How to select good quality canned tuna.

( Joenomias Menno de Jong Images. )

Canned tuna is probably the most popular fish food product worldwide.

It has become a staple food and is often found in lunchtime sandwiches.

In fact, half of canned tuna in worldwide is employed

between 2 slices of bread.Tuna canning was invented at the turn of

the 20th century to preserve the fish product without an icebox.

After the tuna is caught, head and tail are removed

and the fish are gutted. It is pre-cooked in a steam oven for 2-4 hours, then

cooled. Afterwards, the cooked fish is boned, fileted, and divided into a 6-ounce

portion that goes into a can. A liquid medium (water or vegetable oil)

is added,and the can is vacuum sealed. One final step is a heat

treatment to kill off any potential bacteria.

There are 5 types of tuna species but only albacore, skipjack,

and occasionally yellowfin are used for canned tuna. Bigeye (aka ahi)

and bluefin are usually served as sushi or steaks.

( Tim Boyle / Getty Images )

Canned tuna sold in supermarkets comes labeled as either

white or light. The majority of canned tuna is light, a combination of skipjack

and some yellowfin. Albacore tuna is the white tuna. Opt for light tuna, it has

less mercury than white tuna, as it is made from younger, smaller fish that had

less time to absorb the toxic heavy metal in their fatty tissues.

Opt for tuna canned in water, as it has much less calories than tuna in oil.

A 3-ounce serving of canned tuna has just 90-100 calories.

It boasts 22 grams of protein and virtually no carbs or fat.

Canned tuna is also a great source of vitamin B-12 and vitamin A.

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