Here, Grace Parisi has given it an Italian twist with imported tuna, marinated artichokes, and green olives. What's the difference between Italian tuna and regular tuna? While canned tuna in general can be packed in oil or water, Italian canned tuna is typically packed in olive oil, whereas American canned tuna is more commonly packed in water. Plus, canned Italian tuna is known for its relatively low levels of mercury, in part because it's often processed from younger yellowfin and skipjack as opposed to large albacore. Notes from the Food & Wine Test KitchenKeeping with the Italian flavor profile, these tuna melts are assembled on ciabatta.