Dimethyl dicarbonate

Dimethyl dicarbonate (DMDC) is an organic compound which is a colorless liquid with a pungent odor at high concentration at room temperature. It is primarily used as a beverage preservative, processing aid, or sterilant (INS No. 242), and acts by inhibiting the enzymes acetate kinase and L-glutamic acid decarboxylase. It has also been proposed that DMDC inhibits the enzymes alcohol dehydrogenase and glyceraldehyde 3-phosphate dehydrogenase by causing the methoxycarbonylation of their histidine components.
Use in wine.
In wine, it is often used to replace potassium sorbate, as it inactivates wine spoilage yeasts such as "Brettanomyces". Once it has been added to beverages, the efficacy of the chemical is provided by the following reactions:
The application of DMDC is particularly useful when wine needs to be sterilized but cannot be sterile filtered, pasteurized, or sulfured. DMDC is also used to stabilize non-alcoholic beverages such as carbonated or non-carbonated juice beverages, isotonic sports beverages, iced teas and flavored waters.
DMDC is added before the filling of the beverage. It then breaks down into small amounts of methanol and carbon dioxide, which are both natural constituents of fruit and vegetable juices.
The EU Scientific Committee on Food, the FDA in the United States and the JECFA of the WHO have confirmed the safe use in beverages. The FDA approved its use in wines in 1988, with the maximum level being permitted set at 200 mg/L, and only if there were fewer than 500 yeast cells/mL at time of dosage. It is also approved in the EU, where it is listed under E number E242, as well as Australia and New Zealand.