Is IKEA frozen salmon safe to eat raw in sushi?
Unless if it's labelled "sushi-grade" or "sashimi-grade", they probably don't freeze it deeply enough, so I wouldn't recommend it as-is. This is because of Salmon's high risk of parasites. However, you can turn it into sushi-grade fish if you have a freezer that reaches -20°C, and don't mind waiting.

Here in British Columbia, the government has Sushi Safety guidelines (as there are a huge number of sushi restaurants here) which instructs to use one of the following methods to destroy parasites in raw fish (except for Tuna, in which freezing is not required) when served in restaurants; 


Store frozen at -20°C or below for 7 days
Store frozen at -35°C or below for 15 hours
Store it at -35°C until solid, and then keep it at -20° or below for 24 hours.
Actually, it may be better to read Manitoba's version of this document, as it gives clearer instructions for the same process.


After the fish has gone through this "sushi-grade" process, it is safe to store it at -18° before eating it raw.  This is the most common temperature for household freezers, and probably grocery store freezers.

Disclosure: I have never done this process myself. However, I have never gotten sick from eating sushi in Vancouver, where they are supposedly following these guidelines. I have occasionally heard of others getting sick for a day (allegedly) from sushi, though this may just be because the restaurant (or fish distributor) made a mistake.

Update: It appears that the terms "sushi-grade" &amp; "sashimi-grade" are not regulated by either US or Canadian law, and probably not in the UK either.

It appears the EU laws are more liberal, only requiring 24 hours at -20° for wild salmon, and don't require any freezing for Scottish-farmed Atlantic salmon (due to low risk of parasites). The salmon at Ikea is probably farmed Atlantic, so it might actually qualify (so much for everything that I wrote), though I'm not certain. I unfortunately don't have any research data, so I'm just going by law.

For alternatives, you can go with tuna, which is rather low-risk even without the deep-freezing, which is often not required by law. If you don't mind being less traditional, you can also use smoked salmon or sous-vide salmon.