I looked into this awhile back. While you're correct about previous freezing this is about mitigating microbe risk, not parasite destruction. The FDA has a spec

I looked into this awhile back. While you're correct about previous freezing this is about mitigating microbe risk, not parasite destruction. The FDA has a specification that the fish must be frozen down to in order to ensure destruction of parasites. (I couldn't find a direct link to the FDA's guideline, here's one from MN that's the same: https://www.health.state.mn.us/communities/environment/food/docs/fs/fishrawfs.pdf https://www.health.state.mn.us/communities/environment/food/... ) Ahi Tuna and most farmed Atlantic salmon (Norway is especially safe: https://web.archive.org/web/20200426100625/https://nifes.hi.no/en/anisakis-farmed-salmon-eat/ https://web.archive.org/web/20200426100625/https://nifes.hi.... ) have low to no parasite risk. However, I would not buy and eat wild salmon sashimi without at least freezing for a week first. Even retailers as big as Costco don't have freezers meeting the guideline.