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I ordered some sushi grade steaks online. They came frozen, as they were shipped with dry ice to keep them nice and cold. Frozen, I cut them into pieces and put them back in the freezer, taking out one chunk at a time and thawing in the fridge.

Sushi grade steaks do not need to be cooked, since they are kept frozen at temperatures where parasites cannot survive so there is no concern of the meats contaminating anything.

Once thawed, how long do I have to keep them in the fridge until they pose a health risk?

Since this might depend on the type of fish, I will leave the question open to all fish types. However FYI I ordered yellow fin tuna (Ahi), yellowtail tuna (Hamachi), and salmon (Sake). Also Capelin roe (Masago), and salmon roe (Ikura).

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I have always made sure that I only defrost enough to meet the needs of the moment for sushi. If you cut the blocks into 4 to 8 rolls worth, they should defrost under running water in just fifteen to twenty minutes, just about the time it takes me to do a batch of sushi rice. That said, fish once defrosted will start to lose flavor immediately but will remain edible for 2 days. Once it starts to smell, get rid of it immediately, and I would play it very safe on that "starts to smell" the faintest whiff should be enough to send it to the bin.

  • Thanks for the answer! Could you elaborate a bit on the health risks that the 'smelly' fish could pose to anyone eating it? Are there parasitical or just bacterial issues with the steaks at that point? – Styler Dec 21 '11 at 21:23
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    The freezing killed the parasites if it was done properly, that's why fish meant to be eaten raw is frozen for the lengths of time that it is. Fish itself breaks down into some fairly unhealthy stuff during the rotting process which is what causes that bad smell. Your digestive track will not thank you for eating it and neither will your taste buds. – sarge_smith Dec 22 '11 at 7:46
  • Just to clarify on one point, one should only use cold running water when thawing fish this way. – OmniaFaciat Jun 20 '13 at 20:16
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Some, but not all. Freezing may kill some of the present forms of bacteria. But for the most part, bacteria may simply freeze the growth state and then continue to grow once food has been thawed. A perfect and well known example of bacteria that cannot be killed through freezing is Salmonella.

The bacteria in your food belong to two criteria - a) the "wanted" bacteria b) the "unwanted" bacteria

However they both are bacteria - so the effect of the freezing will be proportionally same on both types. For the bacterial population (in your food) the freezing is a natural catastrophe ! A lot of them may get annihilated because of the severe shear pressures generated by water crystal formation.(Remember ice floats and therefore has more volume than water - for the same mass).

Some bacteria ( unwanted as well as wanted) will survive. That is because their "population" inside is quite huge to begin with. But they will find the going really tough - until the food is thawed ! But once thawed they will multiply quickly to recover populations. In fact this new generation ( according to Charles Darwin) will have more "freeze-hardy" bacteria among them !

Bacteria have been known to grow in extremely hostile conditions elsewhere on earth. Your frozen food hardly nears the "extreme" conditions they are known to survive in.

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There is a big difference between the Professional Freezers used in Sushiya and domestic freezers and the temperatures they work at. Professional freezers are designed to preserve freshness, minimize ice crystal damage and kill parasites and other unwanted agents. So what they do and what you do is another. defrosting and refreezing will degrade your fish particularly at domestic freeze rates and temp but will not make it inedible. I would never "thaw" frozen fish in running water. It is like soaking a raw beef steak in water before you cook it. I would agree 2 days is a max in fridge, keep fridge just above freezing (I have mine on 33-34) and pack it so air does not get at it (inhibits most bacteria and delays spoiling. You will see Saran Wrap is a favorite in Sushiya. Seems not to affect flavor which ziploc bags etc can do. Happy eating

  • Long time after OP but you should not assume what Sushiya do is what you can do with freezers and putting Sushi or Sashimi grade fish in running water to thaw is a waste. – Rich Sep 20 '17 at 14:59
  • There's no indication that the fish ever thawed. Also, thawing under cold water is standard... the fish is wrapped, not in direct contact with the water. – Catija Sep 21 '17 at 4:20

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