CAC/RCP 70-2011 Code of Practice for the Prevention and Reduction of Ethyl Carbamate Contamination in Stone Fruit Distillates
1. INTRODUCTION
1. Ethyl carbamate is a compound that occurs naturally in fermented foods and alcoholic beverages such as bread, yoghurt, soy sauce, wine, beer, and particularly in stone fruit distillates, mainly those made from cherries, plums, mirabelles and apricots.
2. Ethyl carbamate can be formed from various substances inherent in food and beverages, including hydrogen cyanide (or hydrocyanic acid), urea, citrulline, and other N-carbamyl compounds. Cyanate is probably the ultimate precursor in most cases, reacting with ethanol to form ethyl carbamate. Therefore ethyl carbamate reduction measures should focus on hydrocyanic acid and other precursors of ethyl carbamate.
3. Ethyl carbamate is genotoxic and a multisite carcinogen in animals and is probably carcinogenic to humans.
4. Stone fruit distillates, in particular, contain ethyl carbamate in manyfold higher concentrations than other fermented foods and beverages. In stone fruit distillates ethyl carbamate can be formed from cyanogenic glycosides that are natural constituents of the stones. When mashing the fruit, the stones may be damaged and cyanogenic glycosides from the stones may come into contact with enzymes in the fruit mash. Cyanogenic glycosides are then degraded to hydrocyanic acid/cyanides. Hydrocyanic acid may also be released from intact stones during a prolonged storage of the fermented mash. During the distillation process hydrocyanic acid may be enriched in all fractions. Cyanide in the distillates may be oxidized to cyanate, which can react with ethanol to form ethyl carbamate. Certain environmental conditions such as exposure to light, high temperatures and the presence of copper ions promote the formation of ethyl carbamate in the distillate.
