Tuna is known to be an excellent source of high quality protein, Omega-3, as well as important nutrients including magnesium, potassium and B vitamins. Many people choose to can fresh tuna in order to enjoy a premium grade tuna without the premium price of store-bought canned fish. Catch your own tuna or purchase fresh tuna from the store and can it yourself to improve the taste of your tuna salad, casseroles or any number of your favorite tuna recipes.
Wash the canning jars, lids and bands in hot soapy water and rinse.
Sterilize the jars, lids and bands using a complete cycle in an automatic dishwasher; do not use detergent. Or you can use a large canner or pot to boil them for two to three minutes. Remove the items with a jar lifter and set the jars upside down on paper towels to dry. Set the lids and bands in a bowl of hot water.
Add 2 tsp. of olive oil inside each jar.
Place chunks of raw tuna, about one- to two-inch squares, into jars; pack them tightly to avoid air pockets. Leave 1/2 inch of space between the tuna and the top of the jar.
Add a pinch of salt on top of the tuna.
Wipe the rims of jars with a hot, damp towel to remove any oil and salt.
Remove the lids from the hot water and place one on each jar. Screw the bands snugly onto the jars but do not over-tighten.
Set the spacer into the pressure cooker and pour water inside, stopping when the water measures 1-1/2 inches from the bottom of the cooker.
Set the pressure cooker on the stove top and place the jars inside the pressure cooker, stacking them if necessary on top of each other.
Follow the instructions for your particular pressure cooker to securely lock the lid to the cooker. Turn the heat to the highest setting.
Set the pressure cooker to ten to fifteen pounds of pressure. Once it reaches the desired pressure, set the timer to 90 minutes.
Turn the stove top burner off after 90 minutes and let the pressure cooker set for at least 30 minutes. Do not attempt to remove the lid while steam is escaping, no matter how little the steam. Look for the indicator on your cooker to show that it is safe to open the lid.
Remove the jars of canned tuna using a jar lifter; set the jars 1/2 inch apart on a towel. The jars are safely sealed when the raised button on the center of the lids have indented. Some will seal within a few minutes, some may take several hours. Any jars that do not seal within 24 hours should be refrigerated and the contents consumed within seven days.