Bacteriological and sanitary quality of raw cow milk in the central region of Algeria

L’objectif de l’étude consiste à évaluer et à comparer la qualité bactériologique et sanitaire du lait cru de vache provenant de deux circuits de vente: directe (D) et indirect (ID). Au total, 246 échantillons de laits ont été prélevés pour des fins analytiques. Une analyse microbiologique et un dénombrement de la flore totale (FT), coliformes totaux (CT), coliformes fécaux (CF), Escherichia coli (E. coli) et Staphylococcus aureus (S. aureus) ont été réalisés. Les résidus d’antibiotiques (R.ATB) ont été détectés au moyen du DELVOTEST SP-NT. Les résultats ont révélé que la majorité des laits présente une FT dépassant le seuil de 105 UFC.ml-1. Des charges moyennes élevées de CT ont été mis en évidence dans les laits du circuit D (2,6 103 UFC.ml-1)et ID (2,5 103 UFC.ml-1). Comparativement au circuit ID, les laits du circuit D ont été significativement plus contaminés par la FT (91,8 % versus 81,0 %, P<0,05) et ont présenté une charge moyenne en E. coli et un taux de contamination en S. aureus significativement plus élevé. Les R.ATB ont été détectés à des taux de 33,3 et 29,8 %. Les laits crus analysés sont fortement contaminés par les germes et les antibiotiques, quelle que soit leur origine. Mots-clés: Lait commercialisé, qualité bactériologique, résidus d’antibiotiques, AlgérieThe objectives of this study were to evaluate and to compare the bacteriological and sanitary quality of raw cow milk coming from two sales circuits: direct (D) and indirect (ID). In all, 246 milk samples were collected for analysis. Microbiological analysis and enumeration of the total flora (TF), total coliforms (TC), faecal coliforms (CF), Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were carried out. Antibiotic residues (R.ATB) were investigated using DELVOTEST SP-NT. The results revealed that the majority of milk samples have a TF exceeding the threshold of 105 CFU.ml-1. High TC average loads were isolated in milk samples of D (2.6 103 CFU.ml-1) and ID circuit (2.5 103 CFU.ml-1).Compared to the ID circuit, milks of the D circuit were significantly more contaminated by the TF (91.8% versus 81.0 %, P<0.05), and have presented an E. coli medium load and an S. aureus contamination rate significantly higher. The antibiotics residues were detected at the rates of 33.3 and 29.8 %. Analyzed raw milks were highly contaminated by germs and antibiotics, whatever is their origin. Keywords: Marketed milk, bacteriological quality, antibiotic residues, Algeri

Elaboration of biomaterials based on fluor-glasses and boron-glasses : physico-chemical and mechanical evaluations

Ce travail de thèse porte sur le développement des nouveaux verres bioactifs de comblement osseux. Ils sont élaborés par fusion dans le système quaternaire : SiO2-CaO-Na2O-P2O5. Deux éléments chimiques (bore et fluor), ont été incorporés au sein du réseau vitreux. L’effet de la quantité des éléments ajoutés dans le verre, sur le comportement physico-chimique, mécanique et physiologique a été mené par plusieurs techniques originales. L’intégration du bore ou du fluor au sein de la matrice vitreuse, influe sur les caractéristiques thermiques des verres synthétisés. Les performances mécaniques en termes de résistance mécanique, module de Young, module de cisaillement, rigidité et dureté ont été développé par l’incorporation du fluor dans la structure vitreuse. L’effet inverse a été manifesté pour les verres à base du bore. Des essais ''in vitro'' ont prouvé que la présence du bore accélère la dissolution de la matrice vitreuse, la cinétique et la cristallisation de la couche d’hydroxyapatite. Tandis que l’ajout du fluor retarde ces phénomènes physiologiques.This thesis focuses on the development of new bioactive glasses for use as bone filling. They are synthetized by the melting method in the quaternary system CaO-SiO2-Na2O-P2O5. Two chemical elements (boron and fluor), have been incorporated in the glass network. The amount added effect, of elements, in the glass, on the physico-chemical, mechanical and physiological behaviour was led by several original techniques. The boron or fluor integration in the glass matrix, affect the thermal characteristics of the synthesized glasses. The mechanical performance in terms of: mechanical strength, Young's modulus, shear modulus, rigidity and hardness, have been developed by the fluor incorporation into the glass structure. The opposite effect was manifested for boron based glasses. In vitro tests have showed that the boron presence accelerates the vitreous matrix dissolution, the kinetics and the crystallization of the hydroxyapatite layer. While the fluor addition retards these physiological phenomena

Novel alkali borosilicate glasses: Preparation, structural investigation and thermal study

International audienceBioactive glasses are indicated for use as bone substitutes in orthopedic or dental surgery because of their high reactivity once in contact with the biological medium. Boron is known as a glass network former and an activator of the glasses bioactivity. In this work, bioactive glass was doped by 5, 10 and 20 wt% of B2O3 according to the melting process. Adding boron oxide with high content enhances glass materials’ bioactivity. Likewise, thanks to their solubility, borate-containing bioactive glasses were fluently used as orthopedic implants. The aim of our study was to investigate of boron effect on the thermal characteristics of our bioactive glass to better understand their proprieties in order for use as bone biomaterial. The obtained results proved that the more the boron content in the glass network increases, the more the melting temperature decreases and the more the thermal stability increase

Signal breathing losses in filters based on optical channel with high index modulation

International audienceIn this paper, the authors demonstrate the existence of a new type of losses later called ’signal breathinglosses’. They have adopted this name because when the optical signal propagates in the propagationchannel it changes its size and its position each half period. These dimensions changes will force the signalto get out from the transmission channel with signal losses and part of its proper power making it lessconfined. They have been able, theoretically and experimentally, to measure small variations in the signalwhich propagates in the optical propagation channel to 3D or in the plans XY, XZ and YZ.Furthermore, the authors measured and quantified the signal breathing losses based on the depth ofcorrugation, the size and of the number of periods. Then they affirmed that this type of loss increases witha significant number of periods, with periods of large dimensions, or disturbances to index modulationcharacterized by important depths. These measures were performed on a set of Bragg filters done onan optical propagation channel of type broadcasted waveguide.The authors believe the ’signal breathing’ phenomenon is similar to that of 2G and 3G wireless systemsincluding code-division multiple access (CDMA) which is the cell breathing phenomenon due to alterationof the data traffic

ABORTIONS IN CATTLE AND SHEEP HERDS IN ALGERIA, DESCRIPTIVE STUDY AND RISK FACTORS

The objective of this study is to evaluate the epidemiological situation of abortions on cattle and sheep herds and to identify some risk factors related to them. A descriptive analysis of 139 dairy cattle and 34 sheep farms showed that abortions affect 40.29% and 79.41% of cattle and sheep herds respectively; with an average abortion rate of 11.86% and 4.55% per herd respectively. The identification of risk factors was performed by univariate analysis followed by multiple logistic regression analysis. The results identified three risk factors for cattle (herd size, contact with animals from neighboring farms and presence of stillbirths/malformations) and four risk factors for sheep by univariate analysis only (housing in zriba, presence of stillbirths/malformations, infertility and presence of weak lambs). In conclusion, abortions are an important health problem in livestock farming. Identifying risk factors could help to make optimal decisions to minimize economic losses

ABORTIONS IN CATTLE AND SHEEP HERDS IN ALGERIA, DESCRIPTIVE STUDY AND RISK FACTORS

The objective of this study is to evaluate the epidemiological situation of abortions on cattle and sheep herds and to identify some risk factors related to them. A descriptive analysis of 139 dairy cattle and 34 sheep farms showed that abortions affect 40.29% and 79.41% of cattle and sheep herds respectively; with an average abortion rate of 11.86% and 4.55% per herd respectively. The identification of risk factors was performed by univariate analysis followed by multiple logistic regression analysis. The results identified three risk factors for cattle (herd size, Contact with animals from neighboring farms and presence of stillbirths/malformations) and four risk factors for sheep by univariate analysis only (housing in zriba, presence of stillbirths/malformations, infertility and presence of weak lambs). In conclusion, abortions are an important health problem in livestock farming. Identifying risk factors could help to make optimal decisions to minimize economic losses

Effet de la pasteurisation sur la qualité microbiologique du lait commercialisé dans la région de Blida (Algérie) [Effect of pasteurization on the microbiological quality of milk marketed in the region of Blida (Algeria)]

Introduction. La pasteurisation est destinée à détruire la flore pathogène et la majorité de la flore non pathogène d’altération du lait. Objectif. La présente étude avait pour objectif l’évaluation de la qualité du lait pasteurisé et la vérification du procédé de pasteurisation dans une laiterie. Matériel et méthodes. Cinquante échantillons de lait pasteurisé (20 laits crus et 30 laits reconstitués) ont été prélevés aux points de vente. Dans la laiterie, 70 échantillons ont été réalisés à des temps différents pendant la pasteurisation. L’analyse microbiologique a concerné le dénombrement de la flore totale (FT) à 30°C. Résultats. Quatre-vingt-dix % et 43% des laits crus et reconstitués pasteurisés, respectivement, sont de mauvaise qualité avec une contamination moyenne de 4,95±1,62(x105) UFC.mL-1 et de 1,64±0,38(x105) UFC.mL-1. Pour le dérou-lement de la pasteurisation, il a été observé une baisse significative de la charge en FT entre la charge initiale du lait cru 28,5±8,3(x105) UFC.mL-1 et la charge finale 0,82±0,27(x105) UFC.mL-1 (p=0,001). Les laits obtenus ont été à 78,6% de qualité acceptable et 21,4% de mauvaise qualité. Conclusion. La mauvaise qualité du lait pasteurisé à la vente est due à la mauvaise qualité du lait cru mais probablement aussi à une contamination post-pasteurisation. [Introduction. Pasteurization is intended to destroy the pathogenic flora and the majority of the non-pathogenic flora of milk alteration. Objective. The objective of this study was to assess the quality of pasteurized milk, and to verify the pasteurization process in a dairy industry. Material and methods. Fifty samples of pasteurized milk (20 raw milks and 30 reconstituted milks) were taken at the sale points. In the dairy, 70 samples were taken at different times during pasteurization. The microbiological analysis concerned the total flora (TF) at 30°C. Results. Ninety % and 43% of pasteurized raw and reconstituted milks, respectively, were of poor quality with an average contamination of 4.95±1.62(x105) CFU.mL-1 and 1.64±0.38(x105) CFU.mL-1. For the pasteurization process, a significant decrease in the TF load was observed between the initial raw milk load 28.5±8.3(x105) CFU.mL-1 and the final load 0.82±0.27(x105) CFU.mL-1 (p=0.001). The milks obtained were 78.6% of acceptable quality and 21.4% of poor quality. Conclusion. The poor quality of pasteurized milk for sale is due to the poor quality of raw milk but probably also to post-pasteurization contamination.

A Biodegradable Bioactive Glass-Based Hydration Sensor for Biomedical Applications

Monitoring changes in edema-associated intracranial pressure that complicates trauma or surgery would lead to improved outcomes. Implantable pressure sensors have been explored, but these sensors require post-surgical removal, leading to the risk of injury to brain tissue. The use of biodegradable implantable sensors would help to eliminate this risk. Here, we demonstrate a bioactive glass (BaG)-based hydration sensor. Fluorine (CaF2) containing BaG (BaG-F) was produced by adding 5, 10 or 20 wt.% of CaF2 to a BaG matrix using a melting manufacturing technique. The structure, morphology and electrical properties of the resulting constructs were evaluated to understand the physical and electrical behaviors of this BaG-based sensor. Synthesis process for the production of the BaG-F-based sensor was validated by assessing the structural and electrical properties. The structure was observed to be amorphous and dense, the porosity decreased and grain size increased with increasing CaF2 content in the BaG matrix. We demonstrated that this BaG-F chemical composition is highly sensitive to hydration, and that the electrical sensitivity (resistive–capacitive) is induced by hydration and reversed by dehydration. These properties make BaG-F suitable for use as a humidity sensor to monitor brain edema and, consequently, provide an alert for increased intracranial pressure

Thermodynamic behavior of bioactive glass in relationship with high fluorine content

International audienceFluoride (F) is important for enhancing illogical activity of bioceramics. To increase fluoride content of derived Hench bioactive glass (BaG), bioactive fluorosilicate glasses (BaG-Fx) were synthesized by using melting method and characterized using different physico-chemical analyses. Fluoride-containing BaGs were synthesized at a temperature of 1350 degrees C. Structural and thermal effect of calcium fluoride (CaF2) insertion into the glass network in the BaG: SiO2-CaO-Na2O-P2O5 quaternary system was studied. Indeed, the incorporated amounts of fluorine (CaF2) (from 5% to 20% by mass) induced significant physico-chemical changes. Through the structural study by X-ray diffraction (XRD), the amorphous character of our fluorosilicate glasses is proven. Infrared (IR) spec-troscopy proved the incorporation of fluorine into the glass matrix. In the microstructural framework, we revealed the morphological changes of the glass powders as a function of the CaF2 content. These results were confirmed by Brunauer, Emmett and Teller (BET) measurements. Through Differential Scanning Calorimetry (DSC) thermal analysis we established the impact of fluoride ions on the structural dynamics and thermodynamic properties of these newly developed bioactive glasses. Accordingly, it was possible for the first time to incor-porate as much as 20 wt% of CaF2 in BaG respecting the conditions of bioactivity and biodegradability required by Hench. After detailed analyses of the transformation entropies of BG-Fx as a function of the added CaF2 content, it can be stated that the intermolecular movements within the fluorosilicate network are more limited as a function of the added CaF2 amount. This slows down the ion exchange phenomena and subsequently the dissociation of the material in vitro, which can be anticipated to occur after implantation in vivo