Will probiotics survive freezing? A nutritional guide to preserving gut health

October 17, 2025 •

5 min read

According to research on probiotic-rich foods, while many probiotic strains can survive freezing by entering a dormant state, their viability may be significantly compromised, with counts decreasing by as much as 50% or more over several months. This makes the question 'Will probiotics survive freezing?' far more nuanced than a simple yes or no, depending heavily on the probiotic source and storage conditions.

Quick Summary

Probiotic viability is often reduced by freezing, but survival rates vary widely depending on the product, strain, and storage duration. Freezing is generally not recommended for probiotic supplements due to potential capsule damage and unnecessary storage issues. Fermented foods like yogurt or kefir can be frozen, but expect some loss of beneficial bacteria over time and a potential change in texture.

Key Points

Viability decreases over time: Freezing can reduce the number of live probiotic bacteria, with studies showing a potential loss of 15-50% in products like kefir after two months.
Ice crystals cause damage: The formation of sharp ice crystals during freezing can physically damage and rupture bacterial cell membranes, leading to a loss of viability.
Avoid freezing supplements: For most encapsulated or powdered probiotic supplements, freezing is unnecessary and not recommended, as it can damage the capsule and compromise potency.
Foods can be frozen with caution: While yogurt and kefir can be frozen, anticipate a change in texture and a reduction in the number of live cultures upon thawing.
Manufacturers use controlled methods: Shelf-stable probiotics are made using advanced techniques like freeze-drying (lyophilization) under controlled conditions, not by consumer-level freezing.
Follow storage instructions: The best practice is to adhere to the storage instructions on the product label, whether it calls for refrigeration or a cool, dry place.
Storage duration is key: The longer a probiotic is frozen, the greater the potential loss of viable bacteria, making short-term freezing preferable if necessary.

For anyone seeking to maximize the health benefits of their nutrition diet, the vitality of live probiotics is paramount. The efficacy of probiotics, whether from supplements or food, depends on a sufficient number of these living microorganisms reaching the gut. When considering freezing as a storage method, it's crucial to understand how this process impacts probiotic survival and activity. While freezing does not instantaneously kill all bacteria, it poses several significant risks that can compromise the potency of your probiotics over time.

The mechanisms behind freezing damage

Probiotic bacteria are sensitive, living organisms vulnerable to environmental stressors like temperature and moisture. The damage caused by freezing is multifaceted and can be attributed to several factors:

Ice crystal formation

As water freezes, it expands to form sharp ice crystals. In food products like yogurt or kefir, these crystals can form both inside and outside the bacterial cells. This mechanical damage can puncture and disrupt cell membranes, leading to cell death. The size and formation rate of these crystals, which are influenced by the cooling speed, are critical to the extent of the damage. Slow freezing tends to form larger crystals, which are more destructive, while rapid freezing can form smaller crystals that cause less damage.

Osmotic shock

During freezing, water is drawn out of the bacterial cells to form extracellular ice crystals. This process concentrates the solutes (salts and other compounds) outside the cells, creating an extreme osmotic pressure difference that can damage the cell membranes. Upon thawing, the sudden rehydration can cause a reverse osmotic shock, which further stresses and kills the delicate microorganisms.

Freezing different probiotic sources

The impact of freezing varies significantly depending on whether you are storing probiotic supplements or food products.

Probiotic supplements

For supplements sold in capsules or powder form, freezing is generally not recommended. Quality probiotic supplements from reputable manufacturers are already formulated to have a long shelf life, often lasting a year or more when stored properly at room temperature.

Unnecessary: These products have been commercially freeze-dried (lyophilized) during manufacturing to make them shelf-stable and dormant. Freezing them again is an unnecessary step for consumers.
Risk of damage: The freezing and thawing cycles can compromise the integrity of the capsule shell, exposing the delicate freeze-dried bacteria to moisture and rendering them less effective.
Manufacturers' instructions: Always follow the storage instructions on the label, which will specify if refrigeration is required for certain strains but almost never recommend freezing.

Fermented foods

Freezing fermented dairy products like yogurt and kefir is possible for short-term storage, but expect a reduction in probiotic count and a change in texture.

Yogurt and Kefir: After being frozen for a couple of months, studies suggest a potential loss of 15% to 50% of the live cultures. The longer the product is frozen, the greater the decrease in the probiotic population. This is exacerbated by added ingredients like fruit, which can increase moisture and ice crystal formation. The texture of thawed yogurt and kefir often becomes grainy or thinner due to the collapse of the protein network.
Kefir grains: If you need to take a break from fermenting, kefir grains can be frozen for several months, with some users reporting success reactivating them after an extended period. However, viability is not guaranteed, and dehydrating the grains is a more reliable long-term storage method.
Kombucha: Freezing kombucha is not advisable. The live cultures and yeasts will be compromised, and the carbonation will be lost. The kombucha might even explode if frozen in a sealed glass bottle due to the liquid expansion.

Comparison: freezing probiotic supplements vs. foods


Feature	Probiotic Supplements (Capsules/Powder)	Probiotic Foods (Yogurt/Kefir)
Freezing Recommended?	No, generally not advised by manufacturers.	Yes, possible for short-term storage.
Effect on Viability	Unnecessary and may harm potency by damaging capsule.	Viability reduced over time (e.g., up to 50% loss after 2 months).
Effect on Texture/Form	Potential damage to capsule integrity, exposing contents to moisture.	Texture can become grainy or watery upon thawing.
Shelf-Life	Long, stable shelf-life (1-2 years) if stored correctly at room temp.	Significantly reduced shelf-life; best to consume thawed products soon.
Storage Conditions	Cool, dry place (unless refrigeration is specified on the label).	Best stored in the freezer for a few weeks to a couple of months.

Proper storage alternatives for maintaining probiotic potency

To ensure you are getting the most out of your probiotic investment, consider these proper storage and preservation methods:

Follow manufacturer instructions: The best guide for storing any probiotic product is the label itself. This will tell you if it's a shelf-stable supplement or requires refrigeration.
Refrigeration for dairy and select supplements: For probiotic yogurt, kefir, and refrigerated supplements, maintaining cold temperatures (e.g., 2°C to 8°C) is essential to preserve the live and active cultures.
Freeze-drying for long-term preservation: For homemade kefir grains, dehydrating them is a safer, more reliable method for long-term storage. For commercial supplements, this process has already been expertly done by the manufacturer.
Protection from moisture, heat, and light: Regardless of the storage temperature, keep probiotics away from sunlight and high humidity, which can prematurely activate or damage the dormant bacteria. This is why keeping them in the original bottle with its desiccant packet is important.
Microencapsulation: Some modern supplements use advanced techniques like microencapsulation, where probiotics are enclosed in a protective matrix to withstand environmental stress, including mild thermal changes and stomach acid. This technology allows for greater viability outside of refrigerated conditions.

Conclusion

While probiotics can survive freezing to some extent, it's not the ideal storage method for maximizing their potency. The viability loss caused by ice crystal formation and osmotic shock means you could be consuming a less potent product, especially with prolonged freezing. For supplements, freezing is unnecessary and potentially harmful to the delivery mechanism. For fermented foods like yogurt and kefir, a mild reduction in potency is expected, alongside changes in texture. By following the manufacturer's storage instructions and exploring alternative preservation methods like refrigeration or dehydration for homemade cultures, you can better preserve the live cultures and ensure your nutritional diet continues to benefit your gut health. A well-stored probiotic is a potent probiotic, ready to support your well-being. More information on probiotic research and stability can be found through scientific review sites, such as the one at ScienceDirect.

Frequently Asked Questions

No, it is generally not recommended to freeze probiotic supplements. Manufacturers typically use controlled freeze-drying processes to make them shelf-stable, and home freezing and thawing can damage the capsules and harm the bacteria.

No, freezing does not kill all probiotics, but it will reduce the number of viable bacteria over time. Studies show that probiotic counts can decrease significantly after a few months in the freezer, and the yogurt's texture will likely become grainy.

The duration of probiotic survival in the freezer depends on the product and strain. For fermented foods like kefir, a noticeable drop in viable cultures occurs after a couple of months. The longer the storage time, the more the probiotic population declines.

The best way to thaw frozen kefir or yogurt is slowly in the refrigerator overnight. Avoid rapid thawing methods like boiling water or the microwave, as extreme temperature changes can harm the remaining beneficial bacteria.

For long-term storage of kefir grains, dehydrating them is a more reliable method than freezing. Frozen grains can be revived, but success is not guaranteed.

Some probiotic capsules do not require refrigeration because the manufacturing process involves freeze-drying (lyophilization), which puts the bacteria into a dormant state. They are also often packaged with protective agents or in moisture-resistant containers to maintain their viability at room temperature.

While you can freeze fermented vegetables, the freezing process and resulting changes in texture upon thawing can damage the live cultures and make the food less appealing. It's generally best to consume them fresh for maximum probiotic benefit.