What you see: A sealed container of yogurt that has been refrigerated, but is months past its “expiry date.”
What it is: Really old yogurt!
Eat or toss: Discard if you see mold growth, gas build up or detect any off smells as those indicate unwanted microbial activity. Otherwise, age-related texture and flavor changes may reduce the yogurt’s quality, but it could still be edible.
How long does yogurt last, really?
As he was cleaning out his refrigerator, EatOrToss reader Larry M. of Chicago, Ill., discovered this very old container of yogurt. Printed across the foil was “Sept. 9, 2021.”
The date of the yogurt discovery: April 13, 2022.
That’s a difference of seven months. Seven months!
As you may know, “best by,” and other dates printed on food products usually aren’t determined by food safety, but rather by when the manufacturer estimates that quality and freshness could fade.
A little passage of time did not deter Larry.
The little tub was still sealed. He peeled back the foil.
The Greek yogurt looked fine, though perhaps a little dried out. It smelled normal and tasted normal, so he ate it, experienced no ill outcomes, and lived to report his findings to EatOrToss headquarters. Way to fight food waste, Larry!
But is eating yogurt older than this baby a good idea?
I asked Nicole Martin, associate director of the Milk Quality Improvement Program at Cornell University, how long yogurt could hold up. She said that if the diary product was properly produced, packaged and sealed, the tub of yogurt would have been protected from contaminants. In fact, if any microbes did manage to sneak in during processing, they probably would have destroyed the yogurt long before Larry pulled off the foil. (To see what contaminated yogurt might look like, check out this post. And, along the same lines of what we we wrote in this post about spoiled milk, there are no symptoms of consuming expired yogurt because expired yogurt is not necessarily something that will cause a foodborne illness, especially if it was stored properly and kept free from uninvited bacteria and other contaminants.) Yogurt’s acidity also prevents many pathogens from growing.
So, in Larry’s case, we’re not very worried about microorganisms. The passage of time can, however, cause physical changes in the chemistry of the yogurt. Martin said the proteins might degrade, leading to flavor and texture changes. The yogurt might have a weaker grip on water, making it drier.
“Even in the absence of protein degradation, I expect that the yogurt will eventually just start to taste old and lack freshness,” Martin wrote. “Depending on the type of yogurt (added flavors, colors, etc.) there could also be additional age-related implications. Colors fade, flavorings can break down causing unintentional flavors and odors, etc.”
But, apparently, seven months was not long enough to cause any of this unpleasantness in Larry’s yogurt.
His assessment: “It tastes fine.”