Abstract: Food quality and safety risk assessment work is a recent development in China.Several studies on risk assessment of pesticide residues in fruits have been reported.The deterministic point estimation approach based on a single-point estimation (such as an average value or a high percentile) was the primary method in these studies.Using this method, dietary intake was evaluated by multiplying the mean agrochemical residual level and mean fruits consumption data.These numbers were easy to derive, but did not take into consideration the variation and uncertainty between individuals in the evaluation process.A nonparametric probabilistic evaluation model could better quantify the health risk for the general population by taking both variation and uncertainty into account.The outputs from Monte Carlo simulations can be specified at any percentile, making the calculation more intuitive and more convenient for evaluating the health risk in the general population.The probabilistic evaluation approach, therefore, is gradually becoming a focus of research into food quality and safety risk assessment in China.Dithiocarbamates (DTCs) are considered as one of the most important organosulfur compounds used as fungicides.These DTCs are widely used as non-systemic fungicides in agriculture and horticulture.Ethylenethiourea (ETU) is a toxicologically relevant degradation and/or biotransformation product of DTCs.It has been reported that ETU has caused cancer in experimental animals and may be carcinogenic in human, which should be considered in a consumer risk assessment.The professional risk assessment software @Risk, based on Monte Carlo simulations, was used to evaluate the dietary intake risk.First, data on the ETU residual content in 282 apple samples were collected for distribution fitting, which was checked by three statistical test methods - the Chi-Squared test, the Anderson-Darling test and the Kolmogorov-Smirnov test; the optimum fitting distribution was selected from the results.Simulations were performed with 10,000 iterations in the process of distribution fitting and with 10,000 simulation calculations for each population subgroups, ensuring that high percentile values would be more stable.The purpose was to ascertain ETU residue level in domestic apple and quantify the dietary intake risk for the general population consuming apple with ETU residues.A total of 282 apple samples were randomly collected from two main apple superior producing areas, including the Bohai bay (Liaoning, Shandong and Hebei) and the Northwest loess plateau (Shaanxi, Shanxi and Henan).To determine whether the human intake of ETU exceeded health safety limits, we evaluated toxicological endpoint values such as the acceptable daily intake (ADI) and acute reference dose (ARfD).The %ADI and %ARfD represented for chronic dietary intake risk and acute dietary intake risk, respectively.The results showed that the detectable rate of ETU was 80.9%, the average of residue contents was 6.1 μg/kg, the maximum residue content was 74.1 μg/kg, and the vast majority of ETU residual content of the 282 apple samples (90.4%) were lower than 10.0 μg/kg.The discrete degree of ETU residual content was large (134.6%) among 282 apple samples.Variation Coefficient of different provinces was in the following order: Shaanxi (150.7%)＞Liaoning (146.8%)＞Hebei (91.2%)＞Shandong (88.1%)＞Henan (54.9%)＞Shanxi (51.8%).Difference of dietary intake risk in different age groups was clear, that the ETU dietary intake risks of the infants (aged 2 to 6) and children (aged 7 to 13) were significantly higher than that of teenagers (aged 14 to 17) and adults (aged 18 to 59), so they were the vital monitoring objects.But overall, the dietary intake risk for different age groups consuming apples was low in China, and chronic and acute dietary intake risk of ETU were 0.35%~13.12% (%ADI) and 0.22%~3.94% (%ARfD), respectively, which was far lower than 100%.Differences of dietary intake risk of different provinces and different main producing areas were obvious, but the dietary intake risk of ETU was still much lower than 100%, which was acceptable.Based on the eMRL, MRL of ETU in apples was proposed to be 0.2 mg/kg.This study will provide references for apple quality safety supervision and carrying out the work of fruits quality and safety risk assessment systemically in the future.