Alkaline liquid detergent compositions comprising a diacyl peroxide, solvent and chelant are disclosed. The solvent is preferably selected based upon the solubility parameter of the diacyl peroxide present. Preferred compositions are for use in automatic dishwashing detergents, are substantially phosphate free and contain detersive enzymes. The compositions are effective in removing stains, especially carotenoid, under various temperature and pH conditions from plastics.