Can you eat yogurt that has been frozen?
In this article, I will answer the question: “Can you eat yogurt that has been frozen?” and explain the effects of freezing on yogurt, as well as the best ways to defrost yogurt so that it is safe to eat.
Can you eat yogurt that has been frozen?
Yes, you can eat yogurt that has been frozen.
If you have yogurt that you won’t consume in the next few weeks, freezing can be an excellent way to keep it fresh.
The amount of probiotic bacteria in the frozen yogurt significantly decreases. A study showed that probiotic bacteria of the Bifidobacterium spp decreased more than 70% during a period of 60 days of storage at -18°C (freezer temperature). However, the quantity of these bacteria that survive is still high (> 108 CFU/ mL) and sufficient to provide the health benefits related to its consumption (1).
Similarly, the amount in starter bacterial cultures (Lactobacillus bulgaricus and Streptococcus thermophilus) also suffer a decrease during frozen storage (2).
If you find that your yogurt has good organoleptic properties after thawing, you can eat it. Otherwise, you can use it in smoothies or bakery recipes.
You may extend the life of yogurt by freezing it for 1–2 months. Yogurt can be frozen for up to two months, whether it’s full-fat or nonfat, strained (like Greek yogurt), plain or swirled with fruit. It’s technically acceptable to consume after 2 months of freezing, but when it comes to quality parameters (taste and texture), freezing may cause them to deteriorate.
What are the effects of freezing on yogurt?
When freezing yogurt, there are a few things to keep in mind, including the active bacteria concentration and texture:
- The active bacteria concentration:
Yogurt contains nutrients such as lactic acid bacteria (Lactobacillus bulgaricus and Streptococcus thermophilus), which play a significant role in the body’s digestion and absorption.
Some yogurt manufacturers supplement these live and active cultures with strains like Lactobacillus acidophilus and Bifidobacteria which have been reported to provide excellent therapeutic benefits. These beneficial effects include improvement of lactose digestibility, anticarcinogenic activity, reduction of serum cholesterol level, synthesis of B vitamins, and facilitation in calcium absorption. Moreover, numerous studies with different strains of Lactobacillus and Bifidobacterium have been performed in vitro and in vivo, in humans and animal models to investigate their immunomodulatory properties and probiotic potential to treat various infectious, allergic, and inflammatory conditions (1).
These health-promoting bacteria are thermophilic (or heat-loving), with an optimum growth temperature of 50°C or more, and a minimum of about 20°C. While they will perish at higher temperatures, they will last at least a few weeks in your freezer. As mentioned before, their concentration in the yogurt will be reduced during storage (1).
Frozen yogurt produced with two typical bacteria strains — L. bulgaricus and S. thermophilus — was the subject of a previous study conducted by the American Dairy Science Association. Researchers discovered substantial reduction in the amount of germs present in the yogurt after a 8 week freezing period. The initial decrease after two weeks of storage was near one log count for all organisms. This decrease probably was due mostly to the temperature shock caused by the freezing process itself, as well as the residual oxygen from the air incorporated during freezing (overrun). After the initial decrease, however, all culture populations remained relatively stable for eight weeks of frozen storage although steady decreases occurred (3).
The live bacteria are thought to be latent during the freezing process, according to the researchers.
- The texture:
When frozen yogurt is thawed, it may separate, becoming lumpy and runny.
As you defrost your yogurt, you may notice tiered layers. This is due to the fact that freezing yogurt causes the protein networks to collapse. When the process is completed, water is released, which separates from the milk solids when frozen.
Freezing processes can affect the structure of milk constituents. The main alteration occurs due to fat globule damage with a consequent release of the membrane’s lipoproteins and fat stability reduction. This leads to: (i) an increase in particle size, causing coalescence and natural cream separation, (ii) an increase in the lipid oxidation rate, and (iii) the lipolysis occurrence. Freezing can also induce micellar protein destabilization, leading to casein aggregation with consequent water holding capacity reduction due to broken hydrogen bonds between polypeptides (4). For this reason, the frozen/ thawed yogurt has low sensorial scores for texture (3).
You can safely eat yogurt after freezing. But if you’re concerned about texture, use it in delicious yogurt recipes like a chilled yogurt smoothie or fruited yogurt shakes.
In conclusion, freezing yogurt has no effect on the bacteria’s survival. However, it is possible that the yogurt’s texture will deteriorate as a result. Hopefully, there are other options for using it in smoothies or for baking.
How to freeze yogurt?
Here are some tips to properly freeze your yogurt:
- It’s better to freeze yogurt in an unopened and sealed container, but you can freeze it even if it’s been opened. If it has been opened, keep it in an airtight container. Always use a marker to write the date of freeze or an expiration date on the container, considering a maximum two-month freeze.
- If you want to make sure that your fruit-flavored yogurt freezes uniformly, stir it thoroughly before freezing it. After that, the yogurt must then be transferred to an airtight container.
- If you want to use yogurt in smoothies or baking, freeze it in pre-portioned amounts. Fill one or two ice cube trays halfway with yogurt and freeze until firm. To keep the frozen cubes fresh, place them in a plastic zip-top bag or an airtight container, date it, and return it to the freezer. Within a maximum two-month expiration time, you can use the cubes whenever you want.
- If you want to eat yogurt straight from the container after freezing it, keep in mind that yogurts containing stabilizers freeze the best. Ingredients that prevent yogurt from separating during the freezing process include pectin, xanthan gum, and gelatin. If your yogurt does not contain these stabilizers, thoroughly stir it with a clean spoon. This inhibits the separation of the milk solids and the water.
How to thaw frozen yogurt?
To defrost the yogurt, simply thaw the container slowly in the refrigerator until it defrosts, which should take at least 24 hours depending on the size of the container.
If the yogurt’s consistency is a little watery or grainy after thawing, that’s okay; a vigorous stir should return it to a smoother texture.
If the texture is still an issue, use it in baking or smoothies, where the texture change will be undetected.
Always double-check the expiration date. Yogurt that has been frozen before its expiration date can still be consumed if eaten as soon as it has thawed.
Last but not least, always apply your common sense. Regardless of whether it has passed its expiration date, any yogurt that smells bad or has visible symptoms of microbial development, such as black mold or a slimy coating, should be discarded.
In this article, I answered the question: “Can you eat yogurt that has been frozen?”and I discussed the effects of freezing on yogurt quality as well as the safest ways for thawing yogurt.
Please do not hesitate to contact me if you require any extra information on this topic.
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Abdelazez, Amro, et al. Production of a functional frozen yogurt fortified with Bifidobacterium spp. BioMed res int, 201.
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Ordonez, A., I. J. Jeon, and H. A. Roberts. Manufacture Of Frozen Yogurt With Ultrafiltered Milk And Probiotic Lactic Acid Bacteria. J Food Process Preserv, 2000, 24, 163-176.
Tribst, Alline Artigiani Lima, et al. Using stirring and homogenization to improve the fermentation profile and physicochemical characteristics of set yogurt from fresh, refrigerated and frozen/thawed sheep milk. LWT, 2020, 130, 109557.
Chandan, Ramesh C. Dairy: yogurt. Food processing: Principles and applications, 2004, 297-318.