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August 30, 2008


"Will diners continue to tolerate it?"

Will people continue to pay extra for bottled water? Will women continue to pay thousands of dollars for designer handbags when they can't tell the difference between a real one and a fake? That does not mean however that the government will not step in and spend huge amounts of money stopping the grievous practice of people eating and thoroughly enjoying fake sushi ;-).

I don't see the difference between this and the turn of the century meat-packing plants that put rats and worse in their meat. We just need more enforcement to keep the sellers from cheating, as technology improves it will become easier.

I wonder, if we compiled all these tidbits into the Big Book Of Unpleasant Truths, how many people would buy it for themselves, how few would dare give it as a gift to a friend, and how many people I know would think it was an appropriate birthday present for me.

"Will diners continue to tolerate it?"

I suspect those paying more than the mean sushi price will. With a slightly higher general awareness of this fraud the stage is set for the few sushi patrons that actually know the difference to rapidly propagate their opinions. Anyone who places sushi high on their list of life's pleasures is a likely candidate to become the vanquishing knight saving the peons from an unsatisfying experience.

I suppose cooking the fish renders it non-identifiable, hence the focus on sushi?

In the Northwest, there is no red snapper. Whenever you see red snapper it's actually rock cod, aka Pacific rockfish, aka "Pacific red snapper". I believe I like red snapper more but haven't double-blinded it.

As a fan of sushi, I'm all in favor of legally confronting the perpetrators of such frauds. Class action lawsuits might be feasible if chains are found doing this. Sushi can be great or it can be so-so, and I suspect that mislabeled fish might be the cause for a fair amount of disappointing experiences. To the extent that you get fully charged for those experiences, which are rendered inferior by the restaurant giving you the wrong fish, this is straight out fraud, pure and simple - like someone stealing money out of your pocket.

According to the Wikipedia entry on DNA barcoding, "Due to various phenomena, Funk & Omland (2003) found that some 23% of animal species are polyphyletic if their mtDNA data are accurate, indicating that using an mtDNA barcode to assign a species name to an animal will be ambiguous or erroneous some 23% of the time (see also Meyer & Paulay, 2005)."

In other words, 1/4 of the time.


As I always say, show me the Methods. In this case, the data isn't published in a peer-reviewed journal, but according to the New York Times article, the two teenagers who performed this experiment used 4 restaurants and 10 markets. One market that was cited has having no mislabeled sushi, according to the owner, buys the fish themselves. We don't know how the others get their sushi. We don't know if many of them get their sushi from the same source. The sample was taken from a single city, and may not have been randomly distributed even within that city.

Do sushi distributors mislabel their sushi? Since, up until now, there was no way to tell the difference, and there was an economic incentive to do it, I'm sure that some do. But the "one in four" number is meaningless. The sample size is too small and nonrandom, and the DNA barcoding technique trades experimental robustness for cheap methodology.

Maybe in reality only 5% of sushi is mislabeled. Would it bother you then?

If it tastes good, I could care less where it comes from, and I don't think most diners do either. Seriously, I really don't believe ordering certain types of sushi over others is a symbol of status...

This isn't the first or only effort to use DNA testing to identify mislabeled fish. Here's a news story about another.

Seconding Grant's reply. I'm sure the vast majority of diners take fancy sushi only to try around and not as a status symbol. It's not the kind of meal you eat everyday, so most people aren't knowledgeable about it anyway.

Cyan: It's a University of Guelph study. That's where the major proponent of DNA barcoding resides. It should be pointed out that DNA barcoding is a specific type of DNA testing, a much simpler and less robust form than common DNA fingerprinting techniques. While forensic DNA fingerprinting typically employs dozens of well-characterized genetic markers, DNA barcoding employs a single one.

And how do you know when fish goes bad? Doesn't it just smell like fish?

Eliezer, great question.

MZ, I could imagine NYC teens making that mistake, but it is harder to believe the Guelph folks are making it.

When I try unusual sushi, the thing I'm trying to satisfy is my curiosity. Being lied to about the species would undercut exactly the thing I'm trying to buy - and obviously I'm ignorant of the cues that would let me notice. From my perspective a very dastardly crime! Just having been primed to expect it has definitely altered my future behavior. (I now weight chain stores as preferable to boutique stores, since they have more to lose.)

Robin, which mistake? The technique of DNA barcoding itself, which employs a single genetic marker, usually the cytochrome C gene in mitochondrial DNA, is not robust and is subject to a lot of error whether a couple of NYC teens do it or Craig Venter does it. The "study" is further complicated by the small and nonrandom sampling methodology of the teens. In short, it would never get published as it stands. Don't treat it with respect just because it appears in the New York Times. :)

If the "fake" substitutes are not endangered or their stocks overfished, then I think the substitution is a very good thing. We are better off when people who don't know any better consume a fish that is in relative plentiful supply.

1) Although this particular study may be questionable, there are good reasons to believe fish is sytematically mislabeled. My mother-in-law worked at a fish counter for 15+ years and routinely catches restaurants making cheaper substitutions (and shocked when she calls them on it); in NYC a few years ago it was shown that the vast majority of "wild" salmon sold in specialty stores was in fact farmed; etc.

2) There's a difference between not being able to tell the difference because you can't tell the difference and not being able to tell the difference because you've never or rarely had the good stuff.

3) Environmental and health issues are one key to why fish labeling matters. Many disapprove of farmed seafood (usually the cheaper choice) on these grounds. (Imagine I was labeling factory-farmed, hormone-and-antibioticked-up meat as "free-range organic.")

I saw an investigative report that said here in Florida fish labeled Grouper on restaurant menus is grouper less than half the time. I once had a fish that was supposed to be grouper but did not taste like grouper but I was afraid to make a fuss. I will not go there again because even if it was grouper it was not good grouper. On the other hand if you buy it because you like the flavor and you cannot tell the difference you do not have much to complain about.

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