Should home-canned tuna be heated before eating?
As long as the tuna was canned according to recommended directions, the tuna should be safe to eat out of the jar. Tuna is canned at sea level for 100 minutes in a pressure canner at 10 pounds of pressure for weighted gauge and 11 pounds of pressure for dial gauge. Canners should be vented 10 full minutes before the weight is put on, and at the end of the processing time, the canner should be cooled slowly until the pressure reaches 0, then wait 10 minutes before opening the canner.
If you have any questions about whether it was canned properly, then heating is recommended.