Whether tuna is raw in sushi and sashimi, grilled as a steak, or scooped from a can, the fish is awash in controversy. Overfishing, mercury levels, and dolphins caught in nets meant for tuna account for this. Where once a tuna sandwich for lunch was a routine event, we no longer eat canned tuna without thinking about it. Still, almost everyone has a can in the cupboard, for that favorite sandwich spread with mayo, or without adornment to add substance to a green salad or a pasta sauce.

Most tuna absorb mercury by feeding on other fish or by eating plants exposed to it, whether naturally or through pollution. Albacore white tuna is a larger species, which generally has more mercury. Skipjack, a smaller species, is used in chunk light canned tuna. Mercury levels also depend on the age and provenance of the fish.

The Food and Drug Administration recommends limiting the amount of fish with higher mercury levels and eating low-mercury fish such as shrimp, canned light tuna,catfish, pollock, and salmon. The complete FDA list is at www.fda.gov.

We tasted seven brands of chunk light canned tuna in water with a group of students from Boston University’s Culinary Arts program. Students alternated slices of apple with plain tuna. Color ranged from light beige to a more tawny, darker shade.

Brands with larger chunks made one taster comment: “The solid chunk of tuna was a good sign of the taste.” Another taster said after sampling Starkist (she didn’t know what brand it was at the time), “Needs a whole apple to cleanse my palate.” One student was happy to taste tuna in water because that’s what she buys, then adds her own olive oil. “I taste the metal in the can when you buy the tuna in olive oil.”

Our future chefs were looking for a “pleasant fish taste,” but nothing “fishy tasting.” For texture they wanted something “moist but not slimy.” Although there was no overwhelming winner, a Stop & Shop house brand, Nature’s Promise, with three ingredients (light tuna, water, and salt) was the favorite. No single brand was considered worst, but Starkist and Natural Sea (bought at Whole Foods) tied for the honor.

Say, did anyone notice that cans of tuna shrank from 7 ounces to 5 ounces? You have to spread it mighty thin for more than two sandwiches. Just another complaint, among many.

Bumble Bee Chunk Light Tuna in Water

$1.49 for 5 ounces

First the appearance: “Slightly wet look that makes it appear fresh. Excess moisture gives it a mushy texture. Pleasant canned tuna flavor.” “Appears moist, but mushy. Small broken pieces. No cohesive coloring. Mix of pink and white. More chewy.” “Great appearance, moist. Has fish flavor with no uncomfortable aftertaste.” Texture: “Kind of bland and the moisture is quite over the top. Wouldn’t make good tuna salad.” “Very wet and finely chopped. Has very fishy smell.” One taster gave it the ultimate insult. “How I imagine cat food to taste. But I like the texture.”

Chicken of the Sea Chunk Light Tuna in Water

$1.83 for 5 ounces

Many noticed the size of the chunks (actually shreds), but the flavor was decent. “Looks over-processed, but nice and moist. Not a lot of flavor.” “Appears crablike due to small shreds. Moist and more salty than rest.” “Grainy and dry with good flavor.” Finally: “Very broken up into small pieces. Moist and good flavor. Lacking in texture, almost chalky.” One pan: “Looks like mushy wet cardboard. Sadly, it tastes like it too.”

Food Club Chunk Light Tuna in Water

$1.19 for 5 ounces

The moist texture elicited “mushy,” “slimy,” and “gummy” comments. “The wet look made it seem fresher but it turns to mush in your mouth. Feels over-processed.” “Small flakes. Moist appearance. Dries out very fast. Slimy in the mouth. Taste is almost nonexistent.” “Not horrible. Way too slimy.” “Salty with a decent tuna flavor. Gummy in the mouth.” “Has an aluminum taste. Very wet and pretty odorless.”

One chose this as least favorite, but submitted a thesis: “Disturbingly moist, soggy, and uncomfortably soft in the mouth. I have a feeling you could spread this tuna as is, but you wouldn’t want to. Similar to the texture of wet cat food, upsetting.” Two tasters were not as put off: “Light and fluffy. Good taste and light color.” “It doesn’t really look bad.”

Geisha Chunk Light Tuna in Water

89 cents for 5 ounces

This brand was the least expensive of the lot. Alas, some skin among the flakes. “I got a piece of tuna skin. Could be either artisanal or sloppy manufacturing. I think it is the latter. Taste-wise, not bad.” “Lighter more delicate flavor, almost like shellfish. Texture is a little mushy.” “Looks very dry but actually fairly moist. A little grainy, not great flavor.” “Very dry in the mouth, almost feels difficult to chew. Mild flavor. Slightly metallic aftertaste.” “Tastes like sawdust.” Still, one chose it as a favorite: “Perfectly chunked. Not fishy, very weak flavor, texture is moist and appealing.”

Nature’s Promise Natural Chunk Light Tuna in Water

(Stop & Shop house brand) $1.65 for 5 ounces

“Best tuna flavor by far. Texture is moderately dry.” “Darker in color. Moist, classic tuna taste. Overall, very pleasant.’’ “Has a good texture and taste not too fishy.” “Very moist and appealing mouth feel but not too pretty to look at because it appears rather soggy. Good flavor, just adequately fishy.” Another expounded on the dryness. “Looks nice and flaky. Very dry, not pleasant to eat. Sticks to your mouth because it lacks moisture.” One who chose it as the worst also noted its dryness. “Thin larger pieces, a hint of unpleasant aroma, like gasoline/oil/fumes. Dries out quickly in mouth. Unpleasant texture that lingers.”

Natural Sea Chunk Light Tuna in Water

$2.99 for 6 ounces

The most expensive of the seven we tasted, this brand, which we found at Whole Foods Market, drew lots of negative comments. “Nasty tuna. Way too fishy. Not even chunked. It has specks.” “Comes in big clumps of tuna. Particularly salty.” “A bolder, even darker, flavor than some of the others, but not overly fishy. I am disturbed by this tuna’s appearance. Rigid concentric circles that remind me of cat food.” It was chosen worst by two tasters. “Parts are dried out. Unpleasant lingering aftertaste. Very fishy flavor.” “Looks very dry and tastes grainy. It felt like I had fine sand in my mouth. Such an unpleasant texture.” But a favorite for one: “Large chunks, appears to have more value. Provides nice chew and dissolves evenly in mouth. Mild aroma, almost unnoticeable.”

Starkist Chunk Light Tuna in Water

$1.55 for 5 ounces

“From the look of it, I have a very good feeling about this one. It doesn’t taste spectacular. Very solid can of tuna.” “Lots of moisture when chewed, but tuna holds its form and texture. Very pleasant tuna taste.” Two could taste the can: “This one has a slightly metallic taste. The texture is only slightly dry.” “Metallic aftertaste that lingers.” Others also found it lacking. “Very dry. No distinctive character. Leaves unpleasant texture in mouth.” “Very bland. Hardly tastes like anything. Mushy and boring.” One chose it the least favorite: “Horrible. Never buy!”