The present invention addresses the problem of providing a deterioration-odor masking agent and a deterioration-odor masking method for effectively masking the deterioration odor of dairy products. This problem is solved by means of a masking agent that contains one or more substances selected from a group consisting of menthyl acetate, linalyl acetate, isoamyl isovalerate, isoamyl butyrate, nerol, acetaldehyde, methyl salicylate, 1,8-cineole, maltol isobutyrate, ethyl pyruvate, heliotropine, diethyl malonate, [gamma]-butyrolactone, ethyl levulinate, benzyl alcohol, hexanal, [gamma]-hexalactone, ethyl propionate, and amyl acetate.本發明係以提供一種可有效遮蔽奶製品之劣化臭味的劣化臭味遮蔽劑、及劣化臭味遮蔽方法為課題。該課題可由一種含有選自由乙酸薄荷酯、乙酸芳樟酯、異戊酸異戊酯、丁酸異戊酯、橙花醇、乙醛、水楊酸甲酯、1,8-桉油醇、異丁酸麥芽酚酯、丙酮酸乙酯、胡椒醛、丙二酸二乙酯、γ-丁內酯、乙醯丙酸乙酯、苯甲醇、己醛、γ-己內酯、丙酸乙酯、及乙酸戊酯所成之群中的1種以上的遮蔽劑來解決。
