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Eating Raw Oysters, Is it safe?

I hear raw oysters are really good for us and I'd like to start eating them, but am hesitant because of all the fear propaganda out there about bacterial infections. I would like to know if anyone has gotten sick from eating raw oysters, or if anyone has had no problems eating them all their lives. Also, has anyone tried freezing them first to kill off all the bacteria, then eating them right after defrosting? I hear that's how fish is prepared for sushi.

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  1. Assuming you are a normal, healthy adult with no immune-system disorders, it should be no issue whatsoever for you to eat oysters -- but --

    1) Make sure they are in season. In North America (where I think you're located) oysters are considered in season during months that have an "r" in them (so they're out of season May through the end of August) -- two reasons -- first, summer is the spawning season, and the oysters are generally leaner and don't taste very good, and second, the warmer waters of summer are perfect to encourage any bacterial growth in the water and therefore in the oysters themselves.

    2) Make sure they're crazy fresh. As in, on the coast, or in a major city where the logistics connections mean that they are on the table within a day or two of harvest. Better yet, plan a trip to the coast and try them close to the port.

    3) For heaven's sake, don't freeze them -- freezing destroys the cell walls, leaving you with leaky mush. You can use frozen oysters in a cooked dish if you have no other alternatives, but you'll wreck 'em if you freeze them to eat raw.

    4) I don't think there's any reason why raw is substantially better for you than cooked. Oysters are tasty and nutritious, whether they're cooked or not.

    5) If you're using "good for you" as a euphemism for "makes you horny" or "is a natural Viagra"? Baloney. If it were true, oysters would have been extinct a long time ago.

    I've been eating raw oysters cooked and raw for most of my life. I have been mindbendingly, horrendously sick from oysters twice -- so I am now **extremely** discriminating about when and I where I eat raw oysters, but it hasn't turned me of of them.

    2 Replies
    1. re: sunshine842

      po' boy

      cooked, but extremely addictive anyway

      'nuff said

    2. In fact, I'd be willing to say that you're more likely to die in a car accident today than you are to get sick from eating a raw oyster at a restaurant.

      They're safe to eat.

      But if you're that concerned about it getting sick from raw oysters, just order them steamed...

      6 Replies
      1. re: deet13

        Please, please tell me 'they' don't really freeze fish for sushi where you're from!
        I've eaten loads of oysters and never been sick. You do have to be careful with shellfish though, and the best safeguard is opening them yourself, or having them shucked in front of you.
        If they smell at all 'off', don't eat them! They should smell briny and tangy, but NEVER dodgy.
        I wouldn't eat oysters just because they were good for me, but I'd definitely eat them because they were delicious.

        1. re: pippimac

          they freeze fish for sushi darned near everywhere as an easy and efficient way to kill parasites and lengthen shelf life-- it's flash-frozen on the boats as it's harvested with the help of liquid nitrogen, which is different than freezing in your home freezer. It freezes in a flash (!) and because of this, it tends to not create the same cell-wall destruction in fish as in your home freezer, even when it thaws.

          Frozen oysters are nasty no matter what.

          I realize that Wiki isn't the all-omnipotent authority, but this discussion is short and sweet enough for this topic: http://en.wikipedia.org/wiki/Flash_fr...

          1. re: sunshine842

            Maybe the whopping great moat around my tiny islands makes for a different fish-freezing paradigm! As far as I know, if fish has been frozen here, it's advertised as such.

            1. re: pippimac

              If it is commercially caught and distributed through the commercial food distribution chain, chances are it's been flash-frozen.

              1. re: pippimac

                Where are you located? (your "tiny islands") Just curious.

                In the US, FDA regulations (1999) state this:

                "3-402.11 Parasite Destruction.*

                (A) Except as specified in ¶ (B) of this section, before service or sale in ready-to-eat form, raw, raw-marinated, partially cooked, or marinated-partially cooked fish other than molluscan shellfish shall be frozen throughout to a temperature of:

                (1) -20°C (-4°F) or below for 168 hours (7 days) in a freezer; or

                (2) -35°C (-31°F) or below for 15 hours in a blast freezer.

                (B) If the fish are tuna of the species Thunnus alalunga, Thunnus albacares (Yellowfin tuna), Thunnus atlanticus, Thunnus maccoyii (Bluefin tuna, Southern), Thunnus obesus (Bigeye tuna), or Thunnus thynnus (Bluefin tuna, Northern), the fish may be served or sold in a raw, raw-marinated, or
                partially cooked ready-to-eat form without freezing as specified under ¶ (A) of this section."


                The updated 2005 regulations say pretty much the same thing, but with expanded statements:
                http://www.fda.gov/downloads/Food/Foo... (see Section 3-402.11)

                A couple other links of interest (there are many others):

                Of course, what you choose to do as an individual may not be what a commercial establishment would need to do to comply with FDA regulations. :-)

                BTW that chapter in the FDA regulations also say a lot a stuff about other stuff, including molluscs (e.g. oysters).

            2. re: pippimac

              Salmon MUST be frozen prior to consuming as sushi. I alway ask server if salmon they serve as sushi has been frozen. It's done to kill parasites.

          2. Oysters are good.

            Go to a restaurant that is known for serving them; tell them you want to try some for the first time; I'm certain they will be happy to help you.

            Get them from a reputable fishmongers, let him pick them for you; if it's a good fishmonger, they can even open them and prepare a platter "to go".

            It can happen that some oysters you buy have gone bad, but it is usually _very_ easy to know they are bad, they will stink. (in a restaurant, you should not get bad ones, they will be discarded when they are opened).

            There are oysters available all year long, as long as you get them from a good source you will be ok.

            Don't freeze them.

            14 Replies
            1. re: Maximilien

              My wife used to dislike oysters but she came from a part of the country where fresh oysters were as plentiful as unicorns so she had only tried those terrible canned/smoked ones. Once we had to take refuge from a week long wicked summer storm up the BC coast. We were in a tiny cove fed by a fresh water stream barely big enough for our boat. After about a week we were out of fresh food. Even in the cove the water was too rough to go ashore. As the storm let up she went for a row in the tender and came back with a pail full of oysters she had picked off the rocks. Now she loves fresh oysters. There is nothing as delicious as a wild oyster. Well, almost nothing. The cove was not named on the charts. We named it 'Pearl Cove' because we found a number of small irregular pearls in the oysters.

              1. re: Maximilien

                Maximilien, your advice is great as long as the OP is in Paris. But since the OP doesn't state, those rules may not apply.

                Fishmongers in many parts of the world won't open the oysters for you, nor will they prepare a platter to go -- not even the best fishmonger in the city, as there are some places in which it would be in violation of health codes (it may also be in violation of retail codes, as it crosses the line between "ingredient" and "meal")

                In the US, oysters are not in season in months that do not have an 'r' in them -- leaving only oysters flown in from somewhere else, which would not be fresh enough to bother with.

                1. re: sunshine842

                  The "months with 'R' in 'em" rule is pretty much a thing of the past in most of the US. Cold water oysters from both coasts are available, and quite tasty, year round. Refrigeration and transportation improvements, as well as the care that goes into the oyster "farming" practices, have basically eviscerated it. Oysters are delivered a day or two out of the water nationwide resulting in the fact that they are certainly fresh enough to enjoy. In fact, one of the true pleasures of oyster eating is being able to sample oysters from different parts of the country, as well as Canada, on the same plate.

                  1. re: MGZ

                    This is true, I have heard many, many times and for a long while that the "r" rule no longer applies. I have had raw oysters in every month of the year, and never gotten sick. But, I only get them at restaurants I really trust - not only because a bad oyster could make me sick, but because I want the best tasting oysters I can get. I agree that getting multiple types from different locales on one plate to try is one of my favorite culinary experiences.

                    1. re: centralpadiner

                      Getting anything raw is probably always best done from one you trust. Your post somehow reminded me of this site: http://www.farm-2-market.com/ Pretty insane stuff available, including plenty of oysters, if anyone's ever looking for a splurge.

                    2. re: MGZ

                      but it doesn't fix the problem with the spawning timeframe...thanks, but I'll skip them in the summer.

                      1. re: sunshine842

                        In a place as vast as North America, and with the aquaculture techniques generally employed, there is no single spawning timeframe. Simply put, high quality oysters are available all year. You should, by all means, eat what you're comfortable with and enjoy seasonally. Local summer shellfish for us means littlenecks and lobsters. I just don't think it's fair to someone who has limited experience with oysters not to point out the truth about what they may find on the market.

                        1. re: MGZ

                          The FDA agrees: http://www.fda.gov/Food/ResourcesForY...

                          Each year millions of Americans enjoy eating raw oysters. However, some people with certain medical conditions are at high risk for becoming seriously ill and dying from eating raw oysters. The U.S. Food and Drug Administration (FDA) is advising these high-risk individuals not to eat raw oysters, and to only eat oysters that have been thoroughly cooked.
                          The Cause: Vibrio vulnificus

                          Vibrio vulnificus (V. vulnificus) is a bacterium that occurs naturally in warm coastal areas, such as the Gulf of Mexico. Vibrio vulnificus is found in higher concentrations in the summer months as water becomes warmer.

                          Oysters feed by filtering water-surrounding areas where vibrios may thrive and as a result concentrate V. vulnificus in their tissues. When a person eats these shellfish raw or undercooked, the bacteria enter the digestive tract and multiply rapidly. In addition to ingestion, high-risk individuals can become infected when cuts, burns or sores come in contact with seawater containing V. vulnificus.

                          1. re: sunshine842

                            Per your post, the FDA agrees that oysters from warm waters such as the Gulf of Mexico should be avoided during the summer. That describes a decided minority of oysters harvested in the US. On the West Coast, source of oysters from Northern California north through the PNW and on up to BC, the Pacific is a cold-water environment all year round, and oysters produced here are not a risk to eat raw in any given months.

                            1. re: Caitlin McGrath

                              Even oysters from the Delaware Bay region are fine anytime. I had 2 dozen Cape May Salts back in June at The Lobster House on Cape May (which harvests them from their own oyster beds nearby) last year which were some of the best oysters I have eaten.

                              1. re: huiray

                                When we vacationed on the Eastern Shore of MD, we spent a day with a 5th generation oyster man. He said the "r" rule was hog wash, that locals consume oysters all year round.

                    3. re: sunshine842

                      In the US, oysters are not in season in months that do not have an 'r' in them -- leaving only oysters flown in from somewhere else, which would not be fresh enough to bother with.


                      this is old school advice. farming, harvesting and shipping methods are vastly superior to even a decade ago and fresh delicious oysters can be had all year.

                      they do spawn in summer, so can be slightly more flaccid, but oysters from cold waters remain delicious. can't stomach a gulf oyster but can eat a pile of about anything else.

                      to the op: i have gotten food poisoning once from cheese and once from cilantro. never from oysters and i have eaten a gajillion of them over the years.

                      1. re: sunshine842

                        I realize I am jumping in on a two year old conversation... but I have really picked up on a difference in flavor and texture in the same type of Oyster eaten now in August than when I have them in cooler months. Cape May salts taste cleaner, sweeter, less briny and aren't so (I hate to use this term but it works here) "flabby" in winter time as they are in the middle of the summer.

                        I just resolved myself this weekend after two of the 6 that I ordered just didn't taste as good to me, that I would wait until at least November for the water to get cold before I eat them again.

                        As was said, it makes sense that the flavor changes. the 'life' of the water in the Delaware Bay would be vastly different in cold weather as it is in warm weather... as the water changes, the flavor of the oysters in that water, stand to reason, would change as well

                    4. Go for it.. I just downed a dozen on Tuesday. Don't get $1 oysters at some random bar during happy hour.

                      Go somewhere that has a proper raw bar, where they'll shuck to order. Know where the oysters are from - if they don't, don't bother ordering. I prefer oysters from the colder waters - e.g. north of Cape Cod on the East Coast. I've never really had a good Gulf oyster. They should be served on the half shell with liquid from the oyster still in the shell. The oyster belly shouldn't be pierced during shucking. Just spoon on a bit of mignonette sauce and slurp 'em down..

                      3 Replies
                      1. re: grant.cook

                        the best oysters I've ever had was standing up to my knees in mud in some isolated Carolina bayou shucking oysters with a screwdriver and eating them with nothing but saltwater.

                        Can't get fresher than that.

                        1. re: sunshine842

                          Sunshine, will you be my calendar girl?

                          1. re: Veggo

                            *disclaimer* -- I can only WISH I still had that body... But sure ;)

                      2. Certainly no more dangerous than, say, living on earth.

                        1. The problem with contaminated oysters is that you cannot see or smell the contamination. Spouse contracted hepatitis A from eating raw oysters; the oysters looked, smelled and tasted fine in fact we both ate them with relish. But only he got sick - very, very sick. Since then I cannot bring myself to enjoy them raw anymore. So it really is a crapshoot and all it takes is that one bad oyster. As others have pointed out, the odds are low, but after witnessing my husband's illness I'm not willing to chance it.

                          1. Don't eat them because you think they'll have a net positive on your health. Eat them because you like them. I think the ones I eat usually have been held in a tank with UV-treated water.

                            1. I have eaten scores of raw and cooked oysters in my life with no ill effects (in all months of the year).

                              That being said, my Godmother's husband contracted an infection from a contaminated oyster that settled in a defective heart valve, and he died.

                              In general, though, I think the inherent risk is VERY low in people with normal immune systems.

                              1 Reply
                              1. re: JenJeninCT

                                Omg that's awful. So sorry.

                                I'm one of those who won't eat oysters unless they're plucked fresh (I either do it or trust the restaurant who's done it) and smell/taste like Puget Sound. I have to travel, by plane, to get them but it's how I roll.

                                1. Since cgarner resurrected ths --

                                  Right now is not a good time to eat fresh oysters in Florida.

                                  There's been a particularly large outbreak of vibrio vulnificus in the warm waters of the Gulf of Mexico -- serious enough that swimming with an open wound puts you at risk of acquiring a vibrio infection in the wound.

                                  Wait til cooler months.

                                  8 Replies
                                  1. re: sunshine842

                                    Plus the Red Tide has rolled in very heavily along certain portions of the western coastline of Florida this summer.

                                    1. re: deet13

                                      it's not on the coastline yet -- only the fish kill has showed up on the beaches thus far. The bloom itself is still 30-50 miles offshore (it's an irregular blob).


                                    2. re: sunshine842

                                      Oysters are susceptible to picking up quite a few bacteria and viruses but they tend to do this en-masse so whole production areas get affected and harvesting and sales stop. The french coast was addicted by a herpes like virus a few years ago, in the UK some areas were affected by Norovirus (closed the Fat Duck). But in general if they are for sale they are OK.

                                      The "R in the month" advices upthread was originally about the loss of condition when oysters spawn in the warmer months. But nowadays nearly all oysters are commercially farmed and they use sterile "triploid" varieties that don't spawn and don't loser condition.

                                      So whilst the warmer months may exacerbate any bacterial/viral infections in oysters you can get the same problems at any time of the year. So no reason to stop eating in the summer but wise to keep any eye on any outbreaks...!

                                      1. re: PhilD

                                        Very little farmed oysters in Florida -- so yeah, they're skinny, not so sweet, and run a high risk of infection.

                                        1. re: sunshine842

                                          I believe they are mainly farmed i.e. the leased beds are seeded with spawn and then harvested.

                                          They are not farmed in the same way as other areas with cages or artificial beds. Instead old shells are dumped into the sea as reefs, these are leased to "farmers" who seed the beds with free swimming larvae. They then harvest from the submerged beds.

                                          1. re: PhilD

                                            but they still spawn in the summer, and the summer still brings water warm enough to breed undesirable microbial populations.

                                            The "farming" in Florida doesn't change the lifecycle or its timing.

                                            1. re: sunshine842

                                              Modern, commercial oyster farming does change the lifecycle of the oyster.

                                              If Florida oyster producers are still using the old diploid (fertile) oysters rather than modern triploid (infertile) ones it maybe the contributory factor to low yields. Diploid's can lose 64% of weight when they spawn. As the triploids are sterile they don't spawn, so don't lose weight each year and thus can be bought to market weight faster (2 to 3 years).

                                              Triploid oysters are seeded into the beds as oyster larvae by the producers. The producers buy the larvae from large breeding companies and then seed or "plant: the larvae onto their oyster beds to let them attach naturally. In florida I believe these are artificial reefs that were laid using old oyster shells and date back to the 1900's.

                                              The use of infertile, Triploid, oysters in commercial production is far from new and very widespread across the world.

                                              The warmer gulf waters in the summer do lead to higher bacterial levels but the bacteria are actually in the water year round so a fat, plump health winter oyster can be as risky.

                                              1. re: PhilD

                                                The bacteria are there year-round, but not at the concentrations in which they're found in the summer, so considerably MORE risky in the summer.

                                                Water temperature is typically in the 50s in the wintertime -- over 90 in the summer. It's only logical that there would be more bacteria in the summer than in the winter.

                                                They post a LOT more warnings in the summer, so apparently the folks at the state fisheries office believe that it's riskier in the summer, too.

                                                There are still a LOT of wild-caught oysters in Florida -- http://myfwc.com/fishing/saltwater/co...


                                    3. It depends. While they may not be inherently more likely to be contaminated, they are certainly capable of being contaminated, as are many other things that we eat. It depends on the sanitation of the restaurant. I have eaten many raw oysters without incident. But the next-to-last time I had them I got gastroenteritis and was sick for a whole week. It was the worst case I have ever had. While I cannot be positive it was the oysters, it seemed like the only likely source. The incident turned me off to eating the raw oysters at that particular place, and now I rarely eat them anywhere. It isn't a big loss, though, because I like pan fried oysters better.

                                      3 Replies
                                      1. re: GH1618

                                        No, contamination of the oysters is not necessarily dependent on the restaurant.

                                        If they've picked up something like v. vulnificus in warm tropical waters, the restaurant could be sterile and it wouldn't help, as the bacteria is in the oysters before they ever get to the restaurant.

                                        1. re: sunshine842

                                          I don't know if the pathogen was V. v. or something else. Sometimes pathogens are introduced in restaurants.

                                          It seems to me that somebody should be screening for V. v. before oysters are sold for raw consumption. If that isn't done, it makes me leery of eating more.

                                          1. re: GH1618

                                            Oh, wasn't saying it was or wasn't v. vulnificus -- only that restaurant hygiene can, but doesn't necessarily, impact the bacteria count of the oyster themselves.

                                            And no, AFAIK, they are not screened for v.vulnificus (or anything else that I'm aware of) because every single oyster would have to be opened in order to screen....and that's not possible for a lot of reasons.

                                            my last case of hardcore oyster puking was in December in France...so there are never any guarantees one way or another.

                                        1. re: grampart

                                          But, the bullets taste way better . . . .

                                          1. re: grampart

                                            Interesting Article... too bad I don't like my oysters with tabasco or mignonette, however I just found that the acidity only deactivates V. cholerae
                                            (from the food and agricultural organization of the United Nations published 2009, maybe there have been new findings since)

                                            V. vulnificus
                                            Survival: More sensitive to environmental
                                            conditions than other Vibrio spp.
                                            Can survive well under refrigeration by entering
                                            “Viable but non culturable” (VBNC) state
                                            Survives quite well in oysters at 0–4oC
                                            Survives to pH 5 at low salinity
                                            Inactivated by mild heat treatment and low pH
                                            D45°C = 50 mins
                                            D51°C = 10 mins
                                            A low temperature pasteurization (50oC) for 10
                                            mins is effective in inactivating the organism in
                                            Freezing reduces the organism in oysters by 95 –
                                            99% but survivors remain fairly stable during
                                            frozen storage.
                                            Inactivation at low pH is slower at lower
                                            Inhibited by some but not all preservatives.
                                            Depuration is ineffective
                                            Relaying shellfish to higher salinity environments
                                            can reduce pathogen numbers
                                            Irradiation is effective and the irradiation dose can
                                            be reduced if used at higher temperatures e.g.
                                            increasing from 25 to 40oC means that
                                            approximately half the dose has the same killing

                                            1. re: cgarner

                                              That's informative. It looks like irradiation is a good option. In fact, that has been thought of:


                                              Of course irradiation has its detractors, so we can argue about that.

                                          2. I say just go for it, they are delicious. I've been pray-for-death sick from eating a bad one, once, in 26 years of eating good fresh oysters when I have the chance. Starting when my college housemate came home from visiting his parents on the texas gulf with a cooler full of oysters and a bottle of whiskey. Ohh such a revelation. I live in KS now so tend to eat them cooked, but if you have access too fresh ones, they are soo much better raw.

                                            1. RAW OYSTERS ARE VERY DANGEROUS ! ! I'll take care of them for you...

                                              1 Reply
                                              1. re: 3MTA3

                                                No hype -- I love raw oysters -- LOVE them.

                                                But after a few agonizing nights clutching the porcelain throne, swearing I just retched so hard I threw up a toenail, yeah, I'm rethinking how I go about it.

                                                Can't even say I've sworn off them...just that I'm going to be a lot less cavalier.