A sandwich filling is a type of food that is used to fill sandwiches. Common sandwich fillings include HAM, TUNA, SALAMI, and egg salad. HAM is a type of cured meat made from pork, usually cut from the hind leg of a pig. TUNA is a type of fish that is often canned and used as a sandwich filling. SALAMI is a type of cured sausage made from pork or beef. Egg salad is a mixture of chopped hard-boiled eggs, mayonnaise, and other ingredients such as mustard, onion, and celery.