  The boiling of possible quark nuggets during the quark-hadron phase
transition of the Universe at nonzero chemical potential is revisited within
the microscopic Brueckner-Hartree-Fock approach employed for the hadron phase,
using two kinds of baryon interactions as fundamental inputs. To describe the
deconfined phase of quark matter, we use a recently developed quark mass
density-dependent model with a fully self-consistent thermodynamic treatment of
confinement. We study the baryon number limit $A_{\rm boil}$ (above which
boiling may be important) with three typical values for the confinement
parameter $D$. It is firstly found that the baryon interaction with a softer
equation of state for the hadron phase would only lead to a small increase of
$A_{\rm boil}$. However, results depend sensitively on the confinement
parameter in the quark model. Specifically, boiling might be important during
the Universe cooling for a limited parameter range around $D^{1/2} = 170$ MeV,
a value satisfying recent lattice QCD calculations of the vacuum chiral
condensate, while for other choices of this parameter, boiling might not happen
and cosmological quark nuggets of $10^2 < A < 10^{50}$ could survive.
