phenotype, the physico-chemical surface properties of the four
strains of L. monocytogenes were estimated by the Microbial
AdhesionTo Solvents(MATS) test. As can be seen inTable 3, the
CIP103574 strain was moderately hydrophobic and had a pronounced
electron donor character. The CIP103573 and CIP78.39
strains were very hydrophilic as shown by their low affinity to
apolar solvents. Finally, the CIP104794 strain had a strongly
basic character which led to hydrophilic property. Under our
experimental conditions, the four strains thus presented very
different physicochemical phenotypes. These results were in
accordance with those obtained by Giovannacci et al. [36] and
underlined an intra-species variability in the physicochemical
surface properties of L. monocytogenes. This variability could
result from differences in the composition of constituents of the
microbial cell surface such as modifications of fatty acid composition
of the plasma membrane [37] or from variations in the
expression of the virulence factors of the listerial strains [38].
Whatever the origin of these variations, they should entail differences
of bioadhesive behavior.