Adesão de Salmonella enteritidis em superfícies de processamento de alimentos / Adesão de Salmonella enteritidis em superfícies de processamento de alimentos

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

Biofilms are structures highly organized in which microorganisms grow and therefore can survive to hostile environments. They are defined as a complex community of microorganisms usually encased in an extracellular matrix of polymeric substances (EPS) attached to a surface. Cells embedded in biofilm are more resistant to sanitizers than free cells. Biofilms in food processing surfaces can cause problems such as cross contamination, product contamination and equipment corrosion. A greater understanding of biofilms formation is important for food quality and safety. The mechanism governing microbial adhesion to surfaces depends on the nature of the contact surface and the bacterial surface properties. The aim of this study was to investigate the factors that are involved in the adhesion of four Salmonella Enteritidis isolates, one Pseudomonas aeruginosa isolate and one Serratia marcescens isolate to different materials (steel 304, polyethylene, polypropylene and granite) used as cover surfaces or as other utensils in kitchens. The bacterial surface properties were correlated with taxes of adhesion and hidrophobicity, which was, evaluated through contact angle measurements using the sessile drop method. The X-ray photoelectron spectroscopy (XPS) and roughness were used to analyze the strains surface characteristics and the inert surfaces studied, respectively. All strains analyzed showed positive values of hidrophobicity and were considered hydrophilic. The XPS results corroborated with the similarity of the hidrophobicity values obtained. P. aeruginosa was the most hydrophobic strain and had the highest amount of N/C. The hydrophilic characteristic observed in S. marcecens was related to the high surface quantity of O/C. All Salmonella strains analyzed showed similar wall cellular composition and the same physical chemical surfaces properties. Statiscally, the extent of adhesion of the different strains to the materials assayed was different (p<0.05). The source of Salmonella spp. isolates does not seem to affect the ability of adhesion. However, S. Enteritidis MUSC showed the highest capacity of adhesion to all surfaces studied (p<0.05) that could be explain by its capacity to accept electrons. All the surfaces had hydrophobic character; at least it is not possible to establish any correlation between the electron donor and electron acceptor capabilities of the interacting surfaces. No correlation between inert surface roughness and bacterial adhesion was found. Polyethylene was the roughest material but it was the material displaying less extent of bacterial colonization. Considering all the tentative explanations based on physico-chemical properties of bacterial cells and surfaces, it is not possible to establish any direct correlation to elicit the hypothesis of a reasonable model of adhesion.

ASSUNTO(S)

salmonela enteritidis food - microbiology bacteriologia food - analysis food - microbiology food - analysis bacteriologia bacteriology bacteriology salmonella enteritidis salmonella enteritidis alimentos - análise alimentos - microbiologia salmonela enteritidis alimentos - análise

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