- Tuna may be canned either precooked or raw. Preooking removes most of the strong-flavored oils. The strong flavor of dark tuna flesh affects the delicate flavor of white flesh. Many people prefer not to can dark flesh. It may be used as pet food.
Note: Glass-like crystals of magnesium ammonium phosphate sometimes form in canned tuna. There is no way for the home canner to prevent these crystals from forming, but they usually dissolve when heated and are safe to eat.
Procedure: Keep tuna on ice until ready to can. Remove viscera and wash fish well in cold water. Allow blood to drain from stomach cavity. Place fish belly down on a rack or metal tray in the bottom of a large baking pan. Cut tuna in half crosswise, if necessary. Precook fish by baking at 250º F for 2-1/2 to 4 hours (depending on size) or at 350º F for 1hour. The fish may also be cooked in a steamer for 2 to 4 hours. If a thermometer is used, cook to a 165º to 175º F internal temperature. Refrigerate cooked fish overnight to firm the meat. Peel off the skin with a knife, removing blood vessels and any discolored flesh. Cut meat away from bones; cut out and discard all bones, fin bases, and dark flesh. Quarter. Cut quarters crosswise into lengths suitable for half-pint or pint jars. Fill into jars, pressing down gently to make a solid pack. Tuna may be packed in water or oil, whichever is preferred. Add water or oil to jars, leaving 1-inch headspace. Add 1/2 teaspoon of salt per half-pint or 1 teaspoon of salt per pint, if desired.
Adjust lids and process following the recommendations in Table 1 or Table 2 according to the canning method used.
Table 1. Recommended process time for Tuna in a dial-gauge pressure canner. Canner Pressure (PSI) at Altitudes of Jar Size Process Time 0 - 2,000 ft 2,001 - 4,000 ft 4,001 - 6,000 ft 6,001 - 8,000 ft Pints and Half-pints 100 min 11 lb 12 lb 13 lb 14 lb
Table 2. Recommended process time for Tuna in a weighted-gauge pressure canner. Canner Pressure (PSI) at Altitudes of Jar Size Process Time 0 - 1,000 ft Above 1,000 ft Pints and Half-pints 100 min 10 lb 15 lb