Info request - Live tuna to Sashimi

[El Pescador]

Brian,
In all seriousness, the next time you are in San Mateo, stop by Takahashi Market on So. Claremont, they make a wonderful Tuna belly Poke, or so says our Son's Girlfriend, she is from Hawaii (Waianae) and tells us it is some of the best she has had here in the States.

Wayne

[Nuvole]

here is a good vid- not too fast so you can see how vs how-fast

This is about exactly how I break mine down too.....but there are about a million vids on the subject- watch as many as you can and use what works for you

Thanks for the link. I must be doing something wrong all the time removing belly bones with longnose plier.

[Dominick]

Great store.  See photo of inside of store at http://www.takahashimarket.com.  Dominick

[edgarz]

Suddenly I'm very hungry.

[jigmaster501]

I really have to be careful of how I answer this due to my regulatory job but to say the least, I am a seafood processing subject matter expert and a Seafood HACCP instructor.

Bleed all of your fish immediately and get the internal temperature down to below 40F ASAP. Fish need to be bled, headed, gutted, washed and iced on the boat as soon as possible.

A saltwater slurry ice works best and the more ice the better. 10lbs of ice per 100lbs of fish in a controlled 32 degree room will only extract 18F of temperature from a fish and the timeframe hinges on the size of the fish. The larger the fish, the slower the time.
Obviously you need lots of ice to chill a large fish that is very hot after fighting and in hot ambient temperatures.

The biggest concern is that of pathogens on the surface of the fish. Fish get dragged on the deck that you walk on, pee on, throw garbage on, etc and finally the fish gets bled, headed and gutted on the same deck by someone who hasn't washed their hands and might be smoking a cigarette right after going to the bathroom in a bucket to boot.

This means the surface of the fish is CONTAMINATED with listeria, salmonella, E coli,  etc.....

The video shows a man processing a fish with cloth gloves which hold pathogens and there was no surface pathogen rinse on the fish before processing.

You can get away with that if the fish is cooked but sushi/sashimi has not heat treatment for pathogen control.

For those who loin their fish on a boat and can't process THAT SAFELY, you need to wash your fish in fresh potable water and then soak the loin in a potable water bath containing approximately 25ppm of bleach and let it sit there for about 10 minutes at the dock or when you get home. Then rinse the loin in fresh water and take a thin layer off the surface, skin the fish and discard those pieces.

Now the remaining section has a drastically reduced pathogen load on the surface and is ready for ready to eat processing once you have cleaned, rinsed and sanitized your cutting surface once again. You should have done that as well before placing the bleach treated loin on it.

If you plan on using acidified rice, don't use brown rice as the acid can adequately penetrate and you run the risk of Bacillus cereus toxin formation in the rice. Also find a vinegar/rice ration that will give you a pH of 4.3 or less.

Last but not least, refrigeration of 40F or less is a must for the prevention of histamine formation (which can't be cooked out) and other pathogenic growth.

Also any fish species that is known to contain parasites (ie: wild salmon, flatfishes, king mackerel, etc) need to be frozen to kill parasites. The home freezer if set coldest might get you there. You need the fish to reach -4F and stay there continuously for 7 days. That will kill parasites. The faster the fish temperature drops, the smaller the ice crystals and the less damage is done to the fish when thawing for use. A big freezer with little in it can do much more that an freezer jam packed........

Anasakiasis is usually asymptomatic but  why get sick?

[Bryan Young]

Ron, you have some of the best bait in the world...from Papio/Ulua, Ono, Opah, Ahi, Aku, Oio,...

[wallacewt]

you should put that to music bryan.

[thedw]

have u tried ike jime?

its the jap technique of dispatching your catch in the freshest and quickest way.
vital for sashmi! do look up the technique on youtube.

and of course when storing your tuna.... dun let it come into direct contact with e fish.... osmotic pressure will cozzz the fish meat to be mushy...

degut fish only when arriving home... this prevents further unnecessary contact with water

and of course a sharp knife..

have fun!

[Makule]

As jigmaster501 has stated, chilling as quickly as possible is very important to preserving the quality of the flesh.  Especially with very large fish, putting ice only on the outside is insufficient.  For the best quality, in addition to what's been previously stated, some people shove a large rod down the backbone of the fish as a heat sink to reduce core temperature faster than just by chilling outside alone, in addition to destroying the neural canal.

Fish that takes a long time to come up has what we call "burn".  The flesh turns brownish, instead of a nice clear red, and is totally useless for sashimi.  This is what typically happens when a large fish is taken on light tackle.  The commercial guys are "meat fishermen" and do not use light gear.  Either very heavy rods and reels (e.g., 300 lb test in the reels with drags locked), or longlines.  Longline fish do not seem to be subjected to the burn, perhaps because they cool down after the initial bite/fight.  The really heavy tackle guys bring up the fish so fast (matter of a few minutes) that the fish doesn't have a chance to generate much heat.  The fish are spiked in the brain immediately, bled, gutted, and chilled in brine.

Cleanliness is essential.  Do not wipe the fish on the outside and then use that same cloth/towel to wipe cut flesh.  Wipe, or wash and wipe, the outside very well, and then cut.  Do not apply any water to cut flesh.  Always wipe with a clean towel/cloth.  Clean the knife frequently.  Do not use the same knife to cut the fish through the skin and to cut sashimi (different kinds of knife anyway).

I'm with Bryan.  Chilled sashimi is better than immediately caught and warm.  The texture and taste are better.

[Ron Jones]

I know that's how guys cark tuna but it always seems wasteful to me. It seems like their is at least 5 pounds of fish in the head of that fish. I grew up scaling and gutting. When I started filleting the old man made me cut the back of the fish into 3 pieces and we would fry those too. I guess I just don't like seeing any meat wasted, we can't say their isn't as much as their used to be and then throw it away.

Ron

[Makule]

What makes you think the head is wasted?  It's put to use also.

[Ron Jones]

OK,
If it's used, great. I've just seen a lot of albacore heads just like that go over the side.
Ron

[erikpowell]

Personally, I like my fish to be rigger before eating it.  Much too soft.  And tuna from the ocean to the cutting board is too warm for my liking.

x2
uh...yeah, few of us tried that on our boat in fiji once.......ONCE !   

....and i Loooove me some sashimi ....but straight outta the ocean..too warm and quivery... a few hours packed in the cooler is a different story though! 

[Bunnlevel Sharker]

Lots of fish make good sashimi. We ate ringtail(considered a nuisance) offshore one day and dang it was good, fresh caught Spanish mack and pompano is good to

[Tightlines667]

I think the best way to treat an Ahi for sashimi is to:
1)Catch and land the fish very quickly, in order to avoid anerobic/lactic acid buildup/muscle burn
2)Pierce the main veins draining returning blood from the main muscles by making a picture cut with a small knife(such as a vitorinox) directly behind the pectoral fins. 
3)Allow muscles to drain while fish remains calm and heart is pumping
4)Make a cut a minute or 3 later into the heart cavity, on either side of gills
5)Spike the fish, by inserting a metal spike into the brain to it's base within 3-4 mins of landing
6)Run a heavy piece of mono or wire from the base of the brain through the entire spinal cord to contract and relax all muscles
7)Gill and gut (or head and gut)
8)Get it cold fast, immersing in cold saltwater brine is the quickest
9)Once temp is down, pack in ice and keep chilled for 12-24hrs
10)Loin out

Other things to consider, whichay affect the quality of the end product, are to:
-Avoid gaffing the fish in the body
-Minimize bruising
-Avoid long fights/anerobic conditions
-Avoid undo stress on the animal
-Avoid using any fresh water
-If storing fish before final preparation, avoid exposing any of the flesh to the external environment, less cutting is better(a small slit at anus, and at each end of the gill arches is all that's needed.

You can use alternative methods for bleeding, just go str8 to spiking,spineing, gill/gut or dress or you can make cuts near the caudal peduncle (tail stock), but this tends to drain the coldest blood first in tunas.  Sometimes on a fish that I have fought for a long time, I will simply make the bleeding cuts (behind pecs, under gills) while the exhausted fish is still in the water, and allow it to pump out blood (and some lactic acid/toxins that have built up), I then land, spike/spine/and brine.  Not sure really what the best way of dealing with a 'burnt fish' is, but I am a strong proponent of getting it cool quickly.  I like my sashimi fresh, but chilling it first will definately firm it up, and improve taste.

Just my 2 cents.