  We explore the dependence of the critical density, separating hadronic matter
from a mixed phase of quarks and hadrons, on the ratio $Z/A$. We use both the
MIT bag model and the Color Dielectric Model to describe the quark dynamics,
while for the hadronic phase we employ various relativistic equations of state.
We find that, if the parameters of quark models are fixed so that the existence
of quark stars is allowed, then the critical density drops dramatically in the
range $Z/A \sim $ 0.3--0.4. Moreover, for $Z/A \sim $ 0.3 the critical density
is only slightly larger than the saturation density of symmetric
nuclear-matter. This opens the possibility to verify the Witten-Bodmer
hypothesis on absolute stability of quark matter using ground-based experiments
in which neutron-rich nuclei are tested.
