Free and hidden fumonisins in raw maize and maize-based products from China

Aflatoxins and fumonisins in conventional and organic corn: a comprehensive review

This review analyzes the occurrence and co-exposure of aflatoxins and fumonisins in conventional and organic corn, and compares the vulnerability to contamination of both. The risks of fungal contamination in corn are real, mainly by the genera Aspergillus and Fusarium, producers of aflatoxins and fumonisins, respectively. Aflatoxins, especially AFB1, are related to a high incidence of liver cancer, and the International Agency Research of Cancer (IARC) classified them in group 1A 'carcinogenic to humans'. The occurrence in conventional corn is reported in many countries, including at higher levels than those established by legislation. IARC classified fumonisins in group 2B 'possibly carcinogenic to humans' due to their link with incidence of esophageal cancer. However, comparing corn and organic and conventional by-products from different regions, different results are observed. The co-occurrence of both mycotoxins is a worldwide problem; nevertheless, there is little data on the comparison of the co-exposure of these mycotoxins in corn and derivatives between both systems. It was found that the agricultural system is not a decisive factor in the final contamination, indicating the necessity of effective strategies to reduce contamination and co-exposure at levels that do not pose health risks.

The natural occurrence, toxicity mechanisms and management strategies of Fumonisin B1：A review

Fumonisin B1 (FB1) contaminates various crops, causing huge losses to agriculture and livestock worldwide. This review summarizes the occurrence regularity, toxicity, toxic mechanisms and management strategies of FB1. Specifically, FB1 contamination is particularly serious in developing countries, humid and hot regions. FB1 exposure can produce different toxic effects on the nervous system, respiratory system, digestive system and reproductive system. Furthermore, FB1 can also cause systemic immunotoxicity. The mechanism of toxic effects of FB1 is to interfere with the normal pathway of sphingolipid de novo biosynthesis by acting as a competitive inhibitor of ceramide synthase. Meanwhile, the toxic products of sphingolipid metabolic disorders can cause oxidative stress and apoptosis. FB1 also often causes feed contamination by mixing with other mycotoxins, and then exerts combined toxicity. For detection, lateral flow dipstick technology and enzyme linked immunosorbent assay are widely used in the detection of FB1 in commercial feeds, while mainstream detection methods such as high performance liquid chromatography and liquid chromatography-mass spectrometry are widely used in the laboratory theoretical study of FB1. For purification means of FB1, some natural plant extracts (such as Zingiber officinale and Litsea Cubeba essential oil) and their active compounds have been proved to inhibit the toxic effects of FB1 and protect livestock due to their antifungal and antioxidant effects. Natural plant extract has the advantages of high efficiency, low cost and no contamination residue. This review can provide information for comprehensive understanding of FB1, and provide reference for formulating reasonable treatment and management strategies in livestock production.

Recent Research on Fusarium Mycotoxins in Maize—A Review

Maize (Zea mays L.) is one of the most susceptible crops to pathogenic fungal infections, and in particular to the Fusarium species. Secondary metabolites of Fusarium spp.—mycotoxins are not only phytotoxic, but also harmful to humans and animals. They can cause acute or chronic diseases with various toxic effects. The European Union member states apply standards and legal regulations on the permissible levels of mycotoxins in food and feed. This review summarises the most recent knowledge on the occurrence of toxic secondary metabolites of Fusarium in maize, taking into account modified forms of mycotoxins, the progress in research related to the health effects of consuming food or feed contaminated with mycotoxins, and also the development of biological methods for limiting and/or eliminating the presence of the same in the food chain and in compound feed.

Matrix-associated mycotoxins in foods, cereals and feedstuffs: A review on occurrence, detection, transformation and future challenges

Matrix-associated mycotoxins that bind with macromolecular components through covalent or non-covalent interactions easily occur in various cereals, cereal-based products, and cereal-based feedstuff. They are "masked" by macro-components, causing the underestimation of total exposure risk of mycotoxins. Most of the current reports focus on the free and modified mycotoxins, while the matrix-associated forms are ignored but still can exert toxic effects after ingestion. In this paper, current researches and future prospects of matrix-associated mycotoxins are reviewed. Especially, a focus is set on the transformation of matrix-associated mycotoxins with their free forms during metabolism and food processing. Enzymes, temperature and pH levels during food processing can induce the interconversion of matrix-associated mycotoxins with free mycotoxins. Furthermore, the analytical methods targeted on matrix-associated mycotoxins are discussed. Due to the lack of efficient methods releasing the mycotoxins from matrix, the standard analytical methods has not developed so far. Also, we further analyzed the challenges of matrix-associated mycotoxins about variety, occurrence, toxicity and transformation, exposure assessment, which contributes to establish preventive measures to control their hazards for consumers. Overall, this overview is significant for perfecting risk assessment, as well as developing effective prevention and control actions to matrix-associated mycotoxins.

LC-MS/MS Analysis of Fumonisin B1, B2, B3, and Their Hydrolyzed Metabolites in Broiler Chicken Feed and Excreta

An accurate, reliable, and specific method was developed for the quantitative determination of fumonisins B1, B2, B3, and their hydrolyzed metabolites, HFB1, HFB2, and HFB3, in broiler chicken feed and excreta using ultra-performance liquid chromatography combined with tandem mass spectrometry (UPLC-MS/MS). The samples were extracted and diluted for the determination of parent fumonisins. Another portion of the extracted samples was alkaline-hydrolyzed and cleaned using a strong anionic exchange adsorbent (MAX) for the determination of hydrolyzed fumonisins. Chromatographic separation was performed on a CORTECS C18 column (2.1 mm × 100 mm, 1.6 μm) using 0.2% formic acid aqueous solution and methanol with 0.2% formic acid as the mobile phase under gradient elution. The six fumonisins, FB1, FB2, FB3, HFB1, HFB2, and HFB3, were analyzed by tandem mass spectrometry using multiple-reaction monitoring (MRM) mode. The six fumonisins showed good linearity, with relative coefficients of r > 0.99. The limits of quantitation (LOQs) were 160 μg/kg. At the low, medium, and high spiked levels, the recovery of fumonisins in chicken feed and excreta ranged from 82.6 to 115.8%, with a precision (RSD) of 3.9–18.9%. This method was successfully applied to investigate the migration and transformation of fumonisins in broiler chickens.

Experimental Study on the Status of Maize Mycotoxin Production in Farmers' Grain Storage Silos in Northeastern China

The scientific rationality of farmers' grain storage technology and equipment is crucial for the biosecurity of grain in the main grain-producing areas represented by Northeast China. In this paper, four farmer grain storage mock silos of different widths were used as a means to track an experimental cycle of grain storage. The absolute water potential of corn in all four silos at the beginning of the experiment was greater than the absolute water potential of air, prompting moisture migration from the grain interior to the air and down to about 14%. Moisture was influenced by wind direction, and moisture decreased faster with better ventilation on both sides of the grain silos. Therefore, grain silo width has a significant effect on the drying effect under naturally ventilated conditions of maize ears. This research focused on the determination and assessment of mycotoxin contamination under farmers' storage grain conditions and analyzed the effect of silo structure on the distribution of mycotoxin contamination. When the width was too large, areas of high mycotoxin infection existed in the middle of the grain silo, and ventilation and tipping could be used to reduce the risk of toxin production. This study proved that reasonable farmer grain storage techniques and devices in Northeast China can effectively protect grain from mycotoxin contamination.

Molecular toxicology and carcinogenesis of fumonisins: a review

Fumonisins, discovered in 1988 are a group of naturally occurring toxins produced by fusarium pathogenic fungi. Besides their presence in animal feeds, contamination of human foods such as corn, millet, oats, rye, barley, wheat and their products are widespread. Exposure to fumonisins results in species and organ specific toxicities including neurological disorders among equids, pulmonary edema in swine, esophageal cancer in humans and both kidney and liver related toxicities in rodents. This review seeks to consolidate groundbreaking research on the science of fumonisins toxicity, highlight recent progress on fumonisins research, and provide an overview of plausible mechanistic biomarkers for fumonisins exposure assessment.

Aptamer-Target-Gold Nanoparticle Conjugates for the Quantification of Fumonisin B1

Fumonisin B1 (FB1), a mycotoxin classified as group 2B hazard, is of high importance due to its abundance and occurrence in varied crops. Conventional methods for detection are sensitive and selective; however, they also convey disadvantages such as long assay times, expensive equipment and instrumentation, complex procedures, sample pretreatment and unfeasibility for on-site analysis. Therefore, there is a need for quick, simple and affordable quantification methods. On that note, aptamers (ssDNA) are a good alternative for designing specific and sensitive biosensing techniques. In this work, the assessment of the performance of two aptamers (40 and 96 nt) on the colorimetric quantification of FB1 was determined by conducting an aptamer-target incubation step, followed by the addition of gold nanoparticles (AuNPs) and NaCl. Although MgCl₂ and Tris-HCl were, respectively, essential for aptamer 96 and 40 nt, the latter was not specific for FB1. Alternatively, the formation of Aptamer (96 nt)-FB1-AuNP conjugates in MgCl₂ exhibited stabilization to NaCl-induced aggregation at increasing FB1 concentrations. The application of asymmetric flow field-flow fractionation (AF4) allowed their size separation and characterization by a multidetection system (UV-VIS, MALS and DLS online), with a reduction in the limit of detection from 0.002 µg/mL to 56 fg/mL.

Mycotoxins Analysis in Cereals and Related Foodstuffs by Liquid Chromatography-Tandem Mass Spectrometry Techniques

In the entire world, cereals and related foodstuffs are used as an important source of energy, minerals, and vitamins. Nevertheless, their contamination with mycotoxins kept special attention due to harmful effects on human health. The present paper was conducted to evaluate published studies regarding the identification and characterization of mycotoxins in cereals and related foodstuffs by liquid chromatography coupled to (tandem) mass spectrometry (LC-MS/MS) techniques. For sample preparation, published studies based on the development of extraction and clean-up strategies including solid-phase extraction, solid-liquid extraction, and immunoaffinity columns, as well as on methods based on minimum clean-up (quick, easy, cheap, effective, rugged, and safe (QuEChERS)) technology, are examined. LC-MS/MS has become the golden method for the simultaneous multimycotoxin analysis, with different sample preparation approaches, due to the range of different physicochemical properties of these toxic products. Therefore, this new strategy can be an alternative for fast, simple, and accurate determination of multiclass mycotoxins in complex cereal samples.

[Assessment of Modified Forms of Fumonisins in Corn-Based Products Retailed in Japan by an Alkaline Hydrolysis Method]

Fumonisins, which are secondary metabolites produced by some Fusarium species, are detected mainly in corn and corn-based products. Recently, the presence of modified forms of fumonisins in fumonisin-contaminated food products has been reported. In order to evaluate the health risk of modified forms of fumonisins to the Japanese population, we analyzed modified forms of fumonisins in corn-based products retailed in Japan. The modified and free forms of fumonisins in food samples were hydrolyzed by alkaline treatment. The resulting hydrolyzed fumonisins were quantified by LC-MS/MS, and total fumonisins (sum of modified and free forms) was calculated. A total of 166 samples of corn-based products were analyzed over two years. The relative ratios of mean total fumonisins to mean free fumonisins in the cornflakes, corn snacks, corn flour and powdered corn soup samples were 4.7, 2.8, 2.1 and 1.2, respectively. Total fumonisins in the residual solid of five cornflake and three corn snack samples obtained after extraction with methanol-water (3 : 1) were quantified. In the cornflakes and corn snacks samples, 56-72 and 83-98% of the modified forms of fumonisins were present in the residual solid, respectively. The average daily intake of fumonisins from cornflakes and corn snacks by the Japanese population was estimated at 1.1 to 3.9 ng/kg body weight/day when the results of free fumonisins were used for the estimate, but when the results of total fumonisins were used, average daily intake increased about three times and was estimated at 3.3 to 12.5 ng/kg body weigh/day. These results indicate that a risk assessment of fumonisins, including the modified forms of fumonisins, is necessary in order to evaluate the true risk of fumonisins to Japanese people.

Mycotoxins in cereals and cereal-based products: Incidence and probabilistic dietary risk assessment for the Brazilian population

A probabilistic dietary risk assessment on mycotoxins was conducted using the Monte Carlo Risk Assessment software, with consumption data from the 2008/2009 Brazilian Household Budget Survey for individuals who were at least 10 years old and occurrence data for 646 samples of rice, maize, wheat, and their products, collected in the Federal District and in the state of Rio Grande do Sul, Brazil. Processing factors were estimated and applied to concentration data. Chronic exposure was estimated for fumonisins (free and bound/hidden), deoxynivalenol (DON) (including the acetylated forms) and zearalenone (ZON) (including alfa-zearalenol) and acute exposure was estimated for DON. For the general population, the chronic exposure exceeded the safe exposure levels at the 95P for DON and at the 99P for fumonisins. Additionally, safe level exceedance occurred at the 97.5P for fumonisins and at the 95P for DON for teenagers, as well as at the 99P for fumonisins for women of child-bearing-age. No exceedances were found for chronic exposure to ZON and acute exposure to DON. Maize couscous contributed most of the total fumonisins (91%) and ZON intakes (~40%) and bread to total intake of DON (~30%). Further studies should be conducted with updated Brazilian consumption data, which should include information for individuals aged less than 10 years old.

Competitive HRP-Linked Colorimetric Aptasensor for the Detection of Fumonisin B1 in Food based on Dual Biotin-Streptavidin Interaction

Fumonisin B1 (FB1) is the most prevalent and toxic form among fumonisin homologues which are produced by fusarium species and it contaminates various types of food products, posing serious health hazards for humans and animals. In this work, a colorimetric assay for the detection of FB1 has been developed based on competitive horseradish peroxidase (HRP)-linked aptamer and dual biotin-streptavidin interaction. In short, a biotinylated aptamer of FB1 was immobilized on the microplate by biotin-streptavidin binding; the complementary strand (csDNA) of the aptamer was ligated with HRP by biotin-streptavidin binding again to form a csDNA-HRP sensing probe, competing with FB1 to bind to the aptamer. The color change can be observed after the addition of chromogenic and stop solution, thereby realizing the visual detection of FB1. Under optimal conditions, good linearity was observed within the concentration range of 0.5 to 300 ng/mL, with a detection of limit of 0.3 ng/mL. This assay is further validated by spike recovery tests towards beer and corn samples, it provides a simple, sensitive and reliable method for the screening of FB1 in food samples and may be potentially used as an alternative to conventional assays.

Free and hidden fumonisins in Argentinean raw maize samples

The concentrations of free fumonisins (FBs) and hydrolysed fumonisins (HFBs) were determined in 72 maize samples collected in 2017 from five Argentine provinces. The methodology for HFBs analysis consisted of alkaline hydrolysis followed by high performance liquid chromatography with a fluorescence detector (HPLC-FLD). The developed analytical methodology presented percentages of recovery greater than 74%. Limits of detection were 4.5, 13.0 and 12.9 μg/kg for HFB1, HFB2 and HFB3, respectively. Presence of FBs was found in 86% of the samples. In all cases, the concentration of total HFBs (after the hydrolysis treatment) was superior to the free FBs content (HFBs to FBs median ratio of 2.5), which indicates the presence of hidden fumonisins in Argentinean maize. 8% of the traditionally analysed samples exceeded the limit established by the European Commission for FB1 + FB2. When applying alkaline hydrolysis to the samples, 24% of them exceed this limit.

Development of an IgY-based lateral flow immunoassay for detection of fumonisin B in maize

Fumonisin is one of the most prevalent mycotoxins in maize, causing substantial economic losses and potential health risks in human and animals. In the present study, in-house polyclonal IgY antibody against fumonisin group B (FB) was applied for the development of a competitive lateral flow immunoassay detecting these mycotoxins in maize grains with the limit of detection of 4000 µg/kg, which corresponds to the maximum residue limit adopted by The International Codex Alimentarius Commission. To this end, factors affecting the test performance including nitrocellulose membrane type, dilution factor of maize homogenates in running buffer, amount of detection conjugate, and incubation time between detection conjugate and samples were optimized. Under the optimal condition (UniSart ^®CN140 nitrocellulose membrane, FB ₁-BSA immobilized at 1 µg/cm, 1:10 dilution factor, 436 ng of gold nanoparticle conjugate, 30 minutes of incubation), the developed test could detect both FB ₁ and FB ₂ in maize with limit of detection of 4000 µg/kg, and showed no cross-reactivity to deoxynivalenol, ochratoxin A, aflatoxin B1 and zearalenone. When applied to detect FB ₁ and FB ₂ in naturally contaminated maize samples, results obtained from the developed assay were in good agreement with those from the high-performance liquid chromatography method. This lateral flow immunoassay is particularly suitable for screening of fumonisins in maize because of its simplicity and cost-effectiveness.

Development of an IgY-based lateral flow immunoassay for detection of fumonisin B in maize

Fumonisin is one of the most prevalent mycotoxins in maize, causing substantial economic losses and potential health risks in human and animals. In the present study, in-house polyclonal IgY antibody against fumonisin group B (FB) was applied for the development of a competitive lateral flow immunoassay detecting these mycotoxins in maize grains with the limit of detection of 4000 µg/kg, which corresponds to the maximum residue limit adopted by The International Codex Alimentarius Commission. To this end, factors affecting the test performance including nitrocellulose membrane type, dilution factor of maize homogenates in running buffer, amount of detection conjugate, and incubation time between detection conjugate and samples were optimized. Under the optimal condition (UniSart ®CN140 nitrocellulose membrane, FB 1-BSA immobilized at 1 µg/cm, 1:10 dilution factor, 436 ng of gold nanoparticle conjugate, 30 minutes of incubation), the developed test could detect both FB 1 and FB 2 in maize with limit of detection of 4000 µg/kg, and showed no cross-reactivity to deoxynivalenol, ochratoxin A, aflatoxin B1 and zearalenone. When applied to detect FB 1 and FB 2 in naturally contaminated maize samples, results obtained from the developed assay were in good agreement with those from the high-performance liquid chromatography method. This lateral flow immunoassay is particularly suitable for screening of fumonisins in maize because of its simplicity and cost-effectiveness.