title: Increased resistance to detachment of adherent microspheres and Bacillus spores subjected to a drying step.
abstract: In various environments, including that of food processing, adherent bacteria are often subjected to drying conditions. These conditions have been shown to result in changes in the ability of biofilms to cross-contaminate food in contact with them. In this study, we investigated the consequences of a drying step on the further ability of adherent bacterial spores to resist detachment. An initial series of experiment was set up with latex microspheres as a model. A microsphere suspension was deposited on a glass slide and incubated at 25, 35 and 50°C for times ranging from 1h to 48h. By subjecting the dried slides to increasing water flow rates, we showed that both time and temperature affected the ease of microsphere detachment. Similar observations were made for three Bacillus spores despite differences in their surface properties, especially regarding their surface physicochemistry. The differences in ease of adherent spore detachment could not be clearly linked to the minor changes in spore morphology, observed after drying in various environmental conditions. In order to explain the increased interaction between spheres or spores and glass slides, the authors made several assumptions regarding the possible underlying mechanisms: the shape of the liquid bridge between the sphere and the substratum, which is greatly influenced by the hydrophilic/hydrophobic characters of both surfaces; the accumulation of soil at the liquid/air interface; the presence of trapped nano-bubbles around and/or under the sphere.
authors.affiliation: UMR UMET: UMET, CNRS, INRA, Univ. Lille 1, 59650 Villeneuve d'Ascq, France. Electronic address: christine.faille@lille.inra.fr.
authors.forename: Christine
authors.initials: C
authors.lastname: Faille
authors.affiliation: IEMN, LIA LICS: Univ. Lille 1, UMR CNRS 8520, IEMN, 59652 Villeneuve d'Ascq, France.
authors.forename: Ilyesse
authors.initials: I
authors.lastname: Bihi
authors.affiliation: UMR UMET: UMET, CNRS, INRA, Univ. Lille 1, 59650 Villeneuve d'Ascq, France.
authors.forename: Annette
authors.initials: A
authors.lastname: Ronse
authors.affiliation: UMR UMET: UMET, CNRS, INRA, Univ. Lille 1, 59650 Villeneuve d'Ascq, France.
authors.forename: Gilles
authors.initials: G
authors.lastname: Ronse
authors.affiliation: IEMN, LIA LICS: Univ. Lille 1, UMR CNRS 8520, IEMN, 59652 Villeneuve d'Ascq, France.
authors.forename: Michael
authors.initials: M
authors.lastname: Baudoin
authors.affiliation: IEMN, LIA LICS: Univ. Lille 1, UMR CNRS 8520, IEMN, 59652 Villeneuve d'Ascq, France.
authors.forename: Farzam
authors.initials: F
authors.lastname: Zoueshtiagh
mesh_terms: D000327:Adsorption; D001407:Bacillus / Q000145:classification / Q000502:physiology*; D001422:Bacterial Adhesion / Q000502:physiology*; D003890:Desiccation / Q000379:methods*; D005898:Glass / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D008863:Microspheres; D013045:Species Specificity; D013171:Spores, Bacterial / Q000502:physiology* / Q000648:ultrastructure; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors
keywords: Adhesion; Bacillus spores; Detachment; Drying; Liquid bridge; Microspheres