Tuna goes upscale: canned tuna - test.(Buyers Guide)

The normally humble canned tuna is putting on airs. Several new developments have this lunchtime stalwart stepping out in style, just two years shy of its centennial. Among the most novel introductions: "canned" tuna sans the can. Bumble Bee, StarKist, and Chicken of the Sea--the top three companies, which account for about 85 percent of sales--now package tuna in vacuum sealed pouches containing virtually no drainable liquid. (At press time, Chicken of the Sea pouches were expected to arrive on store shelves shortly.)

Light tuna is also undergoing something of a sea change. A type of tuna that may be new to you, tongol, is making a splash as the lightest-hued and firmest of the lights. In addition, there are more light tunas in solid, rather than the usual chunk, form. Bumble Bee and StarKist have joined Progresso (a Pillsbury company) and Genova Tonno (a Chicken of the Sea brand) in marketing solid light tuna--what StarKist's web site describes as a hand-cut fillet "for discriminating gourmet-tuna tastes."

Most solid lights are packed in olive oil and, befitting their gourmet aspirations, are pricier than their siblings in chunk form. Other choices for oil-packed tuna now include canola and sunflower oil, in addition to the generic "vegetable oil," which is often soybean oil.

These new developments add more variety to the traditional lineup of white and light in solid or chunk form packed in oil or water. White and light vary in flavor, texture, and price, since they come from different species of tuna, as we'll explain shortly. Chunk light, the cheapest type and the usual fare at delicatessens and cafeterias, accounts for as much as 70 percent of all tuna sales, according to some industry estimates. Water-packed light and white tuna outsell their oil-packed counterparts by almost 9 to 1.

In our tests of more than three dozen products, the new entries proved to be among the best in their class. Tongol, tuna in pouches, and solid lights in oil and in water swept top honors in the light category. Most of the white tunas earned high scores, as they did the last time we tested tuna, in 1992. Our Ratings on page 19 give a complete listing.

Canned tuna gets somewhat mixed reviews on the health front. On the plus side, it's an excellent source of protein and contains heart-healthy omega-3 fatty acids. The downside is that tuna--like many other species of fish--accumulates methylmercury, which can pose a health risk. Many experts recommend that young children, pregnant women and women who may become pregnant, and nursing mothers limit their consumption of fish containing significant amounts of methylmercury. (See "Mercury: Gauging the Risks" on the facing page.)

Still, for most of us, the many benefits of eating seafood far outweigh the risks. And canned tuna is America's favorite fish: Annual consumption averages 3.4 pounds per person. That's less than the 1989 high of 3.9 pounds but a reversal of the slight, steady decline that marked most of the last decade.