Le lait cru constitue un milieu de culture favorable au développement de microorganismes dès la ferme. Malgré les différentes actions comme les nettoyages, la conservation au froid et les traitements thermiques utilisés pour limiter le développement ou détruire les bactéries pathogènes et responsables de l'altération du lait, ces dernières peuvent persister, parfois grâce à la formation de biofilms. Elles vont pouvoir s'établir sur les surfaces des équipements laitiers et seront responsables de pertes financières importantes. L'objectif de ce projet était de former des modèles de biofilms mixtes reproductibles à partir de bactéries isolées de l'environnement laitier afin d'étudier leur capacité à former des biofilms et caractériser ces derniers. Pour cela, six souches bactériennes thermorésistantes responsables d'altérations ont été sélectionnées. Leur capacité à former des biofilms a été évaluée par méthode statique avec des microplaques de 96 puits. Ensuite, les interactions entre les bactéries ont été étudiées grâce à des tests sur géloses. Enfin, la formation de biofilms a été reproduite par méthode dynamique avec un bioréacteur de type CDC. Les résultats de cette étude ont permis de mettre en évidence que des souches de Pseudomonas aeruginosa, Bacillus licheniformis, Streptococcus thermophilus et Enterococcus faecalis sont de fortes productrices de biofilms alors que les souches Clostridium tyrobutyricum et Rothia kristinae sont de faibles productrices de biofilm. En condition mixte, les bactéries fortement productrices de biofilms sont dominantes. Il ne semble pas y avoir de réactions antagonistes entre les bactéries à l'exception de P. aeruginosa qui pourrait freiner la croissance de B. licheniformis et E. faecalis. Les connaissances sur les biofilms mixtes acquises lors de cette étude, ainsi que les interactions observées entre les bactéries, permettront d'envisager des stratégies de contrôle impliquant notamment des phénomènes de compétition au sein des biofilms. / Raw milk is a rich culture medium allowing the development of microorganisms from the farm. Despite the various actions such as cleaning, cold storage and heat treatments used to limit the development of milk pathogenic and spoilage bacteria, they can persist due to the formation of biofilms. They will be able to establish themselves on the surfaces of dairy equipment and will be responsible for significant financial losses. The objective of this project was to establish reproducible multi-species biofilm models from bacteria isolated from the dairy environment in order to study their ability to form biofilms and characterize them. To do this, six heat-resistant bacterial strains responsible of milk adulteration were selected. Their ability to form biofilms was evaluated by a static method with 96-wells microtiter plates. Then, interactions between bacteria were studied through agar tests. Finally, the formation of biofilms was dynamically reproduced with a CDC biofilm reactor. The results of this study have shown that strains such as Pseudomonas aeruginosa, Bacillus licheniformis, Streptococcus thermophilus and Enterococcus faecalis are strong biofilm producers while Clostridium tyrobutyricum and Rothia kristinae are weak biofilm producers. In multi-species biofilms, bacteria producing strong biofilms take over weak producers. There do not appear to be any antagonistic reactions between bacteria except P. aeruginosa which may inhibit the growth of B. licheniformis and E. faecalis. The knowledge on multispecies biofilms acquired during this study, thanks to the model formed as well as the interactions observed between bacteria, will make it possible to consider control strategies involving competition phenomena within biofilms.

The main goal of this thesis is to investigate the effects of consequences of global change on fluvial biofilms. To achieve this objective a multi-marker approach has been used at different experimental scales. Our results revealed that the consequences of eutrophication and riparian simplification caused changes in biofilm spatial organization, microbial structure and functioning. This thesis evidenced that pharmaceuticals and antibiotics detected in Llobregat River waters may cause responses at the base of river food web with still unknown consequences for freshwater ecosystems. Furthermore, we demonstrated that the bactericide Triclosan reduces the capacity of biofilm to remove phosphorus from water column. Our results also evidenced that drought episode may affect biofilms structure and function amplifying the toxicity of Triclosan for these communities. Finally, our study validates the use of biofilm phosphorus uptake capacity as a tool for the understanding of pollutions’ consequences for river self-depuration capacity / L’objectiu principal d’aquesta tesi és investigar els efectes del canvi global sobre els biofilms fluvials. Amb aquesta finalitat s’ha utilitzat un enfoc de multi-marcadors a diferents escales experimentals. Els nostres resultats demostren que l’eutrofització i la simplificació ripària causen canvis en l’organització espacial, l’estructura microbiana i el funcionament dels biofilms. Aquesta tesis evidencia que fàrmacs i antibiòtics que es varen detectar al Llobregat causen respostes a la base de la xarxa tròfica amb conseqüències ecològiques desconegudes. Es va demostrar que el bactericida Triclosan redueix la capacitat dels biofilms de captar fòsfor. Els nostres resultats també evidencien que un episodi de sequera afecta la estructura i funció dels biofilms amplificant la toxicitat del Triclosan per aquestes comunitats. Finalment, el nostre estudi valida l'ús de la capacitat de captació de fòsfor dels biofilms com eina per la comprensió dels efectes de la contaminació sobre la capacitat de auto-depuració dels rius

No description available.

La mucoviscidose reste une maladie génétique grave sans traitement curatif. L’amélioration de la prise en charge de la maladie s’est accompagnée d’une augmentation importante de l’espérance de vie qui était de moins de un an dans les années 1950 et dépasse en moyenne 40 ans pour les enfants nés aujourd’hui. <p>La mucoviscidose se caractérise au niveau pulmonaire par un mucus anormalement épais qui est difficilement évacué. Le mucus s’accumule alors dans les voies respiratoires et les bactéries y persistent et s’y multiplient. 80 à 95% des patients décèdent des suites de l’insuffisance respiratoire causée par les infections chroniques bactériennes concomitantes aux inflammations des voies aériennes. Les patients souffrent particulièrement d’infections à P. aeruginosa qui est la bactérie la plus fréquemment rencontrée dans la mucoviscidose. Lors des premières infections à P. aeruginosa les bactéries sont de phénotype non mucoïde et sont relativement sensibles aux antibiotiques. Les bactéries finissent par s’adapter dans les voies aériennes des patients atteints de mucoviscidose et forment des biofilms multiresistants aux antibiotiques. Les patients sont alors colonisés par P. aeruginosa de façon permanente. Les infections chroniques à P. aeruginosa sont responsables du déclin de la fonction respiratoire, d’exacerbations pulmonaires nécessitant une hospitalisation et de la mortalité des patients atteints de mucoviscidose. Il est donc urgent d’améliorer les traitements symptomatiques existants dans le but d’augmenter la qualité et l’espérance de vie des patients en attendant de nouveaux traitements curatifs visant à corriger l’anomalie génétique.<p>Ce travail s’est donc orienté vers l’étude de l’efficacité in vitro de différentes combinaisons d’antibiotiques vis-à-vis des biofilms bactériens. Parmi l’ensemble des associations d’antibiotiques testées une synergie d’activité a été observée entre la tobramycine et la clarithromycine sur des biofilms âgés de 24 heures mais aussi de 12 jours. Notamment parmi les 26 souches testées une synergie d’action est observée chez 11 souches après une coadministration pendant 28 jours de tobramycine et clarithromycine en doses répétées sur un biofilm « mûr » âgé de 12 jours. Parmi ces 11 souches, 7 biofilms sont entièrement détruits à la fin du traitement. <p>Sur l’ensemble des souches étudiées le traitement avec l’association est soit supérieur ou équivalent à celui de la tobramycine seule et a permis d’obtenir une action dans 53.8% des cas pour la combinaison versus 30.8% pour la tobramycine.<p>Cependant aucune corrélation n’est trouvée entre le profil génétique, le phénotype mucoïde ou non des souches et la présence de synergie d’action ou la destruction entière du biofilm.<p>Cette dernière étude s’inspire du traitement actuel de référence TOBI® qui s’administre par cycle de 28 jours, 2 fois par jour. <p>Les différents travaux de cette thèse ont permis tout d’abord de développer un modèle in vitro proche des conditions rencontrées in vivo chez les patients atteints de mucoviscidose. Ce modèle pourra également être utilisé pour une série d’autres études et mises au point de nouveaux médicaments sous forme de molécule isolée ou en combinaison. <p>Ce travail a également permis d’envisager le développement d’un nouveau médicament dans le traitement d’infections chroniques à P. aeruginosa chez les patients atteints de mucoviscidose.<p>Cependant des études futures in vivo sur souris mais aussi toxicologiques et cliniques seront indispensables pour confirmer le profil d’efficacité et de sécurité de cette association.<p><p> / Doctorat en sciences pharmaceutiques / info:eu-repo/semantics/nonPublished

Thesis (MSc)--Stellenbosch University, 2003. / ENGLISH ABSTRACT: A laboratory-scale model was used to simulate biological sulfate removal. The focus of the research was microbial community response, such as the relative abundance of functional groups to changes in influent medium composition. Specific oligonucleotide probes were obtained that recognised sulfate reducing bacteria (SRB) within the biofilm community. Terminal restriction fragment length polymorphism (T-RFLP) and BIOLOG™ Ecoplate analyses were used to study the SRB community when provided with sodium lactate, sucrose or ethanol as carbon sources in complex Postgate C broth. These two analyses, as well as conventional methods, were applied to follow succession patterns in the laboratory scale reactors, and to determine the possible presence and relative abundance of microorganisms other than bacteria under sulfate reducing conditions. T-RFLP and BIOLOG™ Ecoplate analyses indicated a few dominant organisms in the community and a slight decline after a shift to another carbon source. Fluorescent hybridization showed higher numbers of SRB relative to the total microbial community than conventional culturing techniques. Furthermore, microscopic observations showed that not only SRB and other bacteria, but also yeast and filamentous fungi were integrated in a biofilm under sulfate reducing conditions. These microscopic observations were verified with fluorescent in situ hybridization (FISH) and yeast Live I Dead viability probes. / AFRIKAANSE OPSOMMING: Biologiese sulfaat-verwydering is met behulp van "n laboratoriumskaalmodel gesimuleer. Die doel van die navorsing was om die respons van "n mikrobiese gemeenskap met byvoorbeeld die relatiewe hoeveelheid van funksionele groepe op veranderinge in invloeiende medium samestelling te bestudeer. Spesifieke oligonukleotiedpeilers wat sulfaatreduserende bakterieë (SRB) in "n biofilmgemeenskap kan opspoor is gebruik. Die SRB gemeenskap is bestudeer met behulp van terminale-restriksiefragmentlengtepolimorfisme (TRFLP) en BIOLOGTM Ecoplate analise waar natriumlaktaat, sukrose of etanol as koolstofbronne toegevoeg is. Hierdie twee tipes analise en konvensionele metodes is aangewend om suksessiepatrone in die laboratoriumskaalreaktor te volg en die moontlike teenwoordigheid en relatiewe hoeveelheid van organismes, uitsluitende bakterieë, onder sulfaatreduserende kondisies te bepaal. Analise van T-RFLP en BIOLOGTM Ecoplate het aangedui dat In paar dominante organismes in die gemeenskap teenwoordig was, wat effens afgeneem het na verskuiwing na 'n ander koolstofbron. Fluoresserende hibridisasie het hoër getalle van SRB relatief tot die totale mikrobiese gemeenskap aangedui as konvensionele kultuur tegnieke. Mikroskopiese analises het verder getoon dat benewens SRB en ander bakterieë ook giste en filamentagtige swamme onder sulfaatreduserende kondisies in "n biofilm geïntegreer was. Hierdie mikroskopiese waarneminge is bevestig deur fluoresserende in situ hibridisasie (FISH) en gis Lewe / Dood lewensvatbaarheid peilers.

published_or_final_version / Dentistry / Doctoral / Doctor of Philosophy

Le biofilm est à l’origine d’infections nosocomiales et d’intoxications alimentaires dans les secteurs alimentaire et hospitalier. Les bactéries structurées en biofilm peuvent se détacher et coloniser de nouvelles surfaces. Le risque microbiologique associé aux bactéries détachées de biofilm est peu étudié. Les travaux de thèse ont concerné, l’étude de l’effet des conditions de croissance sur les propriétés physicochimiques de surface de Staphylococcus aureus et Pseudomonas aeruginosa sous leurs formes détachées de biofilm et planctoniques, ainsi que leurs adhésion sur l'acier inoxydable (SS) et le polycarbonate (PC). Le pouvoir pathogène des deux populations bactériennes a été étudié. Les résultats ont montré que les conditions et le mode de croissance influencent les propriétés de surface et par conséquent l’adhésion de S. aureus et P. aeruginosa sur le SS et le PC. De plus, la température de croissance, le type de surface et l’âge physiologique des bactéries influencent significativement leur production des facteurs de virulence et leur cytotoxicité envers les cellules HeLa. Dans un deuxième temps, l'effet de température de croissance sur la résistance des cellules détachées de biofilm et planctoniques au chlorure de benzalkonium (BAC) a été évalué. Pour comprendre les mécanismes de résistance à l’échelle cellulaire, les lésions des membranes bactériennes associées au BAC ont été suivies par l’efflux des ions K+ intracellulaires. En outre, la fluidité membranaire de deux populations bactériennes a été caractérisée à travers l'étude de profils d'acides gras membranaires. Les résultats ont montré que la résistance au BAC dépend de la température et de l’état physiologique des bactéries. / The biofilm formation in food and medical sectors represents a significant source of foodborne and nosocomial diseases. Bacteria structured in biofilm can detach and colonize new surfaces. The microbiological risk associated with biofilm-detached bacteria is poorly studied. On one hand, the thesis concerned the study of growth conditions effect on the bacterial surface physicochemical properties as well as the adhesion of Staphylococcus aureus and Pseudomonas aeruginosa biofilm-detached and planktonic cells to stainless steel (SS) and polycarbonate (PC). The pathogenicity of both bacterial populations has also been studied. The results showed that the conditions and the mode of growth influence the surface properties and consequently the adhesion of S. aureus and P. aeruginosa on the SS and the PC. In addition, growth temperature, surface type and physiological age of bacterial cells significantly influence their production of virulence factors and their cytotoxicity towards HeLa cells. On the other hand, the effect of growth temperature on the resistance of biofilm-detached and planktonic cells to benzalkonium chloride (BAC) was assessed. In order to understand the mechanisms of resistance at the cellular level, bacterial membrane damage associated with BAC was assessed by the efflux of intracellular K+ ions. In addition, the membrane fluidity of bacterial populations was characterized through the study of membrane fatty acid profiles. The results showed that resistance to BAC depends on the temperature and physiological state of the studied bacteria.

Thesis (Master of Engineering in Chemical Engineering)--Cape Peninsula University of Technology, 2018. / Wastewater treatment methods have always gravitated towards the use of biological methods for the treatment of domestic grey water. This has been proven to offer a series of advantages such as the reduction of pollution attributed to the use of synthetic chemicals; therefore, this decreases the requirement of further costly post primary treatment methods. Although such biological methods have been used for decades, their efficiency and sustainability has always been challenged by inhibitory toxicants which renders the systems redundant when these toxins are prevalent in high concentrations, culminating in the deactivation of biomass which facilitates the treatment. In most instances, this biomass is anaerobic sludge. Hence, the proposal to utilize biofilms which are ubiquitous and selfsustaining in nature. The use of engineered biofilms in wastewater treatment and their behaviour has been studied extensively, with current research studies focusing on reducing plant footprint, energy intensity and minimal usage of supplementary synthetic chemicals. An example of such processes include traditional nitrification and denitrification systems, which are currently developed as simultaneous nitrification and aerobic denitrification systems, i.e. in a single stage system, from the historical two stage systems. However, there is limited literature on biofilm robustness against a potpourri of toxicants commonly found in wastewater; particularly for total nitrogen removal systems such as simultaneous nitrification and denitrification (SND). This study was undertaken (aim) to assess the ability of biosurfactant producing biofilms in the removal of total nitrogen in the presence of toxicants, i.e. heavy metals and phenol, as biosurfactants have been proven to facilitate better mass transfer for pollutant mitigation. Unlike in conventional studies, the assessment of biosurfactant producers in total nitrogen removal was assessed in both planktonic and biofilm state. Since biofilms are known to have increased tolerance to toxic environmental conditions, they were developed thus engineered using microorganisms isolated from various sources, mainly waste material including wastewater as suggested in literature reviewed, to harness microorganisms’ possessing specified traits that can be developed when organisms are growing under strenuous environments whereby they are tolerant to toxic compounds. The assessment of these engineered biofilms involved the development from individual microorganisms to form biofilms in 1L batch reactors where the isolated microorganisms were grown in basal media containing immobilisation surfaces. The assessment of the total nitrogen efficiency was conducted using Erlenmeyer flasks (500mL) in a shaker incubator, with the biofilm TN removal efficiency being assessed in batch systems to ascertain simultaneous nitrification and denitrification rates even in the presence of heavy metals (Cu2+, Zn2+) and C6H5OH. Ambient temperature and dissolved oxygen conditions were kept constant throughout the duration of biofilm development with microorganisms (initially n = 20) being isolated for the initiation of biosurfactant studies which included screening. Results indicated that the engineered biofilms, constituted by biosurfactant producing organisms (n = 9), were consisiting of bacteria (97.19%), Protozoa (2.81%) and Archaea (0.1%) as identified using metagenomics methods. Some of the biosurfactant produced had the following functional group characteristics as determined by FTIR: -CH3-CH2, deformed NH, -CH3 amide bond, C-O, C=O, O-C-O of carboxylic acids, and C-O-C of polysaccharides. Other selected microorganisms (n = 5) tolerated maximum concentrations of the selected toxicants (Cu2+, Zn2+ and C6H5OH) of 2400 mg/L, 1800 mg/L and 850 mg/L, respectively. Enzyme analysis of the total nitrogen removal experiments indicated a higher nitrogen removal rate to be the Alcanigene sp. at 180 mg/L/h.

Bacterial biofilms consist of communities of cells encased in self-produced extracellular polymeric substance (EPS) at the interface of different phases. While most of our understanding of biofilms to date has been obtained from submerged biofilms formed at the solid-liquid (S-L) interface, the interface between air and liquid provides a niche for the formation of biofilms with unobstructed access to both liquid and gaseous phases, which is of ecological, clinical and commercial significance. But there is a paucity of information on air-liquid (A-L) interface biofilms. Cultivation and characterization of A-L interface biofilms are still limited to traditional methods created for S-L interface biofilms, mostly based on microtiter plates and tubes. In this thesis, two bioreactors have been designed, fabricated and validated to culture A-L interface and air-liquid-solid (A-L-S) interface biofilms. / The first bioreactor, named hanging drop biofilm reactor (HDBR), has been constructed on an open microfluidic platform to hold hanging droplets culturing biofilms in a suspended fashion. Hanging droplets containing microorganisms were accessed from the topside of the microfluidic platform, whilst measurement and harvesting were performed on the underside. The system was driven by evaporating flows. No additional electronic or mechanical actuation was needed. Biofilms were formed in hanging droplet biofilm reactors with bacterial suspensions. After 24 h of incubation under optimized conditions, biofilm-positive phenotype Bacillus subtilis developed A-L biofilms eliciting distinct developmental stages. Formation and dispersal of A-L interface biofilms were for the first time analytically characterized. Biofilms harvested by dripping droplets showed a spherical cap shape with porous structures. This is the first reported attempt to culture A-L interface biofilms inside a hanging droplet on an open microfluidic platform under evaporation flow. / The second bioreactor, named segmented-flow microfluidic air-liquid-solid interface biofilm reactor (SFMBR), has been implemented to grow A-L-S interface biofilms on chip. A distinct A-L-S interface was made available by introducing a gas phase into successive nutrient flows with a T-junction design, forming a segmented gas-liquid flow. Velocity fields were computed by numerical simulation, involving not only the hydrodynamic fields in the gaseous and aqueous phases, but also of the air-liquidand solid-liquid interfaces. Formation of A-L-S interface biofilms along microfluidic channels was observed and characterized by microscopy techniques non-destructively. The effect of hydrodynamics, interface topology and channel hydrophobicity on A-L-S interface biofilm formation was simulated and tested. Biofilms interacted with the shear forces introduced by the passage of A-L interfaces of an air slug with a shear stress of about 0.66 Pa and relaxed after the A-L interface passed. This device is a low-cost on-chip biofilm reactor to culture A-L-S interface biofilms and to measure in situ biological and mechanical properties of growing biofilm. / We have successfully constructed and validated two novel microfluidic strategies utilizing the interfacial phenomenon at the air-liquid interface and evaporating flow to culture and investigate the complex biology of A-L and A-L-S interfaces biofilms. / 细菌生物膜(生物膜)由生长在固、气、液相的界面上的细菌包裹于由其产生的细胞外间质聚合物内组成。固-液界面生物膜可以利用微流系统低耗材高效培养检测。但没有微流系统可研究生长在气-液界面的生物膜。为了填补这个空白，本论文设计了两种微流生物膜反应器(反应器)培养气-液和气-液-固界面生物膜。 / 一种反应器是培养气-液界面生物膜的基于蒸发产生的微流动和微循环的倒悬液滴反应器。我们创新的利用蒸发产生的微流和微循环增加微流系统中材料混合和供氧。我设计了两种倒悬液滴反应器:倒悬液滴气-液界面反应器微孔板和微流气-液界面反应器在静态和流动培养液条件下培养气-液界面生物膜。我们监控并分析了气-液界面生物膜形成过程。第一次报道了气-液界面生物膜生长阶段的划分。了解反应器的特性，如微流动和反应器形态等对应用反应器有至关重要的作用。我们使用粒子图像测这和数值模拟的方法研究了反应器特性。设计了滴落打印的方法收获并离线测量生物膜。这是第一种可以方便、可重复收获生物膜的方法。我们研究了收获后生物膜的抗药性和微结构，发观倒悬液滴反应器培养的生物膜对干燥和灭菌过程有很高的抗性。我们还首次发现了细菌由纳米管连接的气液界面细菌生物膜。 / 另一种反应器是基于微流分段气-液流的分段流微流反应器。这是首个培养气-液-固界面生物膜的微流反应器。我们创新性的应用了分段气-液流为生物膜滴定供养。我们的微流反应器模拟工业标准方法培养气-液-固界面生物膜的反应器。为了研究生物膜在反应器中的生长和流动对生物膜的影响，我们监测了生物膜的生长，用数值模拟的方法研究了分段流的流动。发现了单层菌落储水的现象。我们还首次报道了微流系统中，用粒子图像測速和数值模拟的方法研究生物膜的弹性松弛过程。 / 这里设计的基于液滴的高通量，高效率，低成本，操作简单的生物膜反应器可以加快生物膜的研究。 / Liu, Songlin. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2015. / Includes bibliographical references (leaves 115-130). / Abstracts also in Chinese. / Title from PDF title page (viewed on 19, September, 2016). / Liu, Songlin. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only.

Orientador: José Paes de Almeida Nogueira Pinto / Banca: Vera Lúcia Mores Rall / Banca: Luciano dos Santos Bersot / Resumo: Apesar dos recentes avanços tecnológicos na indústria de alimentos, ainda se observa a ocorrência de inúmeras enfermidades de origem alimentar, devido à ingestão de alimentos contaminados por micro-organismos patogênicos, dentre eles os do gênero Salmonella. Dentre os produtos envolvidos em processos de contaminação por este agente, as carnes são as mais importantes, sendo a de aves o veículo em numerosos casos de infecções humanas. Além dos problemas em saúde pública, o micro-organismo causa grandes problemas devido à formação de biofilmes na indústria, sendo que esta ocorre em virtude da adesão dos micro-organismos em uma superfície de contato, a qual se fixam, constituem uma matriz de exopolissacarídeos e iniciam seu crescimento. Estes representam uma preocupação à indústria de alimentos por seu efeito como fonte de contaminação crônica, que aumenta as chances de veiculação do patógeno ao consumidor. Inúmeros são os fatores que condicionam o desenvolvimento do biofilme, entres eles o tipo de superfície e suas propriedades físico-químicas, já que as mesmas exercem influência direta sobre a adesão dos micro-organismos. Diversas medidas de controle para resolver o problema são empregadas na indústria, como o uso de sanitizantes, em destaque os à base de ácido peracético, que embora tenham o seu efeito sob células sésseis comprovado, a sua ação sob biofilmes ainda necessita de maior comprovação científica. Nesse sentido, os dados obtidos por este trabalho ratificaram a importância de Salmonella spp. como formadora de biofilme em diferentes superfícies, o que pode induzir a uma maior permanência destes micro-organismos no ambiente de processamento na indústria e, consequentemente, a uma maior chance de contaminação dos alimentos, com riscos ao consumidor. Nossos resultados também confirmaram que as propriedades físico-químicas da superfície dos diferentes materiais influenciaram ... / Abstract: Despite recent technological advances in the food industry, still observed the occurrence of numerous food borne illnesses due to ingestion of contaminated by pathogenic microorganisms, including members of the genus Salmonella spp. Among the products involved in processes of contamination by this agent, the steaks are the most important, being the vehicle of birds in numerous cases of human infections. In addition to problems in public health, the microorganism causes big problems due to the formation of biofilms in the industry, and this occurs because of the accession of microorganisms on a surface of contact, which are fixed, are an array of exopolysaccharides and begin their growth. These are a concern to the food industry for its effect as a source of chronic infection, which increases the chances of placement of the pathogen to the consumer. There are many factors that affect biofilm development, entres they the type of surface and its physicochemical properties, since they will directly influence the adhesion of microorganisms. Several control measures to solve the problem are employed in the industry, such as the use of sanitizers, featured in the peracetic acid, though they have proven their effect on sessile cells in biofilms its action still needs more scientific evidence. In this sense, the data obtained from this study confirm the importance of Salmonella spp. as forming biofilm on different surfaces, which can induce a greater permanence of these microorganisms in the processing environment in the industry and hence a greater chance of food contamination, with risks to the consumer. Our results also confirmed that the physicochemical surface properties of different materials directly influence the adhesion of microorganisms and, consequently, the development of the biofilm. In simple terms, the greater the hydrophobicity of the surface, the greater the ability to promote the development of the biofilm, in order that the ... / Mestre