I left fully cooked lasagna out all night

  • I left fully cooked lasagna out on the counter all night. My house is 72 degrees Fahrenheit (22 degrees Celsius). Is it safe to reheat and eat?

    Aaronut has written some excellent food safety answers, such as http://cooking.stackexchange.com/questions/16665/is-it-really-necessary-to-wash-a-skillet-that-will-be-heated-up-again-soon/16672#16672 and http://cooking.stackexchange.com/questions/12992/why-is-it-dangerous-to-eat-meat-which-has-been-left-out-and-then-cooked/13009#13009 - have a look at those, before you even think about trusting the more "adventurous" (i.e. potentially dangerous) answers here.

    There are a lot of similar questions out there. The fact you post it means you know, deep down, that it's not safe.

    There is insufficient information in the question for anyone to give a definitive answer. For example, how was the dish covered? was is in a container or open for flies and cockroaches to crawl over while you slept.

    I don't have any professional experience so just anecdotal and your mileage may vary: I have done so many times, with lasagne and spaghetti bolognese etc. also where it wasn't covered by any means. I have never been sick. Also, I know plenty of people (including my parents) who will always leave what remains of pizza, lasagne etc. in the oven for the next day so it is just a matter of turning on the oven to heat it up. Seems this is just how they were brought up, and has never caused problems. I will usually put in the refrigerator unless I forgot. But I do, I will eat it anywyay.

  • Throw this out. The general rule of thumb is that food that isn't otherwise preserved (through large quantities of acid or sugar for example) must not be in the danger zone from 40-140 degrees Fahrenheit for more than 2 hours. In practice this is an oversimplification - see the incredible and incredibly detailed food safety section in Modernist Cuisine for the whole story. Overnight is way too long. It is quite possible for bacteria to have multiplied and secreted toxins which are heat stable. E. Coli and Staph. Aureus both do this, for example. Reheating will not make this safe. It isn't worth making yourself or your family horribly ill. Order pizza.

    Well, if my lasagna had a bunch of living *staph* or *e coli* in it after I'd cooked it, I'd think there were bigger problems than it sitting out for a while. There are more sensible bacteria to be concerned about in cooked food, at home.

    It doesn't take "a bunch". *One* cell of these microorganisms, if allowed to thrive in a warm, moist environment for 12 hours could grown into billions of them. Unless of course your house is a surgical operating theater and your tomato sauce contains bleach.

    +1 Completely agree here. Your kitchen isn't a sterile environment - well a *normal* person's kitchen. Its not like any lasagna is worth a potential trip to the hospital. Odds are you'd be fine, but how stupid would you feel telling the doctor at the ER that you ate the food sitting out all night and thats why you're there. If in doubt, throw it out.

    @michael: With a double rate of about 20 minutes, you'd need 10 hours just to get *one* billion, assuming the contamination was instant, the food was in the dangerzone, and also that the food was an ideal growth medium. In practice, you're more likely to get the e coli poisoning from your side salad. I'd put it at higher risk than raw eggs, but at a lower risk than raw chicken.

    @michael I strongly disagree with your perspective here. Staph will not be present unless someone sneezed on the lasagna post-cooking. E coli will have been killed during initial cooking, and will therefore have already released all the toxins they can. If it was safe the first time, and not sneezed on or re-infected with E-coli, it will continue to be safe if reheated.

    Well let's take one obvious way it could be contaminated. Presumably it got wrapped with tin foil. Were the hands of the person who handled that tin foil absolutely sterile? Not likely. It is perfectly possible for a few germs to be present on those hands, which get transferred to the foil or plastic, and from there into the food where it will find an inviting warm, wet environment in which to multiply. This isn't just an opinion, it is the law for food handlers everywhere.

    @Peter, this isn't an issue of agree or disagree, it's one of fact. There are at least a dozen common household bacteria that thrive in warm, moist environments and produce toxins within 2 hours. 4 hours is the absolute maximum time you can leave hot or warm food out and still be safe. Doesn't matter if it's cooked or not. Obviously the danger is greater with raw meat, but that's only because raw meat has a greater likelihood of being contaminated in the first place.

    @michael: It'll find a layer of cheese, which is a crappy growth medium (it's dry, and it's the byproduct of a ton of intensive bacterial growth, which means less food for newcomers). And then a layer of tomato sauce, which is a crappy growth medium (it's acidic and salty). And no, I wouldn't serve it in a restaurant. Restaurants are like hospitals: you'll find more germs there than any other sort of kitchen, and more potential cross contamination. They are held to a high standard for a reason. In a home environment? The risk is much lower. It's not nil, but I wouldn't worry about eating it.

    And let me cite one more source: the USDA Food Safety and Inspection Service: fsis.usda.gov/factsheets/Danger_Zone/index.asp, which is crystal clear on the subject. Two hours in the danger zone, period. Overnight isn't even remotely close to safe.

    @Satanicpuppy: Please, tone it down with your food safety rants. Unless you're an expert on microbiology, you have no basis from which to make such broad, sweeping claims. The fact is, tomato sauce does not have a high enough pH to stop bacterial growth, home kitchens are not sterile environments, and the type of cheese used in lasagna (mozzarella, ricotta, etc.) is more than moist enough to support bacteria, especially after being drenched in tomato sauce and water from the cooked pasta.

    @michael: This is the same USDA that thinks I need to cook my thanksgiving turkey to 165F, right? They make recommendations for being as close to 100% safe as possible. Overnight lasagna ain't it. Nor a hamburger with pink in it, or a pork loin with juice in it, and you can throw your steak tartare out the fricking window, because that is like the worst thing imaginable from their point of view...Or you can accept that sometimes its worth not being 100% safe.

    @satanicpuppy - you are right that some of the USDA advice is overkill (and actually, it turns out some of it is underkill - Nathan Myrhvold spent some time with them trying to get them to update some regs based on the research for Modernist Cuisine). However, the degree to which they overprotect is relatively small. If doublings are every 20 minutes, the difference between 2 hours and 14 hours is 2^36 bacteria - about a factor of 68 billion times the original count. Not close. Just because they are a little overprotective in some cases doesn't mean you should throw out basic research.

    @Satanicpuppy: Yes, exactly, they USDA and other agencies post guidelines that minimize risk. That is exactly what they do, and that is exactly what we need to do when answering food safety questions. It is the **only** responsible thing to do. We can certainly go into more detail and attempt to quantify the risk and let people make their own decisions if they wish to ignore the dangers, but simply telling people to ignore the guidelines because *you* think it's safe is extremely irresponsible and inappropriate. By all means add a caveat to the accepted guidelines but don't ignore them.

    @aaronut: And I didn't add caveats, where? The bias here is so far the other direction that any statement of the form "this probably won't kill you" is viewed as the rankest heresy.

    @Satanicpuppy: You can't say with authority that "this probably won't make you sick", at least not based on any facts presented so far. The best you can say is that it *might* not, and that's not really a very useful or interesting answer to a question which asks, "can this make me sick?" The chances of a plane crashing or falling out of the sky are similarly low, but they still keep oxygen masks and life preservers on board, because a small risk, taken over millions or billions of trials, turns into a near-certainty.

    I haven't had the pleasure of reading Myhrvold's research, sadly. I will say I agree generally with @satanicpuppy's perspective that I would eat reheated lasagna under the terms described above. I agree with Michael and Aaronut that it would not be suitable for guests and certainly not at a professional food establishment.

    Update, I didn't realize Aaronut and Satanicpuppy are in an extended debate on this site re: food-safety questions. I'll bow out now.

    @Peter: It's fine if you would eat it. Really, it is. But the question doesn't ask, *would you eat it?* It asks, *is it safe to eat?* Those are two different questions.

    @aaronut: I said "Kill you" not "Make you sick." And even there I said "Probably."

    @Satanicpuppy: Who cares? Death isn't the subject of the question, or of food safety in general; sickness is.

  • Was the pasta in a sealed container? If it was left open to the air or was touched by anything that could contaminate it, it might not be ok.

    On the other hand, I have left rice and pasta out overnight in the pot with the lid on at room temperature numerous times and never had a problem. This "two hours at room temperature and throw it out" thing is really overkill almost all the time. Only if you are pretty unlucky will the food be unsafe to eat.

    Food safety is not about being safe most of the time, or safe unless you're unlucky. There are a lot of people out there, and we want them *all* to be safe, not just the lucky ones. If everyone follows your advice, a lot of people will get seriously sick.

  • If by reheat you mean get the internal temperature up over 140F for more than 10 minutes (and it won't really taste "hot" until you do so), then it's totally fine, provided that it was fully cooked originally.

    That said, if you cooked it fully originally, unless there's something a little funky about your ingredients, you're probably fine to eat it cold right now. Of course "probably" is very different than definitely.

    Hence, 140F if you wish to be sure. Alternately, touching 165F would be plenty; don't even have to wait the ten minutes.

    I'm sorry, but this is dangerous, terrible advice. Bacteria can leave toxins that you can't destroy by reheating.

    @michael: Eh. I think the lasagna would be fine, but I agree that you shouldn't think heating makes you safer.

    See my answer below, and read http://aggie-horticulture.tamu.edu/extension/poison.html if you have further doubt - there are several bacteria which produce toxins that you aren't going to destroy by reheating. This lasagna could make someone really sick.

    I have thoroughly reviewed the link you post, and stand by my general advice. Which bacteria listed on that link do you believe are at risk of growing here, (and note, at a rate which will cause significant toxins being left out 12 hours?) If the lasagna was safe to eat at first (and in this case, it seems to be, since the author has posted this question), there is nothing on that list that poses a health risk if the lasagna has been re-heated the following day. Food safety is important, but there's no point in spreading fear needlessly.

    See my comment on your answer. Staph and E-Coli would need to be re-introduced to be a significant risk based on the parameters of the question.

    I've explained in the comments above how easy it would be for them to be reintroduced.

    And let me cite one more source: the USDA Food Safety and Inspection Service: http://www.fsis.usda.gov/factsheets/Danger_Zone/index.asp, which is crystal clear on the subject. Two hours in the danger zone, period. Overnight isn't even remotely close to safe.

    The problem is that there *could* be something funky about the ingredients, or the prep/cooking/storage conditions, and we just wouldn't know. "It'd be fine 99% of the time, with no way to tell if you're the one in a hundred who gets sick" is not really an acceptable answer to a food safety question.

    So there is lots of evidence that proves that this might be unsafe, but there is no evidence that actually proves that it is. The USDA regs are a ridiculous standard ... they introduce more harm by over-sterilization then they actually fix. If this was cooked properly to start with, and the food smells good, then eat it and stop wasting your money.

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