Characterization of physicochemical forces involved in adhesion of Listeria monocytogenes to surfaces.
This study investigated the physicochemical forces involving the adhesion of Listeria monocytogenes to surfaces. A total of 22 strains of L. monocytogenes were compared for relative surface hydrophobicity with the salt aggregation test. Cell surface charges and hydrophobicity of L. monocytogenes Scott A were also determined by electrophoretic mobility, hydrophobic-interaction chromatography, and contact angle measurements. Electrokinetic measurements indicated that the strain Scott A has a negative electrophoretic mobility. Physicochemical characterization of L. monocytogenes by various methods indicates that this microorganism is hydrophilic. All L. monocytogenes strains tested with the salt aggregation test method aggregated a at very high ammonium sulfate molarities. The hydrophobicity-interaction chromatography results show that L. monocytogenes Scott A cells do not adhere to octyl-Sepharose unless the pH is low. Results from contact angle measurements showed that the surface free energy of strain Scott A was 65.9 mJ.m-2, classifying this microorganism as a hydrophilic bacterium. In addition, the interfacial free energy of adhesion of L. monocytogenes Scott A estimated for polypropylene and rubber was lower than that for glass and stainless steel. However, these theoretical implications could not be correlated with the attachment capabilities of L. monocytogenes.
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Department of Food Science and Technology, Université Laval, Québec, Canada.
Roy
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Goulet
J
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Savoie
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D001422:Bacterial Adhesion; D002847:Chromatography, Agarose; D004586:Electrophoresis; D006863:Hydrogen-Ion Concentration; D008089:Listeria monocytogenes / Q000502:physiology*; D009994:Osmolar Concentration; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
D014867:Water