Yogurt is a dairy product made by fermenting milk with live bacteria cultures. It has become a popular breakfast and snack food due to its creamy texture, tangy flavor, and health benefits. However, since yogurt contains perishable dairy and live cultures, it also has the potential to spoil if not stored properly. Here are some tips to help you identify if your yogurt has gone bad.
Examine the Expiration Date
The first and easiest way to tell if yogurt is still good is to check the expiration date printed on the container. This will give you an idea of how long the yogurt should last when unopened and stored at proper temperatures. Yogurt expiration dates are usually 3-4 weeks from when it was manufactured.
If your yogurt is past the printed expiration date, it’s best to throw it out. Even if it looks and smells okay, the live cultures may no longer be active or the nutrients can degrade over time. Going by the expiration date ensures you get the probiotic benefits of fresh yogurt.
Check the Consistency
The texture of yogurt is another indicator of freshness. Unexpired yogurt should have a smooth, creamy consistency without any liquid separating on top. As yogurt starts to spoil, it begins to lose thickness and becomes more watery or slimy.
Stir the yogurt and check the body – if it seems excessively runny or thin for the type of yogurt it is, that’s a red flag it may be going bad. Non-fat yogurts in particular get very loose as they age past their prime.
Look For Mold
Mold is a definite sign your yogurt has spoiled and should be discarded immediately. This fuzzy growth can start to develop either on the surface or bottom of the yogurt if it’s been contaminated. Always inspect all sides of the yogurt carefully before eating it.
Even if you can’t see mold, it can send root threads throughout the yogurt that are invisible. Consuming moldy yogurt can cause food poisoning or allergic reactions. Don’t rely on just scraping off the moldy parts – any yogurt that has been exposed to it should be thrown away.
Check For Sour Odors
Your nose can also detect signs of spoiled yogurt. Give the yogurt a good sniff when you open it. Fresh yogurt has a pleasant, mild tangy smell. If you notice a rancid, sour or yeasty odor instead, that indicates the natural bacteria have over-fermented. This gives spoiled yogurt a characteristic pungent smell.
Trust your senses – if it smells funky or off, don’t chance eating it. A drastic change in smell is a clear warning the yogurt has started to turn. Some describe the sour smell as similar to alcohol or vinegar when yogurt has gone bad.
Observe Package Inflation
Check the packaging as well – if the yogurt container lid appears puffed up or inflated, this signals gas production by the yogurt cultures that can spoil it. The lid should lie flat. Bulging or swollen packaging means air or gas has built up inside, pushing the lid upward.
While not always a definite sign of spoilage, this inflation may occur as the active cultures rapidly multiply during fermentation. It’s generally a good idea to throw out bloated yogurt containers to be safe.
Watch Out For Color Changes
The natural color of yogurt can also provide cues if it has gone bad. The white or cream-colored yogurt should not appear discolored or darkened. A yellow, brownish or grayish tinge means the yogurt is oxidizing and becoming old.
Additionally, watery liquid or whey on the surface can make yogurt look curdled. Any odd colors in your yogurt is cause for concern – these changes indicate microbial contamination or chemical reactions breaking it down.
Consider How Long It’s Been Open
The above signs work best for unopened yogurt. Once you open a yogurt container, it introduces additional factors that accelerate spoilage. Exposure to air, light and higher temperatures after opening speeds up bacterial growth.
As a general rule, consume opened yogurt within 7-10 days. The sooner you can finish it up, the better quality it will be. Mark the use-by date on the lid with a pen for reference. And be extra diligent smelling and inspecting open yogurt for any issues before eating.
Store Yogurt Properly
To get the most shelf life out of your yogurt, be sure to store it correctly. Unopened yogurt lasts about a month in the fridge. The cold temperature of the refrigerator slows bacterial growth. Make sure to keep yogurt towards the back where it’s coldest.
Once opened, yogurt should be moved to the front of the fridge where warmer temperatures prevent condensation from ruining it. Always put lids back on tightly and keep open containers in plastic bags to contain spills.
Proper storage keeps yogurt fresh longer and less prone to spoilage. Check fridge settings are cold enough yet not freezing yogurt solid. Knowing how to spot expired yogurt also reduces food waste and protects your health and safety. With a few quick checks, you can feel confident your yogurt is still perfectly good to enjoy.
