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I have a large, unopened container of yogurt that is a couple weeks past the best by date and I wondering if it is safe to eat. It still smells fine. How long past the best by date is yogurt usually still good?

marked as duplicate by rumtscho Mar 31 '17 at 13:16

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  • I don't know that we can really answer this... we tend to toe the line of "when in doubt, throw it out" and "read the expiration date"... there's no way for us to guarantee that your food is safe. You don't even explain whether it's a single-serving, unopened yogurt, or if it's a larger container... at the very least, you'll need to limit your variables. – Catija Mar 30 '17 at 23:19
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    @Catija I don't think that's entirely true - there are tons of things all over the site saying that expiration dates are about trying to guarantee good quality, not just safety. – Cascabel Mar 30 '17 at 23:32
  • People often cite stilltasty.com, stilltasty.com/fooditems/index/18717 , for specific common sense ideas about this topic. – Lorel C. Mar 31 '17 at 0:13
  • Assuming it is pure yogurt, it only gets better with age. If you have the patience leave it for months in the back of the fridge. – aris May 24 at 17:36
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Yogurt was originally a food preservation vehicle.

It is quite acidic and if unopened and refrigerated it can stay good for a very long time.
The pasteurized, inoculated, milk is allowed to ferment in the container.
Foreign bacteria don't have much chance to get in and if they do the yogurt culture crowds them out and the acidity kills them.
Greek yogurt, with its lower moisture level, stays good even longer.

I have had very old yogurt from time to time (months past the expiration) and it has only ever gone bad in one of two ways:
Either it went moldy or the yogurt's own bacteria was allowed to work for too long and the yogurt was too sour and not creamy anymore.

If the yogurt isn't moldy then it is probably fine. If it has continued to ferment then it will be more sour and possibly broken but not unsafe.

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    If you have any publicly accessible scientific sources saying that (safe if no mold, period), they would be great to link here :) – rackandboneman Mar 31 '17 at 7:59
  • @rackandboneman - I didn't notice the duplicate- which I also answered. The link I provided there says that e coli can grow if the milk wasn't pasteurized which yogurt always is. Otherwise it is difficult for anything to grow in that acidic environment. Though unlikely, it is possible, so official sources can't say that it is perfectly safe. I've not seen any source that talks about the likelihood of commercial yogurt being contaminated with harmful, acid tolerant bacteria. I agree it would be nice to have a solid, scientific answer. – Sobachatina Mar 31 '17 at 21:46

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