I know that they do flash freezing to kill parasites. But flash freezing only kills parasites, not bacteria. How they kill salmonella and stuff?
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One thing I wanted to note is that retail consumers advice is different from professional customers. The FDA guidelines consider that by the time the fish reaches a retail consumer, it has spend considerable time in processing or storage already. Hence, a fish that might have a good shelf life of 5 days will have “burned up” 2-3 days before reaching a normal customer.
Professionals have the benefit of getting the fish as straight from the boat as possible (given that fishing boats will also be at sea for several days) and therefore they have the full amount of time to use at their disposal.
And almost all high end sushi chefs will age some of the fish in order to maximize the umami and texture. This is done under controlled conditions and special equipment/fridges but also many chefs learn particular secret recipes. Which fish hold up to aging without seasoning/curing, which fish might need a light sprinkle of salt or vinegar… and for fish that they don’t know anything about, it’s time to experiment/learn.
So this aging process will utilize like 2-3 days of that hypothetical 5 day shelf life. And therefore, yes, a customer should still not keep sushi more than 1-2 days afterwards.
The chef doesn’t except for sanitation and safe food handling procedures to avoid cross contamination or food being too warm for too long.
Commercially depending on your jurisdiction, the government might require that the fish be frozen to a very cold temperature and held at that temperature for a length of time (in the USA -31F for 14 hours) to kill any parasites that might be in the fish.
Fish caught during particular algae blooms or high ocean bacteria counts such as after a land flood that might wash excess sewage out to see from land. And thus have more toxins in the meat and thus higher risks. Such as ciguatera toxins
See https://wwwnc.cdc.gov/travel/yellowbook/2024/environmental-hazards-risks/food-poisoning-from-marine-toxins
Natural wasabi actually has antimicrobial properties, it would kill any bacteria in traditional Japanese sushi. The fake green stuff, not so much. Otherwise, just normal food safety handling and keeping the fish chilled is enough.
A few months ago a video popped up on my YouTube feed about bacteria on food. This is what I learned.
Pork and chicken and the worst when it comes to bacteria, and this is why it has to be thoroughly cooked. Otherwise, off the the hospital you go.
Steak, a chef is pretty much OK with serving it to you rare, simply because the bacteria does not normally penetrate below the surface. So as long as the surface has been cooked under high temp on the grill, the bacteria is killed.
However, the same does not hold true of hamburger. It has been chopped up and mixed, and during this process the bacteria can not be all over. Therefore chefs and restaurants do not want to serve it to you cooked less than medium.
Fish is the least they worry about. For reasons that are not entirely clear, bacteria on fish is not a big concern.
It should be noted that people often have misconception that all bacteria is dangerous and as such everything has to be sanitized.
Only some bacteria are harmful to humans and they can be so in few different ways. The most obvious way is that bacteria can infect humans through digestive track. In such cases the food has to always be cooked to kill even trace amount of bacteria (salmonella is good example) Fish don’t have these kind of bacteria.
Some bacteria can cause dangerous toxic by products (Botulism for example) And these cases it’s important not to give bacteria time to accumulate these waste products. So when stored properly food is edible, but if stored improperly or for too long the food become in edible. Botulism is extream example since it can be deadly but numerous other bacteria just cause diarrhea (which is body way to avoid digesting dangerous toxins) This is actually what refrigeration is for, preventing bacteria from growing too much and accumulate toxins.
Some bacteria produce safe by products. These can actually be used to store food, since other bacteria can’t use the by products of healthy bacteria. These bacteria can be used to produce cheese and actually store food to extend it’s self life.
When we store thing in fridge we slow down the growth of bacteria, but if there was no bacteria to grow freezing wouldn’t do a thing. In fact the food where we have entirely eliminated presence of bacteria can usually be stored in room temperature (like cans) or bacteria is incapable of growing on them (flour for example, unless wet).
To come back to Sushi. Fish generally don’t have bacteria capable of infecting humans, so we are mostly wanting to make sure there isn’t too much time for bacteria to accumulate toxins but that’s why sushi has to be fresh. Additionally the fishes meat is actually relatively bacteria free, though some bacteria can get on the fish from the enviroment or the gut of the fish. Part of the process of preparing the sushi fish is to make sure as little of bacteria has opportunity to get on the meat as possible.
Serious question, are you Filipino? My Filipino in-laws do NOT eat anything raw. It’s blasphemous what they do to steak.
I know a guy who owns a sushi place .. Fresh catch DAILY, what isn’t used that day is donated. Being fresh is the only way to eat real Sushi. Raw, fresh, meat IS the prevention, as fresh meat doesn’t contain decay bacterium. It’s kept on a bed of ice all day to slow decay and keep it fresh. That combined with clean hands and tools = clean food.
Same premise as for why rare steak is safe but ground beef isn’t.
The inside of the beef is sterile, only the surfaces exposed to air pick up environmental contamination and need to be seated. In ground beef everything is a surface and so everything is hypothetically contaminated.
The sushi chef is generally breaking down a whole fish in their prep immediately before the service, not useing a cut of meat that got butchered 3 days ago. In a sanitary kitchen the process of cleaning the fish is usually sufficient, though it is an elevated risk compared to cooked fish.
once tried making sushi at home and ended up with a kitchen that looked like a fish market exploded. Safe to say, I’ll leave the bacteria management to the pros while I stick to eating it!
I watched a video where they said that some places will just freeze the fish at -20 (can’t remember if Celsius or Fahrenheit) tor 7 days and it will kill all the parasites. They just thaw and trim it from there. Can’t confirm this though, it was supposed to be an industry “secret”.
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