DNA arrays, electronic noses and tongues, biosensors and receptors for rapid detection of toxigenic fungi and mycotoxins: a review

Innovative approaches for mycotoxin detection in various food categories

Mycotoxins (MTs), produced by filamentous fungi, represent a severe hazard to the health of humans and food safety, affecting the quality of various agricultural products. They can contaminate a wide range of foods, during any processing phase before or after harvest. Animals and humans who consume MTs-contaminated food or feed may experience acute or chronic poisoning, which may result in serious pathological consequences. Accordingly, developing rapid, easy, and accurate methods of MTs detection in food becomes highly urgent and critical as a quality control and to guarantee food safety and lower health hazards. In this review, we highlighted and discussed innovative approaches like biosensors, fluorescent polarization, capillary electrophoresis, infrared spectroscopy, and electronic noses for MT identification pointing out current challenges and future directions. The limitations, current challenges, and future directions of conventional detection methods versus innovative methods have also been highlighted and discussed.

An Aptamer-Array-Based Sample-to-Answer Biosensor for Ochratoxin A Detection via Fluorescence Resonance Energy Transfer

Food toxins are a hidden threat that can cause cancer and tremendously impact human health. Therefore, the detection of food toxins in a timely manner with high sensitivity is of paramount importance for public health and food safety. However, the current detection methods are relatively time-consuming and not practical for field tests. In the present work, we developed a novel aptamer-chip-based sample-to-answer biosensor (ACSB) for ochratoxin A (OTA) detection via fluorescence resonance energy transfer (FRET). In this system, a cyanine 3 (Cy3)-labeled OTA-specific biotinylated aptamer was immobilized on an epoxy-coated chip via streptavidin-biotin binding. A complementary DNA strand to OTA aptamer at the 3′-end was labeled with a black hole quencher 2 (BHQ2) to quench Cy3 fluorescence when in proximity. In the presence of OTA, the Cy3-labeled OTA aptamer bound specifically to OTA and led to the physical separation of Cy3 and BHQ2, which resulted in an increase of fluorescence signal. The limit of detection (LOD) of this ACSB for OTA was 0.005 ng/mL with a linearity range of 0.01–10 ng/mL. The cross-reactivity of ACSB against other mycotoxins, ochratoxin B (OTB), aflatoxin B1 (AFB1), zearalenone (ZEA), or deoxynilvalenol (DON), was less than 0.01%. In addition, this system could accurately detect OTA in rice samples spiked with OTA, and the mean recovery rate of the spiked-in OTA reached 91%, with a coefficient of variation (CV) of 8.57–9.89%. Collectively, the ACSB may represent a rapid, accurate, and easy-to-use platform for OTA detection with high sensitivity and specificity.

Detection of Mycotoxins in Food Using Surface-Enhanced Raman Spectroscopy: A Review

Mycotoxins are toxic metabolites produced by fungi that contaminate many important crops worldwide. Humans are commonly exposed to mycotoxins through the consumption of contaminated food products. Mycotoxin contamination is unpredictable and unavoidable; it occurs at any point in the food production system under favorable conditions, and they cannot be destroyed by common heat treatments, because of their high thermal stability. Early and fast detection plays an essential role in this unique challenge to monitor the presence of these compounds in the food chain. Surface-enhanced Raman spectroscopy (SERS) is an advanced spectroscopic technique that integrates Raman spectroscopic molecular fingerprinting and enhanced sensitivity based on nanotechnology to meet the requirement of sensitivity and selectivity, but that can also be performed in a cost-effective and straightforward manner. This Review focuses on the SERS methodologies applied to date for qualitative and quantitative analysis of mycotoxins based on a variety of SERS substrates, as well as our perspectives on current limitations and future trends for applying this technique to mycotoxin analyses.

Occurrence, Toxicity, and Analysis of Major Mycotoxins in Food

Mycotoxins are toxic secondary metabolites produced by certain filamentous fungi (molds). These low molecular weight compounds (usually less than 1000 Daltons) are naturally occurring and practically unavoidable. They can enter our food chain either directly from plant-based food components contaminated with mycotoxins or by indirect contamination from the growth of toxigenic fungi on food. Mycotoxins can accumulate in maturing corn, cereals, soybeans, sorghum, peanuts, and other food and feed crops in the field and in grain during transportation. Consumption of mycotoxin-contaminated food or feed can cause acute or chronic toxicity in human and animals. In addition to concerns over adverse effects from direct consumption of mycotoxin-contaminated foods and feeds, there is also public health concern over the potential ingestion of animal-derived food products, such as meat, milk, or eggs, containing residues or metabolites of mycotoxins. Members of three fungal genera, Aspergillus, Fusarium, and Penicillium, are the major mycotoxin producers. While over 300 mycotoxins have been identified, six (aflatoxins, trichothecenes, zearalenone, fumonisins, ochratoxins, and patulin) are regularly found in food, posing unpredictable and ongoing food safety problems worldwide. This review summarizes the toxicity of the six mycotoxins, foods commonly contaminated by one or more of them, and the current methods for detection and analysis of these mycotoxins.

Mycotoxin Contamination in the EU Feed Supply Chain: A Focus on Cereal Byproducts

Mycotoxins represent a risk to the feed supply chain with an impact on economies and international trade. A high percentage of feed samples have been reported to be contaminated with more than one mycotoxin. In most cases, the concentrations were low enough to ensure compliance with the European Union (EU) guidance values or maximum admitted levels. However, mycotoxin co-contamination might still exert adverse effects on animals due to additive/synergistic interactions. Studies on the fate of mycotoxins during cereal processing, such as milling, production of ethanol fuels, and beer brewing, have shown that mycotoxins are concentrated into fractions that are commonly used as animal feed. Published data show a high variability in mycotoxin repartitioning, mainly due to the type of mycotoxins, the level and extent of fungal contamination, and a failure to understand the complexity of food processing technologies. Precise knowledge of mycotoxin repartitioning during technological processes is critical and may provide a sound technical basis for feed managers to conform to legislation requirements and reduce the risk of severe adverse market and trade repercussions. Regular, economical and straightforward feed testing is critical to reach a quick and accurate diagnosis of feed quality. The use of rapid methods represents a future challenge.

Advances in Mycotoxin Research: Public Health Perspectives

Aflatoxins, ochratoxins, fumonisins, deoxynivalenol, and zearalenone are of significant public health concern as they can cause serious adverse effects in different organs including the liver, kidney, and immune system in humans. These toxic secondary metabolites are produced by filamentous fungi mainly in the genus Aspergillus, Penicillium, and Fusarium. It is challenging to control the formation of mycotoxins due to the worldwide occurrence of these fungi in food and the environment. In addition to raw agricultural commodities, mycotoxins tend to remain in finished food products as they may not be destroyed by conventional processing techniques. Hence, much of our concern is directed to chronic health effects through long-term exposure to one or multiple mycotoxins from contaminated foods. Ideally risk assessment requires a comprehensive data, including toxicological and epidemiological studies as well as surveillance and exposure assessment. Setting of regulatory limits for mycotoxins is considered necessary to protect human health from mycotoxin exposure. Although advances in analytical techniques provide basic yet critical tool in regulation as well as all aspects of scientific research, it has been acknowledged that different forms of mycotoxins such as analogs and conjugated mycotoxins may constitute a significant source of dietary exposure. Further studies should be warranted to correlate mycotoxin exposure and human health possibly via identification and validation of suitable biomarkers.

Construction of spherical liposome on solid transducers for electrochemical DNA sensing and transfection

Cationic 1,2-dioleoyl trimethyl ammonium propane (DOTAP) and neutral 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) are anchored on cysteamine (cyst), mercaptopropionic acid (MPA) monolayer (thiol monolayers) modified on an individual gold transducer. DOTAP and DOPE are mixed with gold nanoparticle (AuNP) to form spherical liposome-AuNP. The electrochemical behaviors of the surface attached DOTAP-AuNP and DOPE-AuNP in presence of [Fe(CN)6](3-/4-) depend on the method of layer formation. Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), and ultraviolet (UV)-visible spectroscopic techniques are used to characterize the liposome-AuNP nanocomposite. The studies indicate stability of spherical liposome-AuNP on the gold transducer. Label-free DNA hybridization detection on these surfaces reveals different detection limits. Confocal laser scanning microscopy (CLSM) is used to confirm the cell transfection.

Detection of off-flavor in catfish using a conducting polymer electronic-nose technology

The Aromascan A32S conducting polymer electronic nose was evaluated for the capability of detecting the presence of off-flavor malodorous compounds in catfish meat fillets to assess meat quality for potential merchantability. Sensor array outputs indicated that the aroma profiles of good-flavor (on-flavor) and off-flavor fillets were strongly different as confirmed by a Principal Component Analysis (PCA) and a Quality Factor value (QF > 7.9) indicating a significant difference at (P < 0.05). The A32S e-nose effectively discriminated between good-flavor and off-flavor catfish at high levels of accuracy (>90%) and with relatively low rates (≤5%) of unknown or indecisive determinations in three trials. This A32S e-nose instrument also was capable of detecting the incidence of mild off-flavor in fillets at levels lower than the threshold of human olfactory detection. Potential applications of e-nose technologies for pre- and post-harvest management of production and meat-quality downgrade problems associated with catfish off-flavor are discussed.

Electrochemical affinity biosensors for detection of mycotoxins: A review

This review discusses the current state of electrochemical biosensors in the determination of mycotoxins in foods. Mycotoxins are highly toxic secondary metabolites produced by molds. The acute toxicity of these results in serious human and animal health problems, although it has been only since early 1960s when the first studied aflatoxins were found to be carcinogenic. Mycotoxins affect a broad range of agricultural products, most important cereals and cereal-based foods. A majority of countries, mentioning especially the European Union, have established preventive programs to control contamination and strict laws of the permitted levels in foods. Official methods of analysis of mycotoxins normally requires sophisticated instrumentation, e.g. liquid chromatography with fluorescence or mass detectors, combined with extraction procedures for sample preparation. For about sixteen years, the use of simpler and faster analytical procedures based on affinity biosensors has emerged in scientific literature as a very promising alternative, particularly electrochemical (i.e., amperometric, impedance, potentiometric or conductimetric) affinity biosensors due to their simplicity and sensitivity. Typically, electrochemical biosensors for mycotoxins use specific antibodies or aptamers as affinity ligands, although recombinant antibodies, artificial receptors and molecular imprinted polymers show potential utility. This article deals with recent advances in electrochemical affinity biosensors for mycotoxins and covers complete literature from the first reports about sixteen years ago.

Diverse applications of electronic-nose technologies in agriculture and forestry

Electronic-nose (e-nose) instruments, derived from numerous types of aroma-sensor technologies, have been developed for a diversity of applications in the broad fields of agriculture and forestry. Recent advances in e-nose technologies within the plant sciences, including improvements in gas-sensor designs, innovations in data analysis and pattern-recognition algorithms, and progress in material science and systems integration methods, have led to significant benefits to both industries. Electronic noses have been used in a variety of commercial agricultural-related industries, including the agricultural sectors of agronomy, biochemical processing, botany, cell culture, plant cultivar selections, environmental monitoring, horticulture, pesticide detection, plant physiology and pathology. Applications in forestry include uses in chemotaxonomy, log tracking, wood and paper processing, forest management, forest health protection, and waste management. These aroma-detection applications have improved plant-based product attributes, quality, uniformity, and consistency in ways that have increased the efficiency and effectiveness of production and manufacturing processes. This paper provides a comprehensive review and summary of a broad range of electronic-nose technologies and applications, developed specifically for the agriculture and forestry industries over the past thirty years, which have offered solutions that have greatly improved worldwide agricultural and agroforestry production systems.

Label-free detection of aflatoxin M1 with electrochemical Fe3O4/polyaniline-based aptasensor

The selective detection of ultratrace amounts of aflatoxin M1 (AFM1) is extremely important for food safety since it is the most toxic mycotoxin class that is allowed to be present on cow milk with strictly low regulatory levels. In this work, Fe3O4 incorporated polyaniline (Fe3O4/PANi) film has been polymerized on interdigitated electrode (IDE) as sensitive film for AFM1 electrochemical biosensor. The immobilized aptamers as an affinity capture reagent and magnetic nanoparticles for signal amplification element have been employed in the sensing platform. Label-free and direct detection of the aptamer-AFM1 on Fe3O4/PANi interface were performed via electrochemical signal change, acquired by cyclic and square wave voltammetries. With a simplified strategy, this electrochemical aptasensor shows a good sensitivity to AFM1 in the range of 6-60 ng·L(-1), with the detection limit of 1.98 ng·L(-1). The results open up the path for designing cost effective aptasensors for other biomedical applications.

Fully integrated biochip platforms for advanced healthcare

Recent advances in microelectronics and biosensors are enabling developments of innovative biochips for advanced healthcare by providing fully integrated platforms for continuous monitoring of a large set of human disease biomarkers. Continuous monitoring of several human metabolites can be addressed by using fully integrated and minimally invasive devices located in the sub-cutis, typically in the peritoneal region. This extends the techniques of continuous monitoring of glucose currently being pursued with diabetic patients. However, several issues have to be considered in order to succeed in developing fully integrated and minimally invasive implantable devices. These innovative devices require a high-degree of integration, minimal invasive surgery, long-term biocompatibility, security and privacy in data transmission, high reliability, high reproducibility, high specificity, low detection limit and high sensitivity. Recent advances in the field have already proposed possible solutions for several of these issues. The aim of the present paper is to present a broad spectrum of recent results and to propose future directions of development in order to obtain fully implantable systems for the continuous monitoring of the human metabolism in advanced healthcare applications.

Microarray technology for major chemical contaminants analysis in food: current status and prospects

Chemical contaminants in food have caused serious health issues in both humans and animals. Microarray technology is an advanced technique suitable for the analysis of chemical contaminates. In particular, immuno-microarray approach is one of the most promising methods for chemical contaminants analysis. The use of microarrays for the analysis of chemical contaminants is the subject of this review. Fabrication strategies and detection methods for chemical contaminants are discussed in detail. Application to the analysis of mycotoxins, biotoxins, pesticide residues, and pharmaceutical residues is also described. Finally, future challenges and opportunities are discussed.

The pivotal role of mass spectrometry in determining the presence of chemical contaminants in food raw materials

During recent years, a rising interest from consumers and various governmental organizations towards the quality of food has continuously been observed. Human intervention across the different stages of the food supply chain can lead to the presence of several types of chemical contaminants in food-based products. On a normal daily consumption basis, some of these chemicals are not harmful; however, for those that present a risk to consumers, legislation rules were established to specify tolerance levels or in some cases the total forbiddance of these specific contaminants. Hence, the use of appropriate analytical tools is recommended to properly identify chemical contaminants. In that context, mass spectrometry (MS)-based techniques coupled or not to chromatography offer a vast panel of features such as sensitivity, selectivity, quantification at trace levels, and/or structural elucidation. Because of the complexity of food-based matrices, sample preparation is a crucial step before final detection. In the present manuscript, we review the contribution and the potentialities of MS-based techniques to ensure the absence of chemical contaminants in food-based products.

Optical biosensors: a revolution towards quantum nanoscale electronics device fabrication

The dimension of biomolecules is of few nanometers, so the biomolecular devices ought to be of that range so a better understanding about the performance of the electronic biomolecular devices can be obtained at nanoscale. Development of optical biomolecular device is a new move towards revolution of nano-bioelectronics. Optical biosensor is one of such nano-biomolecular devices that has a potential to pave a new dimension of research and device fabrication in the field of optical and biomedical fields. This paper is a very small report about optical biosensor and its development and importance in various fields.

Development of an impedimetric aflatoxin M1 biosensor based on a DNA probe and gold nanoparticles

The present work describes the construction and application of a new DNA biosensor for detection of aflatoxin M1. In order to immobilize a thiol-modified single stranded DNA (ss-HSDNA) probe that specifically bound aflatoxin M1, a self-assembled monolayer of cysteamine and gold nanoparticles on the SAM were prepared on gold electrodes, layer-by-layer. The assembly processes of cysteamine, gold nanoparticles, and ss-HSDNA were monitored with the help of electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) techniques. K3[Fe(CN)6]/K4[Fe(CN)6] solution was used as a redox probe for electrochemical measurements. The biosensor provided a linear response to aflatoxin M1 over the concentration range of 1-14 ng/mL with a standard deviation of ±0.36 ng/mL. Finally, the biosensor was applied to a series of real milk samples.

Advances in electronic-nose technologies developed for biomedical applications

The research and development of new electronic-nose applications in the biomedical field has accelerated at a phenomenal rate over the past 25 years. Many innovative e-nose technologies have provided solutions and applications to a wide variety of complex biomedical and healthcare problems. The purposes of this review are to present a comprehensive analysis of past and recent biomedical research findings and developments of electronic-nose sensor technologies, and to identify current and future potential e-nose applications that will continue to advance the effectiveness and efficiency of biomedical treatments and healthcare services for many years. An abundance of electronic-nose applications has been developed for a variety of healthcare sectors including diagnostics, immunology, pathology, patient recovery, pharmacology, physical therapy, physiology, preventative medicine, remote healthcare, and wound and graft healing. Specific biomedical e-nose applications range from uses in biochemical testing, blood-compatibility evaluations, disease diagnoses, and drug delivery to monitoring of metabolic levels, organ dysfunctions, and patient conditions through telemedicine. This paper summarizes the major electronic-nose technologies developed for healthcare and biomedical applications since the late 1980s when electronic aroma detection technologies were first recognized to be potentially useful in providing effective solutions to problems in the healthcare industry.

Biosensors and nanomaterials and their application for mycotoxin determination

Mycotoxin analysis and detection in food and drinks is vital for ensuring food quality and safety, eliminating and controlling the risk of consuming contaminated foods, and complying with the legislative limits set by food authorities worldwide. Most analysis of these toxins is still conducted using conventional methods; however, biosensor methods are currently being developed as screening tools for use in field analysis. Biosensors have demonstrated their ability to provide rapid, sensitive, robust and cost-effective quantitative methods for on-site testing. The development of biosensor devices for different mycotoxins has attracted much research interest in recent years with a range of devices being designed and reported in the scientific literature. However, with the advent of nanotechnology and its impact on the evolution of ultrasensitive devices, mycotoxin analysis is also benefiting from the advances taking place in applying nanomaterials in sensors development. This paper reviews the developments in the area of biosensors and their applications for mycotoxin analysis, as well as the development of micro/nanoarray transducers and nanoparticles and their use in the development of new rapid devices.

Development of an electrochemical immunosensor for fumonisins detection in foods

An electrochemical affinity sensor for the determination of fumonisins mycotoxins (Fms) using monoclonal antibody modified screen-printed gold electrode with carbon counter and silver-silver chloride pseudo-reference electrode is reported in this work. A direct competitive enzyme-linked immunosorbent assay (ELISA) was initially developed, exhibiting a detection limit of 100 µg·L^-1 for fumonisins. This was then transferred to the surface of a bare gold screen-printed electrode (SPGE) and detection was performed by chronoamperometry, monitoring the reaction of 3,3’,5,5’-Tetramethylbenzidine dihydrochloride (TMB) and hydrogen peroxide (H₂O₂) catalysed by HRP at −100 mV potential vs. onboard Ag-AgCl pseudo-reference electrode. The immunosensor exhibited detection limit of 5 µg·L⁻¹ fumonisins with a dynamic range from 1 µg·L⁻¹–1000 µg·L⁻¹. The sensor also performed well in extracted corn samples.

Electrochemical immunochip sensor for aflatoxin M1 detection

An investigation into the fabrication, electrochemical characterization, and development of a microelectrode array (MEA) immunosensor for aflatoxin M(1) is presented in this paper. Gold MEAs (consisting of 35 microsquare electrodes with 20 microm x 20 microm dimensions and edge-to-edge spacing of 200 microm) together with on-chip reference and counter electrodes were fabricated using standard photolithographic methods. The MEAs were then characterized by cyclic voltammetry, and the behavior of the on-chip electrodes were evaluated. The microarray sensors were assessed for their applicability to the development of an immunosensor for the analysis of aflatoxin M(1) directly in milk samples. Following the sensor surface silanization, antibodies were immobilized by cross-linking with 1,4-phenylene diisothiocyanate (PDITC). Surface characterization was conducted by electrochemistry, fluorescence microscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM). A competitive enzyme linked immunosorbent assay (ELISA) assay format was developed on the microarray electrode surface using the 3,3,5',5'-tetramethylbenzidine dihyrochloride (TMB)/H(2)O(2) electrochemical detection scheme with horseradish peroxidase (HRP) as the enzyme label. The performance of the assay and the microarray sensor were characterized in pure buffer conditions before applying to the milk samples. With the use of this approach, the detection limit for aflatoxin M(1) in milk was estimated to be 8 ng L(-1), with a dynamic detection range of 10-100 ng L(-1), which meets present legislative limits of 50 ng L(-1). The milk interference with the sensor surface was also found to be minimal. These devices show high potential for development of a range of new applications which have previously only been detected using elaborate instrumentation.

Overview of electrochemical DNA biosensors: new approaches to detect the expression of life

DNA microarrays are an important tool with a variety of applications in gene expression studies, genotyping, pharmacogenomics, pathogen classification, drug discovery, sequencing and molecular diagnostics. They are having a strong impact in medical diagnostics for cancer, toxicology and infectious disease applications. A series of papers have been published describing DNA biochips as alternative to conventional microarray platforms to facilitate and ameliorate the signal readout. In this review, we will consider the different methods proposed for biochip construction, focusing on electrochemical detection of DNA. We also introduce a novel single-stranded DNA platform performing high-throughput SNP detection and gene expression profiling.

Microelectrode arrays for electrochemistry: approaches to fabrication

Microelectrode arrays have unique electrochemical properties such as small capacitive-charging currents, reduced iR drop, and steady-state diffusion currents. These properties enable the use of microelectrode arrays and have captured much interest in the field of electrochemistry. Techniques for the fabrication of such arrays are reviewed. The relative features and merits of different techniques are also discussed.

An overview of conventional and emerging analytical methods for the determination of mycotoxins

Mycotoxins are a group of compounds produced by various fungi and excreted into the matrices on which they grow, often food intended for human consumption or animal feed. The high toxicity and carcinogenicity of these compounds and their ability to cause various pathological conditions has led to widespread screening of foods and feeds potentially polluted with them. Maximum permissible levels in different matrices have also been established for some toxins. As these are quite low, analytical methods for determination of mycotoxins have to be both sensitive and specific. In addition, an appropriate sample preparation and pre-concentration method is needed to isolate analytes from rather complicated samples. In this article, an overview of methods for analysis and sample preparation published in the last ten years is given for the most often encountered mycotoxins in different samples, mainly in food. Special emphasis is on liquid chromatography with fluorescence and mass spectrometric detection, while in the field of sample preparation various solid-phase extraction approaches are discussed. However, an overview of other analytical and sample preparation methods less often used is also given. Finally, different matrices where mycotoxins have to be determined are discussed with the emphasis on their specific characteristics important for the analysis (human food and beverages, animal feed, biological samples, environmental samples). Various issues important for accurate qualitative and quantitative analyses are critically discussed: sampling and choice of representative sample, sample preparation and possible bias associated with it, specificity of the analytical method and critical evaluation of results.

Development of an electrochemical immunosensor for aflatoxin M1 in milk with focus on matrix interference

A simple sensor method was developed for aflatoxin M(1) analysis to be applied directly with milk by using antibody modified screen-printed carbon working electrode with carbon counter and silver-silver chloride pseudo-reference electrode. A competitive ELISA assay format was constructed on the surface of the working electrode using 3,3,5',5'-tetramethylbenzidine dihyrochloride (TMB)/H(2)O(2) electrochemical detection scheme with horseradish peroxidase (HRP) as the enzyme label. The performance of the assay and the sensor was optimised and characterised in pure buffer conditions before applying to milk samples. Extensive interference to the electroanalytical signal was observed upon the analysis of milk. Through a series of chemical fractionations of the milk, and testing the electrochemical properties of the fractions, the interference was attributed to whey proteins with focus towards alpha-lactalbumin. A simple pre-treatment technique of incorporating 18 mM calcium chloride, in the form of Dulbucco's PBS, in a 1:1 ratio to the milk sample or standards and also to the washing buffer stabilised the whey proteins in solution and eliminate the interfering signal. The resulting immunosensor was interference free and achieved a limit of detection of 39 ng l(-1) with a linear dynamic detection range up to 1000 ng l(-1). The developed immunosensor method was compared to a commercial ELISA kit and an in-house HPLC method. The immunsensor was comparable, in term of sensitivity, but vastly superior in term of portability and cost therefore a key instrument for the detection of aflatoxin M(1) at the source of the contamination.

Mycotoxin detection plays "cops and robbers": cyclodextrin chemosensors as specialized police?

As in a cops and robbers play we discover new mycotoxins and metabolites everyday and we are forced to develop new molecules quickly as chemo- or biosensors or to modify existing molecules able to recognize these new hazardous compounds. This will result in an enormous cost saving to agro-food industry through the prevention and reduction of product recalls and reduced treatment costs. Here we present a brief review of the rapid methods used to detect mycotoxins, considering usefulness and limits. Then we propose a new fast, efficient and cheap methodology, based on a combination of computer chemistry aided design and fluorescence, that can help to drive synthesis in a more efficient way.

Mycotoxin analysis: an update

Mycotoxin contamination of cereals and related products used for feed can cause intoxication, especially in farm animals. Therefore, efficient analytical tools for the qualitative and quantitative analysis of toxic fungal metabolites in feed are required. Current methods usually include an extraction step, a clean-up step to reduce or eliminate unwanted co-extracted matrix components and a separation step with suitably specific detection ability. Quantitative methods of analysis for most mycotoxins use immunoaffinity clean-up with high-performance liquid chromatography (HPLC) separation in combination with UV and/or fluorescence detection. Screening of samples contaminated with mycotoxins is frequently performed by thin layer chromatography (TLC), which yields qualitative or semi-quantitative results. Nowadays, enzyme-linked immunosorbent assays (ELISA) are often used for rapid screening. A number of promising methods, such as fluorescence polarization immunoassays, dipsticks, and even newer methods such as biosensors and non-invasive techniques based on infrared spectroscopy, have shown great potential for mycotoxin analysis. Currently, there is a strong trend towards the use of multi-mycotoxin methods for the simultaneous analysis of several of the important Fusarium mycotoxins, which is best achieved by LC-MS/MS (liquid chromatography with tandem mass spectrometry). This review focuses on recent developments in the determination of mycotoxins with a special emphasis on LC-MS/MS and emerging rapid methods.

Assessment of bioinspired models for pattern recognition in biomimetic systems

The increasing complexity of the artificial implementations of biological systems, such as the so-called electronic noses (e-noses) and tongues (e-tongues), poses issues in sensory feature extraction and fusion, drift compensation and pattern recognition, especially when high reliability is required. In particular, in order to achieve effective results, the pattern recognition system must be carefully designed. In order to investigate a novel biomimetic approach for the pattern recognition module of such systems, the classification capabilities of an artificial model inspired by the mammalian cortex, a cortical-based artificial neural network (CANN), are compared with several artificial neural networks present in the e-nose and e-tongue literature, a multilayer perceptron (MLP), a Kohonen self-organizing map (KSOM) and a fuzzy Kohonen self-organizing map (FKSOM). Each network was tested with large datasets coming from a conducting polymer-sensor-based e-nose and a composite array-based e-tongue. The comparison of results showed that the CANN model is able to strongly enhance the performances of both systems.

Mycotoxin assays using biosensor technology: a review

Toxic fungal metabolites - mycotoxins - cause poisonings after consumption of contaminated food commodities. The most probable intoxications are connected with eating poorly stored food or inhaling of moldy dust. One of the effective ways to protect people against mycotoxins is timely detection. Several methods such as affinity chromatography and enzyme-linked immunosorbent assay are commercially available for this purpose. Nevertheless, fast, sensitive, simple, portable, and low-cost devices are difficult to find. Application of biosensors appears to be a possible method to meet this need for mycotoxins assay.