Fresh and frozen The fresh or frozen flesh of tuna is widely regarded as a delicacy in most areas where it is shipped, being prepared in a variety of ways. When served as a
steak, the meat of
most species is known for its thickness and firm texture. In the U.K., supermarkets began flying in fresh tuna steaks in the late 1990s, which helped to increase the popularity of using fresh tuna in cooking; by 2009, celebrity chefs regularly featured fresh tuna in salads, wraps, and char-grilled dishes.
Served raw Various species of tuna are often served raw in
Japanese cuisine as
sushi or
sashimi. Tuna consumption increases the risk of getting cancer. File:Tuna_Sushi.jpg| File:Tuna fish sandwiches for the National School Lunch Program (1).jpg| File:tuna steak.JPG| File:Tekkadon_001.jpg| File:Katsuobushi 02.jpg| File:Mojama de atun.JPG|
Canned Tuna is canned in edible
oils, in
brine, in water, and in various sauces. Tuna may be processed and labeled as "solid", "chunked" ("chunk") or "flaked". When tuna is canned and packaged for sale, the product is sometimes called
tuna fish (U.S.), a
calque (loan translation) from the
German Thunfisch. Canned tuna is sometimes used as food for pets, especially
cats. ;Australia
Canned tuna was first produced in Australia in 1903 and quickly became popular. In the early 1980s canned tuna in Australia was most likely
southern bluefin, it was usually yellowfin,
skipjack, or
tongol (labelled "northern bluefin" or "longtail"). The remaining weight is usually oil or water. ;United States The product became more plentiful in the United States in the late 1940s. In 1950, 8,500,000 pounds of canned tuna were produced, and the
U.S. Department of Agriculture classified it as a "plentiful food". In the United States, 52% of canned tuna is used for
sandwiches; 22% for
tuna salads; and 15% for
tuna casseroles and dried, prepackaged
meal kits, such as
General Mills's
Tuna Helper line. Other canned tuna dishes include
tuna melts (a type of sandwich where the tuna is mixed with mayonnaise and served on bread with cheese melted on top);
salade niçoise (a salad made of tuna, olives, green beans, potatoes, hard-boiled eggs and anchovy dressing); and tuna burgers (served on buns). In the United States, the
Food and Drug Administration (FDA) regulates canned tuna (see part
c). ;Precooked As tunas are often caught far from where they are processed, poor interim conservation can lead to spoilage. Tuna is typically
gutted by hand, and later precooked for prescribed times of 45 minutes to three hours. The fish are then cleaned and
filleted, canned (and sealed), with the dark lateral blood meat often separately canned for
pet food (
cat or
dog). The sealed can is then heated under pressure (called "
retort cooking") for 2–4 hours. This process kills any bacteria, but retains the
histamine that
may have been produced by those bacteria, and so may still taste spoiled. The international standard sets the maximum histamine level at 200 milligrams per kilogram. An Australian study of 53 varieties of unflavored canned tuna found none to exceed the safe histamine level, although some had "off" flavors. in other countries,
yellowfin is also acceptable. ; Ventresca tuna
Ventresca tuna (from
ventre, the Italian word for belly), is a luxury canned tuna, from the fatty
bluefin tuna belly, also used in sushi as
toro.
Nutrition {{nutritional value Canned light tuna in oil is 29%
protein, 8%
fat, 60% water, and contains no
carbohydrates, while providing 200
calories in a 100 gram reference amount (table). It is a rich source (20% or more of the
Daily Value, DV) of
vitamin D and
phosphorus (table).
Mercury and health Mercury content in tuna can vary widely. Among those calling for improved warnings about mercury in tuna is the
American Medical Association, which adopted a policy that physicians should help make their patients more aware of the potential risks. A study published in 2008 found that mercury distribution in the meat of farmed tuna is inversely related to the lipid content, suggesting that higher lipid concentration within edible tissues of tuna raised in captivity might, other factors remaining equal, have a diluting effect on mercury content.
Mackerel tuna is one species of tuna that is lower in mercury concentration than skipjack or yellowfin, but this species is known as "black meat" or "dark meat" tuna, which is a lower grade for canning because of the color, unfavorable flavor, and poor yield. In March 2004, the United States
FDA issued guidelines recommending that pregnant women, nursing mothers, and children limit their intake of tuna and other predatory fish. The Environmental Protection Agency provides guidelines on how much canned tuna is safe to eat. Roughly speaking, the guidelines recommend one can of light tuna per week for individuals weighing less than , and two cans per week for those who weigh more. In 2007, it was reported that some canned light tuna such as
yellowfin tuna is significantly higher in mercury than skipjack, and caused
Consumers Union and other activist groups to advise pregnant women to refrain from consuming canned tuna. In 2009, a California appeals court upheld a ruling that canned tuna does not need warning labels as the
methylmercury is naturally occurring. A January 2008 report revealed potentially dangerous levels of
mercury in certain varieties of
sushi tuna, reporting levels "so high that the Food and Drug Administration could take legal action to remove the fish from the market." ==Management and conservation==