Tuna

Tuna may be canned either precooked or raw. Precooking 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 struvite, or magnesium ammonium phosphate, sometime 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 250° F (121° C) for 2-1/2 to 4 hours (depending on size) or at 350° F (177° C) for 1 hour. The fish may also be cooked in a steamer for 2 to 4 hours. If a thermometer is used, cook to a 165° to 175° F (74 - 80° C) 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 hot 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. Remove air bubbles and adjust headspace if needed. Add 1/2 teaspoon of salt per half-pint or 1 teaspoon of salt per pint, if desired. Carefully clean the jar rims with a clean, damp paper towel; wipe with a dry paper towel to remove any fish oil. Adjust lids and process.

Tuna in Glass Jars
Style of Pack	Jar Size	Process Time	Canner Pressure at "0" ft
			dial-gauge	weighted-gauge
see instructions above	Half-Pints or Pints	100 min	11 lb	10 lb

For processing at above 1,000 ft, see Altitude Adjustment.