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Nov 13, 2013 10:41 AM

If bugs only affect the surface of meat, why do we have to cook through?

A friend brought this question up the other day, and it made me curious since I'm pregnant. I'm apparently not allowed to eat steak that isn't cooked to well done (I normally eat med-rare) because of the potential for poisoning my baby with bacteria from the meat. Now since any bugs from the cow's feces, GI tract, etc. would only touch the surface of my steak, why do I have to worry about the inside? Same question goes for sushi - can't I just sear the outside of whatever I want to eat?

Obviously this is a question coming from someone who desperately misses her undercooked food and is trying to find some justification to eat it…


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  1. My thought is that you've been given some lame information. When you say " I'm apparently not allowed to eat steak that isn't cooked to well done..." what exactly do you mean? Did someone specifically tell you that?

    Your thoughts on cooking the outside is correct, at least relative to the potential problems you brought up.

    11 Replies
    1. re: carolinadawg

      All the websites, guides, books, etc. say that you have to cook your meat through. Here's one example:

      Although in doing more searching, I just found this from Epicurious, although I don't know that I'd consider them a bastion of science:

      It specifically says that searing meat will kill bacteria like e.coli, listeria, etc. that live on the surface, BUT that toxoplasmosis is a parasite that can be within the flesh:

      "Another risk with raw meat is toxoplasmosis. This is a parasite that can be in the flesh. It's killed by freezing or cooking, but only if the meat is cooked all the way through. Toxoplasmosis can cause problems during pregnancy ranging from stillbirth to birth defects. However, it's pretty rare in meat in the U.S. To be completely safe, you'd need to cook all meat until well-done."

      Does this mean that, if I freeze my meat first, I can then cook it to medium-rare?

      I hate all the rules around pregnancy b/c they tell you what you can/cannot eat, but not WHY. I can't just say no to delicious food without knowing why it's worth saying no!

      1. re: jen223

        "why it's worth saying no" - the reason is the risk to you and/or your baby. It's a personal risk decision. They tell many expectant mothers not to drink wine, but there are many obstetricians who think that a glass or two is OK. The issue with pregnant women and particular foods is no different than anyone else but just on a different risk scale.

        1. re: fldhkybnva

          The problem with pregnancy advice in general is that not all the advice you get is actually based on logic, the amount of risk varies wildly (cigarette smoking has been proven to be bad, having a medium steak in the US is very low risk), and the sheer number of things that are restricted gets unmanageable.

          More than once I've seen logic that goes "There is no solid medical evidence that doing X causes harm to an unborn child. Therefore, you should refrain from doing X because it might harm your baby - better safe than sorry."

          I compiled a list once, of things you're supposed to avoid while pregnant - cigarettes, alcohol, prescription drugs, over the counter drugs, recreational drugs, herbal supplements, coffee, tea, caffeine containing soft drinks, most herbal teas, bottled water, sugar free soft drinks, eggnog, meat or eggs cooked less than well done, sprouts, fresh squeezed fruit juices, hot dogs, dry sausages, deli meat, pate, including vegetarian pate, large fish, sushi, shellfish, smoked fish, cod liver oil, fake crab, liver of any sort, soft cheeses, cream cheese, mayonnaise, sprouts, salad bars, buffets, leftovers more than one day old, pre-made salads or anything pre-made deli foods, dietary supplements, junk food.

          On the non-food front, paint, oven cleaner, spray cleaners, spot remover, varnish, weed killer, insectisides, fertilizers, home renovation or repairs, cat litter, hair dye, perms, X-rays, reptiles, birds, pregnant sheep, insect repellant, hot baths, overheating, the sun, sports, amusement park rides, horseback riding, running, skiing, tennis, waterskiing, tanning beds, hiking in areas that have ticks, CRT terminals, microwaves, electric blankets, waterbeds, dandruff shampoo, acne medication, makeup.

          If I add in some non-Western advice from my husband's cultural background, you can add swimming, dairy products, getting chilled, fruit and working for pay after getting pregnant. And traditional Chinese medicine adds melons, for some reason.

          Oh, and avoid stress, of course.

          This book

          is an interesting read. The author took a lot of pregnancy related no-no's and looked at the actual medical evidence to go with it, to compare relative risks.

          1. re: tastesgoodwhatisit

            I ate 99% of what is on your list when I was pregnant; it did nothing to harm my children. The only reason why it's not 100% is because I don't eat rare meat or the rest of the 1% of the list. But my youngest is 26 and you didn't hear about all that what I call "nonsense" 32 years ago when I had my first child. That said, I agree you shouldn't eat your meat rare but all that other stuff, seek professional advice.

            What advice, if any, did the OP get from her OB? I take certain medications; there are always stories online that indicate you shouldn't take this or that with certain foods or medicines. I go straight to my doctor and get the info from her. Speak to your doctor.

            1. re: Cherylptw

              I belong to a OBGYN practice, and I guess the frustrating part is that each OB has their own view on what you can or cannot do. During my most recent visit when I discussed concerns about homemade ice cream with eggs and soft serve from machines along with the undercooked meat, my OB's response was "Stop worrying and enjoy your pregnancy. Just don't eat anything that's not cooked." Well that doesn't help...

              And on the other hand, I've heard about a Japanese-American OB telling her patient that raw fish sushi is completely fine.

              There is no standardization on recommendations, which is what's frustrating. And no one can provide me with numbers that allow me to make my own educated judgments. A recovering chemical engineer, I still look to numbers and seek the "how" and "why" something happens. I read somewhere on the vast interweb that anyone's chance of getting listeriosis is 1 in 20,000. The FDA says pregnant women are 20 times as likely to get listeriosis than a normal adult. I have no idea where either of these #s come from, but a 1/1,000 chance is too risky for me. 1/20,000 I could maybe live with.

              1. re: jen223

                The fact that each OB has their own viewpoint should be a sign to you that there might not be a right answer. It's frustrating because that's how medicine works even though the public thinks it's a certain science, it is far from that. The numbers the FDA are sighting are from data on random food surveys. In fact, they recently published a 200 page report on listeria and cheese if you're so interested to read it but their conclusions are based on pretty faulty evidence and calculations so it's hard to just accept their conclusions as accurate truth.

                1. re: jen223

                  As a CE are you equally frustrated about finding 'hard numbers' regarding the toxicity of various chemicals? For example, BPA in food containers, especially baby bottles? The chemical has a well defined formula, and well understood usage. But is it really harmful to humans? How do we know?
                  What about the newer BPA free polycarbonate alternatives?

                  I don't mean to divert the discussion onto chemical issues, but to point out that even where there is clear engineering data, evaluating the risks for humans, and pregnant mothers and infants, is not easy.

                  1. re: paulj

                    I am frustrated, and I use glass food containers because I feel like I don't have enough info to gauge whether all the hoopla about BPA is warranted. I haven't even THOUGHT about baby bottles yet and am sure there will be another search on my part for guidance or research on the topic (I don't even know if glass baby bottles exist).

                    I agree that evaluating risks for all humans is tough, and I don't expect any doctor to have the one right answer if none exists. But if there is debate, I'd like to see the details for myself so I can make my own judgment and in the end blame no one but myself for any decisions made.

                    1. re: jen223

                      You can get glass baby bottles, and can get BPA free plastic ones as well.

                      One thing to consider with glass though, if you are doing daycare, is that a lot of daycare facilities won't allow anything glass in the classroom. When I worked in daycare, we had to say no to any glass bottles.

              2. re: tastesgoodwhatisit

                Thanks - this book sounds like a good read and will actually provide real information as opposed to a "do not do" list.

                1. re: jen223

                  My pregnant best friend has this book and said it has helpful, concrete info in it.

        2. While cooking or searing red meat should take care of most bacteria there can still be pockets of bacteria inside the meat. It's for that primary reason that they suggest red meat be cooked thoroughly, or in your this case "well done". If you are cooking at home I believe the "safe" point is about 145 degrees for the center of the steak to be cooked to. It's higher for ground meat, like hamburger, but I'm not sure of the exact temp for that.

          If you were to get food poisoning dehydration is a common side affect to food poisoning and that can be VERY dangerous for your unborn baby!

          As they say this is just an example of better safe than sorry.

          1 Reply
          1. re: jrvedivici

            "While cooking or searing red meat should take care of most bacteria there can still be pockets of bacteria inside the meat."
            There is no evidence that this is true unless the meat has been pierced (potentially driving surface bacteria inwards) or ground. Nathan Myrhvold et al came to the same conclusion when writing the very well researched food safety section of Modernist Cuisine. I've yet to see a convincing rebuttal.

            However, parasites can be found in the intramuscular space. Larger, burrowing parasites could even potentially bring a dangerous bacterial load with them, though I've not seen any documented evidence of this either. Or of course parasites can cause their own problems.

            - Intramuscular parasites are relatively common in fish. Many are easy to spot, but some are not. Freezing at very low temperatures for a period of time is known to kill said parasites. The higher temperatures of a home freezer might not be capable of the job at times, or might require a long freeze if they are. Salmon is probably the biggest offender.

            - The parasite that was previously most concerning - trichinosis - has been effectively eradicated from commercial pork in the US. It can still be a problem with some kinds of wild game meat however.

            - Toxoplasmosis might be the most relevant parasite found in non-seafood. Of note, 1/3 of the worlds (human) population is thought to already be infected. Because it is a protozoan that travels by the bloodstream, it is thought capable of existing just about anywhere within an animal. But evidence even on this is scant, as is evidence of its rate of infection for commercial food animals. It appears to be more common in pork lamb and venison than beef or chicken. Frankly, I'm unsure whether you're more likely to get it from your cat than you are to get it from something you eat.


            It's not that the interior is complete safe, but that the immune system of healthy individuals can cope with the 'intruders'. But when it comes to food safety, pregnant women are generally given the same advise as individuals with a compromised immune system.

            listeria is a concern in ready-to-eat foods.


            1. One other issue to worry about. Apparently some meat processors are using mechanical tenderizing, penetrating the meat with multiple fine needles contaminating the inside with the outside. This is not easily detectable visually. This meat can be in both supermarkets or in restaurants. There is a movement to require labeling on raw meats.

              Not an Internet rumor...there have been cases of E.coli attributed to this. References are easy to find with Google.

              1 Reply
              1. re: Sinicle

                Good point, but this also explains why they suggest you just need to cook the outside of steak but ground beef should be cooked thoroughly. Ground beef has had the surface penetrated similar to meat which has been pokd with fine needles such that bacteria are present throughout. In most whole cut meats like steak the surface is most contaminated hence eating a rare or medium rare steak poses less risk than eating a rare burger.

              2. I personally think that you need to decide what level of risk you are willing to take. When I was pregnant, I craved all kinds of raw or rare meats. The idea of fully cooked meats was revolting. I decided for myself that the sushi prepared by the chef from a restaurant I had been going to for years was more than likely completely safe. The steak from the cow raised by my neighbour and butchered down the road, was absolutely delicious very rare. The goat loin from animals raised on my farm, nice and pink, again, so satisfying. And the venison shot on our property was the best thing ever when I nibbled on it raw with just a bit of salt. I made the choice to indulge because I felt that the sources were reliable. Oh, and I can't forget the runny yolks from my chickens. Would I have eaten all of that bought from regular grocery stores? I don't know, it's so hard to say no to those pregnancy cravings.