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
250 degrees F for 2-1/2 to 4 hours (depending on size) or at 350 degrees F
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 degree 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.

Jar Size: Pints and Half-pints. Process Time: 100 minutes. Canner Pressure
(PSI) at Altitudes of 0 – 2,000 ft: 11 lb.
2,001 – 4,000 ft: 12 lb.
4,001 – 6,000 ft: 13 lb.
6,001 – 8,000 ft: 14 lb.

Table 2. Recommended process time for Tuna in a weighted-gauge pressure
canner.

Jar Size: Pints and Half-pints. Process Time: 100 minutes. Canner Pressure
(PSI) at Altitudes of 0 – 1,000 ft: 10 lb.
Above 1,000 ft: 15 lb.

=== * USDA
Agriculture Information Bulletin No. 539 (rev. 1994) * format
courtesy of