Tecnologia de Alimentos
URI permanente desta comunidadehttps://locus.ufv.br/handle/123456789/11783
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Resultados da Pesquisa
Item Effect of cleaning treatment on adhesion of Streptococcus agalactiae to milking machine surfaces(Food and Bioprocess Technology, 2011-08-10) Pires, Ana Clarissa S.; Santos, Adbeel L.; Behaine, José Jorge S.; Araújo, Emiliane A.; Andrade, Nélio J. de; Carvalho, Antônio F. deStreptococcus agalactiae is a common subclinical mastitis agent in dairy cattle. In this study, the influence of hygiene procedure time on the adhesion of S. agalactiae to rubber and silicone surfaces used in milking machines was evaluated. The effect of hygiene practices on the thermodynamic and microscopic features of both surfaces was also evaluated. The hydrophobicity of milking machines and bacterial surfaces was investigated by measuring the contact angle with a goniometer 0, 30, 90, and 180 days after a full hygiene procedure simulated using rubber and silicone coupons. As the time of cleaning procedures enhanced, there was a reduction in the adhesion of S. agalactiae to both surfaces. The rubber and silicone surfaces were hydrophobic in all treatments (ΔGTOTsws<0), while the bacterial surface presented hydrophilic behavior (ΔGTOTsws>0), which makes the adhesion process difficult. Photomicrographs showed rapid wear of both surfaces, pointing to damages caused by cleaning agents. However, the silicone was more resistant to cleaning and sanitizing treatments. Thus, this work shows that changes caused by hygiene procedures in the thermodynamic and in the morphology of milking surfaces have an enormous importance in the S. agalactiae adhesion and, consequently, in mastitis transmission between cattle herd.Item Biofilm and toxin profile: A phenotypic and genotypic characterization of coagulase-negative staphylococci isolated from human bloodstream infections(Microbial Pathogenesis, 2016-10-06) Pedroso, S.H.S.P.; Sandes, S.H.C.; Luiz, K.C.M.; Dias, R.S.; T. Filho, R.A.; Serufo, J.C.; Farias, L.M.; Carvalho, M.A.R.; Bomfim, M.R.Q.; Santos, S.G.Coagulase-negative staphylococci (CNS) represent one of the most prevalent microorganisms in nosocomial infections worldwide, nevertheless little is known about their pathogenicity features. Thus, our aim was to characterize virulence aspects of CNS isolated from patients with bloodstream infections assisted in hospitals of Belo Horizonte, MG, Brazil. Strains were identified using bioMérieuxVitek® and for biofilm production evaluation, Congo Red Agar (CRA) and polystyrene plates were used. PCR was applied to detect icaA, icaB, icaC, atlE, sea, sec, sed, tsst-1 and agr. For statistical analyses were used hierarchical cluster, chi-square test and correspondence. 59 strains were analyzed, being S. haemolyticus the most prevalent. On CRA, 96.5% were biofilm producer, whereas on polystyrene plate, 100% showed adhesion at different times evaluated. Regarding genotypic analyses, 15.2%, 38.9%, 8.4%, 49.1%, 76.2%, 23.7%, 1.6%, 30.5% and 38.9% were positive for icaA, icaB, icaC, atlE, sea, sec, sed, tsst-1 and agr, respectively. Six clusters were formed and frequency distributions of agr, atlE, icaA, icaB, sea, sec, tsst-1 differed (P < 0.001). In conclusion, all strains were biofilm producer, with high prevalence of atlE, and had potential of toxin production, with high prevalence of sea. According to the group-analyses, icaB showed relationship with the strong adherence in samples.Item Aspectos coloidais da adesão de micro-organismos(Química Nova, 2010-09-01) Araújo, Emiliane Andrade; Andrade, Nélio José de; Carvalho, Antônio Fernandes de; Ramos, Afonso Mota; Silva, Cleuber Antônio de Sá; Silva, Luis Henrique Mendes daThe ability of bacteria to attach to surface and develop into a biofilm has been of considerable interest to food industry. Electrostatic, Lifhistz-van der Waals and Lewis acid-base forces are usually considered responsible for the interactions at the interface of the bacterial adhesion. The study of microbial adhesion thermodynamic is important because it represents the reflection of microbial surface and food processing surface physicochemical characteristics. This review examines the most important aspects involved in bacterial attachment to a surface with emphases in thermodynamics of adhesion process.Item Detection of exopolysaccharide production and biofilm-related genes in Staphylococcus spp. isolated from a poultry processing plant(Food Science and Technology, 2014-10-01) Ferreira, Andreza Angélica; Tette, Patrícia Amaral Souza; Mendonça, Regina Célia Santos; Soares, Ariana de Souza; Carvalho, Márcia Maria DeStaphylococcus spp. can survive in biofilms for long periods of time, and they can be transferred from one point to another and cause environmental contamination in food processing. The aim of this study was to detect Staphylococcus strains isolated from a poultry processing plant by the presence of adhesion genes and the phenotypic production of exopolysaccharide. In the present study, the production of exopolysaccharide and the presence of adhesion genes in 65 strains of Staphylococcus spp. were evaluated. All strains of Staphylococcus spp. produced exopolysaccharide, as confirmed by formation of black and opaque colonies in Congo Red Agar. The variation of sucrose content was critical for the production of exopolysaccharide in Congo Red Agar since at low sucrose concentrations all strains presented a characteristic result, i.e., there was no exopolysaccharide production. The atl gene was found in all strains, and the icaA and icaD genes were found in 97% of them. The data obtained suggest that Staphylococcus spp. isolated from the poultry processing plant evaluated has a potential for biofilm formation. An efficient control of this microorganism in food processing environment is necessary as they may represent a potential risk to consumers.