Isolation and Identification of Foodborne Pathogens of Special Interest in Food Safety

[ES] La seguridad alimentaria es una prioridad para la población y en la actualidad cobra mayor importancia por ciertas tendencias alimentarias como el consumo de alimentos crudos y la distribución generalizada de alimentos orgánicos, que pueden ser la causa de enfermedades transmitidas por alimentos. Para garantizar la seguridad alimentaria, la detección de estos microorganismos debe realizarse de manera rápida y eficiente. Par eso, el método de cultivo microbiológico se considera el oficial para la detección de estos patógenos. Sin embargo, adolece de importantes inconvenientes, ya que no solo requiere mucho tiempo, sino que también es laborioso y consume muchos recursos. Además, puede ser limitado con respecto a la detección de bacterias fisiológicamente alteradas y/o estresadas durante el almacenamiento y la conservación. En este trabajo se ha desarrollado un protocolo sencillo y rápido para la detección simultánea de E. coli, L. monocytogenes, S. aureus y S. enterica en alimentos, mediante la combinación de una etapa de co-cultivo en medio líquido y la detección por PCR múltiple. Se ha evaluado la eficiencia de varios medios de enriquecimiento y se seleccionó el agua de peptona tamponada como el medio óptimo para el co-cultivo de las cuatro bacterias diana. También se optimizaron las condiciones de PCR múltiple y se aplicaron tanto a co-cultivos como a muestras de alimentos inoculados artificialmente, lechuga orgánica y carne picada. Después de la optimización, la PCR múltiple desarrollada fue capaz de detectar las cuatro bacterias simultáneamente, hasta con una inoculación inicial de 10^0 UFC/mL. En presencia de ambas matrices alimentarias inoculadas, tras la etapa de co-cultivo, la PCR múltiple pudo detectar simultáneamente las 3 bacterias E. coli, S. enterica y L. monocytogenes, mientras que S. aureus se ha detectado por PCR simplex, a partir del mismo extracto de ADN del co-cultivo. Los resultados obtenidos permiten concluir que el uso de un paso de co-cultivo en Agua peptona tamponada, antes de la detección por PCR simple y múltiple, puede facilitar la detección simultánea de las cuatro bacterias potencialmente presentes en las matrices alimentarias. La presencia o ausencia de la bacteria diana en los alimentos se confirma en unas 30 horas, lo que reduce el tiempo requerido para la detección en comparación con el tiempo mínimo de 7 días por método cultural. Asimismo, permite reducir el número de medios de cultivo y reactivos, para el aislamiento e identificación de bacterias que no son detectadas por PCR y que no están presentes en las matrices alimentarias, lo que supone un importante ahorro económico.[CA] La seguretat alimentària sempre és una prioritat per a la població i en l' actualitat cobra major importància per certes tendències alimentàries, com el consum d' aliments crus i la distribució generalitzada d' aliments orgànics, que poden ser la causa de malalties transmeses per aliments. Per garantir la seguretat alimentària, la detecció d' aquests microorganismes s' ha de realitzar de manera ràpida i eficient. Per a això, el mètode de cultiu microbiològic es considera l' oficial per a la detecció d' aquests patògens. Però, hi ha importants inconvenients, ja que no només requereix més temps, sinó que també és laboriós i consumeix molts recursos. A més, pot ser limitat pel que fa a la detecció de bacteris fisiològicament alterats i/o estressats durant l'emmagatzematge i la conservació. En aquest treball s'ha desenvolupat un protocol senzill i ràpid per a la detecció simultània d' E. coli, L. monocytogenes, S. aureus i S. enterica en aliments, mitjançant la combinació d' una etapa de co-cultiu en medi líquid i la detecció per PCR múltiple. S'ha avaluat l'eficiència de diversos mitjans d'enriquiment i s'ha seleccionat l'aigua de peptona tamponada com el medi òptim per al co-cultiu dels quatre bacteris diana. També es van optimitzar les condicions de PCR múltiple i es van aplicar tant a co-cultius com a mostres d'aliments inoculats artificialment, enciam orgànic i carn picada. Després de l'optimització, la PCR múltiple desenvolupada va ser capaç de detectar els quatre bacteris simultàniament, fins a una inoculació inicial de 10^0 UFC/mL. En presència d' ambdues matrius alimentàries inoculades, després l' etapa de co-cultiu, la PCR múltiple va poder detectar simultàniament els 3 bacteris: E. coli, S. enterica i L. monocytogenes, mentre que S. aureus s' ha detectat per PCR simple, a partir del mateix extracte d' ADN del co-cultiu. Els resultats obtinguts permeten concloure que l' ús d' un pas de co-cultiu en Aigua de peptona tamponada, abans de la detecció per PCR simple i múltiple, pot facilitar la detecció simultània dels quatre bacteris potencialment presents en les matrius alimentàries. La presència o absència del bacteri diana en els aliments es confirma en unes 30 hores, la qual cosa redueix el temps requerit per a la detecció en comparació amb el temps mínim de 7 dies per mètode cultural. Així mateix, permet reduir el nombre de mitjans de cultiu i reactius, per a l' aïllament i identificació de bacteris que no són detectats per PCR i que no estan presents en les matrius alimentàries, la qual cosa suposa un important estalvi econòmic.[EN] Food safety is a priority for the population and is nowadays more important than ever due to certain dietary trends such as the consumption of raw foods and the widespread distribution of organic foods, which may be the cause of foodborne diseases. To ensure food safety, the detection of these microorganisms must be done quickly and efficiently. Although, the microbiological culture method is considered to be the official method for the detection of these food-borne pathogens, it suffers from significant drawbacks, such as time-consuming, laborious and expensive, in addition it may be limited regarding the detection of physiologically altered and/or stressed bacteria, during storage and preservation. In this work has been developed a simple and rapid protocol for the simultaneous detection of E. coli, L. monocytogenes, S. aureus and S. enterica in food, by combining a liquid co-culture step and detection by multiplex PCR. The efficiency of several enrichment media was evaluated and buffered peptone water was chosen as the optimal medium for the co-culture of the four target bacteria. Then, optimized multiplex PCR conditions were applied to both the co-cultures and the samples of artificially inoculated foods, organic lettuce and ground meat. After optimization, the developed multiplex PCR was able to simultaneously detect the four bacteria, up to an initial inoculation of 10^0 CFU/mL. In the presence of the two inoculated food matrices, after a co-culture step, the multiplex PCR could simultaneously detect the 3 bacteria: E. coli, S. enterica and L. monocytogenes, whereas, S. aureus has been detected by simplex PCR, from the same co-culture DNA template. The results obtained allow conclusion that the use of a co-culture step in Buffered Peptone Water, before detection by simplex and multiplex PCR, can facilitate the simultaneous detection of the four bacteria potentially present in the food matrices. The presence or the absence of the target bacteria in food is confirmed in approximately 30 hours, which reduce the time required for the detection compared to the minimum time of 7 days by cultural method. Also, it allows to reduce the number of culture media and reagents, for the isolation and identification of bacteria that are not detected by PCR and which are not initially present in the food matrices, which represents a significant economic savings.Boukharouba, A. (2022). Isolation and Identification of Foodborne Pathogens of Special Interest in Food Safety [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/182828TESI

Monitoring urban sprawl using remote sensing and landscape metrics. The case of sidi bel abbes, Algeria

In Algeria, the advance of the urban front towards the peri-urban area has been confirmed since the 1970s and today takes several forms, in particular peri-urbanisation, a new form of urban sprawl that is generating an unprecedented consumption of peri-urban land. Sidi Bel Abbès, which occupies a strategic position in the north-west of Algeria in terms of population and economic activity, is undergoing a remarkable transformation of its urban space, especially its outskirts. In order to assess this phenomenon, we thought it worthwhile to explore a suitable spatial analysis method to highlight the inconsistencies of peri-urban dynamics and to monitor spatially, quantitatively and qualitatively the consumption of land by artificial surfaces. To do this, we used high spatial resolution remote sensing and landscape metrics to characterise spatial forms and track urban expansion at scale, methods that have profoundly changed traditional methods of spatial analysis and management. the results obtained show that in 1987 the urban area of the city of Sidi Bel Abbès occupied a surface of 972.81 ha, while in 2022 the surface occupied by built-up areas amounted to 2,842.91 ha, out of a total surface of 7,054 ha, representing an increase of 1,870.1 ha over the last thirty-five years. The analysis of spatial metrics illustrates the transition from a phase of accelerated landscape fragmentation to one of continuous expansion of existing urbanisation. This expansion is the result of a high growth rate, which would correspond well to the population evolution observed during this period. The increase in built-up area reflects the changing housing needs of the population. This urban dynamic is supported by the unrestricted expansion of the outskirts of Sidi Bel Abbès

Simultaneous Detection of Four Main Foodborne Pathogens in Ready-to-Eat Food by Using a Simple and Rapid Multiplex PCR (mPCR) Assay

[EN] The increasing consumption of organic or ready-to-eat food may cause serious foodborne outbreaks. Microbiological culture for detection of food-borne pathogens is time-consuming, expensive and laborious. Thus, alternative methods such as PCR are usually employed for outbreaks investigation. In this work we aimed to develop a rapid and simple protocol for the simultaneous detection of E. coli, L. monocytogenes, S. aureus and S. enterica, by the combination of an enrichment step in a single culture broth and a multiplex PCR (mPCR) assay. The effectiveness of several enrichment media was assessed by culture and PCR. Buffered Peptone Water was selected as the optimum one. Then, mPCR conditions were optimized and applied both, to pure co-cultures and artificially inoculated food samples (organic lettuce and minced meat). In culture medium inoculated at 100 CFU/mL, mPCR was able to detect the four microorganisms. When performed on artificially food samples, the mPCR was able to detect E. coli, S. enterica and L. monocytogenes. In conclusion, Buffered Peptone Water broth can effectively support the simultaneous growth of E. coli, S. aureus, L. monocytogenes and S. enterica and could be, thus, used prior to a mPCR detection assay in ready-to-eat food, therefore considerably reducing time, efforts and costs of analyzes.FundingThis research was funded by Ministerio de Ciencia e Innovacion, Spain, Grant number PID2019-105691RB-I00. Miguel Garcia-Ferrus is the recipient of a PEJ2018- 003746A Grant from Ministerio de Economia, Industria y Competitividad, Spain.Boukharouba, A.; González Pellicer, A.; García-Ferrús, M.; Ferrús Pérez, MA.; Botella Grau, MS. (2022). Simultaneous Detection of Four Main Foodborne Pathogens in Ready-to-Eat Food by Using a Simple and Rapid Multiplex PCR (mPCR) Assay. International Journal of Environmental research and Public Health. 19(3):1-18. https://doi.org/10.3390/ijerph1903103111819

Effect of the various amounts of eCG injected after pulling of vaginal sponges on the reproduction performances of Ouled Djellal ewes and lambs

L’économie des élevages est étroitement attachée à la rentabilité des programmes de reproduction (Olynk et Wolf.,2009). Notre travail s’inscrit dans cette optique et pose la problématique de l’impact des différentes doses d’eCG à injecter après une synchronisation des chaleurs chez des agnelles et des brebis dans le but de rechercher une meilleure prolificité

A high precision n-p scattering measurement at 14.9 MeV

The n-p scattering angular distribution was measured with 14.9 MeV incident neutrons using the traditional time-of-flight technique with neutron-gamma discrimination. The scattering angle varied from 20o to 65o (laboratory system) in 5o incremental steps. The efficiency of the neutron detectors was measured in the energy range 2–9 MeV relative to the 252Cf-standard, and was calculated using Monte Carlo methods in the 2–14 MeV energy range. Two methods of analysis were applied for experimental and simulated data: a traditional approach with a fixed threshold, and a dynamic threshold approach. The present data agree with the ENDF/B-VII evaluation for the shape of n-p angular distribution within about 1.5%

Collective Quadrupole Behavior in \u3csup\u3e106\u3c/sup\u3ePd

Excited states in 106Pd were studied with the (n,n′γ) reaction, and comprehensive information for excitations with spin ≤6ℏ was obtained. The data include level lifetimes in the femtosecond regime, spins and parities, transition multipolarities, and multipole mixing ratios, which allow the determination of reduced transition probabilities. The E2 decay strength to the low-lying states is mapped up to ≈2.4 MeV in excitation energy. The structures associated with quadrupole collectivity are elucidated and organized into bands

MEASUREMENTS OF THE H(N,N) ANGULAR DISTRIBUTION OF 10MEV NEUTRON ENERGY.

Relative measurements of the cross section for scattering of neutrons by protons have been made at 10 MeV neutron energy for center-of-mass neutron scattering angles from 60' to 180'. The measurements were made using the Ohio University Accelerator Laboratory's tandem Van de Graaff accelerator with the D(d,n) reaction as the neutron source. The data are in good agreement with predictions from the phase shift analyses of Arndt, the groups of Nijmegen and Bonn, and the ENDF/B-V evaluation. The ENDF/B-VI evaluation does not appear to have the same angular dependence as the data. KEYWORDS: hydrogen cross section, neutron cross section standard, hydrogen angular distribution standar

Collective quadrupole behavior in 106Pd

Excited states in 106Pd were studied with the (n, n′γ) reaction, and comprehensive information for excitations with spin ≤ 6 ℏ were obtained. The data include level lifetimes in the femtosecond regime, spins and parities, transition multipolarities, and multipole mixing ratios, which allow the determination of reduced transition probabilities. The E2 decay strength to the low-lying states is mapped up to ≈ 2.4 MeV in excitation energy. The structures associated with quadrupole collectivity are elucidated and organized into bands