Most people think that all raw fish served in sushi and sashimi is just that – raw i.e unprocessed. However, as usual in our bureaucratic society a whole raft of rules and regulations have now come into existence surrounding the humble piece of fish in your sushi.
Here are some of those regulations as they apply in most of the Western world. Japan has probably the same sort of regulations, but I suspect that these sort of regulations do not exist for the domestic consumption of sushi in other Asian countries.
“Fish used in sushi does not have to be cooked if specific requirements are met.
One of the primary concerns with the consumption of raw fish is the destruction of any parasite which may be present. The following is a simplification of some of the technical requirements in the Food Regulations focused on parasites.
Frozen and stored at a temperature of -4°F (-20°C) or below for a minimum of 168 hours (seven days) in a freezer.
Frozen at -31°F (-35°C) or below until solid and stored at -31°F (-35°C) or below for a minimum of 15 hours; or Frozen at -31°F (-35°C) or below until solid and stored at -4°F (-20°C) or below for a minimum of 24 hours.
Certain Species of Tuna (Yellowfin tuna), (Bluefin tuna, Southern), (Bigeye tuna), and (Bluefin, Northern); are exempt from the freezing requirement Also certain Aquacultured fish, such as salmon may be exempted from the freezing requirement.
The fish must [be] maintained below 41°F prior to serving but the fish may be held at room temperature if it is disposed of after 4 to 6 hours. Variances to the holding temperature requirements specific to cooked sushi rice may be granted if the rice is properly acidified and therefore minimizing bacterial growth.”
As you can see most if not all of the fish in your sushi would have been frozen at some point in its transport to your mouth.
Also there is mention in the regulations about sushi rice, and no doubt all the other ingredients that go into your sushi.
When you see sushi sitting on a platter in a restaurant or supermarket screaming eat me, eat me, at you, do you ever think about the weight of the paperwork and records (the sushi places do keep some, don’t they?) that support that sushi?
The question that springs to mind is, “With all these regulations out there, who checks each piece of fish or sushi ingredient to ensure our natural immune response is not activated?” And are there enough of these inspectors?
Anyone checked the temperature of the sushi served to them lately?
True wasabi, Wasabia japonica, was originally used to counteract the effects of not quite fresh fish in the sushi and sashimi dishes in Japan. It is still used today for the same reason.