R. Briandet et al., Effects of the growth procedure on the surface hydrophobicity of Listeria monocytogenes cells and their adhesion to stainless steel, J FOOD PROT, 62(9), 1999, pp. 994-998
The aim of this study was to examine the physicochemical surface properties
and the ability to adhere to stainless steel of three strains of Listeria
monocytogenes after different cultivation procedures. To this end, bacteria
were cultivated at 37 degrees C after storage at two frequently used tempe
ratures (4 degrees C or -80 degrees C) and were then transferred into the l
iquid medium (trypticase soy broth supplemented with 6 g liter(-1) of yeast
extract, pH 7.3) between one and four times. In addition, the influence of
supplementing the growth medium with lactic acid was explored, this organi
c acid being representative of both the dairy and cured meat industries. Th
e hydrophobic/hydrophilic and electron-acceptor/electron-donor characterist
ics of the strains were evaluated by the microbial adhesion to solvents met
hod. Using this technique, we recorded an increase in the hydrophobic prope
rties of one strain stored at 4 degrees C, with an increasing number of tra
nsfers in the media (P < 0.05), Another plant-isolated strain appeared more
hydrophobic and stuck better to stainless steel when cells were stored at
4 degrees C rather than at -80 degrees C. Preculturing L. monocytogenes in
a lactic acid-supplemented medium increased the affinity of microbial cells
to solvents and the bacterial attachment to stainless steel (P < 0.05).