Some processed and packaged foods have fumaric acid added to them to help stabilize them and enhance their flavor. For example, many processed meats, such as bacon and canned meats, have added fumaric acid. Frozen seafood, smoked meats and the edible casings around sausages might also have fumaric acid added to them. Fermented, canned, dried and processed fruits and vegetables can contain the food additive as well. Rice cakes and other precooked rice foods, dried or preserved eggs, mustard, vinegar, cider, wine and other alcoholic beverages are additional examples of foods that might contain fumaric acid.