Background Chloropropanol esters (MCPDE) have attracted much attention in recent years as a kind of new contaminant found in various refined oils. The pollution of 3-monochloropropane-1,2-diol esters (3-MCPDE) is the most prominent. 3-MCPDE is hydrolyzed in organisms to 3-monochloropropane-1,2-diol which has been shown to have reproductive toxicity, nephrotoxicity, and potential carcinogenicity. Infant formula powders can be polluted by 3-MCPDE when refined edible oils are added during production.

Objective To assess the risk of exposure to 3-MCPDE related to the consumption of infant formula powders for children aged 0-3 years in Shanghai market using the food consumption data and the data of 3-MCPDE contamination in these foods.

Methods Gas chromatography-mass spectrometry was used to determine 3-MCPDE in 133 samples of infant formula powders in Shanghai. Using a multistage stratified random sampling method, a total of 807 infants and toddlers aged 0-3 years were randomly selected from each district/rural/town in Shanghai, including 208 children aged 0-6 months, 276 children aged 6-12 months, and 323 children aged 12-36 months. The food consumption data was investigated using food frequency questionnaire (FFQ) distributed by combining telephone inquiries and face-to-face interviews among guardians. Population's probability distributions of 3-MCPDE exposure were assessed by @Risk 7.5 software and Monte Carlo simulation algorithm. According to the dietary intake assessment model and the tolerable daily intake (TDI) of 3-MCPDE of 2.00 μg·(kg·d)⁻¹ proposed by the European Food Safety Authority (ESFA), a risk assessment of exposure to 3-MCPDE was conducted for infants and toddlers aged 0 to 3 years old in Shanghai who consumed 3-MCPDE via infant formula powders.

Results The average concentration of 3-MCPDE in 133 samples of infant formula powders was 0.115 mg·kg⁻¹ with a positive rate of 100.00%. Among different types of formula powders, infant formula powders for infants of 0-6 months had the highest concentrations of 3-MCPDE and fat 0.136 mg·kg⁻¹ and 25.2 g (per 100 g sample) in average respectively. There was a positive correlation between fat concentration and 3-MCPDE concentration in the samples (r=0.438, P<0.05). The average consumption of infant formula powders of 807 infants aged 0-3 years was 88.3 g·d⁻¹. Among all investigated age groups, the average consumption of infant formula powders by infants aged 0-6, 6-12, and 12-36 months was 87.7, 98.3, and 80.1 g·d⁻¹ respectively. The dietary exposure to 3-MCPDE from infant formula powders of infants aged 0-3 years averaged 0.83 μg·(kg·d)⁻¹ for general intake level or valued 1.44 μg·(kg·d)⁻¹ using the 95 percentile for high intake level. Exposure decreased with increasing age and was highest in infants 0-6 months of age, whose general and high intake levels were 1.41 and 2.34 μg·(kg·d)⁻¹, respectively. The risk population defined with the exposure higher than the TDI proposed by EFSA were proportioned to be 13.90% and 0.50% in infants aged 0-6 months and 6-12 months respectively, indicating a risk that cannot be ignored, and no risk in infants aged 12-36 months.

Conclusion Among the investigated infants aged 0-3 years in Shanghai, those aged 0-6 months are at a high risk of exposure to 3-MCPDE. In view of the sensitivity of infants to pollutant exposure, the risk of exposure to 3-MCPDE should be highly concerned.