The food you eat in restaurants isn't normally labeled, and I don't normally buy too much packaged sushi. When I did today over at the Stata Center, I was surprised to see that they had added carbon monoxide to the sushi. This New York Times article summarized some of the issues with treating sushi with carbon monoxide.
"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."I find this to be quite grim actually. Perhaps I am jaded by the fact that the sushi was quite bad.
So how hard is it tell whether the sushi is fresh? According to the NYT article:
"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."
When I buy fish, I interact it with it deeply in the manner that my father, a chef, always has. Smelling, checking the texture, looking for sheen or oils are all ways to get more info. Since I can't open up the package to do any of that, I'm just not going to buy any more packaged sushi.
Long-run, I'd like to see a better solution such as born-on dating.