​How Long Does Greek Yogurt Last After Opening?

Store-bought Greek yogurt lasts longer. It can stay in the fridge for 7 to 10 days after opening. This is because factories use special machines(yogurt filling machine). These machines pack the yogurt in a clean, sterile space and kill bad bacteria. But you must still store it right. Always close the lid tightly. Never leave it out for more than 2 hours. Even good packaging cannot help if left out. Room temperature will make it spoil days early.

What Factors Affect the Shelf Life of Greek Yogurt?

Storage temperature is the main factor. Greek yogurt must be kept cold in the fridge. Room temperature makes bacteria grow fast. For example, leaving it outside for 3 hours on a hot day will speed up spoiling. Also, do not keep yogurt on the fridge door. The temperature there changes too much. The best place is the middle shelf. The temperature there is stable and cold.
Packaging and contamination matter too. A tight seal keeps out air and bacteria. If the original lid is broken, use a clean container or plastic wrap. A small gap can cause mold in two days. After use, wipe the container's rim. This stops spilled yogurt from attracting bacteria. Never use a spoon that touched other food, like jam or cereal. This brings in new bacteria and sugars. Do not put a used spoon back in the yogurt. Saliva has many bacteria.

Second, smell and feel it. Fresh yogurt has a mild tangy smell. A strong sour, rotten, or moldy smell means it is bad. This bad smell is easy to notice. Spoiled yogurt is also slimy, not smooth and creamy. If it is unusually runny, it is likely bad. If it looks and smells fine, you can taste a tiny bit. If it tastes bitter or very strange, spit it out right away. Pregnant women, older people, or anyone with a weak immune system should not taste it.

What Happens If You Eat Expired Greek Yogurt?

Most people will feel mild stomach problems. Symptoms include bloating, gas, diarrhea, or stomach pain. These usually start 2 to 6 hours after eating and last 1 to 2 days. Bacteria in bad yogurt make waste that bothers the stomach. Drink plenty of warm water and eat light food, like rice or toast. You will normally get better on your own.
Bad food poisoning is rare but can happen. This is true if the yogurt has harmful bacteria like Salmonella. Signs are constant vomiting, a high fever over 101°F (38.3°C), bloody diarrhea, and bad stomach pain. These can last 3 to 5 days and may cause dehydration. Go to a doctor immediately.
Some people are at higher risk. This includes young children, the elderly, pregnant women, and people with weak immune systems. Their bodies fight bacteria poorly. Even a little bad yogurt can cause serious problems. For example, a small child could get dehydrated from one day of diarrhea. These groups must never eat expired Greek yogurt.

First, check if the expired yogurt is okay to use. Make sure there’s no mold. If you see mold, throw it out. If it smells tangy but not rotten, and still feels smooth (not slimy), it might still have live cultures. Don’t use it if it’s been expired for more than three days—the good bacteria are probably gone by then.

To make yogurt, you’ll need:

1 quart (around 1 liter) of milk—whole milk works best for creaminess
2 tablespoons of the expired yogurt (if it’s still good)
A pot, a thermometer, a whisk, and some clean containers with lids
Make sure everything is clean. Wash your tools well with hot soapy water. Dirty equipment can spoil the batch. You don’t need a yogurt maker—your oven will do just fine.
Here’s what to do:
Heat the milk in the pot over the stove. Stir it until it hits 180°F (82°C). This gets rid of bad bacteria.
Let the milk cool down to 110°F (43°C). This is the right heat for the yogurt cultures to grow.

Mix in the 2 tablespoons of expired yogurt. Whisk until it’s smooth.
Pour everything into your clean containers and seal them.
Warm your oven to 200°F (93°C), then turn it off.
Put the containers inside. Keep the oven door slightly open. Leave them for 6 to 8 hours.
Finally, chill the yogurt in the fridge for at least 4 hours before eating.

How to Extend the Shelf Life of Greek Yogurt?

Refrigerate right after opening. Don’t leave yogurt out longer than 2 hours. If it’s hot outside—above 90°F (32°C)—don’t leave it out more than an hour. When you’re shopping, grab yogurt last. Put it in the fridge as soon as you’re home. If you take it out—say, for a picnic—keep it in a cooler with ice. Put leftovers back in the fridge within an hour.
Always use clean utensils. Use a clean spoon every time—don’t use the same one for other foods. Wipe the rim of the container after use. If you transfer yogurt, make sure the new container is clean and dry. Moisture helps mold grow.
You can also store in smaller portions. Divide a large container into several small ones. Open one at a time—this helps the rest stay fresh. You can freeze yogurt too. It’ll keep up to 2 months. But don’t thaw and refreeze. Thawing lets bacteria spread, and freezing again won’t kill them. Only thaw what you’ll eat, and do it in the fridge. Eat within two days.