Cardy-Verlinde entropy formula in the presence of a general cosmological state equation

As recently found by Youm, the entropy of the universe will no longer be expressible in the conventional Cardy-Verlinde form if one relaxes the radiation dominance state equation and instead assumes a more general equation of the form p=(gamma-1)rho, with gamma a constant. We show that Youm's generalized entropy formula remains valid when the cosmic fluid is no longer ideal, but is allowed to possess a constant bulk viscosity zeta. We supply our analysis with some numerical estimates, thus calculating the scale factor a(t) for a k=0 universe, and also calculate via a perturbative expansion in zeta the magnitude of the viscosity-induced correction to the scale factor if the universe is radiation dominated.