I was curious about this so i searched a bit. about 15% of food in us is imported, although the % is higher for groceries,seafood,fresh products https://www.fda.gov/food/importing-food-products-united-stat...

it's interesting also this document about total consumption that excludes from the count foreign sourced items (scroll to the last pragraph for a summary) https://www.commerce.gov/sites/default/files/migrated/report...