For the viable colony count a bacterial suspension of 110
6
cells/ml was grown with shaking at 37
C in presence of 1, 2, 4 mg/
ml coffee extract forS. aureusandS. epidermidisor in presence of
5 mg/ml coffee extract forE. faecalis. At each time point (1, 2, 4 h) an
aliquot of the sample was serially diluted in fresh MH broth and
25ml of the serial dilutions were spotted in triplicate on an MH agar
plate which was then incubated 20 h at 37
C to allow the viable
colony count