What's the Deal With Tuna Scrape? A closer look at the likely source of the sushi-linked SalmonellaFood Safety News
By Gretchen Goetz | APR 18, 2012
Last Friday, a week after announcing they were investigating an ongoing multistate Salmonella outbreak linked to sushi, federal public health officials were able to pinpoint the likely source of the bacteria that has now sickened at least 141 people. The suspect? Something called Nakaochi Scrape distributed by Moon Marine Corporation USA.
Nakaochi Scrape, as described by the Food and Drug Administration, is "tuna backmeat, which is specifically scraped off the bones, and looks like a ground product."
This description has prompted several media outlets to compare scraped tuna with the controversial lean finely textured beef (LFTB) - also known as "pink slime" - that has captured headlines recently.
So what is Nakaochi Scrape? Is it indeed the fish version of LFTB (a.k.a., "Pink Slime"), which is produced by taking leftover scraps from a beef carcass, separating the meat from the fat, sinews and gristle in a heated centrifuge, grinding the meat and then treating it with ammonia? While both products are separated from bones, the similarities seem to end there.
Tuna scrape is the part of the fish that remains after the filets have been removed as whole cuts. Once a knife has been run down both sides of the spine to cut off the filets, meat close to the bone missed by the blade is then scraped out with a spoon-like device. After being collected in this way, it is sometimes chopped into smaller bits but no more processing is done.
"I don't think it's a fair comparison at all," says Ken Gall, Extension Associate at Cornell University and member of the National Seafood HACCP Alliance Steering Committee, referring to the comparison between tuna scrape and LFTB. "[LFTB] is a product that's treated, and treated in a way to sterilize it, which is going to coagulate protein and be a whole different process."
Tuna Scrape in the Food Supply
However, fish scrape is not a commonly recognized food. Indeed no sushi vendor offers "spicy tuna scraped from fish backbone roll." So where is scraped fish meat in our food supply?
Raw fish scrape is served in many Japanese dishes, sometimes over rice, sometimes in sushi rolls and sometimes on its own.
Some scrape is served fresh at restaurants, where chefs may remove the backbone meat themselves.
Just because it's not part of the filet doesn't mean back scrape is an inherently "worse" part of the fish, says Harry Yoshimura, owner of Mutual Fish Company, Inc., a well-known and respected Seattle-based seafood market.
"Usually meat around the bone tastes very, very good," he says. "And when you get a good fish, it's really terrific."
The quality of tuna scrape, says Yoshimura, depends on the fish it came from and how it was prepared.
Moon Marine's Nakaoshi Scrape was imported from India, where it was processed and frozen before shipping.
Frozen imported fish products are usually sold at cheaper prices than domestic fresh fish, says Yoshimura, a sign that they probably -- although not necessarily -- come from a lower-grade fish.
FDA was not able to supply Food Safety News with data on how much tuna scrape is imported into the U.S. each year. The agency also reported in an e-mailed statement that it "does not have data on the frequency of use of this product in sushi."
Fish Scrape and Food Safety
What about the safety of scraped fish product? Is raw tuna scrape known as a particularly risky food?
"The more contact (a food has) with the environment -- and this is true with ground beef or turkey or chicken, too -- if there is surface contamination it is going to be spread throughout the product, so then rather than having an isolated contaminated spot you just mixed it up into the whole unit," explains Gall.
Tuna scrape is "first and foremost, a ready-to-eat product that is raw and not going to be cooked before it's consumed, so that automatically puts it in a higher risk category," he adds.
Seafood sold in the United States must be processed according to Hazard Analysis and Critical Control Points (HACCP) plans, under which processors identify possible contamination points and then take proper sanitation measures at each of those steps.
Gall, who created and manages the National Seafood HACCP Internet training course, says foreign seafood suppliers are also required to have a HACCP system in place before they can sell their products to the U.S.
Because the United States imports 80 percent of the seafood eaten domestically and only 1 percent of that food is inspected by FDA, a large part of the seafood safety system relies on adherence to HACCP plans and on importers testing to ensure that incoming product is not contaminated.
But while the government's investigation is ongoing in the multistate Salmonella outbreak linked to tuna scrape, says Gall, it's "anyone's guess" as to where the safety system broke down in this case.
One possibility is that the contamination likely happened before the scrape was shipped and came from an environmental source such as contaminated water or an employee carrying the bacteria.
Yoshimura points out that it is harder to verify the quality of seafood processed abroad. "With some of this imported stuff, you don't know what condition the fish was in or what condition they're scraping the meat in," he notes.
Whether Moon Marine Corporation tested the product once it arrived in the U.S. has not been disclosed.
"If it was known that the company was going to be selling to sushi restaurants and/or grocery stores knowing that it's a higher-risk product, you would expect more testing to occur," says Gall.
Raw Tuna Outbreak - Not The First Time
While tuna scrape doesn't come to mind as a typical source of a foodborne illness in the U.S., it is not raw tuna's first go-around with food poisoning.
In October of 2007, consumption of previously frozen raw ahi tuna was linked to a multistate outbreak of Salmonella Paratyphi B that sickened 44 people. The tuna was imported from Indonesia and distributed by a company in the U.S.
In 2010, frozen raw ahi tuna was again linked to an outbreak of Salmonella Paratyphi B, which sickened 23. That product was thought to have originated in Asia.
In October of last year, Osamu Corp. of Gardena, CA recalled hundreds of cases of frozen ground tuna after federal inspectors found decomposition in several samples and elevated histamine levels in the fish collected from one retail location. The toxin sickened 3 people, all of whom had purchased sushi at the same location.
Gall speculates that this latest, larger outbreak linked to sushi may serve as a warning to the sushi industry to adhere to safety protocols and strengthen verification procedures.
"It may be a wake-up call that you've got to pay the same attention [to sushi products] as you always have to raw material," he says.
Yoshimura cautions that while tuna scrape is now gaining some notoriety, it does not have a huge market presence.
"With one situation like (the outbreak), you could blow the whole thing out of proportion when there isn't that much of the stuff available," he notes.
According to Yoshimura, the lesson here is to know where your product comes from and how it was made.
More on this outbreak: Moon Marine Co. Yellowfin Tuna Sushi Salmonella Outbreak