Potassium‐ion‐selective fluorescent sensors to detect cereulide, the emetic toxin of B. cereus, in food samples and HeLa cells

We report the development of new chemical probes for cereulide, a toxic metabolite produced by specific strains of Bacillus cereus, through displacement of potassium cations from a preformed specific complex and a subsequent change in the fluorescence emission. For this purpose, we designed fluorescent probes for potassium cations that were suitable for displacement assays with cereulide from organic extracts. The fluorescence detection of natural cereulide in rice samples was achieved by using synthetic cereulide as a reference and a potassium fluorescent reporter, and this was found to be useful as a portable and fast method for the in situ detection of cereulide in food extracts. To study the fate of cereulide in live cells, we designed a procedure that was suitable for live‐cell microscopy imaging of HeLa cells by comparing the cellular location of the potassium fluorogenic probe, which stained intracellular endolysosomes, in the absence and presence of cereulide; we concluded that in the presence of cereulide, the fluorescence of the probe was decreased because of complexation of the potassium ions by cereulide.Ministerio de Econom&a y Competitividad, Spain (Projects CTQ2015-71353-R and AES-PI16/000496), Junta de Castilla y Lejn, Consejer&a de Educaci jn y Cultura y Fondo Social Europeo (Project BU232U13), and the European Commission, Seventh Framework Programme (Project SNIFFER FP7-SEC-2012–312411

EFSA Panel on Biological Hazards (BIOHAZ); Scientific Opinion on public health risks represented by certain composite products containing food of animal origin

This Opinion reviews the factors that affect microbial survival and growth in composite products, and in foods in general. It concludes that the main factors to be considered are: water activity, pH, temperature and duration of storage, processing, and intensity and duration of other non-thermal physical processes applied. Prevalence and concentration of the pathogens in food are important to determine the risk for consumers. The opinion presents a review of the quantitative microbiology models and databases that can be used to provide quantitative estimations of the impact of the above factors on the survival and growth of the main bacterial pathogens. In composite products, migration and diffusion of moisture and substances among the ingredients may change their physico-chemical parameters, particularly at the interfaces. Therefore, the assessment of the risk posed by composite products needs to consider the combinations of parameters most permissive to survival and growth of pathogens. Two complementary approaches are proposed for the identification and profiling of microbiological hazards in different specific composite products. The first one is based on past outbreaks and prevalence of hazards in the products and leads to the conclusion that the most frequent hazard-composite product combinations are Salmonella in cakes and bakery products. The second one consists in decision tools based on the impact on the pathogens of food composition and food processing. Categorisation of the risk for composite products requires information on their composition, processing and further handling, which can largely differ for foods belonging to the same category. Further conditions may influence the risk and should be verified, i.e. hygienic conditions during preparation of the composite products and their ingredients, shelf-life conditions, and reliability of cooking by consumers to inactivate pathogens. The decision tools developed apply to all composite products considered by the mandate, as well as to all other foods. © European Food Safety Authority, 201

Development of new synthetic strategies exploiting an unexpected rearrangement of vinylcyclopropanes

Vinylcyclopropanes are key intermediates in organic chemistry which undergo several important rearrangements. The group of Prof. Robiette recently discovered a new rearrangement of vinylcyclopropanes into skipped dienes proceeding at room temperature and with a high selectivity. Based on this transformation, we developed new synthetic methods targeting important but synthetically challenging scaffolds in organic synthesis: skipped dienes, β,γ-unsaturated aldehydes, primary homoallylic alcohols, α-aryl α,β-unsaturated aldehydes and, via the development of a new (4+3) annulation methodology, cycloheptadienes. We also developed a new one-carbon homologation of olefins enabling the insertion of a CHR group. All these methodologies are atom economic, easy to use and are performed under mild transition metal free reaction conditions from cheap or easily obtained reagents. The substituent effects in the key 1,2-migration process shared by almost all our methodologies was investigated by a combination of experimental and computational methods. This allowed us to improve our understanding of the mechanisms at play and the factors controlling reactivity and selectivity in these processes. These combined studies provide a better insights into the Lewis acid triggered rearrangement of donor-acceptor vinylcyclopropanes, vinylexpoxides and DACPs.(SC - Sciences) -- UCL, 202

Euthanasie et assistance au suicide : une analyse critique de la législation belge enrichie par d'éventuels apports du modèle suisse

Master [120] en droit, Université catholique de Louvain, 201

Aperçu des principaux agents pathogènes alimentaires et de leur origine zoonotique.

Oral presentation about “Aperçu des principaux agents pathogènes alimentaires et de leur origine&nbsp;zoonotique.”</p

L’identification du producteur dans la loi relative à la responsabilité du fait des produits défectueux.

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Development of new synthetic strategies exploiting an unexpected rearrangement of vinylcyclopropanes

Vinylcyclopropanes are key intermediates in organic chemistry which undergo several important rearrangements. The group of Prof. Robiette recently discovered a new rearrangement of vinylcyclopropanes into skipped dienes proceeding at room temperature and with a high selectivity. Based on this transformation, we developed new synthetic methods targeting important but synthetically challenging scaffolds in organic synthesis: skipped dienes, β,γ-unsaturated aldehydes, primary homoallylic alcohols, α-aryl α,β-unsaturated aldehydes and, via the development of a new (4+3) annulation methodology, cycloheptadienes. We also developed a new one-carbon homologation of olefins enabling the insertion of a CHR group. All these methodologies are atom economic, easy to use and are performed under mild transition metal free reaction conditions from cheap or easily obtained reagents. The substituent effects in the key 1,2-migration process shared by almost all our methodologies was investigated by a combination of experimental and computational methods. This allowed us to improve our understanding of the mechanisms at play and the factors controlling reactivity and selectivity in these processes. These combined studies provide a better insights into the Lewis acid triggered rearrangement of donor-acceptor vinylcyclopropanes, vinylexpoxides and DACPs.(SC - Sciences) -- UCL, 202

The use of liquid chromatography coupled to mass spectrometry as a necessary tool for the assessment of cereulide in food

Certain B. cereus strains are able to produce an emetic toxin named cereulide which is at the origin of numerous foodborne outbreaks with even fatal outcomes. This stressed the importance of setting up rapid and reliable quantification methods for cereulide in food products. An optimized LC-MS² method was developed in the first part of this thesis and an in-house validation was performed according to the Commission Decision 2002/657/EC. The method was compared with other concurrent methods in terms of specificity, sensitivity and time consumption. It guaranteed low detection limits in rice (LOD of 0.5 ng/g) with a good repeatability and reproducibility. The robustness of the method was tested in other food matrices coming from industry (red beans, chili con carne, and spices) or from foodborne intoxications (i.e. white and fried rice, and bean soups) in which cereulide was detected at various levels (from 1.5 ng/g up to 13 µg/g). Besides, the actual concentration of cereulide was quantified in the pasta leftovers of a recent Belgian lethal case due to B. cereus and it helped to explicitly incriminate cereulide as the most probable cause of the death. The study of critical conditions (temperature and time of storage, type of strain) influencing cereulide production revealed that the correlation between toxin production and bacterial counts is more complex than proportional. The actual role of cereulide for its bacterial producer was also assessed. The emetic toxin displays a fungistatic activity against nine fungal species (Alternaria alternata, Botrytis cinerea, Cladosporium cucumerinum, Magnaporthe grisea, Monographella nivalis, Mortierella isabellina, Sclerotinia minor, Stemphylium vesicarium and Verticillium dahliae). Finally, the presence and concentrations of cereulide in rice dishes were assessed in Asian restaurants of Brussels and Wallonia. The prevalence of cereulide (7.4 % of the dishes analysed on the day of consumption contained cereulide) was higher than previously studied for the cereulide-producing strains and encourages to further characterize the risk of B. cereus emetic food poisoning.(AGRO 3) -- UCL, 201

Le Fonds des accidents médicaux et le dommage anormal : la Cour constitutionnelle prend position

Dans un arrêt du 30 novembre 20171, la Cour constitutionnelle répond à deux questions préjudicielles posées par le Tribunal de première instance de Liège, division de Huy, dans le contexte de l’indemnisation, par le Fonds des accidents médicaux, d’un dommage consécutif à la contraction d’une infection nosocomiale

The mouse toxicity bioassay as a laboratory confirmation test for tetanus36902

no abstract available</p