DNA Bar Coding Finds Mislabeled Sushi 285
Hugh Pickens writes "The NY Times reports that Kate Stoeckle and Louisa Strauss, who graduated this year from the Trinity School in Manhattan, took on a freelance science project to check 60 samples of seafood using a simplified genetic fingerprinting technique called DNA Bar Coding to see whether the fish New Yorkers buy is what they think they are getting, and found that one-fourth of the fish samples with identifiable DNA were mislabeled: A piece of sushi sold as the luxury treat white tuna turned out to be Mozambique tilapia, a much cheaper fish that is often raised by farming. Roe supposedly from flying fish was actually from smelt." (More below.)
"Seven of nine samples that were called red snapper were mislabeled, and they turned out to be anything from Atlantic cod to Acadian redfish, an endangered species. The project began over dinner with Stoeckle's father, a scientist and early proponent of the use of DNA bar codings. Instead of sequencing the entire genome, bar coders examine a single gene. Dr. Stoeckle said he was excited to see the technology used in a new way and compared the technique to GPS. 'The smaller and cheaper you make something,' he said, 'the more uses it has.'"
Re:Big Surprise (Score:5, Informative)
Here in Tampa, Florida area, this was recently a very big deal. One of the things Tampa is famous for is Grouper, and several well-known restaurants were found to be serving cheaper fish instead of Grouper.
6 out of 11 restaurants served cheaper fish [sptimes.com].
According to that article though it's hard to tell whether the deception was intentional, and even if so, who was deceptive: the restaurant, the wholesaler, etc.
Comment removed (Score:4, Informative)
Re: (Score:5, Informative)
Steve Palumbi did this back in the mid-90's for whale and dolphin products being sold in commercial markets in Korea and Japan (Baker and Palumbi 1994 Science 265: 1538; Baker et al. 1995 Molecular Ecology 5:671). Essentially they went around the fish stalls taking samples and amplifying and sequencing them in their hotel room. From the latter article abstract:
This 'spot check' revealed a surprising variety of species for sale, including minke, fin and humpback whales and one or two species of dolphins sold as 'kujira' or whale. In the Korean survey, DNA amplifications were conducted by two of us (C.S.B. and F.C.) working with independent equipment and reagents. The two sets of DNA amplifications were returned to our respective laboratories and sequenced independently for cross-validation. Among the total of 17 species-specific sequences we found a dolphin, a beaked whale, 13 Northern Hemisphere minke whales (representing at least seven distinct individuals) and two whales which are closely related to the recognized sei and Bryde's whales but could not be identified as either using available type sequences. We suggest that these two specimens represent a currently unrecognized species or subspecies of Bryde's whale, possibly the so-called 'small-form' reported from the tropical waters of the Indo-Pacific.
Until these guys went out and actually did the sequencing, no one knew for sure how much illegal whaling activity was going on.
Re:I'm wondering about the contents of my burrito. (Score:5, Informative)
Outside of Japan, sushi is sometimes misunderstood to mean the raw fish itself, or even any fresh raw-seafood dishes.
In Japan, sliced raw fish alone is called sashimi and is distinct from sushi, as sashimi is the raw fish component, not the rice component.
The word sushi itself comes from an archaic grammatical form of a word that is no longer used in other contexts; literally, sushi means "it's sour".
sushi, sashimi (Score:5, Informative)
This method has some limitations (Score:3, Informative)
Since this relies on segments of mitochondrial DNA(not the nucleus's DNA), it fails in species with endosymbiotic bacteria, such as many arthropods and the Wolbachia bacteria. So it's unlikely this will work on, say, crab or lobster.
Wolbachia [wikipedia.org] is an awesome bacteria, as it can cause those infected with it to be unable to breed with those not infected, which could possibly induce the divergence of species. Some species have been infected with it so long, generationally, that they go sterile if you give them antibiotics.
Re:So..?? (Score:4, Informative)
Seems that it should be a government function, say the FOOD and drug administration, to not only make sure that your food won't kill you but that what you pay for is what you get.
I wonder if it's the restaurants pulling one, or their suppliers (or both)
Restaraunts here sell walleye [wikipedia.org], but walleye is in dangered and illegal (at least accorsing to a restaurant owner I talked to) so they sell pollack [wikipedia.org] and call it walleye. IMO it should be illegal to put "ribeye steak" on the menu and serve you dog.
Walleye endangered? I've never heard of that...sounds wacky to me, they're all over the great lakes, etc. (correction after looking it up -- the BLUE walleye has been extinct for about 30 years, but there are still lots of regular walleye).
I had walleye on a stick at the Minnesota state fair--it was great! My dad used to catch them when he was a kid too.
Common Practice in the Food Industry (Score:4, Informative)
This is a common practice in the food industry. While there might be a few cases of people really not realize what they've bought for their consumers is the wrong stuff, by far and large, especially in the restaurant biz, they know it's not what they've claimed it to be.
Why do this do this? Profits of course! Charge $18 for a mahi meal and serve them cod or tilapia instead. The average persons taste buds aren't refined enough to know the difference.
I've been kindly asked to leave sushi places before when my "fresh super white tuna from Korea" tasted a lot like farm raised cod, which I rudely pointed out when the waitress asked me if "everything was ok". At least I got a somewhat free meal out of it!
And now that I think about it, all of the Sushi places I've been too, there's only been one or two places that actually served what they advertised. Hands down, best tasting sushi I will ever have.
Ultimately, I don't think this will change anything on the restaurant side. Grocery store side? Maybe. When you can make large profits from misrepresenting what you're selling and get away with it, the barcoding won't stop it. All it will do is help the honest business stay honest.
Re:sushi, sashimi (Score:3, Informative)
Not only that, but can't sushi also contain cooked fish?
Of course. I've had many a sushi roll containing tempura shrimp, tataki-style tuna, and so forth.
Re:seems to be common (Score:4, Informative)
I agree. I've traveled all over the US (and abroad), and on average, Houston has more restaurants with better quality food (and a wider variety of cuisines) than just about anywhere in the US. If you love eating out, Houston is the place to live really.
That being said, while there are a number of *great* sushi places in Houston with some really creative chefs making great preparations, the quality of the actual fish meat itself is noticeably superior in the SF Bay Area.
Re:So..?? (Score:1, Informative)
The Japanese government did try to make such organization. Dubbed as sushi police by the media.
http://www.maff.go.jp/gaisyoku/kaigai/english.html
http://www.washingtonpost.com/wp-dyn/content/article/2006/11/23/AR2006112301158.html
A subject I am actually an expert on (Score:5, Informative)
I work as a fish wholesaler. We deal mostly with restaurants but we do a few retail establishments too.
The fish business is surprisingly crooked. With the Russian mafia controlling the caviar trade and various fly by night operations selling foul product that has been color treated to look new.Having a competent chef is vary important when dealing with fish quality. Labeling is a constant problem in the fishing industry even with the COOL act. Domestic red snapper is the worst of the lot when it comes to company's labeling poorly. Mainly because on a wholesale level the fish sells for 13.95-14.95 per pound fillet (regional price only), while tilapia is often sold at 6.95-7.95 per pound fillet. Other things that get sold as red snapper is red rock, corvina, lane snapper, ling snapper. (although ling is often not cheaper) It is so bad that the USDC stepped in and only 1 genus of fish can be sold as red snapper, 2 in California. The trick to buying red snapper is to only buy it skin on, preferably whole. If it is skin off fillet pass because it's almost impossible to identify then. Selling tilapia as tuna is retarded those two fish do not even taste similar although if the fish is drenched in soy sauce and wasabi it is difficult to tell even the widest of gaps in fish taste.
Also since this is going to come up at one point. Scallops that are marked sea scallops or processed scallops ARE NOT skate or shark. These scallops are treated with tripolyphosphate so they soak up water. Dry pack scallops are not treated so they are a better quality scallop. It is very difficult to cut skate in such a way on an industrial level to make it look like a scallop especially when the yield from it would cut into profit and most chefs can tell the difference.
And while I'm at it:
Amberjack is not mahi
Ahi meens tuna or yellowfin tuna. Saying ahi tuna is silly
Ono and wahoo are the same god damn fish just buy the cheaper wahoo
Langostino is from a squat lobster which isn't really a lobster but it still tastes good.
Re:Big Surprise (Score:5, Informative)
.
The same thing happened to orange roughy [mar-eco.no] and monkfish [google.com] (both some of the most hideous looking fish you'll ever see), and shark (difficult to prepare because of the high ammonia content in the meat). All were once considered trash and literally shoveled overboard in the pursuit of (at the time) more valuable fish. Now that those more valuable fish have been overfished, the industry spruces up the image of what was formerly considered trash fish to sell to the public.
BTW, what's sold as red snapper often isn't red snapper. Pretty much any of the snappers [wikipedia.org] and frequently any of the rockfishes (aka rock cod) [wikipedia.org] are sold as red snapper. Most of their meat is pretty similar, but there are subtle differences.
DNA Barcoding (Score:3, Informative)
Actually, this work was based on a really cool research project - to catalog all the species on the planet via a short, standardized region of their DNA [dnabarcoding.ca].
There's an online database, and much of the data is publicly available [boldsystems.org]. (follow the "Published Projects" link to log in anonymously).
They also provide a taxonomy browser [boldsystems.org] which is a bit more fun to play with (there are pictures).
Fish in fish markets is but the tip of the iceberg: customs officials can use this to halt the import/export of endangered and/or invasive species, it can lead to the discovery of new species, and help us to quantify biodiversity on the planet (and how quickly we're fscking it away)....
--jjj