Bacteria on Raw fish for sushi

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Customfan

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I am curious if there is any danger in using a piece of raw fish for sushi from the supermarket aisle...? I've heard all kind of information of everything from contamination of bacteria from boards, knives, other fish, etc. that come in contact with tuna. I've even heard versions that certain fish are more prone to have issues when handled, even that fish that have been frozen has less probability of having issues.

Does washing the piece of fish in cold water and patting down help at all? What should I looking for?

I believe a lot of establishments use certified fish that are supplied for that specific purpose. How concerned should I be about using a piece of over the counter fish for sushi? :chefcut:

Thanks to all for the help!!
 
Depends on how your supermarket handles the fish IMO.
Freezing, thawing and re-freezing will destroy the tissues of the fish, making taste really bad, and may not help in keeping the bacteria count down. Some bacteria goes into "hibernation" when frozen/chilled and are not killed.
How's the fish at your supermarket packaged? I prefer my whole fish to be sitting ON a bed of crushed ice, not touching water. If you are buying whole fish, do the usual checks for freshness.
For filleted fish, the fillets should be DRY and chilled. Much like how the beef and lamb are displayed. Bacteria needs moisture to grow so once the flesh is exposed, it should be as dry as possible.
Finally, depends on WHEN are you going to use that piece of fish. For raw eating, its best to finish it that day and not keep it. Otherwise, pat dry with kitchen paper and wrap in some dry, clean kitchen towels before storing in your CHILLER, separate from other meat items.
Hope this helps :)
 
By Googling "Fish Bacterial Contamination," I found this:

Salmonella
The gastrointestinal tracts of animals and man are common sources of Salmonella. High protein foods such as meat, poultry, fish and eggs are most commonly associated with Salmonella. However, any food that becomes contaminated and is then held at improper temperatures can cause salmonellosis. Salmonella are destroyed at cooking temperatures above 150 degrees F. The major causes of salmonellosis are contamination of cooked foods and insufficient cooking. contamination of cooked foods occurs from contact with surfaces or utensils that were not properly washed after use with raw products. If Salmonella is present on raw or cooked foods, its growth can be controlled by refrigeration below 40 degrees F.
 
I don't do it but I know one of my co-workers who regularly makes sushi from regular supermarket fish or frozen fish and she doesn't seem to get sick.
 
I do it without concern, because I know what I am looking at. If you have a friend who is/was a sushi chef, take them with you! I often find suspect fish in "sushi-grade" departments.

If you aren't talking an Asian market like H-Mart, you will likely be presented with only the safest, most sterilized fish, frozen for God knows how long, pumped full of coloring agents, and very often cooked to whatever degree they can get away with. Also they are banning Japanese seafood I've noticed WHICH IS TOTAL BULLCRAP, but that's another story.

The tuna most grocers sell is tuna that was snap-frozen on a boat, thawed and processed, inspected, treated with Carbon Monoxide, and slow frozen, defrosted for your pleasure by your grocer. I don't buy it, but it has nothing to do with safety.

Just go to a sushi joint! If you want the experience, just get a part time job there! :p
 
I heard all sushi grade means is that it was flash frozen at some point.. is this true?
 
I heard all sushi grade means is that it was flash frozen at some point.. is this true?

I believe the FDA requires and/or recommends that all fish used for sushi in the US be frozen to kill some of the bacteria/parasites that could be in raw fish. Do sushi restaurants bring in fresh fish and then freeze it? No, of course not.
 
By Googling "Fish Bacterial Contamination," I found this:

Salmonella
The gastrointestinal tracts of animals and man are common sources of Salmonella. High protein foods such as meat, poultry, fish and eggs are most commonly associated with Salmonella. However, any food that becomes contaminated and is then held at improper temperatures can cause salmonellosis. Salmonella are destroyed at cooking temperatures above 150 degrees F. The major causes of salmonellosis are contamination of cooked foods and insufficient cooking. contamination of cooked foods occurs from contact with surfaces or utensils that were not properly washed after use with raw products. If Salmonella is present on raw or cooked foods, its growth can be controlled by refrigeration below 40 degrees F.

+1 Great info there. However, note that Salmonella growth is CONTROLLED and not STOPPED at -40 F. Neither is the bacteria that is already present destroyed.

Anyways, if you truly wanna enjoy sushi without any worries at all, I recommend taking up johndoughy's suggestion haha. Otherwise, go to someplace like this:
FISH-PORT.jpg
 
I would NEVER use fish from a supermarket for sushi. Most supermarkets do not have a dedicated fish table or cutting area so you're basically trusting the meat/fish department to properly clean down meat tables for their fish where they've also cut beef, pork and chicken.

Additionally, most supermarkets do not have whole fish, except for trout. All of their fillets are brought in pre-cut, so the fish has been exposed to air (and potentially bacteria) from the moment it was processed. However, they do pack fish using the same equipment for beef, pork and chicken. This alone means that the quality of the fish is far lower than what is normally considered "sushi," "sashimi" or "A" grade. Most sushi grade fish are brought in whole and sold whole, or brought whole to the wholesaler and cut on site (e.g. tuna).

Also, "sushi," "sashimi" or "A" grade is a reflection of the quality of the fish, which includes handling. Badly handled fish will NEVER get this grade as fish requires so much care in handling (from the manner in which it's caught to processing).

Many fish are frozen at sea in commercial blast freezers to preserve fish for transport (some of the big fish boats are on the ocean for months at a time). Many tuna, especially Bluefin, are caught and frozen at sea. For example, at Tsukiji, there's a fresh tuna auction and a frozen tuna auction.

However, from what I understand, any freshwater fish to be used for sushi or sashimi MUST be frozen because they may have freshwater bacteria, parasites, etc. that are harmful to humans. This includes ALL salmon and tilapia (commonly marketed as Izumidai). Otherwise, as in Japan, freshwater fish are cured in salt and/or vinegar. (However, in my experience, a short curing period is usually insufficient to kill parasites or organisms.)

Freezing at below a certain temperature and for a certain amount of time (I don't recall the numbers) is supposed to kill parasites, but I don't believe this applied to bacteria. Therefore, a properly frozen piece of fish may not have parasites, but may have bacteria.
 
It actually depends on where in the world you are tho haha. The major supermarket chains in Singapore are all HACCP certified so they have different sections for fish, halal meats/poultry, normal meats and poultry. So I wouldn't mind getting fish from a supermarket for sushi, especially fish that can't be caught/reared locally and found at the fishery/wet market. If the fillets are pre-cut, if it is kept properly dry, in a clean and dry chiller that contains no other stuff, I would tend to trust it. Anyway, this pertains to the supermarket in Singapore and I can't comment on your supermarket as I haven't been there and seen the set-up and spoken to the fishmonger.
 
Michael,

Thanks for the information -- very interesting.

Is it your understanding that salt-water fish are less susceptible to infection from bacteria?

In any case, I'd never eat raw fish from my local supermarkets. I'm reluctant to eat most of the dried out, nasty looking stuff they sell even when it's cooked! They do get some decent salmon, which is a big seller, and occasionally decent tuna and halibut, but I eye it (and nose it) very carefully before buying. I miss having a good fish market nearby!
 
No. Not at all. Of the hundreds of fish that I've cleaned and gutted, I've seen bacterial infections and/or parasites in numerous large, saltwater fish, including salmon (soft bacterial spots in the flesh of farmed salmon that spend most of their lives in ocean pens, worms in the flesh of wild salmon), yellowfin tuna (soft bacterial spots in the flesh), as well as smaller saltwater fish like black cod (worms in the stomach of fish and flesh), halibut (orange worms in stomach and flesh), pollack (white worms in stomach and flesh), rock cod (worms in stomach and flesh), ling cod (worms in stomach and flesh), flounder/sole/sand dabs (orange worms in stomach and flesh). Since most of these parasites are in the disgestive tract of the fish, if you are going to eat saltwater fish raw, the safest part of the flesh is the back; sometimes you'll see large colonies of worms/parasites around the belly area of a fish.

It's been my understanding (from what I've been told and read) that it has more to do with the environment of the bacteria and parasites. Certain bacteria thrive in freshwater, but cannot live in saltwater due to the salinity. Likewise, parasites that are native to salt water, have difficulty (or cannot) survive in freshwater. But other bacteria can live in both. For example, E coli thrives in freshwater, but can survive in salt water.

I think the logic used to be that saltwater fish were cleaner and safer. Now, I definitely don't buy into this logic. I haven't seen a comprehensive study of the ability of saltwater bacteria or parasites to live in freshwater conditions or vice versa, but I wouldn't risk eating fresh waterfish raw simply because we know that freshwater parasites can affect us.
 
Michael,

Thanks for the information -- very interesting.

Is it your understanding that salt-water fish are less susceptible to infection from bacteria?

In any case, I'd never eat raw fish from my local supermarkets. I'm reluctant to eat most of the dried out, nasty looking stuff they sell even when it's cooked! They do get some decent salmon, which is a big seller, and occasionally decent tuna and halibut, but I eye it (and nose it) very carefully before buying. I miss having a good fish market nearby!

Doug:

Since you're in the LA area, if you have time, go to LA Fish Company and Pacific Fresh Fish in Downtown LA. They're wholesalers but sell retail.

Otherwise, I'd recommend Japanese markets in the area - Marukai, Niijiya and Mitsuwa. I'm in the South Bay as well.
 
Generally speaking fish suited for eating raw comes from specific areas in the ocean where temperature and diet of the fish determine the siutability for sashimi. Specifically the type of algae and plankton present in that geographical area. (think deep cold water)

Also freshness plays a huge role.

I've been told that farm raised salmon should be frozen for three days prior to use. Although I don't use farmed for sashimi.
 
Very interesting! I am glad we brought up this topic, there are so many considerations. It would be interesting to come up with a list... from optimal to less optimal conditions! But there are so many variations... :jumping:

I guess the best possible scenario (For unfarmed saltwater) is fresh, salt water from a specific geographical area that doesn't go on vacations to visit his/her fresh water friends!!, from deep cold water (Think right there! when they pull it from the net, gutting and slicing in a sterile board with an untouched knife and serving sashimi it to the crew right on the boat!). Maybe with a freezing in between?? :biggrin2:

Those of us who do not live on the coast need to look for Japanese or other fresh fish markets on the area that certify their process and even there, we need to look for signs of bacterial spots and smell, weary of evil salmonellosis among others!

Now... I have another question... If you just "seal" a piece of Ahi or any other piece of fish.. raw in the middle.. this is really no assurance that there wont be any bacteria right? I mean.. the only way to kill it is cook the actual complete piece above the aforementioned temperature? My point is... if its raw... there is a risk... very slight.. but there is one, right ?

Thanks to all for taking time to address this topic! I've had these questions for quite a while!!! :thankyou:
 
Restaurants in Texas, at least, require that all sushi fish be flash frozen, and kept below zero for 3 days. If it is salmon, the require 6 full days. If you do not do this, you simply put a warning on the bottom of your menu with some severe disclaimer. I would go with something like "eating raw fish is poisonous and will straight away kill you. Eat at your own risk."

If you "sear" the tuna, and the internal temp does not hit temp required to kill bacteria, you are still exposing yourself to the dangers. Traditionally, sushi is consumed with things that are basically digestive aids--perilla leaf, ground wasabi, pickled ginger, green tea, sake, vinegared rice, etc. Salmonella is not something you will catch from inside the fish, it is caused by poor hygiene of the people handling the fish meat.

When I am in a good grocery store, I look for various things in raw fish--one is smell(or lack thereof). It should smell like nothing--if there is a LOT of meat, the air will smell slightly crisp, but never fishy. Whole fish should look attractive, good colors, clear eyes, and a healthy build. The meat should look bright, sturdy, and dry, with a consistent quality. If it has been trimmed unusually, either is had bad spots, or someone is cutting it that doesn't know what they are doing(and therefore I do not trust them). The fat should have good color as well. Then I pick based on taste(fatty/less fatty etc). Basically, between keeping fish as a hobby and cutting sushi fish all day, I just go into a store and see beautiful fish, recently living, and meat that looks like I'd be proud to serve it, and I eat it.

But I still advise you eat all your uncooked sushi and sashimi at a trustworthy sushi bar(preferably a busy one). Sushi at home is more a novelty. As far as not being on the coast, it doesn't matter. Sushi Bars in LA can get fish faster from Tsukiji in Japan than they can from a dock 20 miles away. I worked at a bar in North Texas, and our Tuna got to us on Saturday, and it was swimming off the coast of Argentina on Monday. That's why it costs so much!

The "best possible scenario" you described is very common. In fact, the newer fad of serving raw fish in italian places as "crudo" was popularized by Dave Pasternack in New York, who is a very avid fisherman, and always carries some olive oil and salt on his boat to eat fish raw right after a catch. They just brought the concept into his restaurant. But while the texture might be best, the flavor, as all meats, benefits from a time of resting, which is really just a mild level of decomposition, breaking up the stuff we taste into nutritionally available forms. The Japanese tradition was to catch a tuna, and bury it in the sand for a day, dig it up, and eat it. It's like aging a steak. If your food is kept in the right temperature conditions, and kept clean, it will dry out and/or rot faster than it will grow any deadly virus or parasite.
 
Very interesting! I am glad we brought up this topic, there are so many considerations. It would be interesting to come up with a list... from optimal to less optimal conditions! But there are so many variations... :jumping:

I guess the best possible scenario (For unfarmed saltwater) is fresh, salt water from a specific geographical area that doesn't go on vacations to visit his/her fresh water friends!!, from deep cold water (Think right there! when they pull it from the net, gutting and slicing in a sterile board with an untouched knife and serving sashimi it to the crew right on the boat!). Maybe with a freezing in between?? :biggrin2:

Those of us who do not live on the coast need to look for Japanese or other fresh fish markets on the area that certify their process and even there, we need to look for signs of bacterial spots and smell, weary of evil salmonellosis among others!

Now... I have another question... If you just "seal" a piece of Ahi or any other piece of fish.. raw in the middle.. this is really no assurance that there wont be any bacteria right? I mean.. the only way to kill it is cook the actual complete piece above the aforementioned temperature? My point is... if its raw... there is a risk... very slight.. but there is one, right ?

Thanks to all for taking time to address this topic! I've had these questions for quite a while!!! :thankyou:


I think one important thing to think about and note is the difference between bacteria due to handling, and bacteria inside food. All food has bacteria, inside and out. So there will always be a risk of getting sick from anything as long as it is not cooked to the point where the bacteria die.

However, given the fact that it is impossible to create a completely sterile environment where one cooks, eating completely "safe" food . . . well, there's no such thing. But, by "searing" the outside, you will have potentially killed any surface bacteria, but not bacteria inside the flesh of the fish. However, most of the harmful bacteria that are the causes for food-related illnesses are (for the most part) surface bacteria, not bacteria within the meat itself. How these surface bacteria get into meat and fish is through improper handling and contamination. If you use one knife on a piece of beef that has salmonella, don't clean that knife well, use it on a fish . . . well you get the idea.

That's why ground beef is the source of many e coli outbreaks. One piece of bad meat ground with hundreds of pounds of other ground meat, and contaminating a huge grinder that's used for a long shift leads the to massive spread of bacteria.
 
Thanks. Downtown is a bit of a trek in L.A. traffic. I am aware of a couple of Japanese markets in nearby Torrance and Gardena -- I'll give them a try one of these days.
 
Glad for this thread. I'm concerned about the comments of Madmel though - as I work with supermarkets in Singapore and I have seen the areas where fish are butchered into fillets. Honestly, in many of the chains, there are inadequate hygiene practices for the cutting and sale of fish parts. The back of the store is where it typically happens, and there is tons of cross contamination.

In fact, much less than thinking about eating it raw, I informed my family to avoid buying any raw fish from them altogether. (SNS, Giant, smaller FairPrice stores - Carrefour, I haven't been there in a while so don't know how things are now)

Typically the safest are the stores with large fish areas within the supermarket with the cuts being made visible to the passserby traffic. These areas are exclusively used for fish, and they tend to be safer. I still wouldn't eat something without a sashimi certification though (3-4x the price) as i just can't be sure. I do still see things like storage of shellfish in recently vacated fish styrofoam boxes and vice versa, recycling old ice to cover fish at the end of the shopping day etc...
 
Glad for this thread. I'm concerned about the comments of Madmel though - as I work with supermarkets in Singapore and I have seen the areas where fish are butchered into fillets. Honestly, in many of the chains, there are inadequate hygiene practices for the cutting and sale of fish parts. The back of the store is where it typically happens, and there is tons of cross contamination.

In fact, much less than thinking about eating it raw, I informed my family to avoid buying any raw fish from them altogether. (SNS, Giant, smaller FairPrice stores - Carrefour, I haven't been there in a while so don't know how things are now)

Typically the safest are the stores with large fish areas within the supermarket with the cuts being made visible to the passserby traffic. These areas are exclusively used for fish, and they tend to be safer. I still wouldn't eat something without a sashimi certification though (3-4x the price) as i just can't be sure. I do still see things like storage of shellfish in recently vacated fish styrofoam boxes and vice versa, recycling old ice to cover fish at the end of the shopping day etc...

Yeah I agree these things do happen, usually with the lower end supermarkets like SNS etc. Carrefour, FairPrice Finest and Cold Storage often have pretty visible work areas and I've seen the HACCP certification on the walls of these places. Please tell me that it is a valid one. As I mentioned, I only do supermarket fish for those species that can't be found at the local fishery and wet market so it's narrowed down mostly to salmon. And I usually buy my fish whole haha. Does the shashimi certification make a difference in the supermarkets? I just thought it was a gimmick to mark up the prices of the fish. And I NEVER buy shellfish/prawns from supermarkets. I prefer my shellfish live and prawns fresh and not soaked in some liquid.

Good thread this. Makes people think of what they are putting into their bodies and where they get their food from.
 
I just got inspected by the health department this afternoon. I asked him about salmon and sushi. He said the FDA requires ALL salmon to be frozen 7 days prior to be served. He added most fish houses do the freezing for the customer and then sell them a thawed product. Also only yellow fin, big eye and blue fin tuna can be served raw.

The salmon rule also applies to ceviche.
 
I just got inspected by the health department this afternoon. I asked him about salmon and sushi. He said the FDA requires ALL salmon to be frozen 7 days prior to be served. He added most fish houses do the freezing for the customer and then sell them a thawed product. Also only yellow fin, big eye and blue fin tuna can be served raw.

The salmon rule also applies to ceviche.
Seems a bit odd since the supermarkets around here all carry FRESH salmon pretty much year round. Or do you mean that salmon used for sushi must be frozen? But even that seems a little odd -- doesn't freezing and defrosting cause the cells of the flesh to burst, increasing the potential for bacterial infection (to say nothing of what it does to texture)?
 
Salmon for sushi must be frozen.

Don't ask me about the rules. I just follow them.
 
From what I understand, if a freezer is super-cold, the meat will freeze fast enough that the ice crystals that form remain small and thus do not burst the cells. A regular freezer isn't cold enough to flash-freeze and gives the water enough time to form large water crystals which will burst the cells, destroying the texture of the meat.
 
Thanks for the article Mhlee... very interesting. Yes, I believe that is one of the purposes of the flash freezing.
 
While I tend to eat what I've killed most of the time, I occasionally buy fish from the local market. I eat what is in season and what is locally harvested. Tuna season was a bust last year so I ended up buying tuna all summer long. I eat alot of poke and sashimi. I do three things when I buy fish at a market I look at it. I smell it. I touch it. Is the color off? Is it shiny? Fish shouldn't smell fishy. Is the flesh firm? Ask how old it is. Buy on special, as the fish was brought in special fresh for the sale.

Best piece of fish you never ate was the one you walked away from!

Pesky
 

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