Since January 2002, the European Union has adopted precise guidelines aimed at protecting the safety of meat and controlling the production chain. To this purpose, the conventional traceability of livestock and meat represents the main tool, but verification of traceability requires genetic support. At present, single nucleotide polymorphisms (SNPs) represent the most innovative molecular markers in genotyping studies. The aim of this study was to verify correct labeling in a bovine meat production chain by a real-time PCR protocol based on SNP analysis. Reference hair samples from 5,000 animals were randomly collected from 22 farms. Twelve hundred meat samples were collected at different steps of the bovine meat production chain. In particular, 1,000 meat samples were collected at the slaughterhouse and 200 samples from the same animals directly at the butcher's shop. The protocol was optimized and validated by testing a set of 16 SNP markers on 95 DNA samples from bovine sires of different breeds. Thereafter, the genotyping of 2,200 samples was conducted with a set of 12 selected SNPs to verify traceability of the meat production chain at three different stages: farm, slaughterhouse, and butcher's shop. Irregularities in conventional traceability were evidenced directly in 1.87% of the samples at the slaughterhouse. This percentage increased to 3.25% when sampling was conducted at the butcher's shop. This study demonstrates that despite the precautions adopted over the meat production chain, some critical points still exist that cause the loss of a correct association between registration numbers and samples. 相似文献
The performance of synthetic ettringite as a sorbent in fluidized bed desulphurization has been assessed and compared with that of a commercial limestone. Experiments have been carried out in a bench scale fluidized bed reactor under simulated desulphurizing (steadily oxidizing) combustion conditions. Sorbent performance has been characterized in terms of desulphurization rate, maximum sulphur uptake and attrition propensity. Fluidized bed sulphation experiments have been complemented by microstructural characterization of solid samples, accomplished via X-ray diffraction analysis, scanning electron microscopy and sulphur mapping of cross-sections of particles embedded in epoxy resin.
Experimental results show that both the rate and the maximum extent of sulphur uptake by ettringite significantly exceed those of the limestone. Maximum degree of free calcium utilization is 0.58 for ettringite compared with 0.27 for the limestone. Sulphation tests also indicate that attrition propensity of ettringite is larger than that correspondingly observed for the limestone. Microstructural characterization indicates that sulphation of ettringite takes place evenly throughout the particle cross-section, whereas sulphation of limestone mostly conforms to a core-shell pattern.
Along a parallel pathway, the rate and yield of ettringite formation by hydration of fly ash from a utility fluidized bed boiler have been assessed. Formation of ettringite in these experiments appears to be quantitative upon curing of ash at 70 °C for times up to 4 days. 相似文献
α-synuclein is a small protein that is mainly expressed in the synaptic terminals of nervous tissue. Although its implication in neurodegeneration is well established, the physiological role of α-synuclein remains elusive. Given its involvement in the modulation of synaptic transmission and the emerging role of microtubules at the synapse, the current study aimed at investigating whether α-synuclein becomes involved with this cytoskeletal component at the presynapse. We first analyzed the expression of α-synuclein and its colocalization with α-tubulin in murine brain. Differences were found between cortical and striatal/midbrain areas, with substantia nigra pars compacta and corpus striatum showing the lowest levels of colocalization. Using a proximity ligation assay, we revealed the direct interaction of α-synuclein with α-tubulin in murine and in human brain. Finally, the previously unexplored interaction of the two proteins in vivo at the synapse was disclosed in murine striatal presynaptic boutons through multiple approaches, from confocal spinning disk to electron microscopy. Collectively, our data strongly suggest that the association with tubulin/microtubules might actually be an important physiological function for α-synuclein in the synapse, thus suggesting its potential role in a neuropathological context. 相似文献
Microbiological quality and the presence of solid impurities in industrial (n = 50) and artisanal (n = 50) fresh filled pasta (n = 100) were investigated. Samples were analyzed for microbiological quality (Enterobacteriaceae and Bacillus cereus counts), pH and aw determination, and solid impurities detection. The 54.0% of artisanal samples showed unsatisfactory values for Enterobacteriaceae with high loads especially for the types filled with ricotta and vegetables. All industrial samples were characterized by Enterobacteriaceae loads <10 CFU/g. B. cereus was found in both production lines, confirming the potential role of fresh filled pasta as source of this pathogen. The light filth test showed a higher presence of solid impurities in artisanal pasta than in industrial one with a filth/sample ratio doubled in artisanal samples. Textile fibers were predominant and were found in 34.0% and 22.0% of artisanal and industrial samples, respectively. Unidentified fragments were present in 10.0% and 14.0% respectively for artisanal and industrial samples.
Practical applications
The presences of several solid impurities in industrial and artisanal samples confirm the necessity of HACCP procedures implementation to avoid their presence. It should be desirable a specific regulation and fixed limits for those foodstuffs, which are more susceptible of foreign materials contamination. 相似文献
One hundred one strains of Listeria monocytogenes isolated from seafood and cheese industry samples and from patients with listeriosis were assessed using a microtiter plate method for adhesion to polystyrene and stainless steel surfaces. The adhesion rate for these strains ranged from 3.10 to 35.29% with an inoculum of 8 x 10(8) cells per well. A strong correlation was found between adhesion to polystyrene and stainless steel microtiter plates, indicating that the intrinsic ability of L. monocytogenes to adhere to inert surfaces is stronger than the influence of the surface's physicochemical properties. The clinical strains were less adherent to inert surfaces than were the industrial strains. By integrating other factors such as location of the industrial strains, contamination type of the clinical strains, serotype, and pulsotype into the analysis, some weak but significant differences were noted. For the industrial isolates, the number of cells attached to both surfaces differed significantly depending on whether they were isolated from food or food-processing environments in the seafood and cheese industry. For clinical isolates, sporadic strains exhibited greater adhesion to polystyrene than did epidemic strains. Strains belonging to the pulsed-field gel electrophoretype clusters A and M (lineages II and I, respectively) were less able to adhere to polystyrene and stainless steel than were strains in the more common clusters. 相似文献
Using time-resolved pump-probe spectroscopy, we have performed the first investigation of the vibrational modes of gold nanoshells. The fundamental isotropic mode launched by a femtosecond pump pulse manifests itself in a pronounced time-domain modulation of the differential transmission probed at the frequency of nanoshell surface plasmon resonance. The modulation amplitude is significantly stronger, and the period is longer than that in a gold nanoparticle of the same overall size, in agreement with theoretical calculations. This distinct acoustical signature of nanoshells provides a new and efficient method for identifying these versatile nanostructures and for studying their mechanical and structural properties. 相似文献
A new complex of the Keggin trilacunary
polyoxomolybdate (PMo9) with Fe3+ ions, having the formula (PFe3Mo9), has been synthesized and characterized by chemical analysis, FT-IR, Raman, UV-VIS-NIR and EPR spectroscopy, as well as
by magnetic susceptibility measurements. Cyclic voltammetry performed at different scan rates, pH and supporting electrolyte
composition, was used to investigate the electrochemical behaviour of the PFe3Mo9 complex in acidic medium and its electrocatalytic effect on H2O2 reduction. The voltammetric waves were assigned, and the enhanced electrocatalytic efficiency of PFe3Mo9 relative to PMo9 was attributed to the presence of Fe atoms. 相似文献
In this work electrical impedance spectroscopy was applied as an alternative method for floral origin determination of unifloral honeys, which may supplement the labeling according to the European Legislation. Impedance measurements, in agreement with data from routine analyses, allowed to distinguish the unifloral honey samples and to acquire information on chemical and physical properties, such as conductivity, ash content and acidity. Equivalent electrical circuits have been extracted for each unifloral honey sample, which have been validated by means of electrical simulation, and every electrical component has been associated to a specific honey characteristic. It can be concluded that the method developed here permits rapid and easy determination of honey floral origin, no sample preparation procedure is required and it could be used in the official control laboratories. 相似文献