Toxin Contamination Research Articles

Distribution of Harmful Algal Growth-Limiting Bacteria on Artificially Introduced Ulva and Natural Macroalgal Beds

The intensity and frequency of harmful algal blooms (HABs) have increased, posing a threat to human seafood resources due to massive kills of cultured fish and toxin contamination of bivalves. In recent years, bacteria that inhibit the growth of HAB species were found to be densely populated on the biofilms of some macroalgal species, indicating the possible biological control of HABs by the artificial introduction of macroalgal beds. In this study, an artificially created Ulva pertusa bed using mobile floating cages and a natural macroalgal bed were studied to elucidate the distribution of algal growth-limiting bacteria (GLB). The density of GLB affecting fish-killing raphidophyte Chattonella antiqua, and two harmful dinoflagellates, were detected between 106 and 107 CFU g−1 wet weight on the biofilm of artificially introduced U. pertusa and 10 to 102 CFU mL−1 from adjacent seawater; however, GLB found from natural macroalgal species targeted all tested HAB species (five species), ranging between 105 and 106 CFU g−1 wet weight in density. These findings provide new ecological insights of GLB at macroalgal beds, and concurrently demonstrate the possible biological control of HABs by artificially introduced Ulva beds.

Is Disease Intensity a Good Surrogate for Yield Loss or Toxin Contamination? A Case Study with Fusarium Head Blight of Wheat.

Sometimes plant pathologists assess disease intensity when they are primarily interested in other response variables, such as yield loss or toxin concentration in harvested products. In these situations, disease intensity potentially could be considered a surrogate of yield or toxin. A surrogate is a variable which can be used instead of the variable of interest in the evaluation of experimental treatments or in making predictions. Surrogates can be measured earlier, more conveniently, or more cheaply than the variable of primary interest, but the reliability or validity of the surrogate must be shown. We demonstrate ways of quantifying two facets of surrogacy by using a protocol originally developed by Buyse and colleagues for medical research. Coefficient-of-determination type statistics can be used to conveniently assess the strength of surrogacy on a unitless scale. As a case study, we evaluated whether field severity of Fusarium head blight (i.e., FHB index) can be used as a surrogate for yield loss and deoxynivalenol (DON) toxin concentration in harvested wheat grain. Bivariate mixed models and corresponding approximations were fitted to data from 82 uniform fungicide trials conducted from 2008 to 2013. Individual-level surrogacy-for predicting the variable of interest (yield or DON) from the surrogate (index) in plots with the same treatment-was very low. Trial-level surrogacy-for predicting the effect of treatment (e.g., mean difference) for the variable of interest based on the effect of the treatment on the surrogate (index)-was moderate for yield, and only low for DON. Challenges in using disease severity as a surrogate for yield and toxin are discussed.

Fusarium Head Blight, Mycotoxins and Strategies for Their Reduction

Mycotoxins are secondary metabolites of microscopic fungi, which commonly contaminate cereal grains. Contamination of small-grain cereals and maize with toxic metabolites of fungi, both pathogenic and saprotrophic, is one of the particularly important problems in global agriculture. Fusarium species are among the dangerous cereal pathogens with a high toxicity potential. Secondary metabolites of these fungi, such as deoxynivalenol, zearalenone and fumonisin B1 are among five most important mycotoxins on a European and world scale. The use of various methods to limit the development of Fusarium cereal head diseases and grain contamination with mycotoxins, before and after harvest, is an important element of sustainable agriculture and production of safe food. The applied strategies utilize chemical and non-chemical methods, including agronomic, physical and biological treatments. Biological methods now occupy a special place in plant protection as an element of biocontrol of fungal pathogens by inhibiting their development and reducing mycotoxins in grain. According to the literature, Good Agricultural Practices are the best line of defense for controlling Fusarium toxin contamination of cereal and maize grains. However, fluctuations in weather conditions can significantly reduce the effectiveness of plants protection methods against infection with Fusarium spp. and grain accumulation of mycotoxins.

Phenyllactic Acid Produced by Geotrichum candidum Reduces Fusarium sporotrichioides and F. langsethiae Growth and T-2 Toxin Concentration.

Fusariumsporotrichioides and F. langsethiae are present in barley crops. Their toxic metabolites, mainly T-2 toxin, affect the quality and safety of raw material and final products such as beer. Therefore, it is crucial to reduce Fusarium spp. proliferation and T-2 toxin contamination during the brewing process. The addition of Geotrichum candidum has been previously demonstrated to reduce the proliferation of Fusarium spp. and the production of toxic metabolites, but the mechanism of action is still not known. Thus, this study focuses on the elucidation of the interaction mechanism between G. candidum and Fusarium spp. in order to improve this bioprocess. First, over a period of 168 h, the co-culture kinetics showed an almost 90% reduction in T-2 toxin concentration, starting at 24 h. Second, sequential cultures lead to a reduction in Fusarium growth and T-2 toxin concentration. Simultaneously, it was demonstrated that G. candidum produces phenyllactic acid (PLA) at the early stages of growth, which could potentially be responsible for the reduction in Fusarium growth and T-2 toxin concentration. To prove the PLA effect, F. sporotrichioides and F. langsethiae were cultivated in PLA supplemented medium. The expected results were achieved with 0.3 g/L of PLA. These promising results contribute to a better understanding of the bioprocess, allowing its optimization at an up-scaled industrial level.

Harmful algal blooms and associated fisheries damage in East Asia: Current status and trends in China, Japan, Korea and Russia

Occurrences of harmful algal blooms (HABs) and associated fisheries damage have been continuously monitored since the 1970s along the coasts of East Asia. Fisheries damage comprises mass mortalities of fish and shellfish mainly by harmful dinoflagellates and raphidophytes (e.g., Chattonella antiqua/marina, Cochlodinium polykrikoides and Karenia mikimotoi), and contamination of algal toxins in shellfish in particular Diarrhetic Shellfish Toxins by Dinophysis spp. and Paralytic Shellfish Toxins by Alexandrium spp. Shellfish mass mortalities due to Heterocapsa circularisquama in Hong Kong and western Japan, and fish kills by Karlodinium digitatum are unique incidents for this region, whereas C. antiqua/marina, C. polykrikoides and K. mikimotoi are common also in other regions. Time series data showed that the highest bloom numbers were recorded in 1980 (Japan), in 1998 (Korea) and in 2003 (China), followed by decreasing trends in these countries. These data suggest a shift in microalgal species composition, from dominance by diatoms to dinoflagellates after 1980s in Korea, and from diatoms to small haptophytes and cyanobacteria after 2013 in eastern Russia. HAB species composition and the changes were compared among countries, for better understanding on current status and trend of HAB species in East Asia.

Losses in the Grain Supply Chain: Causes and Solutions

Global grain production needs a significant increase in output in the coming decades in order to cover the food and feed consumption needs of mankind. As sustainability is the key factor in production, the authors investigate global grain production, the losses along the value chain, and future solutions. Global wheat, maize, rice, and soybean production peaked at 2.102 million tons (mt) of harvested grain in 2018. Pre-harvest losses due to diseases, animal pests, weeds, and abiotic stresses and harvest destroy yearly amount to about 35% of the total possible biological product of 3.153 mt, with 1051.5 mt being lost before harvest. The losses during harvest and storage through toxin contamination are responsible for 690 mt, with a total of 1.741 mt or 83% of the total newly stored grain. Limited cooperation can be experienced between scientific research, plant breeding, plant protection, agronomy, and society, and in addition, their interdependence is badly understood. Plant breeding can help to reduce a significant part of field loss up to 300 mt (diseases, toxins, water and heat stress) and up to 220 mt during storage (toxin contamination). The direct and indirect impact of pest management on production lead to huge grain losses. The main task is to reduce grain losses during production and storage and consumption. Better harvest and storage conditions could prevent losses of 420 mt. The education of farmers by adopting the vocational school system is a key issue in the prevention of grain loss. In addition, extension services should be created to demonstrate farmers crop management in practice. A 50% reduction of grain loss and waste along the value chain seems to be achievable for the feeding 3–4 billion more people in a sustainable way without raising genetic yields of crop cultivars.

Current PCR-based methods for the detection of mycotoxigenic fungi in complex food and feed matrices

Mycotoxins are toxic secondary fungal metabolites produced by certain types of filamentous fungi, such asAspergillus, Fusarium, andPenicillium spp. Mycotoxigenic fungi and their produced mycotoxins are considered to be an important issue in food and feed safety due to their toxic effects like carcinogenicity, immunosuppression, neurotoxicity, nephrotoxicity, and hepatotoxicity on humans and animals. To boost the safety level of food and feedstuff, detection and identification of toxins are essential at critical control points across food and feed chains. Zero-tolerance policies by the European Union and other organizations about the extreme low level of tolerance of mycotoxins contamination in food and feed matrices have led to an increasing interest to design more sensitive, specific, rapid, cost-effective, and safer to use mycotoxigenic fungi detection technologies. Hence, many mycotoxigenic fungi detection technologies have been applied to measure and control toxins contamination in food and feed substrates. PCR-based mycotoxigenic fungi detection technologies, such as conventional PCR, real-time PCR, nested PCR, reverse transcriptase (RT)-PCR, loop-mediated isothermal amplification (LAMP),in situ PCR, polymerase chain reaction-denaturing gradient gel electrophoresis (PCR DGGE), co-operational PCR, multiplex PCR, DNA arrays, magnetic capture-hybridization (MCH)-PCR and restriction fragment length polymorphism (RFLP), would contribute to our understanding about different mycotoxigenic fungi detection approaches and will enhance our capability about mycotoxigenic fungi identification, isolation and characterization at critical control points across food and feed chains. We have assessed the principles, results, the limit of detection, and application of these PCR-based detection technologies to alleviate mycotoxins contamination problem in complex food and feed substrates. The potential application of these detection technologies can reduce mycotoxins in complex food and feed matrices.

Graphene-Based Steganographic Aptasensor for Information Computing and Monitoring Toxins of Biofilm in Food.

Fungi-forming biofilm would produce various toxins in food. The toxin contamination will cause great harm to food and human health. Herein, a novel graphene-based steganographic aptasensor was assembled for multifunctional applications, which depended on the specific recognition and information encoding ability of DNA aptamers [mycotoxins, including zearalenone (ZEN) and ochratoxin A (OTA) aptamers, as models] and the selective absorption and fluorescence quenching capacities of graphene oxide (GO). The graphene-based steganographic aptasensor can be regarded as an information encryption and steganographic system using GO as a cover, aptamers for specific target recognition as information carriers and dual targets (ZEN and OTA) as special keys. In our work, the fluorescence of capture probes (Cy3 aptamer and Alexa Fluor 488 aptamer) was quenched by GO to realize information encryption. In the presence of dual targets in the GO–APT solution, Cy3 aptamer (APT1), and Alexa Fluor 488 aptamer (APT2) were released from the surface of GO, decrypting the hidden information. In addition, our work offers a sensor for rapid and sensitive simultaneous fluorescence determination of ZEN and OTA. The detection limit of the aptasensor was 1.797 ng/ml for ZEN and 1.484 ng/ml for OTA. In addition, the graphene-based steganographic aptasensor can be used to construct a molecular logic gate system in which GO, aptamers, and mycotoxins are employed as the input and compounds and fluorescence signals were used as the output. This would be helpful to control the biofilm toxin in the future.

Isolation and Identification of Fungal Species in Kurdish Walnut Morphologically and using some Molecular Technique.

Walnuts are world widely consumed in many local dishes in southeast Asian countries, especially in Iraq-Kurdistan-Tawella which is one of the major walnut cultivars area in this region, particularly in Hawraman region. Three species of filamentous fungi Asperagillus were identified in this study including A. niger, A. flavus, A. parasiticus and in walnut product including (salted walnut). Therefore, Aspergillus species, which produced a significant amount of aflatoxin, ochratoxin and T2- toxin contamination in walnuts during storage are becoming major concerns due to the insufficient condition that favors the growth of aflatoxigenic and ochratoxigenic fungi. The current study thus aimed to morphologically and molecularly identify and characterize the A. niger, A. Flavi, A. parasiticus isolated from Kurdish walnuts and its product. The DNA isolation from all fungal species wee r from agar cultures after inoculating and purifying for more times by using commercial kit (Bio basic INC kit). Agarose gel electrophoresis fractionation of the fungi DNA, showed clear individual bands. A. niger distinct band is 500 bp, A. flavus and A. parasiticus distinct band is 1032 bp. ELISA technique was applied for detection quantitatively for aflatoxin, ochratoxin and T2 toxin in Kurdish walnut. As stated in table two the result of ELISA method used for quantitative detection of aflatoxin, ochratoxin and T2 toxin is 5.9, 10.4 and 129 part per billion ppb respectively, it is safety range for all toxins.

How to Avoid Toxigenic Problems in Animal Husbandry?

All mistakes in plant breeding, plant production, storage will be manifested in the animal husbandry and will become a veterinary problem with far reaching economic consequences. The managing of the field originated toxins is far not enough because the cleaning losses are high, toxin binding is only moderately effective and expensive and this is valid for the use of antibiotics. We should prevent toxin contamination in the field as far it is possible with varieties and hybrids with higher and increasing resistance, better agronomy and plant protection. A well-organized harvest (separation of the grain according toxin contamination), excellent storage facilities and management are also highly important. The veterinary side can be successful when cooperates with the breeding and production and delivers the results supporting better limits for toxins and support extensive prevention also in the government.

Wheat cleaning and milling technologies to reduce DON toxin contamination

Mycotoxicosis caused by Fusarium fungi holds a huge risk considering economic and food safety issues worldwide. By applying milling technologies, we attempted to reduce the concentrates of DON toxin, as it is the most often found toxin in wheat.
 The processes of sieving, aspiration and combination had been used on wheat with high DON toxin concentration. As a next step, grains were sorted using a horizontal cylinder separator, assorted by an optical and a gravity separator, and finally, the products were scoured and ground. The contamination level of the wheat and flour samples were defined by the HPLC-MS method.
 Regarding the results, it can be stated that toxin concentration was most effectively reduced by optical separation and scouring, and by applying these milling techniques, food safety can be increased significantly.

Critical Assessment of Streptomyces spp. Able to Control Toxigenic Fusaria in Cereals: A Literature and Patent Review.

Mycotoxins produced by Fusarium species on cereals represent a major concern for food safety worldwide. Fusarium toxins that are currently under regulation for their content in food include trichothecenes, fumonisins, and zearalenone. Biological control of Fusarium spp. has been widely explored with the aim of limiting disease occurrence, but few efforts have focused so far on limiting toxin accumulation in grains. The bacterial genus Streptomyces is responsible for the production of numerous drug molecules and represents a huge resource for the discovery of new molecules. Streptomyces spp. are also efficient plant colonizers and able to employ different mechanisms of control against toxigenic fungi on cereals. This review describes the outcomes of research using Streptomyces strains and/or their derived molecules to limit toxin production and/or contamination of Fusarium species in cereals. Both the scientific and patent literature were analyzed, starting from the year 2000, and we highlight promising results as well as the current pitfalls and limitations of this approach.

Use of Competitive Filamentous Fungi as an Alternative Approach for Mycotoxin Risk Reduction in Staple Cereals: State of Art and Future Perspectives.

Among plant fungal diseases, those affecting cereals represent a huge problem in terms of food security and safety. Cereals, such as maize and wheat, are very often targets of mycotoxigenic fungi. The limited availability of chemical plant protection products and physical methods to control mycotoxigenic fungi and to reduce food and feed mycotoxin contamination fosters alternative approaches, such as the use of beneficial fungi as an active ingredient of biological control products. Competitive interactions, including both exploitation and interference competition, between pathogenic and beneficial fungi, are generally recognized as mechanisms to control plant pathogens populations and to manage plant diseases. In the present review, two examples concerning the use of competitive beneficial filamentous fungi for the management of cereal diseases are discussed. The authors retrace the history of the well-established use of non-aflatoxigenic isolates of Aspergillus flavus to prevent aflatoxin contamination in maize and give an overview of the potential use of competitive beneficial filamentous fungi to manage Fusarium Head Blight on wheat and mitigate fusaria toxin contamination. Although important steps have been made towards the development of microorganisms as active ingredients of plant protection products, a reasoned revision of the registration rules is needed to significantly reduce the chemical based plant protection products in agriculture.

Multi-species okadaic acid contamination and human poisoning during a massive bloom of Dinophysis acuminata complex in southern Brazil

On June 2016, a major bloom of Dinophysis acuminata complex was noticed over the coast of Paraná State (PR), southern Brazil, an area unprotected by any official monitoring program. Here we report the results of an extensive sampling effort that ultimately led PR authorities to issue the first State shellfish-harvesting ban due to multi-species okadaic acid (OA) contamination. During its peak, the bloom covered an area of 201 km2 (∼2.0–3.5 × 54.0 km), attaining unprecedentedly high cell densities along the shallow (<15 m) continental shelf (mean 2.2 × 105, maximum 2.1 × 106 cells L−1) and adjacent sandy beaches (mean 2.8 × 105, maximum 5.2 × 106 cells L−1). Only OA was detected in suspension (max. 188 ng L−1). Toxin levels measured in bivalves were several times greater than the regulatory limit of 160 ng g−1, reaching up to 3600 ng g−1 in Crassostrea gasar, by far the highest OA concentrations ever reported in oysters worldwide, 7700 ng g−1 in brown mussels, Perna perna, and lower levels in clams, Anomalocardia brasiliana, and mangrove mussels, Mytella spp. Nine cases of human intoxication were officially reported and five people were hospitalized with typical symptoms of Diarrhetic Shellfish Poisoning linked to the consumption of contaminated bivalves. All bivalves quickly converted most of the OA into its esterified form, DTX-3, and eliminated the toxins only a few weeks following the bloom, with C. gasar being the slowest-detoxifying species. Lower OA levels were accumulated in zooplankton, gastropods and several novel toxin vectors, including benthic organisms such as sand dollars Mellita quinquiesperforata and the ghost-shrimp Callichirus major, which may act as a good indicator of the presence of toxins in sandy beaches, and pelagic fish species that can serve as potential alternative sources of OA to humans (Chaetodipterus faber and Mugil liza). Monitoring toxin contamination in seafood other than bivalves is thus recommended to ensure comprehensive human health protection during massive Dinophysis blooms. Additionally, since OA was also present at low concentrations in the liver of Guiana dolphins Sotalia guianensis and penguins Spheniscus magellanicus, exposure to biotoxins should be considered in conservation actions involving threatened and near-threatened marine organisms in this region.

Heterologous Hyaluronic Acid Production in Kluyveromyces lactis.

Hyaluronic Acid (HA) is a biopolymer composed by the monomers Glucuronic Acid (GlcUA) and N-Acetyl Glucosamine (GlcNAc). It has a broad range of applications in the field of medicine, being marketed between USD 1000–5000/kg. Its primary sources include extraction of animal tissue and fermentation using pathogenic bacteria. However, in both cases, extensive purification protocols are required to prevent toxin contamination. In this study, aiming at creating a safe HA producing microorganism, the generally regarded as safe (GRAS) yeast Kluyveroymyces lactis is utilized. Initially, the hasB (UDP-Glucose dehydrogenase) gene from Xenopus laevis (xlhasB) is inserted. After that, four strains are constructed harboring different hasA (HA Synthase) genes, three of humans (hshasA1, hshasA2, and hshasA3) and one with the bacteria Pasteurella multocida (pmhasA). Transcript values analysis confirms the presence of hasA genes only in three strains. HA production is verified by scanning electron microscopy in the strain containing the pmHAS isoform. The pmHAS strain is grown in a 1.3 l bioreactor operating in a batch mode, the maximum HA levels are 1.89 g/L with a molecular weight of 2.097 MDa. This is the first study that reports HA production in K. lactis and it has the highest HA titers reported among yeast.

Influence of Two Garlic-Derived Compounds, Propyl Propane Thiosulfonate (PTS) and Propyl Propane Thiosulfinate (PTSO), on Growth and Mycotoxin Production by Fusarium Species In Vitro and in Stored Cereals.

Two garlic-derived compounds, Propyl Propane Thiosulfonate (PTS) and Propyl Propane Thiosulfinate (PTSO), were examined for their efficacy against mycotoxigenic Fusarium species (F. graminearum, F. langsethiae, F. verticillioides). The objectives were to assess the inhibitory effect of these compounds on growth and mycotoxin production in vitro, and in situ in artificially inoculated wheat, oats and maize with one isolate of each respectively, at different water activity (aw) conditions when stored for up to 20 days at 25 °C. In vitro, 200 ppm of either PTS or PTSO reduced fungal growth by 50–100% and mycotoxin production by >90% depending on species, mycotoxin and aw conditions on milled wheat, oats and maize respectively. PTS was generally more effective than PTSO. Deoxynivalenol (DON) and zearalenone (ZEN) were decreased by 50% with 80 ppm PTSO. One-hundred ppm of PTS reduced DON and ZEN production in wheat stored at 0.93 aw for 20 days, although contamination was still above the legislative limits. Contrasting effects on T-2/HT-2 toxin contamination of oats was found depending on aw, with PTS stimulating production under marginal conditions (0.93 aw), but at 0.95 aw effective control was achieved with 100 ppm. Treatment of stored maize inoculated with F. verticilliodies resulted in a stimulation of total fumonsins in most treatments. The potential use of such compounds for mycotoxin control in stored commodities is discussed.

Risk assessment for mycotoxin contamination in fish feeds in Europe

Mycotoxins are difficult to monitor continuously, and a tool to assess the risk would help to judge if there is a particular risk due to the inclusion of certain feed ingredients. For this, the toxin contents of 97 commercial fish feeds have been estimated, and the most prominent toxins in fish feed are calculated to be deoxynivalenol, zearalenone, fumonisins and enniatins. These pose a risk to fish well-being, as can be calculated by the Bayesian models for determining the critical concentrations 5% (CC5) for the different toxins. Besides fishmeal, wheat, soybean products and corn are regularly used as fish feed ingredients. The calculated scenarios show that fish are at high risk of toxin contamination if feed ingredients of low quality are chosen for feed production. Due to this, specific maximum allowable levels for several mycotoxins in fish feeds should be established.

Plasma frio: una alternativa para reducir la viabilidad de los conidios de Aspergillus flavus presentes en granos de lenteja

Microbiological food safety is a major issue and the genus Aspergillus is of great interest given the frequency of its toxin contamination in grains. This paper describes the use of cold plasma generated with argon and a mixture of argonnitrogen as a method of sanitizing lentil beans. Lentil beans were sanitized and exposed to Aspergillus flavus conidia then four different experimental sets were prepared, using only argon and a mixture of argon-nitrogen to generate plasma at nitrogen flow rates of 1.2, 0.81 and 0.32 L/min. Each lentil bean was exposed for 5, 10 and 15 min to plasma. Assays were performed in triplicate. Beans not exposed to plasma were used as controls. All plasma treatments caused a lethal effect on A. flavus conidia within exposure periods of 5 to 15 min. The application of argon plasma showed a log10 reduction of 0.81 (84%) after 15 min. The mixture of argon: nitrogen at 0.81 and 0.32 L/min had a higher lethal effect than argon alone. Although lentil beans sterilization was not completely achieved, an important log10 reduction of 1.43 (96.44 %) and 5.53 (99.99 %) of A. flavus conidia was obtained after 15 min of exposure to the plasma generated by argon-nitrogen mixture using nitrogen at flow rates of 0.81 and 0.32 L/min, respectively. Nitrogen flow rate of 0.32 L/min showed a reduction above 3.0 logarithmic units, so this treatment showed a fungicidal activity. The lowest reduction, 0.3 logarithmic units (50.3 %) was observed at a nitrogen flow rate of 1.2 L/min. Additionally, as a consequence of plasma exposure, conidia of A. flavus showed a delay in germination process and also conidia formation was affected. It was concluded that cold plasma could be used as an alternative to sanitize grains and avoid contamination by microorganisms, which cause grain deterioration and affect its nutritional properties.

Fusarium Toxins in Chinese Wheat since the 1980s.

Wheat Fusarium head blight (FHB), caused by Fusarium species, is a widespread and destructive fungal disease. In addition to the substantial yield and revenue losses, diseased grains are often contaminated with Fusarium mycotoxins, making them unsuitable for human consumption or use as animal feed. As a vital food and feed ingredient in China, the quality and safety of wheat and its products have gained growing attention from consumers, producers, scientists, and policymakers. This review supplies detailed data about the occurrence of Fusarium toxins and related intoxications from the 1980s to the present. Despite the serious situation of toxin contamination in wheat, the concentration of toxins in flour is usually lower than that in raw materials, and food-poisoning incidents have been considerably reduced. Much work has been conducted on every phase of toxin production and wheat circulation by scientific researchers. Regulations for maximum contamination limits have been established in recent years and play a substantial role in ensuring the stability of the national economy and people’s livelihoods.

Machine learning algorithms for the automated classification of contaminated maize at regulatory limits via infrared attenuated total reflection spectroscopy

Mould infested maize poses a severe problem for farmers, food producers and for consumers worldwide. Mycotoxins are secondary metabolites produced by certain mould species that contaminate food and feed. The consumption of these toxins may cause serious health problems for humans and animals. The trichothecene deoxynivalenol (DON) constitutes one of the most commonly occurring Fusarium toxins encountered in maize and requires improved methods to limit its entrance into the food and feed system. While a variety of chromatographic and mass spectrometry methods for the identification of such toxins have been established, these are considered time-consuming, cost-intensive and require highly qualified personnel. Alternatively, optical techniques, such as mid-infrared spectroscopy offer rapid detection of fungal infections in cereals and other commodities with minimised sample preparation and analysis time. The present study demonstrates a rapid fungal contamination detection strategy in maize taking advantage of IR-spectroscopy combined with advanced machine learning algorithms. The developed method represents an advancement for the analysis of differences in protein and carbohydrate content revealed in the associated IR-spectra related to the amount of toxin contamination at the European Union (EU) regulatory limits for DON in maize (i.e. 1,250 μg/kg). The employed maize varieties are naturally infected samples or have been infected with Fusarium verticillioides, Fusarium graminearum or Fusarium culmorum. Sieved maize samples at the EU regulatory limit were correctly classified using machine learning approaches, therefore enabling the differentiation between DON-contaminated and non-contaminated maize samples. Specifically, a variety of machine learning methods, including Adaptive Boosting (AdaBoost), Random Forests, Support Vector Machine (SVM) and Multilayer Perceptron (MLP) demonstrated excellent classification and validation performance using the obtained IR-spectra. As a result, 183 maize samples of different varieties and infection levels were accurately classified. 94% of the non-contaminated samples and 91% of the contaminated samples were correctly classified using an MLP classification approach.