Marlene Parrish - What Einstein Told His Cook 2

Imust duck your question for two reasons: (1) I don’t know the answer, and (2) you’re not going to drag me into the raging battle among salmon farmers, wild-salmon fishermen, and environmentalists. However, to muddle a few metaphors, I will walk a tightrope through the minefield and drop what pearls I can.

From decades-long experience, we consumers have expected our salmon to be a nice, orange-pink color. The muscle tissue of wild salmon ranges from deep red in the sockeye to pale pink in Chinook or king salmon. The colors come from the fish’s diet of tiny shrimp-like crustaceans called krill that contain a pink carotenoid compound called astaxanthin . Wild (not lawn-dwelling) flamingoes are pink for the same reason.

Carotenoids are the chemical pigments largely responsible for the variety of beautiful colors in nature, both in plants and, via feeding, in many animals as well. There are over six hundred known carotenoids in flowers, fruits, vegetables, and birds.

Salmon raised in aquaculture pens do not have much access to the carotenoid pigments in krill, and are fed an artificial diet containing an added colorant: either astaxanthin itself or another FDA-approved carotenoid, canthaxanthin. (The latter, oddly enough, is also sold as a human skin-tanning drug.) Astaxanthin produces a somewhat redder hue (in salmon) than canthaxanthin, and salmon farmers can actually choose the shade they want in their fish by selecting their feed mixture from a color wheel.

On April 23, 2003, a Seattle law firm filed three class-action suits against the supermarket chains Kroger, Safeway, and Albertson’s, claiming that all consumers who purchased farm-raised salmon over the preceding four years—not to mention the lawyers themselves—should be showered with literally millions of dollars because the stores failed to disclose the shocking fact that their salmon had been artificially colored. The families of those consumers who, we must presume, died of humiliation upon learning that they had eaten colored salmon certainly deserve to be compensated most generously, don’t you think? Fortunately, the court didn’t think so, and the suit was thrown out.

(Insert your favorite lawyer joke here.)

Less frivolous concerns about salmon farming are based upon such issues as whether the wild salmon population is endangered; whether fugitive farm fish will interbreed with wild stock, to the detriment of genetic diversity; whether crowded, net-caged salmon pollute their environment with parasites and disease; and whether their pens are contaminated with PCB’s ( polychlorinated biphenyls ), any of about two hundred probably carcinogenic synthetic industrial chemicals that have not been manufactured since 1997 but that still show up in the environment.

And by the way, your suggestion of feeding salmon lycopene instead of astaxanthin is probably impractical unless we could get salmon to eat tomatoes, in which lycopene is the predominant pigment. Might be worth a try.

Blistered Wild Salmon

When leading chefs cook wild salmon, they like to keep it simple. For best results, they caution, don’t overwhelm the fish with exotic sauces and ingredients. Just season it and cook it until the center is barely opaque. This oven method is a favorite at our house. Bob loves the crisp skin and keeps reminding me that it contains all those healthful omega-3 fatty acids.

2 tablespoons olive oil

4 wild king salmon fillets, skin on, 6 to 8 ounces each

Salt and freshly ground pepper

1.Preheat the oven to 275°F.

2.Heat the olive oil in a large, ovenproof nonstick sauté pan. Add the fillets, skin side down. When the skin blisters, after about 1 minute, place the pan in the oven and roast for 8 to 12 minutes for medium-rare.

3.Remove the pan from the oven and place it over high heat for about 2 minutes, or until the skin crisps. Think undercooked and it will be perfect. Serve the salmon skin side up.

MAKES 4 SERVINGS

THE FOODIE’S FICTIONARY:Poached salmon—salmon stolen from a fish farm

A TUNA TONER

I love sushi, especially the yellowfin nigiri. The raw tuna sometimes has different colors, however, ranging from pink to dark red. I never thought much about it, but I just saw a story in the newspaper saying that raw tuna is being treated with carbon monoxide to give it a bright red color, even if it isn’t fresh. Isn’t carbon monoxide lethal?

Yes it is, under the right—that is, the wrong—circumstances. But not in the case of monoxide-treated tuna.

First, for the uninitiated, yellowfin tuna, which may be listed on the menu as maguro , the generic Japanese word for tuna, is not to be confused with yellowtail, a kind of amberjack, or with toro , the prized fatty belly of the bluefin tuna. Nigiri sushi is a filet of the raw fish on a pillow of vinegared rice.

Every year in the United States, several thousand people are treated in hospital emergency rooms for carbon monoxide poisoning. Some two hundred per year die from carbon monoxide given off by improperly vented gas-burning appliances such as furnaces, ranges, water heaters, and room heaters, while many others are killed by automobile engines running in enclosed spaces.

Carbon monoxide gas is particularly toxic because it goes from the lungs into the bloodstream, where it replaces the oxygen in the blood’s oxyhemoglobin, destroying its ability to deliver oxygen to the body’s cells. And the organs most likely to crash from oxygen starvation are the heart and brain.

All devices that burn carbon-based fuels, including gasoline-burning automobiles, gas-burning furnaces, kerosene-burning heaters, and even charcoal-burning hibachis, emit carbon monoxide because their fuels don’t burn completely; the combustion process is inevitably inefficient. Instead of burning all the way to carbon dioxide, CO 2(two oxygen atoms for every carbon atom), some of the carbon atoms in the fuel can’t find that second oxygen atom and end up as carbon monoxide, CO. That’s why these devices should never be operated in an enclosed space: the inevitable CO can build up to a lethal concentration.

Eating raw tuna that has been exposed to carbon monoxide gas is another matter entirely. In this case you’re not breathing the gas, and for that matter you’re not even eating it. Gases, of course, are ephemeral, and the carbon monoxide doesn’t hang around on the fish after it has done its job of brightening its color. The FDA has declared carbon-monoxide-treated tuna to be GRAS—generally regarded as safe—because residual carbon monoxide on the fish is virtually absent.

But why should a food processor do such an outlandish thing as exposing fish to a poisonous gas? Well, follow the money. The red color of freshly cut tuna can change within a few days to an unappetizing brown. Consumers don’t like brown fish and are willing to pay more for “fresher-looking” red. Hence, the cosmetic application of carbon monoxide “rouge.”

Tuna flesh, like the flesh of many land animals, contains myoglobin, a pigmented protein that stores oxygen in the muscle tissue. Myoglobin changes color, however, depending among other things on how much oxygen is available to it. The dark, purplish-red color of freshly cut tuna is due to deoxymyoglobin , which in air changes first to bright red oxymyoglobin and then to brown metmyoglobin . Tuna purveyors must therefore rush their tuna from the boat to the sushi bar while it is still in the red oxymyoglobin stage.

Carbon monoxide thwarts these color changes by replacing the oxygen in the oxymyoglobin molecules (as it does in our blood’s oxyhemoglobin molecules), converting them into a very stable complex: the watermelon-red carboxymyoglobin . The oxymyoglobin is thus derailed from being oxidized to brown metmyoglobin .