“Tailpipe Tuna” Is a Real Thing – but You’ll Never Find It at Mikuni

If the idea of gassing tuna with carbon monoxide to give it a bright, fluorescent color seems like something out of science fiction, think again. This practice is widespread in the United States, and “tailpipe tuna,” as it is known, has made its way into supermarkets, fish markets, and restaurants throughout the country.

As far back as 2004, the news media has been shining light on this dirty little secret. An article entitled “Tuna’s Red Glare? It Could Be Carbon Monoxide” appeared in the food column of The New York Times in October of that year, highlighting the fact that “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.”


Fresh tuna, depending on its fat content, ranges in color from pale pink to deep red. (The more fat, the lighter the color.) Tuna tends to oxidize quickly, which cause it to turn an unappetizing grey or brown. Even though it may still be relatively fresh at that point, no one wants to eat it because of the way it looks.

That’s where the practice of gassing comes in. To maintain a color that is appealing to consumers, some restaurants and retailers treat the fish with carbon monoxide. The gas reacts with the myoglobin in the tuna, resulting in a stable pigment no matter how old the fish is. Carbon monoxide can even affect tuna that has turned brown, miraculously changing it to a fresh-looking, rosy color.

While carbon monoxide preserves the color of the fish, it does nothing to maintain freshness. It is therefore possible to have a piece of appealingly ruby-red tuna that is, in reality, days—or even weeks—old. A sales representative for an international seafood supplier was quoted in The Times article as saying, “You could put it in the trunk of your car for a year, and it wouldn’t turn brown.”

To make matters worse, most of the carbon monoxide-treated tuna comes from third-world countries that do not follow safe food-handling laws. According to the CDC, 425 peopled were sickened in a 2012 salmonella outbreak linked to a gassed tuna product.


Our guests can rest assured that we at Mikuni will never engage in such deceptive, potentially dangerous practices. In fact, our habits fall firmly on the opposite end of the spectrum. We use only grade-one tuna for our sashimi—the highest possible grade based on initial appearance, size and shape, color, texture, and fat content.

The grading process is relatively subjective, and one company’s number-one grade is not necessarily the same as another’s. Because of these variations, we get our tuna from very limited and extremely trusted sources that we have come to rely on over the years. We purchase both yellowfin and bigeye tuna, and our sourcing changes daily depending on conditions. Lately, most of our fish comes from the Marshall Islands, Fiji, and Hawaii.

At Mikuni, food that looks deliciously appealing is important to us, and we will always focus on the beauty of each and every presentation. But our commitment to perfection goes far beyond the surface, and we embrace a dedication to quality and freshness that simply cannot be surpassed anywhere else.

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