Guidelines for the establishment of microbiological criteria for foods

O Grupo de Trabalho Ocorrência Microbiológica na Cadeia Alimentar (GTOMCA) do Programa PortFIR considerou de grande importância o desenvolvimento de um documento que compilasse uma seleção de legislação e de informações relativas a Critérios Microbiológicos (CM), visando apoiar e facilitar, aos operadores e entidades do setor alimentar, a sua aplicação na validação do processo de produção, na segurança e/ou higiene dos géneros alimentícios, na adesão a boas práticas de fabrico dos mesmos, e/ou, ainda, na manutenção da sua qualidade durante o seu tempo de vida útil. Deste modo, o GTOMCA desenvolveu o Guia para o estabelecimento de critérios microbiológicos em géneros alimentícios, que foi publicado em abril de 2017, contemplando a identificação, caraterísticas e propósito dos CM, os fatores a considerar para a sua definição, nomeadamente: a categoria do alimento, o microrganismo e/ou as suas toxinas, os metabolitos e a virulência, os valores limite, o plano de amostragem, o tipo de utilização e consumo assim como o método de análise laboratorial, o ponto da cadeia alimentar onde se aplica, as medidas a tomar no caso de resultados não satisfatórios e a necessidade de revisão e atualização dos CM.The Working Group on Microbiological Occurrence on the Food Chain (GTOMCA) of Por tFIR Program considered unanimously, as an important need, the existence of a document with a selection and compilation of existing legislation and information concerning microbiological criteria (CM) as a tool to suppor t and facilitate its application by operators and entities in the food sector to validate the acceptability of the production process or the food safety or hygiene, the obser vance to good manufacturing practices or the maintenance of the food quality during its lifetime. So, GTOMCA developed a Guide for the establishment of microbiological criteria in foodstuf fs, which was published in April 2017, regarding the identification, characteristics and purpose of microbiological criteria, the factors to consider for its definition, identification, characteristics and purpose of CM and, as impor tant factors to consider the food categor y, the micro-organism and its metabolites, toxins and virulence factors, the limit values, the sampling plan, the type of food consumption as well as the analy tical method for testing the food, the point of the food chain where it is applied, the measures to be taken in the event of unsatisfactor y results and the need to review and update of the CM.info:eu-repo/semantics/publishedVersio

Simulations of Weighted Tree Automata

Simulations of weighted tree automata (wta) are considered. It is shown how such simulations can be decomposed into simpler functional and dual functional simulations also called forward and backward simulations. In addition, it is shown in several cases (fields, commutative rings, Noetherian semirings, semiring of natural numbers) that all equivalent wta M and N can be joined by a finite chain of simulations. More precisely, in all mentioned cases there exists a single wta that simulates both M and N. Those results immediately yield decidability of equivalence provided that the semiring is finitely (and effectively) presented.Comment: 17 pages, 2 figure

Electronic structure investigation of Ti3AlC2, Ti3SiC2, and Ti3GeC2 by soft-X-ray emission spectroscopy

The electronic structures of epitaxially grown films of Ti3AlC2, Ti3SiC2 and Ti3GeC2 have been investigated by bulk-sensitive soft X-ray emission spectroscopy. The measured high-resolution Ti L, C K, Al L, Si L and Ge M emission spectra are compared with ab initio density-functional theory including core-to-valence dipole matrix elements. A qualitative agreement between experiment and theory is obtained. A weak covalent Ti-Al bond is manifested by a pronounced shoulder in the Ti L-emission of Ti3AlC2. As Al is replaced with Si or Ge, the shoulder disappears. For the buried Al and Si-layers, strongly hybridized spectral shapes are detected in Ti3AlC2 and Ti3SiC2, respectively. As a result of relaxation of the crystal structure and the increased charge-transfer from Ti to C, the Ti-C bonding is strengthened. The differences between the electronic structures are discussed in relation to the bonding in the nanolaminates and the corresponding change of materials properties.Comment: 15 pages, 8 figure

Behavioral Modernity and the Cultural Transmission of Structured Information: The Semantic Axelrod Model

Cultural transmission models are coming to the fore in explaining increases in the Paleolithic toolkit richness and diversity. During the later Paleolithic, technologies increase not only in terms of diversity but also in their complexity and interdependence. As Mesoudi and O'Brien (2008) have shown, selection broadly favors social learning of information that is hierarchical and structured, and multiple studies have demonstrated that teaching within a social learning environment can increase fitness. We believe that teaching also provides the scaffolding for transmission of more complex cultural traits. Here, we introduce an extension of the Axelrod (1997} model of cultural differentiation in which traits have prerequisite relationships, and where social learning is dependent upon the ordering of those prerequisites. We examine the resulting structure of cultural repertoires as learning environments range from largely unstructured imitation, to structured teaching of necessary prerequisites, and we find that in combination with individual learning and innovation, high probabilities of teaching prerequisites leads to richer cultural repertoires. Our results point to ways in which we can build more comprehensive explanations of the archaeological record of the Paleolithic as well as other cases of technological change.Comment: 24 pages, 7 figures. Submitted to "Learning Strategies and Cultural Evolution during the Paleolithic", edited by Kenichi Aoki and Alex Mesoudi, and presented at the 79th Annual Meeting of the Society for American Archaeology, Austin TX. Revised 5/14/1

Foliar δ15N values characterize soil N cycling and reflect nitrate or ammonium preference of plants along a temperate grassland gradient

The natural abundance of stable 15N isotopes in soils and plants is potentially a simple tool to assess ecosystem N dynamics. Several open questions remain, however, in particular regarding the mechanisms driving the variability of foliar δ15N values of non-N2 fixing plants within and across ecosystems. The goal of the work presented here was therefore to: (1) characterize the relationship between soil net mineralization and variability of foliar Δδ15N (δ15Nleaf − δ15Nsoil) values from 20 different plant species within and across 18 grassland sites; (2) to determine in situ if a plant’s preference for NO3− or NH4+ uptake explains variability in foliar Δδ15N among different plant species within an ecosystem; and (3) test if variability in foliar Δδ15N among species or functional group is consistent across 18 grassland sites. Δδ15N values of the 20 different plant species were positively related to soil net mineralization rates across the 18 sites. We found that within a site, foliar Δδ15N values increased with the species’ NO3− to NH4+ uptake ratios. Interestingly, the slope of this relationship differed in direction from previously published studies. Finally, the variability in foliar Δδ15N values among species was not consistent across 18 grassland sites but was significantly influenced by N mineralization rates and the abundance of a particular species in a site. Our findings improve the mechanistic understanding of the commonly observed variability in foliar Δδ15N among different plant species. In particular we were able to show that within a site, foliar δ15N values nicely reflect a plant’s N source but that the direction of the relationship between NO3− to NH4+ uptake and foliar Δδ15N values is not universal. Using a large set of data, our study highlights that foliar Δδ15N values are valuable tools to assess plant N uptake patterns and to characterize the soil N cycle across different ecosystems

First report of the ectomycorrhizal status of boletes on the Northern Yucatan Peninsula, Mexico determined using isotopic methods

Despite their prominent role for tree growth, few studies have examined the occurrence of ectomycorrhizal fungi in lowland, seasonally dry tropical forests (SDTF). Although fruiting bodies of boletes have been observed in a dry tropical forest on the Northern Yucatan Peninsula, Mexico, their occurrence is rare and their mycorrhizal status is uncertain. To determine the trophic status (mycorrhizal vs. saprotrophic) of these boletes, fruiting bodies were collected and isotopically compared to known saprotrophic fungi, foliage, and soil from the same site. Mean δ15N and δ13C values differed significantly between boletes and saprotrophic fungi, with boletes 8.0‰ enriched and 2.5‰ depleted in 15N and 13C, respectively relative to saprotrophic fungi. Foliage was depleted in 13C relative to both boletes and saprotrophic fungi. Foliar δ15N values, on the other hand, were similar to saprotrophic fungi, yet were considerably lower relative to bolete fruiting bodies. Results from this study provide the first isotopic evidence of ectomycorrhizal fungi in lowland SDTF and emphasize the need for further research to better understand the diversity and ecological importance of ectomycorrhizal fungi in these forested ecosystems

Biogenic Volatile Organic Compound and Respiratory CO2 Emissions after 13C-Labeling: Online Tracing of C Translocation Dynamics in Poplar Plants

Globally plants are the primary sink of atmospheric CO(2), but are also the major contributor of a large spectrum of atmospheric reactive hydrocarbons such as terpenes (e.g. isoprene) and other biogenic volatile organic compounds (BVOC). The prediction of plant carbon (C) uptake and atmospheric oxidation capacity are crucial to define the trajectory and consequences of global environmental changes. To achieve this, the biosynthesis of BVOC and the dynamics of C allocation and translocation in both plants and ecosystems are important.We combined tunable diode laser absorption spectrometry (TDLAS) and proton transfer reaction mass spectrometry (PTR-MS) for studying isoprene biosynthesis and following C fluxes within grey poplar (Populus x canescens) saplings. This was achieved by feeding either (13)CO(2) to leaves or (13)C-glucose to shoots via xylem uptake. The translocation of (13)CO(2) from the source to other plant parts could be traced by (13)C-labeled isoprene and respiratory (13)CO(2) emission.In intact plants, assimilated (13)CO(2) was rapidly translocated via the phloem to the roots within 1 hour, with an average phloem transport velocity of 20.3±2.5 cm h(-1). (13)C label was stored in the roots and partially reallocated to the plants' apical part one day after labeling, particularly in the absence of photosynthesis. The daily C loss as BVOC ranged between 1.6% in mature leaves and 7.0% in young leaves. Non-isoprene BVOC accounted under light conditions for half of the BVOC C loss in young leaves and one-third in mature leaves. The C loss as isoprene originated mainly (76-78%) from recently fixed CO(2), to a minor extent from xylem-transported sugars (7-11%) and from photosynthetic intermediates with slower turnover rates (8-11%).We quantified the plants' C loss as respiratory CO(2) and BVOC emissions, allowing in tandem with metabolic analysis to deepen our understanding of ecosystem C flux

Effects of rose hip intake on risk markers of type 2 diabetes and cardiovascular disease: a randomized, double-blind, cross-over investigation in obese persons

BACKGROUND/OBJECTIVES:In studies performed in mice, rose hip powder has been shown to both prevent and reverse high-fat diet-induced obesity and glucose intolerance as well as reduce plasma levels of cholesterol. The aim of this study was to investigate whether daily intake of rose hip powder over 6 weeks exerts beneficial metabolic effects in obese individuals.SUBJECTS/METHODS:A total of 31 obese individuals with normal or impaired glucose tolerance were enrolled in a randomized, double-blind, cross-over study in which metabolic effects of daily intake of a rose hip powder drink over 6 weeks was compared with a control drink. Body weight, glucose tolerance, blood pressure, blood lipids and markers of inflammation were assessed in the subjects.RESULTS:In comparison with the control drink, 6 weeks of daily consumption of the rose hip drink resulted in a significant reduction of systolic blood pressure (-3.4%; P=0.021), total plasma cholesterol (-4.9%; P=0.0018), low-density lipoprotein (LDL) cholesterol (-6.0%; P=0.012) and LDL/HDL ratio (-6.5%; P=0.041). The Reynolds risk assessment score for cardiovascular disease was decreased in the rose hip group compared with the control group (-17%; P=0.007). Body weight, diastolic blood pressure, glucose tolerance, and plasma levels of high-density lipoprotein (HDL) cholesterol, triglycerides, incretins and markers of inflammation did not differ between the two groups.CONCLUSIONS:Daily consumption of 40 g of rose hip powder for 6 weeks can significantly reduce cardiovascular risk in obese people through lowering of systolic blood pressure and plasma cholesterol levels.European Journal of Clinical Nutrition advance online publication, 14 December 2011; doi:10.1038/ejcn.2011.203

Small- bowel mucosal changes and antibody responses after low- and moderate-dose gluten challenge in celiac disease

<p>Abstract</p> <p>Background</p> <p>Due to the restrictive nature of a gluten-free diet, celiac patients are looking for alternative therapies. While drug-development programs include gluten challenges, knowledge regarding the duration of gluten challenge and gluten dosage is insufficient.</p> <p>We challenged adult celiac patients with gluten with a view to assessing the amount needed to cause some small-bowel mucosal deterioration.</p> <p>Methods</p> <p>Twenty-five celiac disease adults were challenged with low (1-3 g) or moderate (3-5g) doses of gluten daily for 12 weeks. Symptoms, small-bowel morphology, densities of CD3+ intraepithelial lymphocytes (IELs) and celiac serology were determined.</p> <p>Results</p> <p>Both moderate and low amounts of gluten induced small-bowel morphological damage in 67% of celiac patients. Moderate gluten doses also triggered mucosal inflammation and more gastrointestinal symptoms leading to premature withdrawals in seven cases. In 22% of those who developed significant small- intestinal damage, symptoms remained absent. Celiac antibodies seroconverted in 43% of the patients.</p> <p>Conclusions</p> <p>Low amounts of gluten can also cause significant mucosal deterioration in the majority of the patients. As there are always some celiac disease patients who will not respond within these conditions, sample sizes must be sufficiently large to attain to statistical power in analysis.</p