(Image by Margo Lipa from Pixabay)
You may have heard the term sushi grade or sashimi-grade fish. FDA recommends freezing the fish (some) for sushi, raw consumption to kill parasites.
The question is this: Are frozen fish at the supermarket suitable for raw consumption?
The short answer is No because some fish, even frozen, are unsuitable for raw consumption.
Though freezing kills parasites, some of the bacteria and germs will survive, which can cause foodborne illness.
"Once thawed; however, these microbes can again become active, multiplying under the right conditions to levels that can lead to foodborne illness. Since they will then grow at about the same rate as microorganisms on fresh food, you must handle thawed items as you would any perishable food." — Does freezing food kill bacteria?, Ask USDA
If this sounds crazy to you, well, there are many organisms that can survive in a condition where humans cannot, even in space:
Extremophiles are organisms that thrive under extreme conditions. Conditions that would kill a human in less than a microsecond. Most extremophiles are microorganisms as fungi, algae, bacteria and especially archaea. - Artic Microphia
The other issue is how fresh fish was when it was frozen. Sounds obvious but freezing does to make the fish any fresher than it was. If it was frozen at a condition that was not OK to eat it raw, it would not make OK to it eat raw after thawed either.
Then, what makes fish OK to eat raw?
There are several factors that determine a fish is OK for raw consumption.
1. Type of fish
There are some fish you can eat raw safely. Tuna (yellowfin, Bigeye, and Bluefin) is one of them. Scallops are pretty safe to eat raw. However, Mackerel, Saba is NOT safe to eat raw even if when it's frozen (it needs to be cured). Almost all the cod is unsuitable for raw consumption, even if they are fresh or frozen. That is because most of the cod come with parasites. Though freezing will kill most of the parasites, it does not kill all the bacteria and germs. Therefore, fresh frozen cod is not recommended for raw consumption and is usually not served as sushi grade or sashimi-grade at the supermarket.
2. The freshness of the fish
Given the fish the type of fish that is safe to eat raw (like Tuna), then as long as it was frozen when it was in a condition still safe to eat raw (meaning fresh enough), then it's OK to eat raw after thawing it. Salmon is one of these fish.
3. If it's labeled as "Sashimi," "Sushi" or "For Raw Consumption.
The picture is a Hamachi Sashimi package sold at a Supermarket in San Jose, CA. You can find similar products at Japanese and Asian supermarkets in the US, some in the freezer section. As you can see the label "Hamachi Sashimi," which means it's OK to eat raw. If you find similar products in the freezer section, then, they are OK to eat raw. If no labeling, you are taking a chance.
If you want to find fish that is OK to eat raw, my recommendation is to ask the fishmonger and follow their advice. As attempting to buy the fish and take it home and try, it's much safer to do so because it takes years of watching and learning about the fish to determine if a certain fish is OK to eat raw or not.
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