Retrospective trends and current status of ethyl carbamate in German stone-fruit spirits

Abstract

Ethyl carbamate (urethane, C(2)H(5)OCONH(2)) is a known genotoxic carcinogen of widespread occurrence in fermented food and beverages with highest concentrations found in stone-fruit spirits. Between 1986 and 2004, 631 cherry, plum or mirabelle (yellow plum) spirits were analysed for ethyl carbamate using gas chromatography in combination with mass spectrometry after extrelut extraction. The ethyl carbamate concentration of the samples ranged between 0.01 mg l(-1) and 18 mg l(-1) (mean 1.4 mg l(-1)). After exposure of the samples to UV light, significantly (p=0.001) higher concentrations between 0.01 mg l(-1) and 26 mg l(-1) (mean 2.3 mg l(-1)) were found. The ethyl carbamate concentration increased on average by 1.3 mg l(-1). A linear correlation between the year of sampling and ethyl carbamate concentration showed a statistically significant but very slight decrease (R=-0.10, p=0.024). However, if only samples which officially were non-compliant were considered exceeding the upper limit of 0.4 mg l(-1) more than twice, a significant reduction (R =-0.56, p=0.018) of the quota was evident. This shows that measures to reduce ethyl carbamate were successfully introduced in many distilleries. However, nearly 20 years after the first warnings about ethyl carbamate in spirit drinks, the problem persists especially in products derived from small distilleries. During experimental production of stone-fruit spirits using state-of-the-art technologies, it was shown that the occurrence of ethyl carbamate in stone fruit spirits is preventable. Even for small distilleries, simple possibilities like destoning exist to minimize the ethyl carbamate content.

Formação de carbamato de etila em aguardentes recém-destiladas: proposta para seu controle

“…Como se observa as duas curvas apresentam perfil semelhante e são idênticas, dentro dos limites de erro experimental, com respeito aos teores finais de uretana. A reprodução deste resultado utilizando-se aguardentes de outros produtores sugere que, contrariamente ao descrito na literatura para outros destilados [4][5][6][7][8][9]21,22,38,39 e no caso das aguardentes aqui estudadas, é pouco provável a ocorrência de um precursor ativado fotoquimicamente.…”

“…1,[13][14][15][16][17][18][19][20] Além disto, a temperatura da fermentação, o pH, a luz e o tempo de estocagem estão relacionados com aumento nos teores de CE. [2][3][4][5][6][7][8][9][20][21][22] Para bebidas destiladas como uísque, rum e destilados de frutas com caroço (stone-fruit brandies) apenas uma pequena concentração de uretana presente no mosto fermentado é incorporada ao destilado final, 1,[3][4][5][6] sendo o íon cianeto relatado como o principal precursor de CE. 1,[3][4][5][6]12,[21][22][23][24] O cianeto (CN -), ânion do acido cianídrico, seria formado quando glicosídeos cianogênicos (Figura 1) presentes na cevada (epiheterodendrin), mandioca, aveia e em cereais (linamarin e lotaustralin), no centeio e no trigo (dhurrin), na maçã (amygdalin), manga e no arroz, por exemplo, 25 são degradados enzimaticamente liberando cianeto, passível de ser oxidado a cianato (CNO -) o qual reage com o etanol para formar o CE.…”

Ethyl carbamate and hydrocyanic acid in food and beverages - Scientific Opinion of the Panel on Contaminants

“…Cyanide (CAS number 57-12-5) is the anion of hydrocyanic acid. In stone fruit spirits, ethyl carbamate is formed when cyanogenic glycosides (such as amygdaline) from the stones are degraded through enzymatic action (mainly beta-glucosidase) to cyanide, which is then oxidised to cyanate and reacts with ethanol (Lachenmeier, 2005b;Schehl et al, 2007). Another source of ethyl carbamate is urea, resulting from the degradation of arginine by yeasts, which reacts with ethanol as illustrated in Figure 1.…”

Carcinogens in Food: Opportunities and Challenges for Regulatory Toxicology

“…Its highest concentrations occur in certain alcoholic beverages [30][31][32][33][34]. This may contribute to carcinogenicity due to the synergistic effects between ethanol, ethyl carbamate and other possible carcinogenic contaminants of alcoholic beverages, or of foods that are co-ingested with alcoholic beverages [35].…”