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Hypoglycin A (HGA) and its homologue methylenecyclopropylglycine (MCPrG) are present in ackee and lychee as well as seeds, leaves, and seedlings of some maple (Acer) species. They are toxic to some animal species and humans. The determination of HGA, MCPrG, and their glycine and carnitine metabolites in blood and urine is a useful tool for screening for potential exposure to these toxins. In addition, HGA, MCPrG, and/or their metabolites have been detected in milk. In this work, simple and sensitive ultra-performance liquid chromatography tandem mass spectrometry (UPLC–MS/MS) methods without derivatization were developed and validated for the quantification of HGA, MCPrG, and their metabolites in cow’s milk and urine. An extraction procedure from milk samples has been developed, whereas a dilute-and-shoot approach was implemented for urine samples. For quantification, the MS/MS analysis was performed in multiple reaction monitoring mode. The methods were validated according to the European Union guidelines using blank raw milk and urine as matrices. The limit of quantification presented here for HGA in milk (1.12 µg/L) is noticeably lower than the lowest published limit of detection (9 µg/L). Acceptable values for recovery (89–106% and 85–104% in milk and urine, respectively) and precision (≤ 20%) were obtained for all the quality control levels. The stability of HGA and MCPrG in frozen milk over a period of 40 weeks has been demonstrated. The method was applied to 68 milk samples from 35 commercial dairy farms and showed the absence of any quantifiable amounts of HGA, MCPrG, and their metabolites. Graphical Abstract

The midbrain is a subcortical area involved in central functions such as integrating sensory modalities, movement initiation and bottom-up and top-down attention. In chicken, the midbrain roof is termed optic tectum (TeO) and consists of 15 layers with distinct in- and output regions. Visual input targets the superficial layers, while auditory input terminates in deeper layers. It has been shown that ablation of sensory epithelia leads to changes in the cellular patterning and structural organization of the sensory pathways. For the tectum, ablation of the eye anlagen was shown to affect retinorecipient neurons. While the gross morphology remained intact after enucleation, the shape of dendritic endings was changed presumably due to missing presynaptic input during synaptic pruning. We investigated the effect of deafferentation in a multisensory cell type, the Shepherd's crook neuron (SCN) in the TeO. SCNs have distinct dendritic branches in retinorecipient layers (superficial layers 1 to 5 and 7) and in layers where auditory input terminates. To assess whether removal of a single sensory input only affects the dendrites recipient for that input, we removed the eye anlagen and retrogradely labeled SCNs later in embryogenesis to visualize the morphology in lesioned and non-lesioned embryos. We found no changes in the gross morphology or in the basal dendrites, but an altered growth of the fine structures at the apical dendrite of SCNs in the retinorecipient layers. Our data indicate that the neuronal morphology of SCNs is mostly predefined before retinal innervation affect the fine structure.

Single-particle inductively coupled plasma mass spectrometry (sp-ICP-MS) promises fast and selective determination of nanoparticle size and number concentrations. While several studies on practical applications have been published, data on formal, especially interlaboratory validation of sp-ICP-MS, is sparse. An international interlaboratory study was organized to determine repeatability and reproducibility of the determination of the median particle size and particle number concentration of Ag nanoparticles (AgNPs) in chicken meat. Ten laboratories from the European Union, the USA, and Canada determined particle size and particle number concentration of two chicken meat homogenates spiked with polyvinylpyrrolidone (PVP)-stabilized AgNPs. For the determination of the median particle diameter, repeatability standard deviations of 2 and 5% were determined, and reproducibility standard deviations were 15 and 25%, respectively. The equivalent median diameter itself was approximately 60% larger than the diameter of the particles in the spiking solution. Determination of the particle number concentration was significantly less precise, with repeatability standard deviations of 7 and 18% and reproducibility standard deviations of 70 and 90%. Electronic supplementary material The online version of this article (doi:10.1007/s00216-017-0427-2) contains supplementary material, which is available to authorized users.

Estimating consumer exposure to nanomaterials (NMs) in food products and predicting their toxicological properties are necessary steps in the assessment of the risks of this technology. To this end, analytical methods have to be available to detect, characterize and quantify NMs in food and materials related to food, e.g. food packaging and biological samples following metabolization of food. The challenge for the analytical sciences is that the characterization of NMs requires chemical as well as physical information. This article offers a comprehensive analysis of methods available for the detection and characterization of NMs in food and related products. Special attention was paid to the crucial role of sample preparation methods since these have been partially neglected in the scientific literature so far. The currently available instrumental methods are grouped as fractionation, counting and ensemble methods, and their advantages and limitations are discussed. We conclude that much progress has been made over the last 5 years but that many challenges still exist. Future perspectives and priority research needs are pointed out. Graphical Abstract Two possible analytical strategies for the sizing and quantification of Nanoparticles: Asymmetric Flow Field-Flow Fractionation with multiple detectors (allows the determination of true size and mass-based particle size distribution); Single Particle Inductively Coupled Plasma Mass Spectrometry (allows the determination of a spherical equivalent diameter of the particle and a number-based particle size distribution).

Die Authentizitatsprufung von Lebens- und Futtermitteln umfasst eine grose Bandbreite an Fragestellungen, Matrizes, analytischen Techniken und Forschungsansatzen, weshalb die Vernetzung von offentlichen Instituten eine immer grosere Rolle spielt. Um den Austausch zwischen Experten auf eine breitere Basis zu stellen, organisierte das Bundesinstitut fur Risikobewertung (BfR) erstmals eine bundesweite Veranstaltung fur offentliche Institute mit dem Titel „Status quo der Authentizitatsprufung von Lebens- und Futtermitteln - Analytische Routineverfahren und Forschungsansatze“. Auf Einladung des BfR berichteten Expertinnen und Experten diverser Einrichtungen des Bundes, der Landesuberwachungsbehorden und Universitaten am 13. und 14. Juni 2016 in den Tagungsraumen des BfR uber ihre bisherigen Erfahrungen und Aktivitaten in der Echtheitsuberprufung – Authentizitatsprufung – von Lebens- und Futtermitteln. Das Ziel des BfR, mit dieser Veranstaltung den wissenschaftlichen Austausch in diesem aktuellen Forschungsgebiet durch den Aufbau eines Expertennetzwerkes zu fordern, wurde erreicht.

Nanotechnology has the potential to innovate the agricultural, feed and food sectors (hereinafter referred to as agri/feed/food). Applications that are marketed already include nano-encapsulated agrochemicals or nutrients, antimicrobial nanoparticles and active and intelligent food packaging. Many nano-enabled products are currently under research and development, and may enter the market in the near future. As for any other regulated product, applicants applying for market approval have to demonstrate the safe use of such new products without posing undue safety risks to the consumer and the environment. Several countries all over the world have been active in examining the appropriateness of their regulatory frameworks for dealing with nanotechnologies. As a consequence of this, different approaches have been taken in regulating nano-based products in agri/feed/food. The EU, along with Switzerland, were identified to be the only world region where nano-specific provisions have been incorporated in existing legislation, while in other regions nanomaterials are regulated more implicitly by mainly building on guidance for industry. This paper presents an overview and discusses the state of the art of different regulatory measures for nanomaterials in agri/feed/food, including legislation and guidance for safety assessment in EU and non-EU countries.

Nanomaterials are developed for and applied in food, food additives, supplements and food contact materials. In an inventory of internet databases 140 products in the food and food-related sectors were identified that claim to contain nanomaterials. A great diversity of nanomaterials is applied, ranging from inorganic metal and metal oxides to organic nanomaterials that carry bioactive ingredients. Here we present an overview of nanomaterial applications that are currently available, discuss state of the art analytical chemical characterization and toxicological assessment methods, as well as categorization methods to support the safety evaluation of the application of nanomaterials throughout food production.

The potential impact of nanomaterials on the environment and on human health has already triggered legislation requiring labelling of products containing nanoparticles. However, so far, no validated analytical methods for the implementation of this legislation exist. This paper outlines a generic approach for the validation of methods for detection and quantification of nanoparticles in food samples. It proposes validation of identity, selectivity, precision, working range, limit of detection and robustness, bearing in mind that each “result” must include information about the chemical identity, particle size and mass or particle number concentration. This has an impact on testing for selectivity and trueness, which also must take these aspects into consideration. Selectivity must not only be tested against matrix constituents and other nanoparticles, but it shall also be tested whether the methods apply equally well to particles of different suppliers. In trueness testing, information whether the particle size distribution has changed during analysis is required. Results are largely expected to follow normal distributions due to the expected high number of particles. An approach of estimating measurement uncertainties from the validation data is given.

We have designed a cell culture system for thoracic neurons of adult Locusta migratoria that enables the establishment of functional synapses in vitro. Patch-clamp recordings revealed three different neuron classes. About half of the neurons (47%) had unexcitable somata with outward and no inward conductance. The other half generated either single (37%) or multiple action potentials (18%) and differed mainly in lower outward conductance. Selectively stained motor neurons were analyzed to demonstrate varied physiological properties due to culture conditions. Using paired patch clamp recordings we demonstrate directly synaptic transmission in morphologically connected neurons in vitro. Presynaptic stimulation resulted in postsynaptic potentials in 42 pairs of neurons tested, independent of the type of neuron. According to pharmacological experiments most of these synapses were either glutamatergic or GABAergic. In addition to these chemical synapses, electrical synapses were found. With the demonstration of synapse formation in cell culture of adult locust neurons, this study provides the basis for the future analysis of more defined insect neuronal circuits in culture.

Silver nanoparticles are recognized as effective antimicrobial agents and have been implemented in various consumer products including washing machines, refrigerators, clothing, medical devices, and food packaging. Alongside the silver nanoparticles benefits, their novel properties have raised concerns about possible adverse effects on biological systems. To protect consumer’s health and the environment, efficient monitoring of silver nanoparticles needs to be established. Here, we present the development of human metallothionein (MT) based surface plasmon resonance (SPR) sensor for rapid detection of nanosilver. Incorporation of human metallothionein 1A to the sensor surface enables screening for potentially biologically active silver nanoparticles at parts per billion sensitivity. Other protein ligands were also tested for binding capacity of the nanosilver and were found to be inferior to the metallothionein. The biosensor has been characterized in terms of selectivity and sensitivity towards different types of silver nanoparticles and applied in measurements of real-life samples—such as fresh vegetables and river water. Our findings suggest that human MT1-based SPR sensor has the potential to be utilized as a routine screening method for silver nanoparticles, that can provide rapid and automated analysis dedicated to environmental and food safety monitoring. Figure Surface plasmon resonance biosensor for rapid detection of silver nanoparticles was developed. Human metallothionein 1A (hMT1A) was immobilized on the sensor chip surface and showed dose dependent binding to the silver nanoparticles with part per billion sensitivity. Electronic supplementary material The online version of this article (doi:10.1007/s00216-012-5920-z) contains supplementary material, which is available to authorized users.

A liquid chromatography–tandem mass spectrometry method for the analysis of seven antiviral drugs, zanamivir, ribavirin, oseltamivir, oseltamivir carboxylate, amantadine, rimantadine and arbidol, in poultry muscle is reported. The antiviral drugs were extracted from the homogenized poultry muscle sample using methanol. The extract was purified using tandem solid-phase extraction combining a cation exchange cartridge and a phenylboronic acid cartridge. To prevent excessive matrix effects, the analytes were separated from the matrix constituents using a column-switch liquid chromatography system combining a reversed-phase and a Hypercarb analytical column. Detection was carried out using tandem mass spectrometry. The method was fully validated according to 2002/657/EC [1] and proved to be adequate for quantification and confirmation of zanamivir and ribavirin at 10 μg kg−1, oseltamivir, oseltamivir carboxylate, amantadine and rimantadine at levels below 1.0 μg kg−1 and for qualitative confirmatory analysis of arbidol at levels below 1 μg kg−1. Electronic supplementary material The online version of this article (doi:10.1007/s00216-011-5581-3) contains supplementary material, which is available to authorized users.

Peking duck is one of the most well-known Chinese dishes. GC–MS analysis revealed that, either benzo(a)pyrene alone, or the total amount of major PAHs with carcinogenic potential for humans, reached levels of 8.7 and 54.7 μg/kg, respectively. These levels greatly exceeded those found in grilled poultry in European countries. However, the intake of benzo(a)pyrene from a Peking duck meal (about 0.65 μg) was not higher than that from the daily intake (for residents in the same area) from vegetables alone (about 2 μg/day). Since Peking duck is still not a plebeian meat in this country, people would not consume it very often.

This article presents research based on a case study of Bern University Hospital and the Greater Bern Area that analyses the hospital's influence on innovation in the regional medical device industry. The study draws upon the concept of sectoral innovation systems enlarged with a space-oriented model of agents' innovation-related behaviour. Its main data stem from semi-structured interviews with representatives from regional companies and the hospital. The findings confirm the systemic character of innovation in medical technology and the role of university hospitals as the main functional source of medical device innovation. At the inception of the medical device industry, innovations were implemented in a regional setting, but with the maturation of the industry, this setting has yielded to an almost global setting for innovation. This international setting became prevalent largely due to the marketing considerations of the industry, showing that from an industrial management point of view, product inno...

Interest in nanoparticles (NPs) has increased explosively over the past two decades. Using NPs, high loadings of vitamins and health-benefit actives can be achieved in food, and stable flavors as well as natural food-coloring dispersions can be developed. Detection and characterization of NPs are essential in understanding the benefits as well as the potential risks of the application of such materials in food. While many such applications are described in the literature, methods for detection and characterization of such particles are lacking. Organic NPs suitable for application in food are lipid-, protein- or polysaccharide-based particles, and this review describes current analytical techniques that are used, or could be used, for identification and characterization of such particles in food products. We divide the analytical approaches into four sections: sample preparation; separation; imaging; and, characterization. We discuss techniques and reported applications for NPs or otherwise related particle compounds. The results of this investigation show that, for a successful characterization of NPs in food, at least some kind of sample preparation will be required. While a simple sample preparation may be satisfactory for imaging techniques for known analytes, for other techniques, a further separation using chromatography, field-flow fractionation or ion-mobility separation is necessary. Subsequently, photon-correlation spectroscopy and especially mass spectrometry techniques as matrix-assisted laser desorption/ionization combined with time-of-flight mass spectrometry, seem suitable techniques for characterizing a wide variety of organic NPs.

Carbon nanotubes (CNTs) are among the most promising novel nanomaterials and their unique chemical and physical properties suggest an enormous potential for many areas of research and applications. As a consequence, the production of CNT-based material and thus the occupational and public exposure to CNTs will increase steadily. Although there is evidence that nanoparticles (NPs) can enter the nervous system via the blood stream, olfactory nerves or sensory nerves in the skin, there is still only little knowledge about possible toxic effects of CNTs on cells of the nervous system. The goal of the present study was to analyse the influences of single-walled CNTs (SWCNTs) with different degrees of agglomeration on primary cultures derived from chicken embryonic spinal cord (SPC) or dorsal root ganglia (DRG). As measured by the Hoechst assay treatment of mixed neuro-glial cultures with up to 30mug/mL SWCNTs significantly decreased the overall DNA content. This effect was more pronounced if cells were exposed to highly agglomerated SWCNTs as compared to better dispersed SWCNT-bundles. Using a cell-based ELISA we found that SWCNTs reduce the amount of glial cells in both peripheral nervous system (PNS) and central nervous system (CNS) derived cultures. Neurons were only affected in DRG derived cultures, where SWCNT treatment resulted in a decreased number of sensory neurons, as measured by ELISA. Additionally, whole-cell patch recordings revealed a diminished inward conductivity and a more positive resting membrane potential of SWCNT treated DRG derived neurons compared to control samples. The SWCNT suspensions used in this study induced acute toxic effects in primary cultures from both, the central and peripheral nervous system of chicken embryos. The level of toxicity is at least partially dependent on the agglomeration state of the tubes. Thus if SWCNTs can enter the nervous system at sufficiently high concentrations, it is likely that adverse effects on glial cells and neurons might occur.

The performance of a previously developed immunochemical biosensor screening method for fluoroquinolone (FQ) antibiotics in poultry muscle, fish and egg was compared with established methods. Blank sample material of the target matrices was individually spiked with the FQs at half maximum residue levels. Homogeneity of the test materials was confirmed by liquid chromatography-mass spectrometry (LC-MS/MS). Identical sets of spiked samples as well as incurred samples from a previous feeding experiment were sent to three independent laboratories and analysed by LC-MS/MS, a microbiological assay and the new biosensor assay. The new method correctly identified all contaminated samples and demonstrated advantages in sensitivity and analysis time compared to the microbiological screening assay.

A surface plasmon resonance biosensor immunoassay has been developed for multi-residue determination of 13 (fluoro)quinolone antibiotics in poultry meat, eggs and fish. The following performance characteristics were determined according to the guidelines laid down for screening assay validation in European Decision 2002/657/EC: detection capability, specificity/selectivity, decision limit, repeatability, ruggedness and stability. The detection capability estimated for norfloxacin, the reference fluoroquinolone, was below 0.5, 1 and 1.5 ng g⁻¹ for poultry meat, egg and fish, respectively. The screening assay proved specific and showed satisfactory sensitivity below the MRL levels even though flumequine and oxolinic acid had lower cross-reactivities. A wide range of non-MRL substances were also detected at concentrations below 10 ng g⁻¹. Repeatability was good with both intra- and inter-assay coefficients of variation 56%; ruggedness was also demonstrated.

The aim of this study was to develop an optical biosensor inhibition immunoassay, based on the surface plasmon resonance (SPR) principle, for use as a screening test for 13 (fluoro)quinolones, including flumequine, used as veterinary drugs in food-producing animals. For this, we immobilised various quinolone derivatives on the sensor chip and tested binding of a range of different antibodies (polyclonal and one engineered antibody) in the presence and absence of free (fluoro)quinolones. The main challenge was to detect flumequine in an assay giving good results for the other compounds. One antigen-antibody combination proved satisfactory: polyclonal antibodies raised against a dual immunogen and, on the sensor chip, a fluoroquinolone derivative. It was the first time that this concept of the bi-active antibody was described in the literature. The assay, optimised for detection in three matrices (poultry muscle, fish, and egg), was tested on incurred samples prepared by liquid extraction followed by two washing steps. This rapid, simple method proved adequate for detecting at least 13 (fluoro)quinolones at concentrations below established maximum residue levels (MRLs). The reference molecule norfloxacin could be detected in the range of 0.1-10 microg kg(-1) in extracts of egg and poultry meat and in the range of 0.1-100 microg kg(-1) in extracts of fish. The determined midpoints of these calibration curves were about 1, 1.5 and 3 microg kg(-1) in poultry meat, egg and fish, respectively.

Solid-phase extraction of 20 L seawater samples enabled the enrichment and determination of a wide array of organic substances, including compounds of medium to high polarity, in the pg/L-range. A number of contaminants was detected and quantified throughout the North Sea, among them the pesticides dichlobenil (2,6-dichlorobenzonitrile), metolachlor and terbuthylazine as well as the industrial chemicals dichloropyridines (DCPy, 4 isomers) and nitrobenzene. Concentrations attained values up to 1.4 ng/L for dichlobenil, 0.83 ng/L for terbuthylazine, 0.61 ng/L for metolachlor, 0.13 ng/L for 2,6-DCPy, 4.37 ng/L for nitrobenzene and 1-8 ng/L for tris(chloropropyl)phosphates (TCPP). A number of North Sea water samples was screened for non-target compounds, revealing the presence of further contaminants, e.g., lindane and TCPP, as well as several biogenic and/or anthropogenic organobromine substances, among which bromoindols, -phenols and -anisoles were identified.

Seven polymeric solid-phase extraction (SPE) sorbents were evaluated with regard to their ability to extract acidic, neutral and basic pharmaceuticals and estrogens simultaneously from water at neutral pH. Highest recoveries (70-100%) for the majority of the analytes were obtained with styrene-methacrylate and styrene-N-vinylpyrrolidone co-polymers. The latter one (Oasis HLB) was chosen for further refinement of an extraction method for the quantitative determination of acidic and neutral drugs in surface water samples at detection limits below 1 ng/l. A sequential elution protocol was applied for clean-up and separation of the extracted analytes into fractions suitable for further compound specific processing. The neutral analytes as well as the acidic compounds after derivatisation were quantified by GC-MS. Caffeine, ibuprofen, its metabolites and diclofenac were detected in river water samples in the 1-100 ng/l range.

A bioassay-directed fractionation and identification (toxicity identification evaluation procedure) was performed on extracts of 10 l River Elbe water samples. The experimental method included a SDB-1 solid phase extraction followed by RP-HPLC fractionation and subfractionation. Chemical analysis by GC–MS as well as acute toxicity testing using a luminescent bacteria assay were conducted in the respective fractions. Many substances were identified, among which were pesticides and pharmaceuticals, but many compounds remained unknown.

Dendritic computation is essential for understanding information processing in single neurons and brain circuits. Optical methods are suited best to investigate function and biophysical properties of cellular compartments at high spatial and temporal resolution. Promising approaches include the use of voltage sensitive dyes, genetically encoded voltage sensors, or hybrid voltage sensors (hVoS) consisting of fluorescent proteins and voltage-dependent quenchers that, so far, are not available in avian neuroscience.We have adapted a hVoS system for a chicken midbrain slice preparation by combining genetically expressed farnesylated eGFP with dipicrylamine (DPA). Depending on the cellular potential, DPA is shifted in the membrane, resulting in quenching of eGFP fluorescence linearly to the membrane potential by Förster resonance electron transfer.In ovo electroporation resulted in labelled neurons throughout the midbrain with a high level of fine structural detail. After application of DPA, we were able to optically record electrically evoked action potentials with high signal-to-noise ratio and high spatio-temporal resolution.Standard methods available for avian neuroscience such as whole-cell patch clamp yield insufficient data for the analysis of dendritic computation in single neurons. The high spatial and temporal resolution of hVoS data overcomes this limitation. The results obtained by our method are comparable to hVoS data published for mammals.With the protocol presented here, it is possible to optically record information processing in single avian neurons at such high spatial and temporal resolution, that cellular and subcellular events can be analysed.