Food Toxins Research Articles

Determination of T-2 and HT-2 toxins in food and feed: an update

Based on the recent scientific opinion of the European Food Safety Authority (EFSA) Panel on Contaminants in the Food Chain on the risks to human and animal health related to the presence of T-2 and HT-2 toxins in food and feed that was published by EFSA in the EFSA Journal, this article provides an update on the determination of these Fusarium mycotoxins. After a brief introduction into the chemistry of these toxins, both chromatographic and immuno-analytical methods are discussed for the determination of these type A trichothecenes. During the last decade, liquid chromatography with (tandem) mass spectrometry has become the most frequently used method for the determination of T-2 and HT-2 toxins, often within a multi-analyte approach. However, complex matrices and the resulting signal suppression effects, as observed particularly in electrospray-mass spectrometry methods owing to matrix effects, may require careful optimisation of clean-up, usage of matrix matched standards, or e.g. the use of internal standards. For specific purposes where extremely low limits of quantification are needed, e.g. for the analysis of duplicate diets, a dedicated gas chromatography method with multistage mass spectrometry has become available. Other novel analytical approaches to determine T-2 and HT-2 toxins in food and feed include biosensor-based methods in surface plasmon resonance and electrochemical formats, as well as DNA microchip assays. For rapid screening, several immunochemical methods (mostly ELISAs) have become available and some are sold as commercial test kits. Whereas these methods work fast, cross-reactivities with other trichothecenes can have an undesired effect on their accuracy. While proficiency tests including T-2 and HT-2 toxins have been carried out, none of the chromatographic or immunochemical methods have been formally validated in interlaboratory validation studies. There are no certified reference materials available for T-2 and HT-2 toxins.

Recent Advances in Potential Nanoparticles and Nanotechnology for Sensing Food-Borne Pathogens and Their Toxins in Foods and Crops: Current Technologies and Limitations

Recent Advances in Potential Nanoparticles and Nanotechnology for Sensing Food-Borne Pathogens and Their Toxins in Foods and Crops: Current Technologies and Limitations

The choice of preparation method for the determination of Alternaria toxins from wheat samples by LC-MS/MS

Cereals are the primary source of human diet, wheat being the third most produced grain worldwide, and in Serbia second most produced grain, just behind corn. As a result of climate change and global warming, frequent occurrences of mycobiota on steep grains can produce a negative impact on the safety of food products and their quality, which inevitably leads to large economic losses. Although Fusarium spp. remains a main source of mycotoxins contamination of wheat, in recent years, due to the evident climatic changes affecting agricultural production, other mycotoxigenic fungi have been pointed out as important wheat contaminants. Among them are the fungi of the genus Alternaria, especially A. alternata, which under favourable conditions, produces mycotoxins such as alternariol, alternariol monomethyl ether, tenuazonic acid, and other Alternaria toxins. Taking into account the toxicity of metabolites produced by certain species of fungi of the genus Alternaria in the system from farm to table, it is necessary to develop specific and sensitive analytical methods in order to implement systematic controls of occurrence of Alternaria toxins. Liquid chromatography coupled to (tandem) mass spectrometry (LC-MS/MS) has become the technique of choice for the detection and quantification of Alternaria toxins in food and feed. There are several limiting factors such as the efficiency of sample cleanup and the lack of reference materials for food and feed. The aim of this study was to choose the most suitable preparation method for the determination of Alternaria toxins from wheat samples by LC-MS/MS technique based on published sample preparation methods, with possible modifications, which are used in analysis of mycotoxins. Modified method of wheat samples preparation by extraction with ethyl acetate was selected as acceptable based on extraction efficiency of analytes of interest.

Recent Advances in Potential Nanoparticles and Nanotechnology for Sensing Food-Borne Pathogens and Their Toxins in Foods and Crops: Current Technologies and Limitations

Recent Advances in Potential Nanoparticles and Nanotechnology for Sensing Food-Borne Pathogens and Their Toxins in Foods and Crops: Current Technologies and Limitations

Belief in the paranormal and modern health worries

It has been found, that despite the improvement of the objective health indicators, people's subjective perception of health is that health indicators are getting worse (Barsky A.J., 1988), which is one of the reasons why a new term “modern health worries” is coming into use in medical literature (Petrie K.J., Wessely S., 2002). People are worried and scared of the effect of new high tech innovations (effect of cell phone radiation, environmental pollution, ozone layer depletion, etc.), changes in manufacturing of food products (genetically modified food, food concentrates etc.). Nowadays, many people, being worried about their health, turn to new eating habits (veganism), defend themselves against various innovations in the health system (vaccination), etc. It could be defined as fear of consequences of scientific progress. The reason of fear is not only the misunderstanding of scientific innovations. Quite often, it is a belief in pseudoscientific theories (for example, “conspiracy”) or belief in the paranormal phenomena (karma violations, disruption of the cosmic plan). In a part of cases protesters against vaccines and genetically modified food belong to new religious movements which are based on belief in the paranormal and magical thinking. Magical thinking predisposes to the negative attitude towards scientific assumptions and innovations, like a genetically modified food (Saher, 2006). Aim of study. To study the correlation between pseudoscientific assumptions, belief in the paranormal and modern health worries. This condition of modern health worries is becoming important for health care system. It causes the increase in the number of symptoms (Koteles et al., 2011), which, in its turn, increases the doctors' visit rate on one hand (Rief W et al., 2012), but, on the other hand, increases evasion to attend traditional medical care activities. Part of supporters of pseudoscientific beliefs experiences anxiety as to the bad food toxins accumulating in the body and undertake unnecessary procedures, like an excessive detoxication of the body by means of enema. Some are of the opinion that meat promotes aggressiveness, while different esoteric theories advise to develop peacefulness and altruism. Consumption of meat can be addressed to as an offense against cosmic morality and karma. Part of supporters of pseudoscientific theories considers scientifically-educated doctors as wreckers, the disinterested, persons who are financially interested in orders of commercial firms and therefore entrust the treatment of even serious diseases to alternative medicine specialists (SKDS, 2012). Turning to unconventional, magical medicine is promoted also by the fact, that part of the people who believe in the magic, view the “healing energy” as being more “natural” and harmless. Functional somatoform disorders, due to modern health worries, can also be “healed” by specialists of unconventional medicine. Since the emotional factors are decisive in the etiopathogenesis of these symptoms, the unconventional medical approach promotes the decrease of functional symptoms. A vicious circle develops – belief in the magic and the paranormal things causes symptoms, at the same time the belief in the magic alleviates the same symptoms. Asa result, a literature review was done on the interrelationship of pseudoscientific assumptions and health worries. Conclusion. When treating the patients worried about their health, one has to take into account the aspects of complicated subjective perception, including belief in paranormal phenomena, pseudoscientific theories and prevalence of magical thinking.

Human Diseases Prosecution Among Viral Infection and Food Toxins: A Review

Human Diseases Prosecution Among Viral Infection and Food Toxins: A Review

A comparison of ELISA and HPLC methods for determination of ochratoxin A in human blood serum in the Czech Republic

Ochratoxin A (OTA) is one of the most naturally occurring fungal toxins in food. It has been detected in high concentrations in serum samples of nephropathic patients and can be applied as one of the markers of potential risk of this disease. Also, OTA can cause adverse effects on human health such as genotoxicity and is anticipated to be a potential human carcinogen. In this study, enzyme-linked immunosorbent assay (ELISA) and high performance liquid chromatography (HPLC) were applied in analysis of 115 blood serum samples of women in the child rearing age from the Czech Republic and both methods were compared. The OTA was presented in a broad range of concentrations from 0.037 to 1.130μg/L. The outcome of ELISA and HPLC measurements were well correlated (r=0.907). However, it was observed that ELISA tend to result in underestimating the OTA level at the low serum concentrations. Both methods had the same limits of quantification of 0.050μg/L under standard operation conditions. When OTA concentration in a sample was too low, the sample was redissolved in only 300μL of methanol and the detection limit for HPLC was lowered to 0.030μg OTA/L.

Ultrasensitive food toxin biosensor using frequency based signals of silicon oxide nanoporous structure

We report an electrochemically fabricated silicon oxide nanoporous structure for ultrasensitive detection of AfB1 in food by shift in peak frequency corresponding to maximum sensitivity. It has been observed that the impedance sensitivity changes from 19% to 40% (which is only twice) where as the peak frequency shifts from 500 Hz to 50 kHz, for a change in concentration from 1 fg/ml to 1 pg/ml. This has been attributed to the combined effect of the significant pore narrowing with increasing AfB1 concentration and the opposing nature of impedance change within the nanopores and the conducting substrate immediately below the nanoporous layer.

Hsp70 from Cyprinion macrostomus macrostomus and Garra rufa obtuse: Stability and stability-dependent activity

Two fish species, Cyprinion macrostomus macrostomus and Garra rufa obtuse, tolerate adverse conditions in the Kangal hot springs and cope with multiple stressors such as food deprivation, extreme temperature, toxins, protein degradation, hypoxia, and microbial damage. These fish have evolved strategies to counteract the stressors including the induction of heat shock proteins (Hsps). Hsps play an essential role in maintaining cellular homeostasis, and one of the key proteins in the mechanism is Hsp70. Hsp70 itself is exposed to the same stressors as all other proteins, and, hence, the stability of Hsp70 was investigated. For this purpose, Hsp70 ATPase activity was determined at different urea concentrations. It was found that the protein maintains considerable ATP hydrolysis activity at higher denaturant conditions. Temperature effects on the substrate peptide binding showed that Hsp70s bind prominently at elevated temperatures. Furthermore, temperature effects on Hsp70 aggregation indicated that the presence of nucleotides decreases the aggregation process. The present work has determined the stability and activity of cmHsp70 and grHsp70 themselves under extreme conditions. The stability of the Hsp70 proteins maintains substrate proteins in the native state, which may aid in the adaptation of the fish species to the hot spring environment.

Thermal inactivation reaction rates for ricin are influenced by pH and carbohydrates

Ricin is a lethal protein toxin produced by the castor bean plant. Ricin is known to possess significant heat resistance. Therefore, we placed it in a variety of foods to study the influence of the food matrix on behavior of a thermally stable protein toxin. First order rate constants for the thermal inactivation of ricin in foods and simple buffers were measured using cytotoxicity assays. We observed greater thermal stability at 75 °C for the cytotoxic activity of ricin when it was placed in a yogurt-containing fruit drink compared to its stability when placed in the other foods tested. We found that galactose and high molecular weight exopolysaccharides present in various dairy products contributed to the thermal stability of ricin. Differential scanning calorimetry also showed enhanced thermal stability for ricin at pH 4.5. Our results demonstrate the importance of considering pH and the presence of stabilizing ligands in the thermal inactivation of protein toxins in foods.

A simple and rapid optical biosensor for detection of aflatoxin B1 based on competitive dispersion of gold nanorods

This report illustrates a promising one-step and label-free optical biosensor for determination of aflatoxin B1 (AFB1) that is most commonly found in foods and highly dangerous even at very low concentrations. In this research, gold nanorods (GNRs) were employed as a sensing platform, which showed high stability under high ionic strength conditions without addition of any stabilizing agent. GNR-AFB1–BSA (bovine serum albumin) conjugates aggregated after mixing with free antibodies, resulting in significant changes in absorption intensity. At the same time the existence of AFB1 molecules in samples caused dispersion of nanorods, as a result of competitive immune-reaction with antibodies. By taking advantages of the competitive dispersion of GNRs, the developed method could effectively reduce false results caused by undesirable aggregation, which is a big problem for spherical gold nanoparticles. Absorption intensity of UV–vis spectra served as the sensing indicator, with dynamic light scattering (DLS) measurement as another sensing tool. The designed biosensing system could detect AFB1 in a linear range from 0.5 to 20ngmL−1, with a good correlation coefficient of 0.99. And the limit of detection (LOD) was 0.16ngmL−1, indicating an excellent sensitivity with absorbance result. The recoveries of the spiked AFB1 in real peanut samples ranged from 94.2% to 117.3%. Therefore the proposed nano-biosensor was demonstrated to be sensitive, selective, and simple, providing a viable alternative for rapid screening of toxins in agriculture products and foods.

Pyrrolizidine Alkaloids - Hidden Toxins in Food and Medicinal Plants

Pyrrolizidine Alkaloids - Hidden Toxins in Food and Medicinal Plants

Use of a new functional dual coating (FDC) assay to measure low toxin levels in serum and food samples following an outbreak of human botulism

Clostridium botulinum type A toxin is the most prevalent cause of naturally occurring outbreaks of human botulism in the world. The active dichain neurotoxin molecule is composed of a heavy chain (H-chain) of ~100 kDa with the carboxy-terminal end consisting of a receptor-binding (HC) domain, while the amino-terminal (HN) domain is linked by a critical disulfide bond to a light chain (L-chain) of ~50 kDa. Although the mouse bioassay (MBA) is traditionally used to confirm the presence of toxin in serum or food, its sensitivity is insufficient to detect low toxin levels in approximately 30 to 60 % of botulism patients. A novel FDC (functional dual coating) microtitre plate immuno-biochemical assay, which quantifies botulinum toxicity by measuring the HC domain linked with L-chain endopeptidase activity, was modified to allow human serum (lysed or unlysed) to be tested without interference from the matrix, with toxin detection down to 0.03 mouse LD50 per ml serum or 0.13 pg ml(-1) using just 100 µl of clinical samples. The assay was specific for type A toxin and could additionally be applied to whole blood and food samples. Low levels of 1 to 2 mouse LD50 per ml serum of type A toxin were quantified for the first time using the modified FDC assay in two severely intoxicated UK patients who required mechanical ventilation and antitoxin. Toxin levels in recovered food sample extracts were also detected and one MBA-negative sample was found to contain 0.32 LD50 per ml extract. The FDC assay provides a real alternative for public health laboratories to unambiguously confirm all cases of type A botulism and, due to its sensitivity, a promising new tool in toxin pharmacokinetic studies.

Reduction of Oxalate Levels in Tomato Fruit and Consequent Metabolic Remodeling Following Overexpression of a Fungal Oxalate Decarboxylase

The plant metabolite oxalic acid is increasingly recognized as a food toxin with negative effects on human nutrition. Decarboxylative degradation of oxalic acid is catalyzed, in a substrate-specific reaction, by oxalate decarboxylase (OXDC), forming formic acid and carbon dioxide. Attempts to date to reduce oxalic acid levels and to understand the biological significance of OXDC in crop plants have met with little success. To investigate the role of OXDC and the metabolic consequences of oxalate down-regulation in a heterotrophic, oxalic acid-accumulating fruit, we generated transgenic tomato (Solanum lycopersicum) plants expressing an OXDC (FvOXDC) from the fungus Flammulina velutipes specifically in the fruit. These E8.2-OXDC fruit showed up to a 90% reduction in oxalate content, which correlated with concomitant increases in calcium, iron, and citrate. Expression of OXDC affected neither carbon dioxide assimilation rates nor resulted in any detectable morphological differences in the transgenic plants. Comparative proteomic analysis suggested that metabolic remodeling was associated with the decrease in oxalate content in transgenic fruit. Examination of the E8.2-OXDC fruit proteome revealed that OXDC-responsive proteins involved in metabolism and stress responses represented the most substantially up- and down-regulated categories, respectively, in the transgenic fruit, compared with those of wild-type plants. Collectively, our study provides insights into OXDC-regulated metabolic networks and may provide a widely applicable strategy for enhancing crop nutritional value.

Cassava food toxins, konzo disease, and neurodegeneration in sub-Sahara Africans

Endemoepidemic neurodegenerative diseases putatively caused by food toxins have been reported around the globe with no clear understanding of their pathogenetic mechanisms. These diseases include the amyotrophic lateral sclerosis/parkinsonism dementia complex among the Guamanians; neurolathyrism among Europeans, Indians, and populations of the Horn of Africa; and tropical ataxic neuropathy or konzo among sub-Sahara Africans.1,2 We focus on the molecular determinants of susceptibility to konzo, a poorly known self-limited and irreversible upper motor neuron disease (spastic paraparesis) highly prevalent in Congo-Kinshasa, Mozambique, Tanzania, Central African Republic, Angola, and Cameroon. The main clinical picture consists of a symmetrical, permanent, and irreversible spastic paraparesis with no signs of sensory or genitourinary impairments.2,3 Severely affected individuals may present with a tetraparesis and pseudobulbar signs. The disease konzo was named after a fetish used by the “Yaka” population of Congo-Kinshasa. The World Health Organization has adopted the following epidemiologic criteria for the disease: 1) an abrupt onset (<1 week) of weakness in legs and a nonprogressive course of the disease in a formerly healthy person, 2) a symmetrical spastic abnormality when walking and/or running, and 3) bilaterally exaggerated knee and/or ankle jerks without signs of disease of the spine.

EN

Aquatic food accounts for over 40% of global animal food products, and the potential contamination with toxins of algal origin--marine biotoxins--poses a health threat for consumers. The gold standards to assess toxins in aquatic food have traditionally been in vivo methods, i.e., the mouse as well as the rat bioassay. Besides ethical concerns, there is also a need for more reliable test methods because of low inter-species comparability, high intra-species variability, the high number of false positive and negative results as well as questionable extrapolation of quantitative risk to humans. For this reason, a transatlantic group of experts in the field of marine biotoxins was convened from academia and regulatory safety authorities to discuss future approaches to marine biotoxin testing. In this report they provide a background on the toxin classes, on their chemical characterization, the epidemiology, on risk assessment and management, as well as on their assumed mode of action. Most importantly, physiological functional assays such as in vitro bioassays and also analytical techniques, e.g., liquid chromatography coupled mass spectrometry (LC-MS), as substitutes for the rodent bioassay are reviewed. This forms the basis for recommendations on methodologies for hazard monitoring and risk assessment, establishment of causality of intoxications in human cases, a roadmap for research and development of human-relevant functional assays, as well as new approaches for a consumer directed safety concept.

Per os feeding with antisera specific to peritrophic matrix proteins stimulates larval growth in Mamestra configurata Walker (Lepidoptera: Noctuidae)

Peritrophic matrix (PM) is an acellular, porous sheath composed of chitin and proteins that lines the midgut epithelial cells. The PM serves as a barrier against food particles, pathogens and toxins. Several studies in dipteran systems revealed that antibodies specific to PM proteins retard insect development by binding to their target antigens in the PM and blocking PM pores. To test whether antisera specific to PM proteins also inhibit larval growth in a lepidopteran system, antisera specific to chitin deacetylase 1, insect intestinal mucin 2, insect intestinal mucin 4 and PM protein 1 were fed to 2nd instar Mamestra configurata Walker (Lepidoptera: Noctuidae) larvae, a major pest of Brassica plants in North America. Interestingly, all larvae feeding on antisera gained more weight than the larvae feeding on the diet containing non-immune sera or no antiserum. The anti-McPM1 and anti-McIIM4 antisera treatments showed the highest larval weight gains, followed by the anti-McCDA1 and anti-McIIM2 antisera treatments. The interaction of treatment with time was found significant by the 6th day and the interaction of concentration with time was found significant only by the 12th day. No difference was found between the larval weights from all treatments at concentrations of 1 or 4%.

A highly efficient rare earth metal oxide nanorods based platform for aflatoxin detection.

The nanostructured rare earth metal oxide (samarium oxide, n-Sm2O3) nanorods, prepared using a forced hydrolysis technique, have been electrophoretically deposited (EPD) onto an indium-tin-oxide (ITO) glass substrate. This novel platform has been utilized for co-immobilization of monoclonal antibodies of aflatoxin B1 (Ab-AFB1) and bovine serum albumin (BSA) via electrostatic interactions for food toxin (AFB1) detection. Thus prepared n-Sm2O3 nanorods have been characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopic techniques. The results of electrochemical response studies of the BSA/Ab-AFB1/n-Sm2O3/ITO immunoelectrode obtained as a function of aflatoxin concentration reveal a linearity of 10-700 pg mL-1, a detection limit of 57.82 pg mL-1 cm-2, a response time of 5 s and a sensitivity of 48.39 μA pg-1 mL-1 cm-2 with a regression coefficient of 0.961. The association constant (Ka) for antigen-antibody interactions obtained is 47.9 pg mL-1, which indicates high affinity of antibodies towards the antigen (AFB1). The application of n-Sm2O3 modified electrode for immunosensor analysis offers a novel platform and efficient strategy for the application of rare earth metal oxide materials in bioelectronics.

Electrophoretically deposited reduced graphene oxide platform for food toxin detection

Reduced graphene oxide (RGO) due to its excellent electrochemical properties and large surface area, has recently aroused much interest for electrochemical biosensing application. Here, the chemically active RGO has been synthesized and deposited onto an indium tin oxide (ITO) coated glass substrate by the electrophoretic deposition technique. This novel platform has been utilized for covalent attachment of the monoclonal antibodies of aflatoxin B1 (anti-AFB1) for food toxin (AFB1) detection. The electron microscopy, X-ray diffraction, and UV-visible studies reveal successful synthesis of reduced graphene oxide while the XPS and FTIR studies suggest its carboxylic functionalized nature. The electrochemical sensing results of the anti-AFB1/RGO/ITO based immunoelectrode obtained as a function of aflatoxin concentration show high sensitivity (68 μA ng(-1) mL cm(-2)) and improved detection limit (0.12 ng mL(-1)). The association constant (ka) for antigen-antibody interaction obtained as 5 × 10(-4) ng mL(-1) indicates high affinity of antibodies toward the antigen (AFB1).

Molecularly Imprinted Polymers for the Detection of Food Toxins: A Minireview

Food contamination from natural or anthropogenic sources poses severe risks to human health. It is now largely accepted that continuous exposure to low doses of food Toxins such as mycotoxins, phycotoxins can be related to several chronic diseases, including some type of cancer and serious hormonal dysfunctions. Contemporary analytical methods have the sensitivity required for contamination detection and quantification, but direct application of these methods on real samples can be rarely performed because of matrix complexity. Thus, selective analytical methods, relying on intelligent functional materials are needed. Recent years have seen the increasing use of molecular imprinted polymers in contaminant analysis in food because these materials seem to be particularly suitable for applications where analyte selectivity is essential. It offers several advantages to the agrofood industry in areas such as analysis, sensoring, extraction, or preconcentration of components. It has the potential of becoming a tool for acquiring truly simple, rapid, and robust direct measurements.