The Transportation Security Administration (TSA) will not permit beverages and some food items through the security checkpoint. See Food and Drinks Permitted and Prohibited page on TSA Web site. However, all these items can be purchased and brought on the plane after you have been screened at the security checkpoint.
There are exceptions for medical purposes such as juice for diabetic travelers, and baby formula/milk for young children that can be taken through the security checkpoint.
Avoid packing food and drink items in luggage that will be checked at the ticket counter. Certain foods have a density that is not easily read by the screening equipment, and if detected your bags will be opened and inspected.
Related Links TSA is the federal agency that has total responsibility for the policies, procedures, equipment and staffing associated with security screening at all U.S. airports.
TSA Web Site – Food & Drinks Permitted & Prohibited TSA Web Site – Permitted and Prohibited Items Portland International Airport – Restaurants