What is a Tuna Loin?
There are four tuna loin cuts on a tuna fish. The two top loins are the dorsal loins and run from behind the head to the tail. Like the belly loins, there is a right and a left dorsal loin. The belly loins run along the bottom of the fish from the pelvic fin to the anal fin. The other parts of the fish are called chunk tuna, which are normally canned, and scraps, which processors use for pet food.
Choosing the Freshest Tuna Loins
Many times, location and price determine the type of tuna loin that will be the best to serve. Another factor is whether the cook will serve the tuna raw, such as in Oriental dishes like sashimi. Contrary to popular belief, fresh fish is not always the best fish to buy. Any fish that has dull flesh that is falling apart is inferior. Modern processing methods can flash freeze fish, ensuring a minimal loss of flavor and texture.
Cooks who live near the sea where fishermen catch tuna can choose whole tuna and cut the loin sections themselves or choose hand cut loins. As mentioned previously, the appearance of the flesh is the key to choosing the best tuna loins. The flesh should be moist looking and firm. The color will vary depending upon the tuna species, but it should not be brown. Because of an osmosis process, rinsing saltwater fish in fresh water will frequently change the texture of the flesh and turn it brown.
Many vendors do not allow customers to sniff the fish, usually for sanitation reasons. If the vendor allows you to smell the fish, it should have a fresh smell. Old fish or improperly cooled and stored fish will have a strong fishy odor.
Fresh or Frozen: the Great Debate!
Some cooks prefer fresh tuna loins, but others prefer to use fish that has been frozen. Some government agencies, such as the European Union and the United States Food and Drug Administration (FDA), require processors to freeze tuna to kill parasites that are harmful to humans. The FDA recommends flash freezing for 15 hours at – 31 degrees Fahrenheit (- 35 degrees Celsius) or 7 days at – 7 degrees Fahrenheit (- 22 degrees Celsius) whereas the EU requires 24 hours at – 4 degrees Fahrenheit (- 20 degrees Celsius) for 24 hours . Typically, tuna loins thaw in 8 to 12 hours in a refrigerator, with little flavor or texture loss.
Raw, Rare, and Cooked
There are several ways to prepare tuna loins. The key to cooking fish is to not overcook it because that often causes the fish to be dry and flavorless. Some people cook them as loins, similar to whole tenderloins. Other recipes call for steaks cut from the loin. Loins processed for sashimi, sushi, and other dishes usually are thinly sliced. Many cookbooks and recipe websites explain the correct way to cut the loin for these dishes.
Tuna fish are strong swimmers and one of the fastest fish known to man. As a result, tuna flesh is muscular and firm. It holds up well to grilling and pan searing. Other cooking methods include broiling, baking, and steaming. Often tuna is served rare or medium rare to prevent overcooking, especially in thick steaks.
Give Tuna Loins a Try
Regardless of whether you live near the sea and can catch your own tuna or you live on a farm in the middle of Kansas, you can enjoy tuna loins. Flash freezing does not significantly affect the flavor or texture and many governments recommend freezing the fish to kill harmful parasites if you are going to eat the flesh raw or rare. People who do not have access to fresh fish can enjoy frozen tuna, if they thaw it safely in the refrigerator. Most food experts recommend using thawed tuna within 2 to 3 days to prevent spoilage.
Sources:
Cutting loins: http://wfoa-tuna.org/kitchen/
http://www.star-k.org/kashrus/kk-palate-fish.htm
http://www.dol.gov/whd/as/sec3.htm
