Is it dangerous to eat yogurt that has been left out overnight?
Will unrefrigerated yogurt spoil? I left a tub of strawberry yogurt out overnight and don’t know if I should pitch it or if it will be safe to eat. It looks and smells fine but I really don’t want to poison myself!
Answer from Green Energy Efficient Homes
Your yogurt is probably safe to eat. Yogurt will not spoil if left out for a short time – 24 hours or less. Don’t forget that yogurt, along with cheese, sour cream, kefir, and buttermilk are created by bacterial action on milk, and were developed by early farming peoples as ways of preserving milk, centuries or millenia before modern refrigeration was invented. Cheese is a great way to store milk protein and fats for long periods – my nephew led a 75 day canoe trip through Canada’s arctic last summer, and they carried something like 40 lbs of unrefrigerated cheese (cheddar), some of it for over two months. Unrefrigerated yogurt won’t last that long but certainly it will last at least a day.
Yogurt is a live culture of lactose-eating bacteria. The bacteria convert the lactose (a complex sugar in milk) into lactic acid; the acid causes the milk to curdle and provides the thick yogurt texture. Acidic foods are much less prone to spoilage than neutral or alkaline foods, and acid is especially important in inhibiting the growth of botulin-producing bacteria (botulin is the toxin that produces botulism, one of the worst forms of food poisoning). That’s one reason why unrefrigerated yogurt can last quite a long time without spoiling, and yogurt kept in the fridge lasts even longer – often several months.
The most common form of spoilage in yogurt that has been left out or has gone past its best before date, is mold growing on the surface. It may be safe in such cases to skim off the mold and eat the remaining yogurt, but I don’t recommend it. Mold growth in an acidic food can actually reduce the acidity of the food, which means that while the mold itself might not make you sick, the reduced acidity can make the yogurt susceptible to other forms of spoiling, including the botulism mentioned above. So if you are thinking about eating yogurt that has been left out, or yogurt that’s past its best before date, be sure to check for signs of mold before trying it.
Making yogurt yourself
I love doing just about everything myself, and I have made my share of yogurt over the years. It’s not a lot of work and as long as you use a good starter, and follow directions carefully, the results are typically as good as or better than store-bought yogurt. If you do make yogurt yourself you will understand why unrefrigerated yogurt is not a major food safety problem.
Along with the natural yogurt to use as a starter, you’ll also need something to keep the growing yogurt culture at the proper temperature for a few hours. Yogurt cultures grow best at 100F or 38C. I made a fair bit of yogurt a decade ago, with a yogurt maker similar to the one pictured here. I would bring the milk to a simmer (160F on my candy thermometer) to kill any bacteria in it that might compete with the yogurt, then let it cool, covered, to body temperature, then pour it into yogurt-making cups that already have a tablespoon of starter culture in them. I would give the yogurt a very gentle stir, then cover it for 7 or 8 hours inside the yogurt maker.
Longer incubation times make the yogurt thicker but also more acidic, and if you wait too long the yogurt can get granular. Once it has set, you can let it drop to room temperature and keep it unrefrigerated for at least a day. You’ll save a lot of money making your own yogurt. In my neighborhood a 24 oz container of yogurt costs about $3.19, while I can buy that much milk for about $1.35 and turn it into yogurt for about 1 cent worth of electricity. You can make your own yogurt with any milk from skim to 3.25%. If you really want to economize you can even make it partly with powdered milk (but you still need to scald the reconstituted powdered milk).
I’ve noticed that North Americans in particular are paranoid about food poisoning and tend to throw everything in the refrigerator, and then throw it out if it accidentally gets left out for more than an hour or so. I once talked a health food store owner into giving me an entire case of fruit-bottom yogurt that was already a month past its best before date, and a month later I finished the last tub of it; not one of them had spoiled. I lived in Costa Rica for a year, and noticed that even supermarkets there leave eggs at the end of a regular grocery aisle; no one there seems to put eggs in the fridge. We ate plenty of unrefrigerated eggs during the year we lived there and never had a problem with spoilage.
As I said above, and elaborate on in my main article Energy saving refrigerators, refrigeration is a very recent invention, and especially for foods that were created as ways of extending the shelf life of perishable agricultural products – foods such as yogurt, cheese, pickles, sauerkraut, jams and marmelades, smoked meats, etc. – the food is not automatically dangerous to eat just because it hasn’t spent its entire life confined to your refrigerator. Of course, you should apply common sense here: if you see any signs your yogurt has turned, throw it out. One common sign of spoilage is bulging of the container, which suggests fermentation is happening inside; note that this bulging can also be caused by expansion of the air in the tub as the yogurt warms when left out, and the less yogurt there is in the tub, the more likely it is to expand. Other spoilage signs are pretty obvious – mold spots, a moldy or yeasty taste, or a sense of effervescence or bubbling in your mouth. In any of these situations you should stop eating the yogurt and throw it in the garbage or compost or down the sink.
Because fruit yogurts are sweeter, there is an increased chance of fermentation in these than in plain yogurt. I would personally be more willing to risk eating plain unrefrigerated yogurt that had been left out for a full 24 hours, than fruit-bottom or blended-fruit yogurt left out the same amount of time.
I left a small container of yogurt in my car a couple times. The first was only for about an hour and it was fine. The second time was for 5 hours and by that point the interior of the car was scorching hot. I figure that with yogurt’s bacterial properties and that it’s a sealed container it should be ok… tastes alright so we’ll see. For the most part our foods keep very well when refrigerated and if not left out for any length of time; the exception is usually when someone has been eating from the container, even a small amount of saliva shortens a product’s shelf life.
Please note that Brad (above) has not posted since he ate his 5-hour-old yogurt. I believe that is sufficient proof that he had passed away, and nobody should eat yogurt that has been left out for 4+ hours at high temperatures.
You might be right. Then again he might be feeling so great that he has been running marathons ever since and hasn’t had time to reply.
I’ve eaten yogurt that was left out 24 hours or more and am still alive, I think.
I left an unopened cup of yoplait on my table for 8 to 10 days, it tastes a little less sweet than normal (I think Yoplait is usually too sweet anyways) it tastes great! I’ll let you guys know if it doesn’t sit well.
I hope you survived eating 8-10 day old Yoplait. I’m not sure I would trust it that long.The reason it tastes less sweet is likely that some of the sugar has fermented, which means the yogurt will be high in live yeast cultures.
thanks for the good chuckle before i head off to work.
Haha thanks for the chuckle as I am leaving for work! I am throwing out the fancy whole foods yogurt that brought me to google and then here. Gotta start eating my breakfast.
Haha! I am on this thread because I had my plain yogurt with blueberries in my insulated lunch bag for 6 hours and got paranoid. I just ate it and I think I am going to live. I probably won’t come back on to tell you if I lived (or died, for that matter), so wish me luck.
I can say that I have had sealed fruit on the bottom Greek yogurt that has gone un refrigerated for over a week and there was no problem with taste or quality. My refrigerator failed and getting the part took some time then I ended up having to buy a new fridge anyway. i decided to try the yogurt and its fine. sealed cheese fine..sour cream not so good.
What is the difference between the making of greek yogurt and yogurt?
Greek yogurt is a marketing term used to describe yogurt that has either been strained after the yogurt has set, in order to remove some of the whey and thicken the yogurt, or that has had the starting milk mixture enriched before making the yogurt, through addition of milk solids or boiling away of some of the water.
So that yoghurt which doesnt need refrigeration. What is in it that stops culture activity?
It’s not that yogurt doesn’t need refrigeration. The high acidity of cultured yogurt (produced by the yogurt bacteria converting lactose into lactic acid) helps prevent harmful microorganisms from breeding in it, so if you do find you’ve left it unrefrigerated, it is likely still safe to eat if not left out for too long. As for what stops culture activity, the yogurt culture breeds quickly at the temperatures at which yogurt is made – slightly higher than human body temperature – but breeds quite slowly at normal room temperatures. The culture will typically stop growing when all the lactose has been consumed. This is why if you make your own yogurt and let it sit at its breeding temperature too long, it gets very acidic and has a high whey content.
I have left my yogurt in the car for 2 days. Eating it tomorrow.
So how was it? Are you ok… because the same thing happened to me, and I plan on eating it today!! 🙂
Unfortunately, Meg passed away after eating the yogurt… I would not recommend trying to duplicate her experience.
Interesting that Meg herself is posting that she passed away after eating the yogurt – could she be trying to fake her own death?
You are all hilarious lol
RIP all of the above
I left my Chobani Plain Greek Yogurt in the car accidentally last evening. It was unrefrigerated from 5PM until 10:30AM, the temps outside were high of maybe 75 and cloudy, and low 44. I plan to eat the yogurt and will report back tomorrow.
I want to report that I am fine. The yogurt tasted normal, and I had no ill effects from eating it.
JLM has not reported again after the post shortly after eating it. So it’s safe to assume he has also died after posting that he is fine.
After reading your post I booked a séance with a local spiritualist to ask her if she could track JLM down in the spirit world. She was unable to do so (in spite of rightly guessing that as a child I was traumatized at the death of my hamster Happy) so I think it’s safe to say that the absence of evidence of his death probably trumps the absence of evidence of his still living.
The indisputable evidence you have provided convinced me 105%!
Side comment on: “I lived in Costa Rica for a year, and noticed that even supermarkets there leave eggs at the end of a regular grocery aisle; no one there seems to put eggs in the fridge” — but In the US, unlike in Europe and perhaps Costa Rica, most of the eggs sold in supermarkets are washed, this removes a natural protective coating which then renders US eggs more susceptible to bacterial contamination if unrefrigerated
This is a valid caveat for sure. Since I use mostly store-bought eggs, if they are well beyond the sell-by date, I subject them to the swimming test: sinkers are for plain egg dishes, standupers for cooking and baking; floaters go to the dog (he can have one a week) or out to the edge of the woods to biodegrade or be a treat for some scavenger.
Thank you good to know.
My yogurt has been left out for probably a week at least. Past date 7/2/17. What do you say Robin? Our neighbor gets extra food all the time and shares with us. They eat it and said it’s fine. Doesn’t have mold.
A week is a bit long, but it is a live culture and assuming it’s plain (not fruit-bottom or other flavored yogurt) it is probably fine.
Found this when investigating the idea of leaving today’s batch of yogurt out on the counter to drip/strain (I always do this to make a very thick product that is in texture about halfway between Greek-style yogurt and cream cheese. It isn’t quite as acidic as I prefer, so decided to just leave it out on the counter and let those little bugs work a little longer… I, too, sometime ago decided that our ideas about food safety border on paronia here in The Mitten, reminding myself about all the open-air markets on the globe. I’m happy with a clean kitchen and reasonable care, realizing that my standards might not satisfy everyone. Yeah, I keep chlorine bleach on hand for kitchen cleaning, but I also know better than to throw away eggs that are past–or even well past-their use-by date, cheese with a little mold, and–especially–dark beef. But then, I lived for some time in a home that was so far off the grid that they had not yet run the power lines out that far. A privileged childhood, in my opinion.
Left my organic strawberry banana flavored yogurt sitting out for about 24 hours at room temperature in the house. Decided to eat it after reading this post, and it tasted just fine.
And everything is just fine, not even a tummy ache 🙂
Greek yogurt (no fruit) left in office for 2.5 days and it seems totally fine. Still alive after eating it =)
I am reading this because I left my Greek yogurt mixed with fresh papaya on my counter for 8 hours, and unsure if it is safe to eat. It tasted fine, so after reading these comments I decided I will finish the yogurt. I am quite busy so please do not assume that I have left this planet if no reply tomorrow.
Left my overnight oats(with yogurt) in the car(parked under hot sun) for 4 hours which led me to this page. I ate it and i’m reporting after 1 hour of consuming… I’M STILL ALIVE!! =D
I came home from a trip to Manchester, TN where I had some left-over yogurts from the hotel, which I accidentally left in the car over night, and then in my work desk drawer one more day. I’m tasting it now, seems fine. Will report back… but after reading all these comments, I feel like it is probably fine, seems like yogurt holds up to an edible state pretty well.
I made some tzatziki sauce and left it out about 16 hours – a little more of a gamble because it has other ingredients (olive oil, lemon and cucumber, which are fine at room temp) and more chance for bad bacteria to get in and grow. Hopefully if I eat it within a day, the bacteria won’t have had a chance to grow too much.
I went shopping yesterday afternoon and accidentally left a bag with 3 four packs of fruity yougurt on the floor we are in Arizona it was in the nintys but we had our air on it’s been about 24 hours should I toss it?
If it was inside and you had your air conditioning on I assume it was cooler than the 90’s it was outside. Based on that, I would guess that it’s safe. Put it in the fridge now. Taste one and make sure it’s okay. If it tastes unusually sour toss it, but it’s almost certainly not going to poison anyone.
I bought my son these Horizon Organic brand strawberry yogurt pouches with omega and left it in the car by accident. It’s been in there for 3 hours unopened and I just put them in the fridge. It was room temp in the car, figure 60ish degrees. Ok for him to eat?
It doesn’t sound like they got very warm so I expect they should be fine.
I left 12 yogurts unopened yogurt out all night. Fell asleep after Bringing the groceries in. I don’t think it’s spoiled but I wondered if room temperature has any effect on the probiotics which is the main reason I’m eating yogurt right now to get my stomach and kidneys back on track. Any input would be appreciated
The reason yogurt doesn’t spoil quickly is that it is a living culture. The probiotics are bacteria; they fight off “infections” from harmful bacteria and yeast. Yogurt left out for 12 hours will still have plenty of probiotics in it.
I left a pack of yogurts under my bed (I was really hungry so I was going to eat them all in one, but forgot and over time they just were pushed further back behind my bed) for three weeks to a month, when I had seen them again I was like oh damn, they’re still here I thought I ate these!…. I was curious, ngl… It had been a while, so I opened them to see the damage. Nothing, looked as though the were new, I smelled them…. Nothing! Not even sour…. So I ate them, four years later, here I am googling if I made a mistake AHAHAHA
I just ate unrefrigated yogurt for 1 week and am still here typing comments hahahah
I admit to having found this site after looking for counter-arguments to the conventional wisdom (expressed most often with unequivocal certainty) that yogurt absolutely shouldn’t be left unrefrigerated for more than 2 hours. I have fairly often eaten yogurt that I took from the refrigerator hours earlier, and have never gotten sick. Sure, it’s possible that I just got lucky, and that the idea that the probiotics protect against rapic spoilage aren’t scientifically sound, but…. it seems unlikely that I wouldn’t ever have gotten sick. Appreciate everyone’s anecdotal reinforcement, just wish I could find a credible food safety authority for a definitive answer!
I’ve been eating forgotten yogurt for years. Yogurt left on counters, yogurt left in my son’s lunch box, yogurt on long road trips…it’s always been fine from hours to even a few days. Like stated above, the yogurt will usually display mold, an slight odor or an unpleasant sour taste if not good. I feel that our expiration dates in the US are getting shorter and shorter and the pricing higher and higher. The shelf life for food when I was younger was much longer. I always wonder if some of these dates are motivated by greed…just wondering.
I think concern over lawsuits is probably behind the excessive and overly conservative use of best before dates. Not sure if they are shortening best before dates.