No, just things where they want to fake higher protein content.
I suspect the whole problem could be fixed by a change in the way China regulates food production that would not require heavy-handed enforcement.
The only reason an unscrupulous producer has for adulterating food products with melamine is to inflate the protein content on some coarse assay in which the C_3N_3(NH_2)_3 molecule tests as being protein. If the Chinese either used a finer assay that would distinguish the molecule from actual amino acids; or went to a model where the protein content of foods was measure by formulation, so that milk counted for as much protein as milk actually contains; or even abolished the protein assay entirely, there would be no motive to mix melamine in food products.