Adhesion of Bacillus spores and Escherichia coli cells to inert surfaces: role of surface hydrophobicity

Abstract

The ability of bacterial spores and vegetative cells to adhere to inert surfaces was investigated by means of the number of adherent spores (Bacillus cereus and Bacillus subtilis spores) and Escherichia coli cells and their resistance to cleaning or rinsing procedures (adhesion strength). Six materials (glass, stainless steel, polyethylene high density (PEHD), polyamide-6, polyvinyl chloride, and Teflon) were tested. Slight differences in the number of adherent spores (less than 1 log unit) were observed between materials, but a higher number of adherent E. coli cells was found on the hydrophobic materials PEHD and Teflon. Conversely, the resistance of both B. cereus and B. subtilis spores to a cleaning procedure was significantly affected by the material. Hydrophobic materials were harder to clean. The topography parameter derived from the Abbott-Firestone curve, RVK, and, to a lesser extent, the widely used roughness parameters RA (average roughness) and Rz (maximal roughness), were related to the number of adherent cells. Lastly, the soiling level as well as the adhesion strength were shown to depend largely on the microorganism. The number of adhering B. cereus hydrophobic spores and their resistance to a cleaning procedure were found to be 10 times greater than those of the B. subtilis hydrophilic spores. Escherichia coli was loosely bound to all the materials tested, even after 24 h biofilm formation.

New PLA/ZnO:Cu/Ag bionanocomposites for food packaging

“…The important characteristics of bacteria which influence their adherence to a surface are the hydrophobicity and the surface charge [42]. The adhesion process of bacteria to the surfaces include interactions, such as van der Waals, Lewis acid-base, hydrophobic and electrostatic interactions [43]. However the molecular and physical interactions that govern bacterial adhesion to materials have not been understood in detail.…”

Adhesion Capacity of Bacillus thuringiensis Spores and its Relation with Biofilm Formation

“…It is known that Bt spores and those of other Bacillus species, presenting exosporium, have a higher hydrophobicity, conferring them a higher adhesive potential to diverse materials [8,9], such as those used in industrial food processing [1,[10][11][12][13]. To this respect, there are several reports on the in vitro capacity of these bacteria to adhere to stainless steel laminae and/or synthetic polymers [14][15][16][17][18].…”

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Open Access Research Articlehaving an attenuated immuneresponse [7].It is known that Bt spores and those of other Bacillus species, presenting exosporium, have a higher hydrophobicity, conferring them a higher adhesive potential to diverse materials [8,9], such as those used in industrial food processing [1,[10][11][12][13]. To this respect, there are several reports on the in vitro capacity of these bacteria to adhere to stainless steel laminae and/or synthetic polymers [14][15][16][17][18].

Bacterial adhesion to a surface is a two-phases process: in the first phase, planktonic bacteria are moved to a surface by the effect of physical forces such as Brownian motion, van der Waals attraction forces, gravitational forces, the effect of surface electrostatic charge and hydrophobic interactions; in the second phase of adhesion, molecular irreversible reactions between bacterial surface structures and substratum surfaces become predominant [19,20].

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Bacterial Biofilms on Food Contact Surfaces - a Review

“…Metal surfaces have a high surface energy, are negatively charged, and hydrophilic as shown by water contact angles, while polymers such a Tefl on have a low surface energy, are less electorostatically-charged and hydrophobic [Faille et al, 2002]. The hydrophobicity of a metal surface has been determined mainly by contact angle measurement [Liu et al, 2004].…”

“…These bacteria are of special signifi cance in ready-to-eat and minimally-processed food products, where microbiological control is not conducted in the terminal processing step [Herald & Zottola, 1988b;Cabanes et al, 2002;Faille et al, 2002;Gunduz & Tuncel, 2006; Kim et al, 2006]. In addition, bacterial colonization of food processing equipment is the main concern of damage to metal surfaces (pitting and corrosion) and breakdown of plastics.…”