Tuna's Red Glare? It Could Be Carbon Monoxide

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http://www.nytimes.com/2004/10/06/dining/06TUNA.html?th

 

Tuna's Red Glare? It Could Be Carbon Monoxide

 

By JULIA MOSKIN

 

BUYERS of fresh tuna, whether at the sushi bar or the supermarket,

often look for cherry-red flesh to tell them that the fish is

top-quality. But it has become increasingly likely that the fish is

bright red because it has been sprayed with carbon monoxide.

 

The global seafood trade has expanded so much over the last decade

that tuna, once a seasonal delicacy, is available year-round. But

getting it to consumers while it still looks fresh is difficult. Tuna

quickly turns an unappetizing brown (or chocolate, as it is called in

the industry), whether it is fresh or conventionally frozen and thawed.

 

Carbon monoxide, a gas that is also a component of wood smoke,

prevents the flesh from discoloring. It can even turn chocolate tuna

red, according to some who have seen the process.

 

People in the seafood industry estimate that 25 million pounds of

treated tuna, about 30 percent of total tuna imports, were brought

into the United States last year, mostly from processors in Southeast

Asia. Retailers in the United States buy it already treated.

 

The Food and Drug Administration says the process is harmless. But

Japan, Canada and the countries of the European Union have banned the

practice because of fears that it could be used to mask spoiled fish.

 

Carbon monoxide preserves only the color of the fish, not its quality.

Suppliers and retailers who use the treated fish say the process

allows them to sell high-quality, flash-frozen fish that still looks

good enough to eat. Jerry Bocchino, an owner of Pescatore, a fish

store in Grand Central Market in New York, said that his sales of tuna

have tripled since he switched to the treated kind two months ago.

 

" With fresh tuna, you're always racing the clock to keep the color and

keep it from spoiling, " Mr. Bocchino said. " And once it turns brown,

no one wants to buy it. People love the color of this stuff. "

 

Tim Lauer, a seafood dealer in the Minneapolis-St. Paul area, said

that most sushi bars and supermarkets there have switched to the

product since it was introduced in the late 1990's. " I've lost all my

sushi customers for tuna, since I won't sell it, " he said.

 

Just because a slice of tuna is brown, it does not mean it is not

fresh. And other factors determine the color, including the fat

content, species and cut. The finest fresh bluefin, which sells for up

to $40 a pound at Tokyo's wholesale fish markets, is not a deep red

but a pale pink because of the fine web of white fat that permeates

the red flesh. Top-quality toro is often a brownish red.

 

But for most consumers around the world, vendors say, lollipop-red

flesh signals freshness and quality. Tuna treated with carbon monoxide

is bright red when first defrosted, and fades within a couple of days

to a watermelon pink. But " you could put it in the trunk of your car

for a year, and it wouldn't turn brown, " said one sales representative

at Anova Foods, a distributor in Atlanta, who spoke on condition of

anonymity.

 

The use of carbon monoxide in food is hardly new, as any barbecue or

smoked salmon fan should know. (Wood smoke contains carbon monoxide.)

But the gas used by many overseas producers, although tasteless, is

more concentrated; it can be as much as 100 percent carbon monoxide,

said Bill Kowalski, an owner of Hawaii International Seafood.

 

American processors like Hawaii International and Anova Foods are

racing to market their own versions of the technology, using wood

smoke that is filtered to remove the elements that make food taste

smoky. These processors use lower concentrations of the gas and tag

their product with trademarked names like Tasteless Smoke, Clearsmoke

and Crystal Fresh.

 

Opinion about carbon-monoxide-treated tuna is sharply divided, and

illustrates the complex issues that consumers have to wade through at

the fish market.

 

To supporters like Mr. Bocchino, Mr. Kowalski and Dr. Steve Otwell, a

researcher at the University of Florida, carbon monoxide treatment is

an important advance in food safety that accommodates the realities of

the marketplace. Instead of fresh tuna that is likely to spoil

quickly, they reason, consumers get a high-quality frozen product that

can be transported safely, thawed when needed, and keep its fresh

look. " The industry scrambles to get fresh tuna to market, but the

reality is that by the time a long-line Pacific tuna makes it to an

American supermarket, it could be as much as 30 days out of the

water, " Dr. Otwell said. " That's much more of a health risk than

treated tuna, as long as the raw material is good and the treatment is

controlled. "

 

Roman Choudhury, the manager of two sushi restaurants in Manhattan,

buys treated tuna when he cannot get it fresh, particularly for tuna

rolls. " At my price point, it's almost impossible to have a steady

supply of fresh tuna, " he said. " And people always, always want tekka

maki. "

 

Detractors call the process risky and dishonest. " There's no reason to

do this other than to deceive the consumer, " Mr. Lauer said. " There

are natural solutions to the problem of browning. "

 

One is ultra-low-temperature freezing, which keeps tuna at about 80

degrees below zero for months or even years without browning. But

maintaining such low temperatures during the long trip from boat to

plate is a very expensive proposition.

 

Caroline Smith DeWaal, food safety director for the Center for Science

in the Public Interest, a nutrition advocacy group, said, " Anything

that masks the true age of a piece of fish is a public safety risk. "

 

As tuna ages, it becomes more likely to cause scombrotoxin poisoning,

which is rarely severe or fatal. It is the most common form of food

poisoning from seafood in the United States, the Center said.

 

The F.D.A. has put carbon-monoxide-treated tuna on its list of

substances generally regarded as safe. The agency permits its use to

preserve the color of fresh tuna, not to enhance brown tuna, and

requires stores to label treated fish. But they often do not.

 

What does all this mean at the market? Any tuna that is hot pink has

probably been treated with carbon monoxide. Tuna that is bright red

may be extremely fresh, and therefore very expensive, or may have been

treated with the gas.

 

" Outside of Hawaii bright red tuna that is selling for less than $12 a

pound is probably treated, " Mr. Lauer said. " On the other hand,

there's nothing to stop people from selling treated tuna for $20 a

pound if they can get away with it. "

 

Copyright 2004 The New York Times Company