How Long Does Kefir (Fermented Milk) Last in the Fridge?
Written by Jordan Morley · Storage times from the USDA FoodKeeper database · Last updated 28 October 2026
Kefir (Fermented Milk) keeps 1 week while sealed and 1–2 days once opened, in a fridge running at 0–5°C.
Storage tips for kefir (fermented milk)
- Fridge at 0–5°C. A fridge thermometer is the cheapest food-safety upgrade — many home fridges run warmer than their dial suggests.
You can also check the calorie content of kefir (fermented milk) alongside its safety information. Want to know exactly what's in your food? Our ingredient checker covers E-numbers, allergens and vegan status.
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Store it properly
Fridge thermometer
These storage times assume 0–5°C — check what your fridge actually runs at.
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Kefir (Fermented Milk) next to similar foods
| Food | Fridge time |
|---|---|
| Commercial Eggnog | 3–5 days |
| Kefir (Fermented Milk) | 1 week |
| Single Cream (Opened) | 1 week |
| Double Cream (Opened) | 10 days |
| Whipping Cream | 10 days |
Of the 16 dairy foods with a fridge time in this guide, kefir (Fermented Milk) keeps for longer than 3, the same time as 1 and less time than 11.
Common questions
How long does kefir (fermented milk) last in the fridge?
1 week while sealed and unopened, and 1–2 days once opened, in a fridge running at 0–5°C. Count from the day you open it, and use the printed date if it is earlier.
How can I tell if kefir (fermented milk) has gone off?
A sour smell, lumps or curdling, a changed taste or any mould (other than on hard cheese) mean it should go. Do not rely on this alone: the time guideline matters even when everything looks fine.
Can I freeze kefir (fermented milk) to keep it longer?
Freezing is not recommended for this food; the texture tends to suffer badly. Buy or cook only what you will use in time.
Does my fridge temperature really matter?
Yes. These times assume a fridge at 0–5°C, which is what the Food Standards Agency says to set it to. Bacteria grow faster in a warmer fridge, and many fridges run warmer than their dial suggests, so a cheap fridge thermometer is worth having.
Related answers
Primary source: USDA FoodKeeper.
General information only, not medical advice: see the medical disclaimer. Feeling unwell after eating something? Contact NHS 111 or your GP.