If something such as food or drink is adulterated, someone has made its quality worse by adding water or cheaper products to it. The food had been adulterated to increase its weight + adulteration adul·tera·tion the adulteration of tobacco. to make food or drink less pure by adding another substance of lower quality to it unadulterated (past participle of adulterare, from ad- + alter )
corrupt, debase, or make impure by adding a foreign or inferior substance; often by replacing valuable ingredients with inferior ones; "adulterate liquor"