  The expansion and hadronization of a quark meson plasma is studied using an
effective chiral interaction Lagrangian. The particles we consider are light as
well as strange quarks, which can form pions, kaons and eta mesons via
collision processes. The transport equations for the system are solved using a
QMD type algorithm. We find that in chemical equilibrium at high temperatures
the strange quark mass is considerably higher than the strange current quark
mass and becomes even higher if we assume an initial state free of strange
quarks. This leads to a considerably higher production threshold. In contrast
to simpler scenarios, like thermodynamics of free quarks with their bare mass,
we observe that strangeness production in a plasma is hindered and not
favoured. The different particle species created during the evolution become
separated in coordinate as well as in momentum space. We observe, as at CERN
experiments, a larger mean momentum of kaons as compared to pions. Thus the
radial collective velocity may as well originate from a plasma expansion and
not necessarily from a hadronic scenario.
