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Thursday, May 3, 2018

How To Measure Your Tuna Fat

Ever wonder just how fat your tuna (maguro) is?

Me either... should I? Why don't I? How will this affect me getting into a good university?

Apparently this is a very important thing for people in Japan's fish sales.

In the old days, IE yesterday, the highly skilled professionals who gauge the fattiness in tuna had to actually touch and look at a fish, specifically by looking at a cross-section of the tail in order to guess the amount of fat the fish contains.

Now, a machine is going to put those poor fish fat guesstimators out of business. Probably not, but it might.

The National Institute of Advanced Industrial Science and Technology research facility in Tsukuba-shi (Tsukuba City), Ibaraki-ken (Ibaraki Province) (though headquartered south in nearby Tokyo) has created a a device that uses nuclear magnetic resonance to determine three levels of fat within a tuna without having to cut into it.

Using the same technology as medical personnel use to diagnostically image a person, the fish fat technology machine can determine is a tuna fish is:
  • otoro (most fatty);
  • chutoro (medium fattiness), or;
  • akami (lean, red meat).
According to the researchers who developed the device with no name, but somehow know it will cost over ¥10 million ~ US $91.1 million to produce, to analyze fat content, the machine radiates electromagnetic waves onto the present hydrogen atoms in order to analyze the differences between the signals from the fat and the water found in the fish's muscle.

I'm unsure just how practical the device is at the moment, as it can only
measure fat at a depth of about three centimeters (1.18 inches) from the surface of a tuna within 10 seconds.

I'm no fish fat determining Japanese expert (at the moment), but I'm pretty sure most tuna are wider than three centimeters, implying that in order to do a proper examination of a tuna fish, you are still going to have to cut into it for the machine to provide a proper analysis.

In fact, in order to prove that you no longer have to slice INTO a tuna fish to determine its fat content, the researchers at the National Institute of Advanced Industrial Science and Technology used a fillets of blue fin tuna and determined just how lean or fat each fillet was.

I'm not a research scientist at at high-paying science lab, but isn't a fillet something that is actively cut away from a whole carcass of something else... in this case a slice of blue fin tuna filleted from a whole blue fin tuna?

I thought the purpose was to use the device to avoid having to physically cut into the fish?

And the point is being proved by using fillets?

Maybe I SHOULD be a researcher at a high-paying science lab. Or maybe this is just an error by the reporter who wrote the story for the Yomiuri Shimbun newspaper who should not have stated that the device would stop fish fat guesstimators from having to deface every fish they examine.

It is reported that the researchers who created the device say it can be used to help assess the fat in living tuna.
Tuna varieties (from top): albacore, Atlantic bluefin, skipjack, yellowfin, bigeye. Image from NOAA's Fishwatch,
Uh... sure, if the tuna is no more than 1.8 inches wide and providing it can still lead an active life as a tuna with a fillet sliced out of its side.

Here are some tuna sizes:
  • bullet tuna: maximum length = 50 centimeters (1.6 feet), weight: 1.8 kilograms (4 pounds);
  • Atlantic bluefin tuna: max. length: 4.6 meters (15 feet), weight: 684 kilograms (1,508 pounds)
Apparently chief senior researcher Nakashima Yoshito (surname first) told the Yomiuri Shimbun that while the device is currently as large as a small refrigerator, “Reducing the cost and miniaturizing it are tasks for us.”

Uh, dude... don't divulge the price of the product without having a marketing name for it, and don't tell us that cost and size reductions are key. I would think that finding a way to use device to scan deeper than three centimeters of a fish would be better.

Also, to prove your point about scanning a whole fish by actually scanning a whole fish, rather than to do so using fillets.


On the plus side (like a fatty tuna), the gentlemen who physically hazard a best guess to fishy fat—like has been done for hundreds of years in the past, with their well-trained best guess—I'm pretty sure their jobs aren't on the line just yet.

Did you see how I did that... jobs on the line... like fishing?

Yup, while commercial fishermen use purse seining, trolling and long line methods, they also use pole and line as well as handline, though I would imagine if anyone actually catches a tuna by handline and manages to land it, they are the most awesome fisherman this side of Jeremy Wade ever!

Wanna hear a joke?

My tuna is so fat...
(audience): How fat is it?
Ask the tuna fat guesstimator!!!

... (crickets)...

It's, uh, apparently funnier in its native Japanese.

I'm not an Andrew Joseph but I play one in this blog,
Andrew Joseph
PS: Jeremy Wade is the host of the fantastic show River Monsters, where he goes and tries to capture or solve a fish problem... some rare giant, nasty fish. Trust me, it's waaaaaay more funand interesting and horrific than it sounds. And it's all real.
PPS: While I taught piano, and my uncle was a conductor of the New Delhi Symphony and the Indian Army, his father (my grandfather) whom I never met (died in 1951), used to rebuild and tune pianos. For him, this classic joke:
What is the difference between a piano and a fish? 
You can tune a piano but you cannot tuna fish.
I first heard it over 45 years ago... and still remember it, so I must have thought it had some merit.
PPPS: And because I'm apparently very finny today: Why do fish always know how much they weigh? Because they have their own scales. Hey... did you hear about the one-armed fisherman? He caught a fish this big (hold out one hand straight up like a handshake). That one is my favorite.

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