No description available.

Background: The aim of this study was to investigate the risk of cross-contamination in dental tray adhesives with reusable brush systems. Methods: Four dental tray adhesives with different disinfectant components were examined for risk as a potential transmission medium for Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Streptococcus oralis, and Candida albicans. Bacterial and fungal strains were mixed with artificial saliva. The contaminated saliva was intentionally added to tray adhesive liquid samples. At baseline and up to 60 min, 100 microliters of each sample were collected and cultivated aerobically on Columbia and Sabouraud agar for 24 or 48 h, respectively. Results: At baseline, contamination with Staphylococcus aureus and Candida albicans could be identified in three out of four adhesives. In the subsequent samples, low counts of up to 20 colony-forming units per milliliter could be observed for Staphylococcus aureus. All other strains did not form colonies at baseline or subsequently. Adhesives with isopropanol or ethyl acetate as disinfectant additives were most effective in preventing contamination, while adhesives with hydrogen chloride or acetone as a disinfectant additive were the least effective. Conclusion: Within 15 min, the tested adhesives appeared to be sufficiently bactericidal and fungicidal against all microorganisms tested.

No description available.

No description available.

<p dir="ltr">Healthcare-acquired infections (HAIs) cause a burden in acute care hospitals in the United States. HAIs are caused by <i>Staphylococcus aureus</i>, along with other pathogens found on high-touch and non-high-touch surfaces in hospital environments (e.g., bed rails, blood pressure cuffs, countertops, and floors). To minimize the growth and cross-contamination of pathogens, it is vital to use disinfectants for surface decontamination. In this work, the impact of different application methods and disinfectant active agents was evaluated for use on different healthcare-related surfaces. The first study examined the cross-contamination potential of an auto-scrubber when used to clean and disinfect a 2m² vinyl floor contaminated with <i>S. aureus</i>. Five EPA-registered disinfectants and a cleaner were used with three application methods. Hydrogen peroxide and quaternary ammonium compounds-based disinfectants significantly resulted in less cross-contamination compared to the cleaner. However, there were no significant differences among the application methods used. In the second study, manual floor cleaning and disinfecting on a two-square-meter vinyl floor with three different moping materials were evaluated to assess their ability to prevent cross-contamination. Evidence showed that there were significant differences among the products used, with Hydrogen peroxide and quaternary ammonium compound products being the most effective. The cleaner caused the most cross-contamination, while cotton mops resulted in significant cross-contamination among materials used. Study three investigated the differences among four application methods used with three different wiping cloths (Cotton, microfiber, and nonwoven) on a 2m² Formica board. A spray surface and wipe method was successful in decreasing <i>S. aureus</i> on the surface. A hydrogen peroxide-based product was most effective in reducing bacteria at contamination areas and minimizing cross-contamination. Microfiber cloth picked up significantly more bacteria at contaminated areas. Post disinfection, there was evidence of cross-contamination at sampling areas regardless of product type, wiping cloth, and application methods used, with the cotton cloth causing the most cross-contamination. Viable bacteria were found on the wiping cloths used and on worker's gloves. Together, this work shows that the use of disinfectants is important in hospital environments. The choice of product, wiping material, and application method are principal in the disinfection process as they influence disinfection failure or success.</p>

Tesis por compendio / [ES] En la presente tesis doctoral se ha evaluado el uso de nuevos soportes celulósicos y silíceos como sistemas de filtración para la estabilización y conservación de alimentos líquidos con el fin de afrontar dos grandes retos de la industria de bebidas. Por un lado, evitar o minimizar los cambios en las propiedades nutricionales, estructurales y organolépticas de los alimentos, ocasionados por la pasteurización térmica tradicional, y ofrecer una alternativa al problema de la baja viabilidad debida a los altos costos de inversión/producción al aplicar nuevas tecnologías no térmicas. Por ello, esta tesis doctoral se centra en el desarrollo y evaluación de una nueva tecnología no térmica de conservación de alimentos líquidos basada en la filtración. Se han desarrollado sistemas de filtración a partir de soportes celulósicos y silíceos, sin funcionalizar o funcionalizados con compuestos antimicrobianos. En el primer capítulo se evaluó el uso de materiales de celulosa como soportes filtrantes para el tratamiento de alimentos líquidos. Como primera aproximación se desarrolló un material poroso nano-micro tubular a partir de la extracción y deslignificación del material celulósico presente en el corazón o raquis de la mazorca de maíz. El uso de este soporte resultó ser efectivo como material filtrante para el tratamiento de agua y zumo de naranja, en un sistema de flujo continuo, eliminando la carga microbiana. La aplicación de este soporte como sistema de filtración presenta diversas ventajas como su capacidad de retención microbiana, la reutilización de sub-productos del maíz y, por tanto, su respeto al medioambiente. Sin embargo, sería necesario optimizar el proceso de filtrado para evitar la frecuente obturación de sus poros que requirió varios ciclos de lavado durante el proceso, así como establecer un método de regeneración del material para incrementar su vida útil. Además, este sistema afectó al color del zumo filtrado, que no se mantuvo constante durante el proceso, lo que supone una importante desventaja que es necesaria abordar. Como segunda aproximación, se evaluó el potencial de la inmovilización de una molécula bioactiva sobre membranas de celulosa, para mejorar la capacidad de retención microbiana del material celulósico, así como permitir su reutilización. Los filtros de celulosa funcionalizados con poliaminas demostraron ser eficaces en la eliminación de patógenos en agua, debido a las cargas positivas generadas por los grupos amina inmovilizados en la superficie de las membranas, que atraen y retienen las bacterias cargadas negativamente. Dada la fácil preparación y procedimiento de uso de las membranas de celulosa funcionalizadas con poliaminas, éstas podrían ser consideradas una buena opción para el desarrollo de sistemas de tratamiento de aguas in situ, rápidos, de fácil manejo y de bajo coste. El segundo capítulo describe el desarrollo y aplicación de partículas de sílice funcionalizadas con compuestos de aceites esenciales, con el fin de diseñar coadyuvantes de filtración con actividad antimicrobiana. La filtración de diversas matrices alimentarias (agua, cerveza y zumo de manzana) a través de los soportes funcionalizados con los antimicrobianos naturales demostró ser eficaz en la reducción del recuento de la cepa patógena Escherichia coli, así como frente a la microflora endógena de la cerveza y el zumo (bacterias acidolácticas, aerobios mesófilos, psicrófilos, mohos y levaduras). La eficacia en el control microbiano se debe a la combinación de la adsorción física y la inactivación por contacto con los compuestos de aceites esenciales inmovilizados. Además, la evaluación de las propiedades físico-químicas y sensoriales de los alimentos líquidos demostró un efecto poco significativo, éste depende del tamaño de las partículas de sílice usadas y de la molécula bioactiva inmovilizada. Por lo tanto, el sistema de conservaci� / [CA] En la present tesi doctoral s'ha avaluat l'ús de nous suports cel·lulòsics i silicis com a sistemes de filtració per a l'estabilització i conservació d'aliments líquids, amb la finalitat d'afrontar dos grans reptes de la indústria de begudes. D'una banda, evitar o minimitzar els canvis en les propietats nutricionals, estructurals i organolèptiques dels aliments, ocasionats per la pasteurització tèrmica tradicional, i oferir una alternativa al problema de la baixa viabilitat deguda als alts costos d'inversió/producció en aplicar noves tecnologies no tèrmiques. Per això, aquesta tesi doctoral es centra en el desenvolupament i avaluació d'una nova tecnologia no tèrmica de conservació d'aliments líquids basada en la filtració. S'han desenvolupat sistemes de filtració a partir de suports cel·lulòsics i silicis, sense funcionalitzar o funcionalitzats amb compostos antimicrobians. En el primer capítol es va avaluar l'ús de materials de cel·lulosa com a suports filtrants per al tractament d'aliments líquids. Com a primera aproximació es va desenvolupar un material porós nano-micro tubular a partir de l'extracció i deslignificació del material cel·lulòsic present en el cor o raquis de la panolla de dacsa. L'ús d'aquest suport va resultar ser efectiu com a material filtrant per al tractament d'aigua i suc de taronja, en un sistema de flux continu, eliminant la càrrega microbiana. L'aplicació d'aquest suport com a sistema de filtració presenta diversos avantatges com la seua capacitat de retenció microbiana, la reutilització de subproductes de la dacsa i, per tant, el seu respecte al medi ambient. No obstant això, seria necessari optimitzar el procés de filtrat per a evitar la freqüent obturació dels seus porus que va requerir diversos cicles de rentada durant el procés, així com establir un mètode de regeneració del material per a incrementar la seua vida útil. A més, aquest sistema va afectar el color del suc filtrat, que no es va mantenir constant durant el procés, la qual cosa suposa un important desavantatge que és necessari abordar. Com a segona aproximació, es va avaluar el potencial de la immobilització d'una molècula bioactiva sobre membranes de cel·lulosa, per a millorar la capacitat de retenció microbiana del material cel·lulòsic, així com permetre la seua reutilització. Els filtres de cel·lulosa funcionalitzats amb poliamines van demostrar ser eficaces en l'eliminació de patògens en aigua, a causa de les càrregues positives generades pels grups amina immobilitzats en la superfície de les membranes, que atrauen i retenen els bacteris carregats negativament. Donada la fàcil preparació i procediment d'ús de les membranes de cel·lulosa funcionalitzades amb poliamines, aquestes podrien ser considerades una bona opció per al desenvolupament de sistemes de tractament d'aigües in situ, ràpids, de fàcil maneig i de baix cost. El segon capítol descriu el desenvolupament i aplicació de partícules de sílice funcionalitzades amb compostos d'olis essencials, amb la finalitat de dissenyar coadjuvants de filtració amb activitat antimicrobiana. La filtració de diverses matrius alimentàries (aigua, cervesa i suc de poma) a través dels suports funcionalitzats amb els antimicrobians naturals va demostrar ser eficaç en la reducció del recompte del cep patogen Escherichia coli, així com enfront de la microflora endògena de la cervesa i el suc (bacteris àcid làctics, aerobis mesòfils, psicròfils, floridures i llevats). L'eficàcia en el control microbià es deu a la combinació de l'adsorció física i la inactivació per contacte amb els compostos d'olis essencials immobilitzats. A més, l'avaluació de les propietats fisicoquímiques i sensorials dels aliments líquids estudiats va demostrar un efecte poc significatiu, aquest depèn de la grandària de les partícules de sílice usades i de la molècula bioactiva immobilitzada. Per tant, el sistema de conserv / [EN] In the present doctoral thesis the use of new cellulosic and silica supports as filtering systems for the stabilization and preservation of liquid foods has been evaluated to overcome two major challenges of the beverage industry. On the one hand, avoid or minimize the changes in the nutritional, structural and organoleptic properties of food caused by traditional thermal pasteurization, and offer an alternative to the problem of low viability due to high investment/production costs when applying new non-thermal technologies. Therefore, this doctoral thesis focuses on the development and evaluation of a new non-thermal technology for the preservation of liquid foods based on filtration. The filtering systems have been developed from cellulosic and silica supports, non-modified or functionalized with antimicrobial compounds. In the first chapter, the use of cellulose materials as filtering supports for the treatment of liquid foods was evaluated. As first approximation, a porous nano-micro tubular material was developed from the extraction and delignification of the cellulosic material present in the corn stalk. The use of this support was effective as filtering material for the treatment of water and orange juice, in a continuous flow system, eliminating the microbial load. The application of this support as filtering system has several advantages, such as its microbial retention capacity, the reuse of corn by-products and, therefore, its respect for the environment. However, it would be necessary to optimize the filtering process to avoid the frequent clogging of its pores that required several washing cycles during the process, as well as to establish a method of material regeneration to increase its life. In addition, this system affected the color of the filtered juice, which did not remain constant during the process, representing an important disadvantage that must be addressed. As a second approach, the potential of the immobilization of a bioactive molecule on cellulose membranes was evaluated to improve the microbial retention capacity of the cellulosic material, as well as to allow its reuse. The cellulose filters functionalized with polyamines proved to be effective in eliminating pathogens in water, due to the positive charges generated by the amine groups immobilized on the surface of the membranes, which attract and retain the negatively charged bacteria. Given the easy preparation and usage of the polyamines-functionalized cellulose membranes, these could be considered a good option for the development of fast, easy to use and low cost in situ water treatment systems. The second chapter describes the development and application of silica particles functionalized with essential oil components to design filtering aids with antimicrobial activity. The filtration of various food matrices (water, beer and apple juice) through the supports functionalized with natural antimicrobials proved to be effective in reducing the load of the pathogenic strain Escherichia coli, as well as reducing the endogenous microflora of beer and the juice (lactic acid bacteria, mesophilic, psychrophilic, mold and yeast). The removal capability is due to the combination of physical adsorption and contact inactivation with the essential oil compounds immobilized. In addition, the evaluation of the physicochemical and sensory properties of the liquid foods studied showed a not significant effect, it depends on the size of the silica particles used and the immobilized bioactive molecule. Therefore, the proposed preservation system has a high potential for cold beverage pasteurization processes. / N. Peña-Gomez would like to thank for financial support in the frame of her PhD project to Operational Programme of the European Social Fund (ESF) 2014-2020, the Agencia Estatal de Investigación, Generalitat Valenciana and FEDER-EU (Projects RTI2018-101599-B-C21 and AGL2015-70235-C2-1-R). The authors also thank the Electronic Microscopy & Microanalysis Laboratory at Patras University for support. / Peña Gomez, N. (2020). Development of polymeric and silica filtering materials functionalized with antimicrobial compounds for the elimination of microorganisms in liquid food [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/137041 / Compendio

Natto and sprout soybeans are produced using small-seeded soybeans and their production is a high value alternative to grow grain soybeans for food in U.S. The development of soybean cultivars with improved natto and sprout quality is crucial for maintaining and increasing the soyfood market. However, there is insufficient information on sprout soybean characteristics. Therefore, the first objective of this study was to evaluate seed and sprout traits as potential selection criteria and study the storage effect on sprout quality. Seeds can be a vehicle for transmission of pathogens capable of causing human illness. That is why, the second objective was to identify seed-borne pathogens on a commercial soybean cultivar and to evaluate different seed decontamination treatments. Finally, seed coat deficiency is an undesirable trait for natto soybean seeds because it causes inferior appearance of the product. Thus, the third objective was to identify quantitative trait loci (QTL) underlying seed coat deficiency (SCD) and associated markers. Results showed that seed size, high-, average- and low-quality sprout percentage, hypocotyl thickness and length and sprout yield are the most important variables for breeding sprout cultivars; and one-year seed storage at room temperature reduced sprout quality. Fusarium, Alternaria and Diaphorte were the most frequent genera isolated from soybean seeds, and 2% calcium hypochlorite and 5% acetic acid were promising seed disinfection treatments. A stable QTL, qSCD20_1, was identified across two years explaining up to 25% of the variation of SCD; and eight molecular markers tightly linked and nearby qSCD20_1 were identified. Information presented will be helpful for sprout and natto soybean cultivar development. / Master of Science / Natto and sprout soybeans are produced using by small-seeded soybeans and their production is a high value alternative to grow grain soybeans for feed in U.S. The development of soybean cultivars with improved natto and sprout quality is crucial for maintaining and increasing the soyfood market. However, there is insufficient information on sprout soybean characteristics. Therefore, the first objective of this study was to evaluate important seed and sprout traits as potential selection criteria of soybean cultivars and study the storage effect on sprout quality. Seeds can be contaminated with fungi capable of causing human illness. So, the second objective was to identify fungus species associated with seeds of a sprout soybean cultivar and evaluate different seed disinfection treatments. Finally, seed coat deficiency is an undesirable trait for natto soybean seeds because it causes inferior appearance of the product. Thus, the third objective was to identify molecular markers associated with seed coat deficiency. Results showed that seed size, high-, average- and low-quality sprout percentage, hypocotyl thickness and length and sprout yield are the most important variables for breeding sprout cultivars; and one-year seed storage at room temperature reduced sprout quality. Fungal species that may cause human illness were isolated from sprout soybean seeds and calcium hypochlorite and acetic acid are promising seed disinfection treatment for reducing fungus incidence. Finally, eight molecular markers associated with seed coat deficiency were identified which may be potentially used in selecting natto soybean cultivars with low seed coat deficiency. Information presented will be helpful for sprout and natto soybean cultivar development.

Thesis (M. Tech. Environmental health) -- Central University of technology, Free State, 2011 / In nature microorganisms do not exist alone, but in association with one another. These kinds of associations can also be found in food industries, where cells of the same or different species can attach to pipes (biofilm formation) and a variety of surfaces in food processing environments and in food product such as yoghurt which can contain both yeast and bacteria originating from the starter culture as well as fruit. To control food spoilage organisms and food-borne pathogens preventative measures such as good manufacturing processes, the use of sanitizers and preservatives as well as hazard analysis critical control points (HACCP) are crucial in food industries. Sanitation of the working surface, floors, pipes, containers and equipment is a stepwise application of a detergent, acid or alkali rinse, a disinfectant treatment followed by final rinsing. If rinsing of the sanitizer is not done properly it may end up in the product in sub-lethal doses. In this study the influence of Liquid Hypochlorite (LH) and Liquid Iodophore (LI) sanitizers on organism growth and toxicity was evaluated. The organisms investigated included Escherichia coli 0113, Escherichia coli 026 and Zygosaccharomyces bailii Y-1535 in yeast malt broth, which was supplemented with LH and LI at sub-lethal concentrations 0.05% LH, 0.2% LH and 0.075% LI. Subsequently, bacterial and yeast growth responses as pure cultures and in combination (E. coli + Z. bailii) were measured as colony forming units and optical density values. Incorporation of the sanitizers in the growth media resulted in different levels of growth inhibition. Z. bailii proved more robust and the growth rate was not influence significantly by the addition of sanitizers or communal growth with either E. coli strains. The growth rate of both E. coli strains decreased where grown in combination with Z. bailii as well as in the presence of sanitizers, with the most influence exerted by LH. Changes in endotoxicity following the growth of the test samples (stressed cells) and the control (unstressed) were measured by the limulus amoebocyte lysate (LAL) and porcine IL-6 ELISA methods. Where E. coli strains were cultured together with Z. bailii the toxicity of tire mixture showed a decrease over time when measured with the limulus amoebocyte assay method. Interestingly the communal growth of the E. coli strains and Z bailii produced different toxicity profiles when the IL-6 porcine method was used, hi both cases, where E. coli strains were cultured together with Z. bailii the toxicity of the mixture showed an increase over tune when measured by this assay. Other than a similar toxicity profile for E. coli 0113 grown in pure culture, the comparison between results obtained using the LAL or porcine IL-6 methods yielded no correlation in determined toxicity. It was established that LH and LI sanitizers as well as communal growth had an influence in the toxicity of LPS/EPS and the method used to determine such toxicity should be carefully considered.

Thesis (D. Tech. (Biomedical Technology)) -- Central University of Technology, Free State, 2015 / This study reviewed national and international literature to develop an audit-feedback instrument (AFI) to monitor adherence of South African oral health care facilities with compliance to infection prevention and control precautions. In a multi-phased literature search, existing infection prevention and control recommendations, guidelines and audit-feedback instruments were reviewed and broadened to include “dental audit tools”, as well as audit tools from other health care disciplines. Audit-feedback instruments were scrutinised for user friendliness, the use of simple language, electronic calculations and feedback possibilities. A new South African AFI was proposed, considering the differences between public and private oral health care facilities and also the diversity of training levels of oral health care personnel employed. Eleven focus areas supporting all aspects of infection prevention and control in oral health care facilities, including administrative controls; personnel protection controls; environmental- and work controls; surface contamination management; equipment maintenance, service or repair; air- and waterline management; personal protective equipment usage; personal and hand hygiene practices; sterilisation practices; safe sharps handling and waste management were included. The AFI was tested in a sample of 50 oral health care facilities. None of the participating facilities demonstrated 100% compliance. Personal- and hand hygiene practices and waste management performed the best, at respectively 75% and 63%, while administrative controls and air- and waterline management scored the lowest mean values; 31% and 36% respectively The general lack of compliance with infection prevention and control precautions in the participating oral health care facilities clearly poses a safety hazard to both patients and oral health care workers. Results indicate that adherence of South African oral health care facilities with compliance to infection prevention and control precautions need to be improved. The AFI should go a long way towards improving safety and the high expectations about providing quality infection prevention and control outcomes in oral health care.

Dans les environnements naturels, industriels ou médicaux, les microorganismes sont majoritairement présents en étant associés aux surfaces dans des communautés hautement organisées appelées biofilms. Ces édifices biologiques constituent une stratégie de survie étonnement efficace témoignant d’une grande capacité de résistance à différent stress environnementaux tels que les traitements de nettoyage et de désinfection. L’impact des biofilms d’un point de vue sanitaire est donc considérable du fait qu’ils permettent la persistance et la transmission de germes pathogènes dans l’environnement. Dans ce contexte, ce travail de thèse avait pour objectif une meilleure compréhension des phénomènes limitant l’efficacité de désinfectants au sein des biofilms en s’appuyant notamment sur des techniques innovantes d’imagerie de fluorescence non-invasive. Le but final étant d’apporter des éléments utiles à l’optimisation des traitements de désinfection. Dans une première partie, une méthode d’investigation structurale à haut-débit par microscopie confocale a été développée et utilisée pour étudier la diversité architecturale des biofilms bactériens formés par un large panel de souches. Cette étude nous a permis d’identifier des souches d’intérêt en termes de structures de biofilms formés pour la suite du travail. Nous avons notamment pu mettre en évidence la capacité de B. subtilis à former des structures importantes et avec une architecture spécifique dans un système immergé. Dans une deuxième partie, les dynamiques d’action spatiotemporelles de désinfectants ont été visualisées dans les biofilms de souches de P. aeruginosa ou B. subtilis par des approches de microscopie confocale de fluorescence en temps réel. L’utilisation de cette technique nous a permis de mettre en évidence les difficultés de pénétration du chlorure de benzalkonium au sein des structures formées par différentes souches de P. aeruginosa. La corrélation des paramètres cinétiques d’inactivation et des données obtenues par la caractérisation biochimique de la matrice suggère un rôle majeur des substances extracellulaires dans la limitation de pénétraton du désinfectant. Nous avons également pu montrer une résistance marquée du biofilm formé par une souche de B. subtilis isolée d’un dispositif médical à l’acide péracétique, à la concentration et au temps d’utilisation du biocide dans le milieu médical. De plus, les structures tridimensionnelles formées par cette souche étaient capables de protéger le pathogène Staphylococcus aureus dans un biofilm mixte vis-à-vis du même traitement soulignant l’importance des interactions multi-espèces dans la résistance des bactéries aux désinfectants et la persistance de pathogènes dans nos environnements. / In natural, industrial or medical environments, microorganisms are present mainly in being associated with surfaces in highly organized communities called biofilms. These biological structures cosntitute a surprisingly effective survival strategy showing a large ability to withstand environmental stresses such as cleaning and disinfection treatments. Therefore, biofilms have a considerable impact on public health because they allow the persistence and transmission of pathogens. In this context, this work aimed to better understand the phenomena limiting the effectiveness of disinfectants in biofilms noticeably by using innovative imaging fluorescence non-invasive techniques. The ultimate goal was to provide data which can help to optimize disinfection treatments. In the first part, a high-throughput structural method based on confocal microscopy was developed and used to study the architectural diversity of bacterial biofilms formed by a wide range of strains. This study allowed us to identify strains of interest in terms of biofilm structure for the second part of the work. In particular, we demonstrated the ability of B. subtilis to form protruding structures with a specific architecture in a submerged system. In the second part, the spatiotemporal dynamic of the action of disinfectants were visualized in the biofilms of P. aeruginosa or B. subtilis strains by a time-lapse fluorescence confocal microscopy method. Using this technique, we showed that benzalkonium chloride encountered problems of penetration in the biofilms formed by P. aeruginosa strains. The correlation of kinetic inactivation parameters and data obtained by the characterization biochemical matrix suggested a key role of extracellular substances in the penetration limitations of the disinfectant. We also observed a pronounced resistance of the biofilm formed by a strain of B. subtilis isolated from a medical device to peracetic acid at the in-use concentration and time of biocide in medical areas. In addition, three-dimensional structures formed by this strains afforded protection to the pathogen Staphylococcus aureus in mixed biofilm against the same treatment This point highlights the importance of multi-species interactions in bacterial resistance to disinfectants and in the persistence of pathogens in our environments.