Illustration by Martina Lo

Sushi lovers often dismay over the hefty amounts of cash they spend at restaurants.  But cravings must be satisfied.  Many contemplate buying fresh fish at a local supermarket in order to prepare their own sushi and save money.  These poor souls usually end up dismissing the idea when they recall they have no idea how to judge the safety of a particular fish for raw consumption. 

If you count yourself among these downtrodden sushi lovers, know you can gain confidence in purchasing fish for sushi by understanding the risks involved, and learning how to mitigate them. 

Note: If you are pregnant, extremely young, at an advanced age, or have a compromised immune system, you should stop reading here and consult a doctor or dietitian before anything else.  In my perfect world, we could all enjoy sushi with the same abandon, but it is better to take the proper precautions in the world we live in. 

The Risks with Raw

By consuming raw fish, you have two main concerns you would otherwise avoid through heat-based cooking: parasites and bacteria.  These are the culprits behind the stomach aches, cramps, and nausea normally associated with a sushi meal gone wrong. 

Parasites

Parasites in fish (most commonly anisakids and tapeworms) can be completely eliminated through freezing.  However, your standard home freezer, which only keeps an internal temperature of ~18°C (0°F), won’t quite cut it. 

Image Credit: Pixabay

For restaurants intending to serve raw fish, the Food and Drug Administration outlines the following freezing options for reliable “parasite destruction”:

Freeze and store fish at a temperature of -20°C (-4°F) or below for a minimum of 168 hours (7 days)

or below for a minimum of 168 hours (7 days) Freeze and store fish at a temperature of -35°C (-31°F) or below for a minimum of 15 hours

Larger tuna and farm-raised salmon fed with parasite-free feed are notable exceptions.  The FDA has identified these types of fish as relatively safe from parasitic infection, so no superfreezing is required. 

If you can confirm with a seller that their fish meets the FDA freezing guidelines, then you at least ensure the fish is parasite-free.  But if you really want to be the master of your own fate, and you happen to have cash leftover from selling your car, purchasing a low-temperature freezer (which could set you back a mere couple thousand bucks) allows you to superfreeze fish on your own, even those caught yourself. 

Image Credit: Wikimedia Commons

Bacteria

Compared to that of parasites, assessing the risk of bacteria in fresh fish is much more difficult.  Freezing fish (even superfreezing) only halts the growth of bacteria, but does not destroy them.  When you find yourself staring at a beautiful slab of salmon on display, remember that the amount of bacteria it carries depends not only on the proper handling of the fish by the store, but also on its handling by the entire chain of catchers, suppliers, and distributors it passes through. 

Ultimately, it comes down to whether or not you trust that the store knows what it’s doing — maintaining clean tools and work spaces, dealing with reputable and responsible partners, keeping fish on ice, etc.  Checking their website, having a conversation with the owner or an employee, sending an e-mail, or reading online reviews can provide some much needed assurance. 

Image Credit: NeilsPhotography

Keep your chin up

Without a doubt, hunting down all this information can feel overwhelming and excessive.  In an effort to help out aspiring home sushi chefs, many stores use the “sushi-grade” label (words of caution about the label below) to advertise fish they specifically recommend for raw preparation.  Presumably, this selection of fish would meet the standards described here. 

At the end of the day, eggs, meats, fruits, and vegetables pose their own threats in the form of Salmonella, E. coli, and other bacteria and viruses.  Some may argue that the occasional bout of food poisoning is simply the price to pay for eating food — perhaps even a small price, when considering just how delicious raw slices of fish on top of vinegared rice can be. 

Further Questions

What does “sushi-grade” mean? 

Many stores label a certain selection of their fish as “sushi-grade”, or sometimes “sashimi-grade”, to ease customers’ minds about purchasing them for sushi.  In reality, the term is unregulated, and simply used for marketing purposes. 

Practically speaking, it serves the stores’ and sellers’ best interests not to mislead customers into eating food that makes them sick — they will reserve the label only for their highest quality fish.  Otherwise, a bad reputation for making customers sick would probably put them out of business.  However, the fact remains that any store can technically call their fish sushi-grade without having to prove anything about freshness, quality, or edibility. 

Image Source: Pixabay

For ceviche, does citric acid from lemon or lime kill bacteria or parasites in the raw fish? 

Nope.  Apparently, cooking and superfreezing are the only two effective options for sanitizing raw fish. 

Random Research Fun Fact

The term “sushi” actually refers to the vinegared rice

When someone mentions sushi, you normally think of small mounds of rice topped with slices of tuna, salmon, or mackerel.  But the definition of sushi is simply vinegared rice paired with other ingredients, typically raw fish but which can also include egg, fish roe, vegetables, and more.