FDA 21 CFR 177.2600 also sets the product extraction limits for both aqueous and fatty foods. Extractables in fatty foods must be less than 20 milligrams/square inch after the sample is refluxed with hexane for seven hours and then just 1 mg/square inch for the next 2 hours. For aqueous foods, the criteria is 175 mg/square inch of extractables when refluxed with water for 7 hours and 3 mg/square inch for the next two.