How long is yogurt good for? (+3 ways you can tell)

In this article, we will answer the question “How long is yogurt good for?”, and how to tell if the yogurt is bad?

How long is yogurt good for?

The shelf life of yogurt can vary depending on several factors, including the type of yogurt and how it is stored. In general, unopened yogurt can last for 1-2 weeks in the refrigerator (1).

Once opened, there is no guarantee for how long the yogurt will be safe for consumption, because there are many factors that can influence its safety, such as the cleanliness of the tools used to scoop the yogurt, and the conditions of the refrigerator.

Dairy products including yogurt will spoil much earlier than their best-by if they were mishandled during transport or storage. Therefore, read the sell-by and the best-by dates before buying yogurt. 

Like other refrigerated items, it is best to buy yogurt at the last minute and refrigerate it immediately once you get home.

Do all types of yogurt have the same shelf life?

No, not all types of yogurt have the same shelf life? The composition of the yogurt has a great influence, as for the starter culture used to produce them. For example, yogurt made with L. acidophilus have a longer shelf life than yogurt made with L. casei (2).

The addition of antioxidants, flavors, sugars, and other additives can also affect the storage stability. For example, antioxidants may help avoid deleterious processes prolonging the shelf life, while other substances like sugars may favor the growth of unwanted microorganisms.

Greek yogurt, which is a yogurt with higher percentage of protein than regular yogurt, has a higher concentration of latic acid, a compound that can prevent the growth of bacterial pathogens (3).

How to tell if the yogurt is bad?

Consuming spoiled yogurt can lead to foodborne illness, so it is important to know the signs of spoilage. Some common signs of spoiled yogurt:

1.    If you notice any discoloration or mold growth near the lid and on the surface of the yogurt, discard it immediately.

2.    If the yogurt gives off a sour smell, throw it away. If the yogurt looks apparently fine but tastes too sour, it has started to spoil.

3.    If the smooth texture of the yogurt is lost as it becomes clumpy and the water that separates floats on the top, it is spoiled.  Sometimes the whey in the form of liquid can also sit on top, this is normal, and the yogurt can be consumed after stirring it in, if there aren’t any other signs of spoilage.

What are the factors that affect the shelf life of yogurt?

Several factors can impact the shelf life of yogurt, including:

Microbial growth and activity: If left unchecked, the live bacteria in yogurt can continue to grow and multiply, resulting in the deterioration of the aromas (4).

Milk source and processing: The quality of the milk used to make yogurt, as well as the processing methods employed, can have an impact on the final product’s shelf life. For example, yogurt made from unheated or inadequately heat-treated milk has been linked to having a poor texture (5).

Many commercial yogurts contain additives and preservatives that can extend shelf life and improve flavor and texture, such as potassium sorbate or natural antioxidants (6).

What does the expiration date of the yogurt mean?

Yogurt expiration dates are printed on the packaging to indicate how long the yogurt should be fresh and safe to consume. Expiration dates are classified into two types:

The use by date indicates the last day the yogurt should be consumed for maximum freshness and safety. After this date, the yogurt may begin to spoil and become unsafe to consume.

The best before date is: This date indicates the best date to consume the yogurt for the best quality and flavor, but the yogurt may still be safe to eat after this date.

Other FAQs about Yogurt which you may be interested in.

Can yogurt go bad?

Can you eat expired yogurt?

Yes, you can eat expired yogurt. However, it is not recommended, since there are no guarantees of its quality. The nutritional quality of yogurt might decrease after the expiration date, because some components, like vitamins, and functional ingredients may be oxidized (7).

Yogurt contains live cultures that produce different metabolite compounds over time and that can promote flavor changes. Also, the viability of some important organisms, such as probiotics, tends to decline throughout shelf life (7), lowering the yogurt’s quality.

How to store yogurt?

Yogurt should be refrigerated at all times irrespective of its type. Do not place it in the door of the fridge. Because the temperature fluctuations will make it go bad quickly.

After opening, the yogurt container must be tightly sealed to prevent spoilage.

Use clean spoons to scoop out the yogurt. Do not put the leftover yogurt portion back into the rest of the yogurt.

Before buying, check the best-by date on the label. Keep it away from foods that have a pungent smell because the yogurt will pick up odors easily.

Avoid exposing yogurt to direct sunlight or other sources of heat.

Can you freeze yogurt?

Yogurt can be frozen but the quality won’t be the same. Just like buttermilk, the solids in yogurt will separate from the liquid. If the yogurt is to be used in baking or cooking, depending on the recipe, the altered texture won’t be a problem. Yogurt with a thick consistency like greek-yogurt freezes better than its plain counterparts.

Conclusion

In this article, we answered the question “How long is yogurt good for?”, and how to tell if the yogurt is bad?

References

1.      UDSA. Ask USDA [Internet]. Available from: https://ask.usda.gov/s/article/How-long-can-you-keep-dairy-products-like-yogurt-milk-and-cheese-in-the-refrigerator

2.      Mani-López E, Palou E, López-Malo A. Probiotic viability and storage stability of yogurts and fermented milks prepared with several mixtures of lactic acid bacteria. J Dairy Sci [Internet]. 2014;97(5):2578–90. Available from: https://www.sciencedirect.com/science/article/pii/S0022030214002549

3.      Lange I, Mleko S, Tomczyńska-Mleko M, Polischuk G, Janas P, Ozimek L. Technology and factors influencing Greek-style yogurt – a Review. Ukr Food J. 2020 Mar 1;9:7–35. Available from: 10.24263/2304-974X-2020-9-1-3

4.      Harasawa N, Tateba H, Ishizuka N, Wakayama T, Kishino K, Ono M. Flavor Deterioration in Yogurt BT  – Process-Induced Chemical Changes in Food. In: Shahidi F, Ho C-T, van Chuyen N, editors. Boston, MA: Springer US; 1998. p. 285–96. Available from: https://doi.org/10.1007/978-1-4899-1925-0_24

5.      Soukoulis C, Panagiotidis P, Koureli R, Tzia C. Industrial yogurt manufacture: monitoring of fermentation process and improvement of final product quality. J Dairy Sci. 2007;90 6:2641–54. Available from: https://doi.org/10.3168/jds.2006-802

6.      Caleja C, Barros L, Antonio AL, Carocho M, Oliveira MBPP, Ferreira ICFR. Fortification of yogurts with different antioxidant preservatives: A comparative study between natural and synthetic additives. Food Chem [Internet]. 2016;210:262–8. Available from: https://www.sciencedirect.com/science/article/pii/S0308814616306422

7.      MacBean R. Packaging and the Shelf Life of Yogurt. In: Food packaging and shelf life: A practical guide. 2009. p. 143–56. Available from: 10.1201/9781420078459-c8