Compositions and processes for producing high purity acesulfame potassium are described. One process comprises the steps of forming a cyclic sulfur trioxide adduct; hydrolyzing the cyclic sulfur trioxide adduct to form an acesulfame-H composition comprising acesulfame-H; neutralizing the acesulfame-H in the acesulfame-H composition to form a crude acesulfame potassium composition comprising acesulfame potassium and less than 2800 wppm acetoacetamide-N-sulfonic acid, wherein the neutralizing step is conducted or maintained at a pH at or below 11.0; and treating the crude acesulfame potassium composition to form the finished acesulfame potassium composition comprising acesulfame potassium and less than 37 wppm acetoacetamide-N-sulfonic acid.