Section 189.140 - Diethylpyrocarbonate (DEPC)(a) Diethylpyrocarbonate is the chemical pyrocarbonic acid diethyl ester, C6 H10 O5 . It is a synthetic chemical not found in natural products at levels detectable by available methodology and has been used as a ferment inhibitor in alcoholic and nonalcoholic beverages.(b) Food containing any added or detectable level of DEPC is deemed to be adulterated in violation of the act based upon an order published in the FEDERAL REGISTER of August 2, 1972 (37 FR 15426).