I used to be a tuna fiend, eating tuna sushi several times a week, and on the days when I didn't eat it raw, I'd have a tuna sandwich. Then all the reports came out about heightened mercury levels. Then new reports about even higher levels of contaminates, and recommendations that women of childbearing age limit tuna intake to once or twice a week. And now this, from yesterday's New York Times, Tuna's Red Glare? It Could Be Carbon Monoxide
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…
…[F]or 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.
Oy. Ick. This reminds me of when I read about a lot of sushi being frozen. Sometimes ignorance is bliss.