Recently I wrote another article that described some of the different options an at-home sushi chef had for purchasing raw fish, and whether or not these sources truly provided safe fish for raw consumption. Because there is so much widely propagated misinformation on the subject I felt it was important to cover more thoroughly, in order address all the questions associated with it and answer them to the fullest.
Sushi Grade Fish
The term “sushi grade” is not an FDA regulated title, which means anyone can use it, accurately or inaccurately, without oversight or repercussion. False advertising aside, suppliers of what is considered to be sushi grade fish typically establish their own micro and chemical parameters for determining the quality of their products, and of course traditional Japanese culture has an elaborate series of guidelines for distinguishing what fish is acceptable taste-wise for use in sushi (location caught, fat content, age, etc.)
So how does “sushi grade” compare to all the other fish money can buy? Well, when you’re dealing with fish of any kind you have a couple of standard options.
Fresh is typically envisioned in the consumer’s mind as meaning “not previously frozen,” because we seem to associate freezing with a reduction in quality (which is actually not the case.) It is also a common misnomer since many restaurants and supermarkets advertise “fresh fish” that has in actuality been frozen at some point in time. You’re only going to get truly “fresh” fish if you live in a coastal region and can catch it yourself or buy it straight from the fisherman, or eat at a restaurant that does so.
Nearly of the fish that are commercially caught or farmed are frozen sometime during their processing, usually during the shipping process. This is also true for sushi grade fish, which may be caught in one location, flash frozen and shipped to Japan for processing, then turned around and shipped back the United States for sale. Even so, any good sushi chef will “flash freeze” their fish to a very low temperature for a set amount of time in order to ensure it is safe for raw consumption. So, sushi grade fish has several different distinguishing characteristics, but “freshness” is not among them. All sushi grade fish is frozen at some point, because it is not safe to eat raw otherwise.
Hazards Associated With Consuming Raw Fish
And why exactly is fresh (meaning not previously frozen) fish dangerous to eat raw? From what I’ve gathered through my research, there are two types of hazards associated with eating raw fish:
- Parasites – examples are tapeworms and flukes; these are organisms that are living inside of the fish at the time of its capture. The likelihood of the presence of parasites in a fish is determined in large part by the type of fish and whether it is wild or farmed.
- Bacteria – introduced after the catching of the fish, via contamination, and likely attributed to improper handling practices.
Parasites that live in fish can be killed by both cooking and freezing. The FDA does have a guideline for serving raw seafood called the “parasite destruction guarantee” which is done by freezing fish for 7 days at -4 degrees F or below. If a fish becomes contaminated with bacteria, however, the only way to kill it is with cooking, as freezing will only temporarily slow its growth.
Is Grocery Store Fish Safe for Sushi?
Based on the information about parasites and bacteria, we can thus draw the following conclusion: since the vast majority of fish found in supermarkets has been previously frozen we can reasonably assume it to be free of parasites and thus safe to eat raw. If you want a little extra assurance, simply freeze it yourself for at least seven days prior to use. This can be done without detracting from the texture if it is a fatty fish like salmon (make sure you allow 24 hours to defrost in the fridge,) though lean fish is essentially ruined by refreezing.
As far as bacteria goes, this has less to do with whether or not the fish is “sushi grade” and more to do with how the fish is processed; howsoever, one caveat to that statement is that fish specifically processed for raw consumption may have more stringent processing standards to ensure cleanliness. Generally speaking, a reputable market will usually make use of a reputable supplier, which has established standards to ensure there is no contamination in their products. Even if fish is intended to be eaten cooked, not all techniques (such as ceviche) are guaranteed to kill harmful bacteria if they are present, so companies cannot afford to process fish with zero regard for health and safety.
In a Nutshell
A good summary of the information presented here is this: sushi grade fish maintains the taste quality standards associated with traditional sushi, with perhaps some extra care taken to ensure sanitary processing and packaging. Typical grocery retailed fish can be effectively rid of parasites with freezing, and is packaged with a “normal” consideration for sanitation. It is for this reason probably slightly more likely to be exposed to contamination than sushi grade fish, however any fish can realistically become contaminated, and there is always an inherent risk to be considered when consuming uncooked seafood.
Don’t forget that people continue to die every year from E. coli which is present in cows as a result of the techniques used in mass commercial livestock farming — and yet the beef industry thrives. Know the risks associated with your actions, and if you aren’t comfortable with them then you can always order the tempura.