Ethyl carbamate (EC) is a probable human carcinogen (Group 2A) found in fermented foods and alcoholic beverages. The objective of this study was to develop EC analysis methods for nine matrices (apple juice, milk, soju, corn oil, rice porridge, flat fish, sea mustard, peanut butter, and beef) chosen as representative food matrices in the Korean total diet study. Extraction procedures were based on the AOAC official method 994.07 with some modifications.
Standard curve had a good linearity (R2>0.999) in nine food matrices. Limit of detection (LOD) and limit of quantification (LOQ) were in the range of 0.7-6.1 μg/kg and 2.1-18.4 μg/kg, respectively. Recovery rates ranged from 80.8 to 121.8% for intra-day and ranged from 84.1 to 117.0% for inter-day in nine food matrices. The relative standard deviation (RSD) were below 15%. These results are in the acceptable range of AOAC, indicating that these methods are suitable for EC determination in nine food matrices.
Of the 1,245 samples analysed, EC was detected in 9 samples, corresponding to 0.7%. The levels of EC ranged from not-detected to 166.5 μg/kg. EC were detected in fermented food (soy sauce) and alcoholic beverages (maesilju, whisky, and bokhunjaju). The estimated intakes of EC from fermented foods and alcoholic beverages were 4.1 ng/kg body weight (bw)/day for average consumers and 12.4 ng/kg bw/day for 95th high consumers. The major foods contributing to dietary intake of EC were soy sauce (63%), followed by maesilju (30%), whisky (5%), and bokbunjaju (2%). Based on a benchmark dose confidence limit 10% (BMDL10) of 0.3 mg/kg bw/day, the margin of exposure (MOE) of EC were 73,000 for average dietary exposure and 24,000 for 95th percentile dietary exposure. This indicates the dietary exposure of the Korean population for EC is of low concern. However, careful vigilance should be continued for 95th percentile consumers of fermented foods and alcoholic beverages.
Of the 90 soy sauce samples analyzed, EC was detected in 34 samples, amounting for 38%. The levels of EC ranged from not-detected to 73.2 μg/kg, with a mean content of 7.4 μg/kg. The estimated intakes of EC from Korean soy sauce were 0.8 ng/kg bw/day for averages consumers and 2.8 ng/kg bw/day for 95th high consumers. The MOEs of EC were 374,000 for average dietary exposure and 106,000 for 95th percentile dietary exposure. This indicates that dietary exposure to EC of is low concern. The MOEs of 95th high consumers in the Korean population was between 58,000 and 132,000. The risks of EC in Korean soy sauce were shown to be of low concern.
EC was detected in all 38 maesilju samples. The levels of EC in home-made and commercial maesilju were 7.2-278.2 μg/kg and 36.6-183.8 μg/kg, respectively. The estimated intakes of EC from the consumption of maesilju were 0.3 ng/kg bw/day from averages levels and 1.2 ng/kg bw/day from maximum levels. The estimated intake of EC was highest in 19-29 years with the value of 3.2 ng/kg bw/day. The exposure to EC from maesilju in the Korean population is of low health concern.