  We study the propagation of non-strange and strange meson modes in hadronic
matter considering both isospin and strangeness mixings induced by quantum
fluctuations in the medium. Baryons are described using the Quark Meson
Coupling model extended to include interactions of strange quarks. In
particular we evaluate the dependence of the meson masses on the baryonic
density, the strangeness fraction and the isospin asymmetry of the medium. We
have found a considerable admixture of strangeness and isospin in the
sigma-mode in the high density regime.
