Food Toxins Research Articles

Label-free electronic detection of bio-toxins using aligned carbon nanotubes

A facile route for sensitive label-free detection of bio-toxins using aligned single walled carbon nanotubes is described. This approach involves patterning of a catalyst on the surface of a quartz substrate using a sub-100μm stripe-patterned polydimethylsiloxane stamp for aligned carbon nanotube generation followed by fabrication of field effect transistor (FET). Atomic force microscopy, field emission scanning electron microscopy and Raman spectroscopy are employed to characterize the synthesized nanotubes. Unlike previous reports, the adopted approach enables direct electronic detection of bio-toxins with sensitivities comparable to ELISA. As a proof of concept, the fabricated FET responds to nM concentration levels (with a LOD of ∼2nM) of epsilon toxin produced by Clostridium perfringens and a prominent food toxin. This facile approach could be customized to detect other classes of toxins and biomarkers upon appropriate functionalization of the aligned carbon nanotubes. Finally, we demonstrate the use of the FET-platform for detection of toxin in more complex matrices such as orange juice.

Application of proteomics and metabolomics for investigation of food toxins

Fungi, bacteria and other organisms secrete into the extracellular environment numerous compounds that are required for their survival. The secreted proteins and the components of the translocation systems themselves can be scrutinized in-depth by the proteomic and other “omic” tools. Many of these secretion systems are involved in pathogenic processes and indicate mechanisms of pathogenesis and could as well be of great interest for the applications in food technology and biotechnology. Further improvements in existing and developing “omic” strategies and techniques will enable studies of fungal, plant and microorganism secretomes in order to build comprehensive and confident data sets of secreted proteins and other metabolites. Network of these components will lead to the increased understanding of interactions between the host and pathogen. The identification of proteins and small molecules that are produced by a still unknown pathogen will be the first step on the way of detection and further prevention of foodborne diseases.This perspective brings the opportunity to develop new targets in order to ensure food safety that is important for human health as well as for the agriculture, food processing and storage. Ensuring food safety in the future will require new methods for identification, monitoring and assessing of foodborne hazards during production, storage, delivery and consume.In present review the use of proteomics, peptidomics and metabolomics for determination of metabolic pathways and biomarkers of pathogenicity and resistance of biotoxins in the animal and plant food contamination is discussed.

Determination of paralytic shellfish poisoning toxins by HILIC–MS/MS coupled with dispersive solid phase extraction

This paper describes the use of QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) for the extraction, cleanup and detection of 10 paralytic shellfish toxins (PSP) in sea food by HILIC–MS/MS with positive ESI. Matrix matched calibration standards were used to compensate for matrix effects. The toxins were extracted with acetonitrile/water (90:10, v/v) containing 0.1% formic acid and cleaned by HLB and GCB sorbents. Qualitative and quantitative detection for the analytes were carried out under the multiple reaction monitoring (MRM) in positive ionization mode after chromatography separation on a TSK-gel Amide-80® column (150mm×2.0mm×3μm). Studies at three fortification levels for the toxins in the range of 8.1–225.5μg/kg gave mean recoveries from 71.3% to 104.6% with relative standard deviation (RSD)⩽15.8%. The limit of detection (LOD) was below the recommended regulatory limit of 170μgSTXequ./kg and the proposed method fully meets the needs of daily monitoring.

Selective occlusion of the portal vein while maintaining hepatic artery blood flow during partial hepatectomy: a new method for preventing ischemia-reperfusion injury?

DOI of original article: 10.1016/j.jss.2012.0 * Corresponding author. Department of Obst Tel.: þþ49-89-5160-4111; fax: þþ49-89-5160E-mail address: ioannis.mylonas@med.un 0022-4804/$ e see front matter a 2013 Elsev http://dx.doi.org/10.1016/j.jss.2012.09.010 The liver is an essential multifunctional organ with diverse Severalmethods have been developed to control blood flow vital functions in nutrient metabolism, blood and bile formation, detoxification, and hormone production. Liver function can be impaired by drug and alcohol abuse, food and environmental toxins, metabolic disorders, viral infections, and congenital defects. Primary liver cancer and liver metastases, primarily from colorectal cancer, can also cause life-threatening damage to the liver [1]. Depending on comorbidities, tumor size, and the segmental distribution of tumors in the liver, the techniques of ablation, resection, or liver transplantation remain the most important and successful treatment modalities for primary and secondary liver cancer [2,3]. Because the liver is a highly vascularized and blood-rich organ, bleeding from the liver is one of the most feared complications of liver surgery. Indeed, intraoperative bleeding and the need for perioperative blood transfusion are negative predictors of mortality and longterm outcomes [4e6]. Bleeding from the liver may also cause the surgeon to convert from laparoscopic liver surgery to laparotomy [7].

Development of a rapid low cost fluorescent biosensor for the detection of food contaminants

A prototype fluorescent based biosensor has been developed for the antibody based detection of food related contaminants. Its performance was characterised and showed a typical antibody binding signal of 200–2000mV, a short term noise of 9.1mV, and baseline slope of −0.016mV/s over 4h. Bulk signal detection repeatability (n=23) and reproducibility (n=3) were less than 2.4%CV. The biosensor detection unit was evaluated using two food related model systems proving its ability to monitor both binding using commercial products and inhibition through the development of an assay. This assay development potential was evaluated by observing the biosensor's performance whilst appraising several labelled antibody and glass slide configurations. The molecular interaction between biotin and an anti-biotin antibody was shown to be inhibited by 41% due to the presence of biotin in a sample. A food toxin (domoic acid) calibration curve was produced, with %CVs ranging from 2.7 to 7.8%, and a midpoint of approximately 17ng/ml with further optimisation possible. The ultimate aim of this study was to demonstrate the working principles of this innovative biosensor as a potential portable tool with the opportunity of interchangeable assays. The biosensor design is applicable for the requirements of routine food contaminant analysis, with respect to performance, functionality and cost.

Prevalence and Levels of Bacillus cereus Emetic Toxin in Rice Dishes Randomly Collected from Restaurants and Comparison with the Levels Measured in a Recent Foodborne Outbreak

Whereas the prevalence of Bacillus cereus emetic strains in the environment has been shown to be very low, there is a lack of information on the prevalence of its toxin, cereulide, in food. Yet, the rice leftovers of a family outbreak which occurred after the consumption of dishes taken away from an Asian restaurant revealed significant amounts of cereulide, reaching up to 13,200 ng/g of food. The occurrence of cereulide in rice dishes collected from various restaurants was therefore evaluated using the liquid chromatography coupled with tandem mass spectrometry method, which allows for the direct quantification of the toxin in food. The cereulide prevalence was found to be 7.4% when samples were analyzed at the day of sampling, but reached 12.9% when exposed to temperature abuse conditions (25°C). The cereulide concentrations observed in cooked rice dishes were low (approximately 4 ng/g of food). However, since little is known yet about the potential chronic toxicity of cereulide, one needs to be very careful and vigilant.

Developing cost-effective aflatoxin detection kits

Food safety is equally important to food and nutritional security, and hence ICRISAT has given priority to this area of research. Aflatoxins are an important group of mycotoxins and pose a serious threat to food safety worldwide, but more particular developing countries where inappropriate post-harvest handling and processing facilities increase the risks. Currently >75% of the countries in the world have their own regulations on aflatoxins, indicating the level of concern that the present day world is putting on food safety issues. Unfortunately, aflatoxin contamination is often invisible, and it is difficult to physically separate contaminated grains. So it is inevitable to estimate and quantify toxins in commodities to safeguard human and animal health. Commercially available analytical and chromatographic techniques to researchers and traders are expensive. Hence ICRISAT has developed simple and cost-effective methods for detecting aflatoxins in various foods and feed commodities. ICRISAT has a fully equipped Mycotoxicology lab to produce monoclonal and polyclonal antibodies for Aflatoxin B1 and polyclonal antibodies to other mycotoxins such as Aflatoxin M1, Ochratoxin A, Fumonisin B1 by immunizing the animals with respective toxin-BSA conjugate (Devi et al. 1999, 2002). The antibodies are utilized to develop competitive ELISAs for the estimation of the toxin(s) in food, feed and milk. Two types of competitive ELISAs (direct and indirect) have been developed, and both types are heterogeneous assays that produce uniform results. The competitive ELISAs are simple, sensitive, rapid, versatile, and cost-effective for aflatoxins estimation and the results obtained were comparable with that of HPLC analysis (Waliyar et al., 2009). The sensitivity of aflatoxin M1 detection is 0.5 μg/kg, and 1.0 μg/kg for other aflatoxins and ochratoxin, and 20 μg/kg for fumonisins. This suggests that these assays meet global standards for screening food samples. In all the assays the analysis cost is about US$ 1 per sample as against the $ 30 with HPLC systems. These detection tools provide unique opportunity for ICRISAT and its partners to test a large number of samples from field trials to devise pre- and post-harvest management strategies and to deploy appropriate interventions in value chains to enhance the food safety, human/animal health, and trade. ICRISAT's thrust towards capacity building of its national partners lead to setting up of more than 20 aflatoxin detection laboratories and trained more than 150 scientists/technicians in India, Kenya, Malawi, Mali, Mexico, Mozambique, Nigeria, Philippines and Vietnam, that rely on ELISA technology. These laboratories are successfully contributing to the quality certification of farmers’ produce and enhancing product competitiveness in the global market. Recently ICRISAT developed a simple ELISA for quantitative estimation of Aflatoxin B1 albumin adducts in humans (Anitha et al., 2011).

Applications of Gas Chromatography–Mass Spectrometry (GC–MS): An Examination of Selected African Cases

As a result of the new economic order in Africa, scientists face enormous challenges due to an increase in socio and economic activities. Gas chromatography–mass spectrometry (GC–MS) will be expected to play a big role in providing some of the solutions to the challenges. Up to now, applications of GC–MS in Africa have focused on profiling natural products for their chemical composition as seen from the number of papers published between 2005 and 2011, i.e. at approximately 62 % of the total. In order to meet the new challenges, a paradigm shift is suggested in the design of research projects. Some economic activities envisaged to boom are food and beverage production for local consumption and for export to markets in the developed world. To meet the requirements of these markets, monitoring pesticides and metabolites of veterinary drugs and other toxins in food will become paramount. Africa also needs to put stringent environmental monitoring policies in place. This will aid remediation following accidental or intentional spillages of chemicals not benign to the environment.

Fluorescent nanoparticles: Sensing pathogens and toxins in foods and crops

Emerging tools in molecular nanotechnology will be useful to monitor and quantify pathogen levels and toxin production inter-and intra-cellularly and on the surface of foods. Recent developments in the manufacture and modification of fluorescent nanoparticles, quantum dots (QD), in conjunction with established molecular beacon (MB) technology, have demonstrated potential for on-the-food detection and quantification of pathogens and toxins harmful to human health. Recent research has demonstrated QDs effective use for in vivo cellular imaging, demonstrating its potential use in detecting live bacterial contamination in foods and crops. We envisage food protection systems using automated sampling of food products with near instantaneous detection and reporting of food contaminants using molecular nanotechnologies. We also address the potential limitations of these emerging technologies and how shortcomings can be addressed.

Rapid Quantification of Clostridial Epsilon Toxin in Complex Food and Biological Matrixes by Immunopurification and Ultraperformance Liquid Chromatography-Tandem Mass Spectrometry

Epsilon toxin (ETX) is one of the most lethal toxins produced by Clostridium species and is considered as a potential bioterrorist weapon. Here, we present a rapid mass spectrometry-based method for ETX quantification in complex matrixes. As a prerequisite, naturally occurring prototoxin and toxin species were first structurally characterized by top-down and bottom-up experiments, to identify the most pertinent peptides for quantification. Following selective ETX immunoextraction and trypsin digestion, two proteotypic peptides shared by all the toxin forms were separated by ultraperformance liquid chromatography (UPLC) and monitored by ESI-MS (electrospray ionization-mass spectrometry) operating in the multiple reaction monitoring mode (MRM) with collision-induced dissociation. Thorough protocol optimization, i.e., a 15 min immunocapture, a 2 h enzymatic digestion, and an UPLC-MS/MS detection, allowed the whole quantification process including the calibration curve to be performed in less than 4 h, without compromising assay robustness and sensitivity. The assay sensitivity in milk and serum was estimated at 5 ng·mL(-1) for ETX, making this approach complementary to enzyme linked immunosorbent assay (ELISA) techniques.

A concept study on identification and attribution profiling of chemical threat agents using liquid chromatography–mass spectrometry applied to Amanita toxins in food

Accidental or deliberate poisoning of food is of great national and international concern. Detecting and identifying potentially toxic agents in food is challenging due to their large chemical diversity and the complexity range of food matrices. A methodology is presented whereby toxic agents are identified and further characterized using a two-step approach. First, generic screening is performed by LC/MS/MS to detect toxins based on a list of selected potential chemical threat agents (CTAs). After identifying the CTAs, a second LC/MS analysis is performed applying accurate mass determination and the generation of an attribution profile. To demonstrate the potential of the methodology, toxins from the mushrooms Amanita phalloides and Amanita virosa were analyzed. These mushrooms are known to produce cyclic peptide toxins, which can be grouped into amatoxins, phallotoxins and virotoxins, where α-amanitin and β-amanitin are regarded as the most potent. To represent a typical complex food sample, mushroom stews containing either A. phalloides or A. virosa were prepared. By combining the screening method with accurate mass analysis, the attribution profile for the identified toxins and related components in each stew was established and used to identify the mushroom species in question. In addition, the analytical data was consistent with the fact that the A. virosa specimens used in this study were of European origin. This adds an important piece of information that enables geographic attribution and strengthens the attribution profile.

How a socio-ecological metabolism approach can help to advance our understanding of changes in land-use intensity

How a socio-ecological metabolism approach can help to advance our understanding of changes in land-use intensity

Campylobacter as a cause of gastroenteritis in humans and animals

Campylobacter is a zoonotic microorganism in human and animal population which causes gastroenteritis; it is widespread in nature. Under the present systematics, Campylobacter (Campylobacteriaceae) family consist of 16 species and 6 subspecies. Illness can occur in various animals. It causes dysentery in swine, abortion and infertility in cows, abortions in sheep and goats, avian hepatitis in poultry, and enteritis in many species including primates and pets. Campylobacter do not produce toxins in food and it is known that Campylobacter jejuni produce endotoxin (unstable at higher temperature), enterotoxin and citotoxin. Humans can be infected if they have a direct contact with animals and contaminated food. Campylobacteriosis in humans caused by C. jejuni is also known as Campylobacter enteritis. Infective dose of less than 500 cells can cause infection. Key words: Campylobacter, gastroenteritis, humans, animals, food.

Ring like self assembled Ni nanoparticles based biosensor for food toxin detection

The self-assembled ring like nickel (RnNi ∼ 10-20 nm) nanoparticles have been prepared by pulsed laser ablation method and confirmed by transmission electron microscopy. These RnNi nanoparticles electrophoretically deposited onto the indium-tin-oxide (ITO) glass substrate have been functionalized with dimethyl sulfoxide (DMSO) for covalent immobilization of anti-aflatoxin (a-AfB1) monoclonal antibodies and bovine serum albumin as blocking agent. The electrochemical response studies of a-AfB1/DMSO/RnNi-film/ITO bioelectrode reveal linearity as 5-100 ngdL−1, detection limit of 32.7 ngdL−1, sensitivity of 0.59 μA/ng dL−1, and shelf-life of 60 days. The low value (1.3 × 1014 molL−1) of association constant (Ka) shows high affinity towards aflatoxin.

Environmental contaminants and food safety

Food safety is threatened by numerous contaminants, which can originate from environmental pollution, such as toxic metals and organic halogenated compounds; chemicals used in the production of food, such as pesticides and veterinary drugs; contaminants formed during food production and cooking; contaminants arising from food packaging, or natural toxins in food. Consumers’ perceptions of food-related risks have recently been investigated in the 2010 Eurobarometer. The highest concern was reported for pesticides in fruit, vegetables and cereals, with 72% of the respondents being very or fairly worried. Somewhat fewer people were worried about residues like antibiotics and hormones in meat (70%), pollutants like mercury and dioxins (69%), food poisoning from bacteria (62%) or putting on weight (47%). Adverse effects of environmental contaminants may be displayed as developmental toxicity and endocrine disruption, with fetuses and children being vulnerable target groups. One contaminant, which has attracted much attention, is bisphenol A (BPA) and there is a scientific controversy about the low-dose health risks of BPA. BPA is used in the production of polycarbonate plastics and epoxy resins. Human exposure is mainly from packaged food and beverages. BPA binds to estrogen receptors and also acts through other mechanisms on endocrine function. We have investigated effects of BPA on steroidogenic pathways in the human adrenocortical cell line H295R. Secretion of steroidogenic hormones and intermediates were affected at non-toxic levels of BPA. The effects were mediated by inhibition of CYP17 and CYP21 and expressions of steroidogenic genes were downregulated. This may be an additional mechanism behind the endocrine disruptive effects of BPA. One of the greatest challenges in toxicology today is in predicting the risks associated with chemical mixtures. The exposure to contaminants via the diet occurs as a mixture rather than as individual compounds. Thus, food safety is to a high extent dependant on possibilities to predict risks from mixtures. The two models most frequently used are concentration addition and independent action. The main difference between the two models is the assumption of mode of action of the chemicals in the mixture. In concentration addition it is assumed that the chemicals work through a common mode of action and can be regarded as dilutions of each other. In independent action it is assumed that the chemicals act independently via different mode of actions and the mixture effect is predicted by the probabilities of response of the individual chemicals. We have investigated mixture effects of food-related chemicals on secretion of steroids in the human adrenocortical cell line. The results have been compared to the predicted effects from the two prediction models. In general the chemicals acted in an additive manner on secretion of hormones, which could be predicted by both models.

Evaluation and comparison of three enzyme-linked immunosorbent assay formats for the detection of ricin in milk and serum

Abstract When applied to the detection of a specific protein toxin in food or biological fluids in the incidence of a potential contamination, it is crucial that the assay be both sensitive and specific. In order to identify an immunoassay which is sensitive, simple, and accurate for the detection of ricin in milk and serum, three formats of sandwich enzyme-linked immunosorbent assay (ELISA) were compared utilizing the same pair of antibodies. The ELISA using a biotinylated primary detection antibody and streptavidin-linked horseradish peroxidase (HRP) system was shown to be the most sensitive assay with limits of detection (LOD) of 25 pg/mL in phosphate buffered saline (PBS), 50 pg/mL in non-fat milk, mouse serum, and 100 pg/mL in whole milk. The second best was the ELISA using a streptavidinylated primary detection antibody and biotin–HRP system, the LOD for ricin was 100 pg/mL in PBS and milk, and 1 ng/mL in serum. The ELISA using a non-tagged primary detection antibody and HRP-labeled secondary antibody performed the least sensitive among all and the LOD was 1 ng/mL in all matrices tested. Compared with the direct ELISAs (without using the capture antibody), the sandwich ELISAs were 50–500-fold more sensitive in PBS buffer. Estimation of the accuracy of these immunoassays using the Coefficient of Variability (CV) showed that the most sensitive ELISA format also had the lowest inter- (4.28%) and intra-assay CV (2.15%) although the inter- and intra-assay CV for the other two ELISAs were less than 10% and 6%, respectively, well below the maximum acceptable level. To conclude, the ELISA using a biotinylated primary detection antibody and streptavidin–HRP system is the best assay for detection of ricin in PBS, milk and serum among three ELISA formats tested and the application of this assay will be valuable to food safety research and clinical diagnosis.

Clear criteria based on absolute risk: Reforming the basis of guidelines on low‐risk drinking

The paper discusses the approach behind the Australian Guidelines to Reduce Health Risks from Drinking of 2009. The Guidelines involved a new approach to the central conundrum of low-risk drinking guidelines: how to set a guideline threshold on smooth risk curves. The context of the 2009 Guidelines is discussed in terms of previous Australian guidelines and of risk analyses and threshold setting for other risks to health and well-being, such as environmental and food toxins. The Guidelines were accordingly based on new lifetime risk modelling of absolute risk, with specification of the risk attached to the guideline thresholds of 1 in 100 lifetime mortality risk. The Guidelines thus specify no more than two Australian standard drinks a day, and no more than four drinks on any occasion. The approach described brings alcohol guidelines within a general analytical frame of guidelines and standards for hazards to health. At the level of 1 in 100 lifetime risk, there is little justification for different guidelines for men and women. On grounds of differential risk, separate guidelines for young adults might be considered, but could not be based on lifetime risk.

Scientific Opinion on the risks for animal and public health related to the presence of T-2 and HT-2 toxin in food and feed

Scientific Opinion on the risks for animal and public health related to the presence of T-2 and HT-2 toxin in food and feed

BIFLAVONOID COMPOUND FROM THE STEM BARK OF GAMBOGE (<i>Garcinia xanthochymus</i>)

Garcinia xanthochymus (Guttiferae) commonly known as gamboge, is a perennial medicinal plant native to the north of Thailand and Myanmar. Gamboge is used in watercolors, as a yellow fabric dye and traditional medicine for treating diarrhea and dysentery, dispelling worms clearing away fire and removing food toxin. Phytochemical investigations on the methanol extract of the stem bark of Garcinia xanthochymus resulted in isolation of one biflavonoid compound (+)-morelloflavon. The structure of this compound was deduced on basis of spectroscopic data including 1H NMR, 13C NMR, HMQC and HMBC and comparison with the reported data. This compound has been reported from others species of Garcinia.

Analyze and compare metabolic pathways of <I>Bacillus cereus</I> group

A large number of data and information was obtained from genome sequencing and high-throughput genomic studies, use of the information to study metabolic networks become a new hotspot in biological research. This article compared different methods to reconstruct metabolic networks and analyzed the advantages and disadvantages of each methods, and then introduced some researches about carbohydrate metabolism pathways, amino acid metabolic pathways, and energy metabolism pathways of 9 strains of Bacillus cereus, 6 strains of B. anthracis,,6 strain of B. thuringiensis, and finds out their similarities and characteristics. These three strains have some necessary metabolic pathways, such as glycolysis, tri-carboxylic acid cycle, alanine metabolism, histidine metabolism, and energy metabolism, but they may have some specific pathways. B cereus has higher efficiency in utilizing monosaccharide, B. anthracis is rich in degradation and transport pathways of amino acids. A glutamate metabolic bypass way exists in B. thuringiensis. Analysis of metabolic pathways provides a new way to study and use food toxin, anthrax toxin, and insecticidal toxin of these strains in future.