Another product I scrutinize is tuna. Not only the tuna I serve but the tuna everyone else serves. I enjoy good tuna and my customers have grown accustomed to quality fresh tuna. Too often when visiting other restaurants I am served a frozen tuna product that has been altered to enhance the color of the flesh. To the best of my knowledge it's a cold smoke process that permanently turns the meat a bright pinkish red color. No matter how old that tuna gets it's still the same fluorescent pinkish color. You may have seen it at your grocery store in the frozen fish section. The tuna is usually triangle shaped and often packed two to a pack. Many restaurants serve it because tuna is a tricky animal. It spoils quickly and the flesh of fresh tuna begins to turn gray when exposed to air. So it's difficult to slip it by the customer. How do you know it's safe to order tuna in a restaurant? Two big factors, the restaurant's reputation and price. Good tuna is not cheap, bad tuna is.
There are different types of tuna varying in quality. The most precious is "Bluefin". Used extensively in sushi and sashimi. It's VERY expensive and is becoming scarce. Next down the tuna chain is "Big Eye". Very nice tuna and a good alternative to Bluefin. Then comes "Yellowfin", this tuna is probably the most abundant among restaurants that serve fresh tuna. It's not as expensive and is still a nice product. It's also broken down into grades of quality. Number one being the best, then two++, two+ and two. It's further broken down by size. The smaller the fish the less expensive. Bigger fish have a higher fat contact. In tuna and many other fish fat is a good thing. The bad thing is the fatter the fish the higher the mercury content. It is most prevalent in Bluefin. They are larger, dive deeper, and have the highest fat content. There was a recent study done in New York city studying Mercury levels in tuna and the amounts were alarming. The highest levels were found in Bluefin. I'm not suggesting you refrain from tuna, you would have to eat tuna often to worry about it.
Other types of tuna are Albacore and Skipjack. I'm seeing Albacore sold fresh and is also used in canning. Skipjack, also known as Bonito is canned and dried.
A couple of terms that are associated with tuna are "Ahi" the name for Yellowfin tuna, "Maguro", the Japanese term for Bluefin tuna and "toro", the fat under belly of Bluefin (Abolutely delicious).
Because of the severe shortage (and the price)of Bluefin I serve Big Eye and #1 Yellowfin. Still great products if you can move enough to keep it fresh. Hence the reason why so many restaurants serve the frozen variety.
I've included a link below about sushi tuna. I encourage you to try it. I like it seared rare with a little soy glaze, pickled ginger and wasabi. Rare seared tuna is also known as "tataki". I also feel it should be eaten with chopsticks. I hate it when I'm served thinly sliced rare tuna with a fork. When we go out I'm going to have to start bringing my own chopsticks with me.
http://www.sushifaq.com/sushi-items/sushi-items-tuna-maguro.htm
