ottawa foodies

when i lived back in Seattle i did a fast track training with a Master Sushi Chef from Kyoto. At his restaurants, no one in the kitchen touched a fish unless they had a full years training with him. no one cut fish unless they had 3 years. he and his sous chef were the only ones that received the seafood from shippers.
anywho, he said all tuna designated for sushi is frozen. -40 he said not only kills the parasites but preserves the taste IF thawed properly he had a blast freezer -40 to -60 F and another holding freezer that over a three day period would bring the fish from -40 to +5 F. Other fish, if fresh, were held up to the light and the parasites could be usually be seen coiled in various spots (i found this only works if the fish hasn't been frozen and is still translucent and is thin enough). he said also fresh fish has to be consumed in two days from catch so the bacteria does no get a chance to build up. hope that helps

I'm guessing Ottawa tuna sushi wouldn't be coming in fresh so it would be frozen. The boxes are marked -18C or lower. At least that's what Sam the owner of Yummy Sushi told me. He bought and installed a brand new walk in freezer capable of -40C. The health inspector told him he didn't need to go that low and would save energy at -18C.

But from reading the book "The Sushi Economy", super freezing technology is used to keep valuable whole tuna fresh indefinitely. What is super freezing? Flash or blast freezing to -60C then a quick plunge of the fish into cold water. This forms a layer of ice around the -60C fish, which protects it from handling damage and freezer burn. No noticeable oxidation of the meat occurs at -60C.

Japan has a whole network of super freezers so than fresh tuna can be brought to housewives for dinner. Also having a "strategic tuna reserve" allows them to de-risk some of the volatility in the tuna market, because if the price goes too high some of the fish can be taken out of super freeze storage (a bluefin sold for over $100,000 in the book, which came out in 2007).

The book said the factory ships are capable of blast freezing to -50C, so almost to the level of a super freezer.

As soon as a tuna is cut up and exposed to air the meat begins to oxidize, even at -18C. Restaurants have to use it and fast! No wonder the Japanese invented JIT (just in time) manufacturing. Compared to the sushi industry JIT is a cakewalk!

And it's not only super freezing that makes a fish marketable. It also has to be killed very quickly and cooled immediately. If it struggles much the meat will be of poor quality. Farmed fish are dispatched by a single shot to the head, then bled immediately via four incisions, and then immediately blast frozen.

if you ask 10 vendors what they mean by "sushi-grade", you are likey to get 10 different answers

This was my impression too. Kind of disturbing, really. It would be interesting to find out what the *restaurants* serving raw fish do to reduce the risk of exposing their clients to parasites and pathogens. :-)

FreshFoodie - good point, well taken. I was just trying to make the point that often vendors will mark on the label "Sushi-grade" so they can charge more. My experience in Ontario is limited, but I have learned that if you ask 10 vendors what they mean by "sushi-grade", you are likey to get 10 different answers. I was fortunate to live in San Diego for several months. San Diego has a very large local tuna fleet, and you can buy freshly caught tuna right from the dock. No where did you see a sign advertising "sushi-grade" tuna. Go figure?

KanataFoodie, I think we determined (read further down) that "sushi-grade" means it has been frozen to kill parasites. Eating never frozen fish that hasn't been visually inspected by an expert could compromise food safety.

There are a couple of rules when buying fish:
a. if you are on the coast,don't buy fish from a vendor on Sundays and Mondays as usually the fish has been sitting around since the Thursday before. Fishermen take the weekends off, like everyone else, so the last day they bring in a fresh catch is on Fridays.
b. fresh fish doesn't smell fishy. If a vendor doesn't allow you to smell the fish, then don't buy from him.

Don't worry about "sushi grade" tuna, any fresh tuna will make great sushi. When buying tuna for sushi or poke, the blood vein (the black meaty portion should be already cut away), if it isn't have the vendor cut it off before he weighs it, or you are just wasting money.

Where to buy? Lapointes normally only carrys previously frozen tuna, but I believe they will special order fresh for you. Believe it or not, Loblaws oftens has very fresh, nice looking tuna. It usually comes in Friday mornings, so its best to get it early. Not all Loblaws carry it, its dependent on who is running the deli/fish area.

Yes, Kadaeya closed in November or December. It's a hair salon now. :(

I always thought that sushi-grade fish had to be kept frozen prior to use. I thought the Ontario ban actually went through, but the common misconception was that it affected sushi when in reality, it didn't. I was working in the media at the time so it was a big story for Centretown, given the number and popularity of sushi places.

Hmm... I better take advantage of the quiet day to do some digging.

There was a big commotion a while back about this when the Ontario Govt. proposed to ban non-previously-frozen sushi.

www.cbc.ca

The ban didn't go through however, as the story indicates.

I always thought it meant it was stored under a certain temp and left for a number of days to kills off any parasites (much like the storing conditions of cold cured salmon)...

I have to admit, having cleaned literally countless fish, I have encountered some funky parasites in my time, like very visible worm like strands from the scales, which is common with freshwater fish in late summer when the water warms up, but I can't take that for granted since lots are microscopic. It's best to freeze fish just in case, unless you know your fish counter guy/girl *really* well, or if you caught/cleaned it yourself. It also helps to have a cryovac sealer for this very purpose!

If you go to the asian food store next to Mandarin Ogylvie, you can find prepacked sliced tuna in the freezer aisle for making sushi (at least, they did have it), Kadaeya used to sell it as well, but they've closed I guess?!

I was under the assumption it was frozen first to make it "safe" to eat raw (despite our society's mentality that 'fresh, not frozen' = better)

Fresh fish is intended to be cooked, I don't think it's safe head down to the local fish market and just slice up some salmon and serve it as sashimi

What is sushi grade fish?
www.sushifaq.com

What requirements must be met for fish to be designated as "sushi-grade"
ask.yahoo.com/20040513.html (states the FDA requires that all fish to be eaten raw [with the exception of tuna] must be frozen first, in order to kill parasites)

^ So maybe it's #1 and #2? If all "sushi grade" fish must be frozen first, but tuna is exempt - how is the tuna designated as sushi grade?