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

Abstract

Ethyl carbamate (urethane, C2H5OCONH2) 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.