The Full Form of MCPD is 3-Monochloropropanediol.

3-MCPD (3-monochloropropane-1,2-diol or 3-chloropropane-1,2-diol) is an organic chemical compound with the formula HOCH₂CH(OH)CH₂Cl. It is a colorless liquid. It is a versatile multifunctional building block. The compound has attracted attention as the most common member of chemical food contaminants known as chloropropanols. It is suspected to be carcinogenic in humans.

It is produced in foods treated at high temperatures with hydrochloric acid to speed up protein hydrolysis. As a byproduct of this process, chloride can react with the glycerol backbone of lipids to produce 3-MCPD. 3-MCPD can also occur in foods that have been in contact with materials containing epichlorohydrin-based wet-strength resins which are used in the production of some tea bags and sausage casings.

In 2009, 3-MCPD was found in some East Asian and Southeast Asian sauces such as oyster sauce, Hoisin sauce, and soy sauce. Using hydrochloric acid is far faster than traditional slow fermentation. A 2013 European Food Safety Authority report indicated margarine, vegetable oils (excluding walnut oil), preserved meats, bread, and fine bakery wares as major sources in Europe