*2.3. Food Matrix Types*

Food matrices were divided into high-fat and low-fat groups. The foods representing each matrix were as follows: high-fat solid, infant purée; high-fat liquid, olive oil; low-fat solid, enoki mushroom; and low-fat liquid, 7.00% ethanol solution. These matrices were selected based on the lipid contents from the standard guidelines of the Korean Total Diet Study by the Korean Ministry of Food and Drug Safety. Although 7% ethanol solution was not a real food, it was selected for the matrix of low fat liquid foods. The 7% ethanol content is in the range of commercial liquor products in Korea, which would represent alcoholic beverages. The additional advantage of its use would be less contamination of nonylphenols compared to other food matrices.
