In a single stage, up to 6 per cent fat milk, usually 2000-2500 psi pressure is sufficient. Higher pressures may increase the tendency for the milk to curdle when cooked, due to the increased destabilizing effect on milk-proteins. For liquid products with more than 6 per cent fat, two-stage homogenization is needed to prevent fat clumping: 2000 psi at the first stage and 500 psi at the second stage (De, 2001).