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Tuna

Also indexed as: Ahi, Aku, Albacore, Bigeye, Bluefin, Bonito, Skipjack, Yellowfin

Americans consume large quantities of canned tuna, while Japanese eat most of theirs raw.

Tuna roasted on a spit and basted with olive oil and spices was a food highly valued in the ancient civilizations of the Mediterranean. Today, Americans consume large quantities of canned tuna, while the Japanese eat most of theirs raw. The taste and quality of tuna varies with the type of tuna and how it has been handled. The highest-quality tuna is sashimi grade, suitable for being eaten raw.

Varieties

Albacore, found in both Atlantic and Pacific waters, is the only kind that can be labeled “white meat tuna.” Bluefin, a large, oily species, is usually canned as “light meat” tuna or eaten raw. Yellowfin (called ahi in Hawaii) is the least oily kind of tuna; it is flavorful (but not strongly so) when cooked, and is good eaten raw. Bigeye is valued for sashimi. Bonito is among the smallest tuna, and has red meat. Tuna comes whole, in steaks, fillets, or loins, and fresh, frozen, or canned.

Buying and storing tips

Quality tuna is easy to recognize. The eyes should appear bright and clear, almost alive. The gills should be reddish, and the skin moist and with tightly adhering, shiny scales. Fresh tuna flesh will be pink or red, without any hint of browning. Fresh tuna never has a rainbow pattern on the surface of the meat. When choosing tuna fillets, steaks, or loins, whether they’re fresh or previously frozen, look for moist, translucent (never dried out) flesh. Keep tuna cool on the trip from the market to your house. Never let it stay unrefrigerated for long.

To store tuna, remove packaging, rinse fish under cold water, and pat dry with paper towels. Fish deteriorates when it sits in its own juices, so place it on a cake rack in a shallow pan filled with crushed ice. Cover with cling wrap or foil and set in the coldest part of the refrigerator. Tuna will store well this way for up to two days.

When well-wrapped, tuna can be frozen for up to two months in a refrigerator freezer compartment and three to four months in a deep-freeze. Use lined freezer paper and wrap fish tightly with at least two layers of paper. To thaw slowly, unwrap, place fish in pan, cover, and leave for 24 hours in the refrigerator. To thaw more quickly, place the whole fish (in a watertight plastic bag) in a sink with cool running water, allowing about 1/2 hour per pound (454g). For fastest thawing, use the defrost cycle of your microwave, allowing 2 to 5 minutes per pound (454g), with equal standing time in between zaps.

Availability

Tuna is available year-round, though most plentiful in the summer.

Preparation, uses, and tips

Remove the strong-tasting brown streak running through the meat.

The secret to successful tuna cookery is to not overcook it; overcooking makes tuna dry out. Whichever of the following cooking methods you choose, your tuna will be cooked when its flesh becomes opaque yet is still moist on the inside.

Baking

Brush with melted butter or oil and season with salt and pepper, or cover with a piquant sauce. Place tuna in a greased baking dish, or wrap in oiled foil and place on a baking sheet. Bake in a preheated 450°F (230°C) oven 10 minutes per inch (2.5cm) of thickness of the fish.

Barbecuing

Place tuna over hot coals on a well-oiled grill. Baste frequently and turn once halfway through the cooking period. Because tuna is lean compared to other protein-rich foods, it does not exude a lot of self-basting fat. Be sure all grills, baskets, racks, and foil are well-oiled to ensure easy handling of tuna while barbecuing.

Broiling

Place seasoned tuna filets or steaks on a well-greased broiler pan and brush with oil. Broil under preheated broiler 4 to 5 inches (about 10 to 12.5cm) from heat until the flesh is opaque yet moist on the inside.

Pan frying

Heat a pan, add a small amount of hot butter or oil, and brown uncoated tuna steaks or fillets, turning once after 3 to 4 minutes and cook the other side 3 to 4 minutes.

Poaching

Bring poaching liquid, consisting of water, broth, and herbs and spices, to a simmer. Slip tuna in, then cover pan and keep liquid at a simmer for about 8 minutes per inch (about 2.5cm) of thickness.

Steaming

Place tuna on a greased perforated rack over 1 to 2 inches (about 2.5 to 5 cm) of rapidly boiling water. Cover with a tight-fitting lid and keep water at a constant boil through cooking time.

Nutritional Highlights

Tuna, 3 oz. (85g) (cooked, dry heat)
Calories: 156
Protein: 25.4g
Carbohydrate: 0.0g
Total Fat: 5.3g
Fiber: 0.0g
*Excellent source of: Selenium (39.8mcg), Niacin (8.9mg), and Vitamin B12 (9.2mcg)
*Good source of: Magnesium (54.4mg)

*Foods that are an “excellent source” of a particular nutrient provide 20% or more of the Recommended Daily Value, based upon United States Department of Agriculture (USDA) guidelines. Foods that are a “good source” of a particular nutrient provide between 10 and 20% of the USDA Recommended Daily Value. Nutritional information and daily nutritional guidelines may vary in different countries. Please consult the appropriate organization in your country for specific nutritional values and the recommended daily guidelines.

When cooked (dry heat), tuna (bluefin, fresh) provides 1.504 grams of omega-3 fatty acids, derived from EPA (0.363g) and DHA (1.141g), per 100 grams of tuna (bluefin, fresh). When canned in water and drained, tuna (light) provides 0.272 grams of omega-3 fatty acids, derived from EPA (0.047g), DHA (0.223g), and ALA (0.002g), per 100 grams of tuna (canned in water and drained). When canned in oil and drained, tuna (light) provides 0.202 grams of omega-3 fatty acids, derived from EPA (0.027g), DHA (0.101g), and ALA (0.074g), per 100 grams of tuna (canned in oil and drained).

Health benefits and concerns

Mercury toxicity

Nearly all fish contain trace amounts of methyl mercury, some more than others. In areas where there is industrial mercury pollution, mercury levels in the fish can be quite elevated. In general, however, methyl mercury levels for most fish are very low. However, certain species of very large tuna, typically sold as fresh steaks or sushi, can contain methyl mercury levels in excess of the Food and Drug Administration’s (FDA’s) 1 part per million (ppm) limit. Canned tuna, composed of smaller species of tuna such as skipjack and albacore, has much lower levels of methyl mercury, averaging only about 0.17 ppm.

The FDA has advised pregnant women, women who could become pregnant, and nursing mothers to avoid fish that contain high amounts of methyl mercury, specifically shark, swordfish, king mackerel, and tilefish. Regular consumption of methyl mercury contained in these fish can harm the child's developing nervous system and may pose risks to the mothers as well. The FDA advises that other fish are permissible for pregnant and nursing women as part of a healthful diet. The agency suggests an acceptable level of 12 ounces per week of cooked fish (a typical serving size of fish is from 3 to 6 ounces). Permissible fish include shellfish, canned fish, smaller ocean fish or farm-raised fish. It is important to eat a variety of different species, rather than just one type of fish, in order to reduce the reduce risk of methyl mercury consumption.

Health benefits and concerns for fish and seafood
Many health benefits and concerns associated with this food are applicable to other fish and seafood. Read about health benefits and concerns for fish and seafood for a full description.