore, it was found that the presence of sugars in water agar medium inhibited the sporulation of the pathogenic fungus F. oxysporum in relation to the control (sporulation of the pathogen on medium without sugar), the strongest inhibiting effect was observed in the case of glucose. Infection caused by F. oxysporum significantly limited the growth of embryo axes, but this effect was more visible on infected axes cultured under sugar deficiency than on the ones cultured with soluble sugars. The obtained results thus showed that high sugar levels may lead to reduced production of mycotoxins by F. oxysporum, limiting infection development and fusariosis.

Parallel validation of a green-solvent extraction method and quantitative estimation of multi-mycotoxins in staple cereals using LC-MS/MS

In this study, 15 different mycotoxins were estimated in three staple cereals from selected agro-ecological regions in Nigeria using a 'novel' green extraction method, pressurized hot water extraction (PHWE) in comparison to a conventional solvent extraction method. Discrimination of the results of PHWE and solvent extraction using principal component analysis (PCA) and orthogonal projection to latent structures discriminate analysis (OPLS-DA) did not yield any differential clustering patterns. All maize samples (n = 16), 32% (n = 38) of sorghum and 35% (n = 37) of millet samples were positive for at least one of the 15 tested mycotoxins. Contamination levels for the cereals were higher in the warm humid rain forest region and gradually decreased towards the hot and arid region in the north of the country. The results demonstrate the applicability of PHWE as a possible alternative extraction method to conventional methods of extraction, which are solvent based.

A loop-mediated isothermal amplification (LAMP) based assay for the rapid and sensitive group-specific detection of fumonisin producing Fusarium spp

Fumonisins are mycotoxins that contaminate maize and maize-based food products, and feed. They have been associated with nerve system disorders in horses, pulmonary edema in swine as well as neural tube defects and esophageal cancer in humans. The fum1 gene codes for a polyketide synthase involved in the biosynthesis of fumonisins. It is present in the genomes of all fumonisin producing Fusarium spp. Reliable detection of fum1 can provide an estimate of the toxicological potential of cultures and food sources. Therefore, a fum1 specific LAMP assay was developed and tested with purified DNA of 48 different species from the Fusarium fujikuroi species complex (FFSC). The fum1 gene was detected in 22 species among which F. fujikuroi, F. globosum, F. nygamai, F. proliferatum, F. subglutinans and F. verticillioides were the most prominent fumonisin producers. None out of 92 tested non-Fusarium species showed cross reactions with the new assay. The lowest limit of detection (LOD) was 5 pg of genomic DNA per reaction for F. fujikuroi, F. nygamai and F. verticillioides. Higher LODs were found for other LAMP positive species. Apart from pure genomic DNA, the LAMP assay detected fumonisin-producers when 10³ conidia/reaction were used as template after mechanical lysis. LAMP-results were well correlated with FB1 production. This is the first report on fumonisin production in strains of F. annanatum, F. coicis, F. mundagurra, F. newnesense, F. pininemorale, F. sororula, F. tjataeba, F. udum and F. werrikimbe. Usefulness of the LAMP assay was demonstrated by analyzing fumonisin contaminated maize grains. The new LAMP assay is rapid, sensitive and reliable for the diagnosis of typical fumonisin producers and can be a versatile tool in HACCP concepts that target the reduction of fumonisins in the food and feed chain.

Health Risks Associated with Exposure to Filamentous Fungi

Filamentous fungi occur widely in the environment, contaminating soil, air, food and other substrates. Due to their wide distribution, they have medical and economic implications. Regardless of their use as a source of antibiotics, vitamins and raw materials for various industrially important chemicals, most fungi and filamentous fungi produce metabolites associated with a range of health risks, both in humans and in animals. The association of filamentous fungi and their metabolites to different negative health conditions in humans and animals, has contributed to the importance of investigating different health risks induced by this family of heterotrophs. This review aims to discuss health risks associated with commonly occurring filamentous fungal species which belong to genera Aspergillus, Penicillium and Fusarium, as well as evaluating their pathogenicity and mycotoxic properties.

Individual and combined effects of feed artificially contaminated with with fumonisin B1 and T-2 toxin in weaned rabbits

Co-contamination of feed and feed raw materials with two or more mycotoxins is frequently reported, however, only a few studies have investigated the combined effects of low doses of multiple mycotoxins. In the present study the individual and combined effects of 10 mg/kg fumonisin B1 and 2 mg/kg T-2 toxin (n=12/group) were investigated in weaned rabbits. Mycotoxin contaminated feed was produced by adding fungal cultures of Fusarium verticillioides and Fusarium sporotrichioides, and fed to 40 days old rabbits during 28 days. Feed intake and body weight were measured weekly, serum biochemistry and antioxidant parameters on day 0, 14 and 28, while histopathological examination and comet assay were performed at the end of the experiment. T-2 exposure both alone and in combination resulted in 15-18% less final body weight compared to the control and FB1 treatment. There was a significant increase in the concentration of plasma total protein, albumin, fructosamine and creatinine in the group treated with FB1 compared to the control. The liver and the kidney of most animals treated with T-2 toxin, FB1 and their combination showed pathological changes, occurring more frequent in animals exposed to both toxins. T-2 resulted in depletion of lymphocytes in the spleen. FB1 and T-2 exerted synergistic effect on the antioxidant/oxidative parameters after 2 weeks of exposure, manifesting in less glutathione and glutathione peroxidase, while more malondialdehyde was produced. Both toxins caused DNA damage in the lymphocytes, which was more pronounced in the group fed T-2 toxin and T-2 combined with FB1, without additive or synergistic effects.

Temporal changes in fungal communities from buckwheat seeds and their effects on seed germination and seedling secondary metabolism

Seed-associated fungal communities affect multiple parameters of seed quality at all stages of production, from seed development to post-harvest storage and germination. We therefore investigated the diversity and dynamics of fungal communities in the seeds of common buckwheat (Fagopyrum esculentum) and Tartary buckwheat (F. tataricum) from harvest to 1 y of storage. Fungal populations in seeds were relatively stable, comprised mainly of field fungi. Incidence of fungi was most likely determined by fungal interspecies direct interactions, as well as by their synthesis of volatile organic compounds. Most prominent antagonistic interactions were seen for two plant pathogens, Alternaria alternata on Botrytis cinerea. Detrimental effects of the fungi on seed germination and seedling development were related to fungal extracellular enzyme activity, and in particular to amylase, cellulase and, polyphenol oxidase. Polyphenol and tannin concentrations in buckwheat seedlings were related to fungal growth rate and intensity of fungal cellulase activity, respectively, which suggests that physical penetration of the fungi through the host tissues is probably the stimulus for the activation of plant defence reactions in these seedlings.

Use of a bio-wipe kit to detect fumonisin B₁ in faecal materials

Fusarium toxins with reference to fumonisin B1 (FB1) have long been regarded as contaminants of maize and maize-based related products. However, when consumed they can cause intoxication, especially in humans. Therefore, effective quantitative methods for assessing the dietary exposure of this toxic fungal metabolite are required. The objective of this investigation was to evaluate the effect on the use of a bio-wipe kit, which is a faecal material collection kit, to detect the presence of FB1. Faecal materials were collected from a rural farming community in Gauteng Province, South Africa. In total, 200 samples of faecal material were analysed for Fusarium species using a serial dilution method, while FB1 was further analysed and quantified by reversed-phase TLC and HPLC. The study showed the presence of 11 different Fusarium species grown on potato dextrose agar culture medium of which F. verticillioides and F. proliferatum, producers of FB1, and F. oxysporum were the dominant species. Fumonisin B1 was recorded at an incidence rate of 65% of the total using TLC. Results from HPLC showed that 84% were positive at different ranges of concentration for FB1. This study supports the use of a bio-wipe as a rapid method to determine human exposure to FB1.

Natural occurrence, analysis, and prevention of mycotoxins in fruits and their processed products

Mycotoxins are small toxic chemical products formed as the secondary metabolites by fungi that readily contaminate foods with toxins in the field or after harvest. The presence of mycotoxins, such as aflatoxins, ochratoxin A, and patulin, in fruits and their processed products is of high concern for human health due to their properties to induce severe acute and chronic toxicity at low-dose levels. Currently, a broad range of detection techniques used for practical analysis and detection of a wide spectrum of mycotoxins are available. Many analytical methods have been developed for the determination of each group of these mycotoxins in different food matrices, but new methods are still required to achieve higher sensitivity and address other challenges that are posed by these mycotoxins. Effective technologies are needed to reduce or even eliminate the presence of the mycotoxins in fruits and their processed products. Preventive measures aimed at the inhibition of mycotoxin formation in fruits and their processed products are the most effective approach. Detoxification of mycotoxins by different physical, chemical, and biological methods are less effective and sometimes restricted because of concerns of safety, possible losses in nutritional quality of the treated commodities and cost implications. This article reviewed the available information on the major mycotoxins found in foods and feeds, with an emphasis of fruits and their processed products, and the analytical methods used for their determination. Based on the current knowledge, the major strategies to prevent or even eliminate the presence of the mycotoxins in fruits and their processed products were proposed.

Cooccurrence of mycotoxins in maize and poultry feeds from Brazil by liquid chromatography/tandem mass spectrometry

The objective of this study was to quantitatively evaluate mycotoxins in samples of maize and poultry feed produced in Brazil. A multimycotoxin method based on HPLC-MS/MS was applied to investigate the occurrence of toxical fungal metabolites in 119 samples collected from poultry feed factory integrated poultry farms: maize grain (74), poultry feed (36), and feed factory residue (9). Twenty of 101 fungal metabolites investigated were detected and quantified in the samples: aflatoxins B₁, B₂, G₁, and G₂, fumonisins B₁, B₂, and B₃, hydrolyzed fumonisin B₁, zearalenone, agroclavine, chanoclavine, deoxynivalenol, and nivalenol, and enniatin A, A₁, B, B₁, beauvericin, kojic acid, and moniliformin. Most samples were contaminated with more than one mycotoxin. All samples were contaminated with fumonisins, with medians values of 1,840 μg/kg, 239 μg/kg, and 23,676 μg/kg for maize, feed, and factory residue samples, respectively. Surprisingly, beauvericin was detected in more than 90% of samples. The median contaminations of aflatoxin and trichothecenes were low, near LOD values. The factory residue presented highest contamination levels for all mycotoxins. This is the first study dealing with agroclavine, chanoclavine, enniatin A, A₁, B, B₁, beauvericin, and kojic acid contamination of maize and poultry feeds from Brazil.

Stable isotope dilution analysis of small molecules with carboxylic acid functions using 18O labeling for HPLC-ESI-MS/MS: analysis of fumonisin B1

(18)O labeling is a well-known method for the stable isotope labeling of proteins and peptides. This study describes a modified procedure for using (18)O labeling on small molecules. Fumonisin B1, a worldwide occurring mycotoxin, which is routinely analyzed by HPLC-MS/MS, was chosen as model compound. (18)O labeling was achieved by acid-catalyzed oxygen exchange from H2(18)O. A mixture of different isotopologues was obtained from the exchange, which, however, could be used as an internal standard for HPLC-MS/MS analysis. The identity of the (18)O-labeled fumonisin B1 was confirmed by NMR and HRMS measurements. The applicability as internal standard has been verified by comparison of results obtained from the method described in this paper to results obtained by reference methods. The presented method is of special interest as the (18)O labeling can be generally applied to a large group of small molecules containing carboxylic groups.

Effect ofin vitro digestion on fumonisin B1 in corn flakes

Low levels of fumonisins have been found frequently in corn based breakfast cereals and can occur bound to protein and other matrix components.In vitro digestion of two samples of corn flakes was carried out under "fed conditions." Fumonisins were measured as o-phthaldialdehyde/mercaptoethanol derivatives by LC-fluorescence. One sample of corn flakes (FN12) had high concentrations of fumonisin B1 (FB) (average 125 ng/g) and total bound FB1, (TB FB1) (average 92 ng/g) and the other (FN11) had a low level of free FB1 (average 29 ng/g) and no detectable TB FB1. After incubation of the samples with gastrointestinal tract solutions simulating saliva plus stomach and duodenal juices, chyme was analysed for FB1, hydrolyzed FB1 (HFB1) and partially hydrolyzed fumonisin B1 (PHFB1). The bioaccessibility (percentage of FB1 released from corn flakes into chyme) was 38-78% for incurred FB1 in FN12, 8-54% for incurred plus spiked FB1 in FN12, and 19-66% for incurred plus spiked FB1 in FN11. HFB1 and PHFB1 were not detected. If free FB1 was first extracted from sample FN12, no FB1 was detected in the chyme, indicating no contribution from TB FB1. Concentrations were corrected for method recovery of FB1 or, for bound FB1, partial method recovery of HFB1.

Contamination of barley seeds with Fusarium species and their toxins in Spain: an integrated approach

Fusarium is a globally distributed fungal genus that includes different species pathogenic to cereals among others crops. Some of these Fusarium species can also produce toxic compounds towards animals and humans. In this work, the presence of the most important Fusarium toxins was determined in barley seeds from Spain, sampled according to European Union requirements. The results obtained were compared with the presence of mycotoxigenic species considered responsible for their synthesis by using species-specific polymerase chain reaction protocols. Fumonisins B(1) and B(2), zearalenone, trichothecenes type A (T-2 and HT-2) and trichothecenes type B (deoxynivalenol and nivalenol) were analysed by using high-performance liquid chromatography. Deoxynivalenol and zearalenone were detected in 72% and 38% of the barley samples, respectively, at levels below European Union limits in all cases. However, the co-occurrence of both toxins in 34% of the samples suggested that synergistic activity of these two mycotoxins should be evaluated. Nivalenol and HT-2/T-2 were detected at low levels in 17% and 10% of the samples, respectively. Fumonisins occurred in 34% of the samples at levels up to 300 µg/kg. This suggested that they might represent a risk in Spanish barley, and to our knowledge, this is the first report on the presence of fumonisins in barley in this country. The species-specific polymerase chain reaction assays to detect mycotoxin-producing Fusarium species showed a very consistent correlation between F. verticillioides detection and fumonisin contamination as well as F. graminearum presence and zearalenone, deoxynivalenol and nivalenol contamination in barley samples. The approach used in this study provided information of mycotoxin contamination of barley together with the identification of the fungal species responsible for their production. Detection of the species with the current polymerase chain reaction assay strategy may be considered predictive of the potential mycotoxin risk in this matrix.

Genetic variation of Fusarium oxysporum isolates forming fumonisin B(1) and moniliformin

Thirty single-spore isolates of a toxigenic fungus, Fusarium oxysporum, were isolated from asparagus spears and identified by species-specific polymerase chain reaction (PCR) and translation elongation factor 1-α (TEF) sequence analysis. In the examined sets of F. oxysporum isolates, the DNA sequences of mating type genes (MAT) were identified. The distribution of MAT idiomorph may suggest that MAT1-2 is a predominant mating type in the F. oxysporum population. F. oxysporum is mainly recognised as a producer of moniliformin-the highly toxic secondary metabolite. Moniliformin content was determined by high-performance liquid chromatography (HPLC) analysis in the range 0.05-1,007.47 μg g(-1) (mean 115.93 μg g(-1)) but, also, fumonisin B(1) was detected, in the concentration range 0.01-0.91 μg g(-1) (mean 0.19 μg g(-1)). There was no association between mating types and the mycotoxins biosynthesis level. Additionally, a significant intra-species genetic diversity was revealed and molecular markers associated with toxins biosynthesis were identified.

Zearalenone removal in synthetic media and aqueous part of canned corn by montmorillonite K10 and pillared montmorillonite K10

The capacities of montmorillonite K10 (K10), aluminum pillared K10 (Al-K10), and iron pillared K10 (Fe-K10) to eliminate zearalenone (ZEN) from synthetic media and the aqueous part of canned corn were studied. Original clay and pillared clays were characterized in terms of X-ray powder diffraction analysis and N(2) adsorption-desorption isotherms. The maximum amounts of adsorption of ZEN by K10, Al-K10, and Fe-K10 at 25°C and pH 7 were 0.202, 1.305, and 1.028 mg/g and 0.264, 0.096, and 0.255 mg/g, calculated from Langmuir and Freundlich isotherms, respectively. The adsorption of ZEN was also studied as a function of adsorbent amount (1 to 30 mg), ZEN concentration (2 to 20 mg/liter), pH of solution (pH 4 to 10), and contact time. Pillared clays could be an excellent alternative for removing ZEN in contaminated food samples and are potentially low-cost adsorbents with a promising future as an alternative to more costly materials.

Levels of total fumonisins in maize samples from Italy during 2006-2008

We analysed a total of 2258 grain samples over a 3-year period (2006-2008) from 93 storage centers in the principal maize cultivation area of Italy to establish the levels of fumonisin contamination. Fumonisin concentrations were measured using ELISA (RIDASCREEN) fumonisin test kits. Mean levels of contamination were remarkably high in each year, with the highest value in 2006 (10.9 mg/kg) and the lowest in 2008 (4.8 mg/kg). Similarly, for each year, variations were quite large: from <LOQ to 77.0 mg/kg, < LOQ to 26.3, and 0.1 to 19.0 mg/kg, respectively, in 2006, 2007 and 2008. The highest fumonisin concentration was found in samples harvested in Veneto (11.1 mg/kg) and Friuli Venezia Giulia (8.9 mg/kg), while the lowest were recorded in Emilia Romagna and Piemonte (4.6 mg/kg).

Formation of fumonisins and other secondary metabolites by Fusarium oxysporum and F. proliferatum: a comparative study

The principal aim of this study was to estimate the formation of fumonisins (FB(1) and FB(2)), moniliformin (MON), and ergosterol (ERG) by Fusarium oxysporum and Fusarium proliferatum, while the formation of beauvericin (BEA) was estimated by the latter Fusarium species only. Moreover, the effect of temperature on the biosynthesis of mycotoxins was also evaluated. Fumonisins were formed by F. proliferatum, with the highest yield at 18 degrees C (720.0-1976.6 microg g(-1) for FB(1), 74.2-670.8 microg g(-1) for FB(2)) and only by three of four F. oxysporum strains at a very low level (0.02-4.77 microg g(-1) for FB(1), 0.02-2.15 microg g(-1) for FB(2)). The amount of MON formed by F. proliferatum was the highest (p < 0.001) at 32 degrees C (3056.87 microg g(-1)), while MON biosynthesis by F. oxysporum was lower 227.54 microg g(-1) (p < 0.001). BEA was produced by F. proliferatum with the highest level at 25 degrees C (p < 0.001). ERG-recognized as an indicator of fungal biomass development and as a consequence of mycotoxin formation-was found at the highest concentration at a biosynthesis temperature of 25 degrees C for F. proliferatum and F. oxysporum (p < 0.001).

Management of fumonisin contamination in maize kernels through the timing of insecticide application against the European corn borer Ostrinia nubilalis Hübner

The European corn borer (ECB), Ostrinia nubilalis, is the principal pest of maize in Central and South Europe. It is known to promote Fusarium verticillioides infection in maize grain, a recognized producer of fumonisins. Field experiments were performed in 2006 and 2007 in two sites in NW Italy to determine the effects of the timing of insecticide application on ECB damage, fungal ear rot and fumonisin contamination under natural conditions. Different insecticide application timings were compared, from maize flowering to approximately 15 days after the flight peak of adult ECB. At harvest, the ears were rated for incidence and severity of ECB damage, fungal ear rot symptoms and fumonisin (FB(1) + FB(2)) contamination. In all years/sites, treatments applied at the beginning of consistent ECB flight activity were most effective in controlling insect damage on ears. Fungal ear rot and fumonisin contamination were significantly affected by ECB control. The efficacy of the best timing of insecticide application in controlling fumonisin contamination was, on average, 93% compared to the untreated control. Contamination levels of these mycotoxins increased with either an earlier or later treatment. Furthermore, an earlier insecticide application showed lower fumonisin contamination than a treatment applied after the adult flight peak. Production of maize kernels and maize-based foods that do not exceed the maximum international and EU permitted levels for fumonisins could be enhanced by appropriate insecticide treatment against second generation ECB. The optimum time for insecticide application is between the beginning of consistent adult flight activity and the flight peak.

Timing clorpirifos + cypermethrin and indoxacarb applications to control European corn borer damage and fumonisin contamination in maize kernels

BACKGROUND

European corn borer (ECB) is the main maize pest in central and southern Europe and it promotes the infection of maize with Fusarium verticillioides, which is able to produce fumonisins. Field experiments were performed from 2006 to 2007 in northwestern Italy to determine the effects of the timing of insecticide applications on maize fungal ear rot and fumonisin contamination in natural infection conditions. Four application timings and two insecticides (clorpirifos + cypermethrin and indoxacarb) were compared each year.

RESULTS

In both years, the treatments applied at the beginning of a consistent ECB flight activity and at the flight peak showed the best efficacy to control the insect damage on ears. Fungal ear rot and fumonisin contamination were clearly affected by ECB control. The efficacy of the best application timing to control fumonisin occurrence was 73% in 2006 and 84% in 2007. Earlier insecticide applications showed lower fumonisin contamination than treatments applied after the adult flight peak.

CONCLUSION

The production of maize and maize-based foods with a low fumonisin content may be enhanced through correct insecticide application against the second ECB generation. The optimum timing of insecticides is between the beginning of a consistent adult flight activity and the flight peak.

Co-occurrence of Aflatoxins, Ochratoxin A, Fumonisins, and Zearalenone in Cereals and Feed, Determined by Competitive Direct Enzyme-Linked Immunosorbent Assay and Thin-Layer Chromatography

Aspergillus, Penicillium, andFusariumspecies frequently contaminate crops. For this reason mycotoxins such as aflatoxins (AFs), ochratoxin A (OTA), fumonisins (FBs), and zearalenone (ZEA) are found in food and feed in a wide range of concentrations, depending on environmental and storage conditions. Consumption of mycotoxin-contaminated food and feed has been associated with acute and chronic poisoning and carcinoma. The aim of this study was to determine the incidence and co-occurrence of AFs (B1+B2+G1+G2), OTA, FBs (B1+B2+B3), and ZEA in 37 samples of cereals and feed randomly collected in 2007 from households of an endemic nephropathy (EN) area in Croatia. The mycotoxins were determined using the competitive direct ELISA test (CD-ELISA) in combination with thin-layer chromatography (TLC). The most frequent mycotoxin was ZEA (92%, mean 318.3 μg kg-1), followed by FBs (27%, 3690 μg kg-1), AFs (24.3%, 4.6 μg kg-1), and OTA (16.2%, 9.8 μg kg-1). Levels of AFs, ZEA, and FBs detected by CD-ELISA significantly correlated with the TLC results. However, only one OTA-positive sample was confirmed by TLC due to its high limit of detection. The levels of these mycotoxins were below the permissible limit for animal feed. Twenty-nine percent of cereals were contaminated with FBs, OTA, or ZEA in mass fractions above the permissible limit for humans. Co-occurrence of two toxins varied between 4.2% and 54% and of three between 4.2% and 7.6%. Prolonged co-exposure to AFs, OTA, FBs, and ZEA might increase the risk of various chronic diseases.

Comparison of enzyme linked immunoassay and high performance liquid chromatography for determination of fumonisin in dried figs

The occurrence of fumonisin in dried figs was investigated by Enzyme Linked Immunoassay (ELISA) and High Performance Liquid Chromatography (HPLC). Total fumonisins (FB1, FB2, FB3) in dried figs were determined using ELISA, whereas only fumonisin B1 (FB1) was determined by HPLC. In the period 2003-2004, one hundred and fifty five dried fig samples were taken during their drying in 7 different districts in the Aegean Region. Among a total of 115 samples, the incidence of total fumonisin in the dried figs was 82% within the range of 0.16 - 108.34 mg/g when determined by ELISA. In comparison, FB1 was detected in 86 samples (74.8%) within the range between 0.046 and 3.649 mg/g by HPLC. Correlation between ELISA and HPLC methods was observed for all samples. However, no correlation between methods was recorded for the samples with less than 1 mg/g Fumonisin B1 level (obtained by HPLC). Although there was a correlation between methods for all the samples, fumonisin levels obtained by ELISA were much higher than those obtained by HPLC. False positive results were obtained by ELISA in 11 out of 115 dried fig samples. The results indicated that ELISA can be used as a screening method for determining the occurence of fumonisin in dried figs.

Fumonisins, trichothecenes and zearalenone in cereals

Fumonisins are phytotoxic mycotoxins which are synthesized by various species of the fungal genus Fusarium such as Fusarium verticillioides (Sacc.) Nirenberg (ex F.moniliforme Sheldon) and Fusarium proliferatum. The trichothecene (TC) mycotoxins are secondary metabolites produce by species that belong to several fungal genera, especially Fusarium, Stachybotrys, Trichothecium, Trichoderma, Memnoniella and Myrothecium. Fusarium mycotoxins are widely dispersed in cereals and their products. Zearalenone (ZEA) is an estrogenic compound produced by Fusarium spp. such as F. graminearum and F. culmorum. Fumonisins, the TCs and ZEA are hazardous for human and animal health. Contamination with TCs causes a number of illnesses in human and animal such as decrease in food consumption (anorexia), depression or inhibition on immune system function and haematoxicity. The purpose of this paper is to give a review of the papers published on the field of fumonisin, TC and ZEA mycotoxins in cereals consumed in the world.