[en] We have studied the bulk viscosity of strange quark matter in the density dependent quark mass model (DDQM) and compared results with calculations done earlier in the MIT bag model where u, d masses were neglected and first order interactions were taken into account. We find that at low temperatures and high relative perturbations, the bulk viscosity is higher by 2 to 3 orders of magnitude while at low perturbations the enhancement is by 1-2 order of magnitude as compared to earlier results. Also the damping time is 2-3 orders of magnitude lower implying that the star reaches stability much earlier than in MIT bag model calculations. (author)