Does Fortisip need to be kept in the fridge? A Guide to Proper Storage

December 13, 2025 •

4 min read

While unopened Fortisip is shelf-stable due to its Ultra-High Temperature (UHT) sterilization, the manufacturer's instructions clearly state that once the bottle is opened, it must be refrigerated. This key distinction is crucial for anyone wondering, "Does Fortisip need to be kept in the fridge?" and ensures both safety and product quality.

Quick Summary

Unopened Fortisip requires storage in a cool, dry place away from direct sunlight. Once a bottle is opened, it must be sealed and refrigerated, with the contents consumed or discarded within 24 hours to ensure safety and quality.

Key Points

Unopened Bottles: Do not require refrigeration and are safe to store in a cool, dry place, between 5°C and 25°C, until the best-before date.
Refrigeration After Opening: Once opened, the bottle must be sealed and refrigerated immediately to prevent bacterial growth.
Consume Within 24 Hours: Any opened Fortisip must be consumed within a maximum of 24 hours, even if refrigerated.
Avoid Heat and Sunlight: Keep unopened bottles away from direct sunlight and heat sources to prevent nutrient degradation.
Taste Best Chilled: Fortisip is best served cold, which can improve the flavour, though this is a preference and not a storage requirement for unopened product.
Discard if Compromised: If an opened bottle is left out for more than 4 hours or not used within 24 hours, it should be discarded.
UHT Sterilization: The reason unopened Fortisip is shelf-stable is due to the UHT sterilization process it undergoes during production.

Storing Unopened Fortisip: Understanding UHT Sterilization

For bottles that have not yet been opened, the question, "Does Fortisip need to be kept in the fridge?" has a clear answer: no. Fortisip undergoes a sterilization process called Ultra-High Temperature (UHT) treatment during its manufacturing. This process kills harmful microorganisms and, combined with airtight packaging, allows the product to remain fresh and safe for a long period when stored at room temperature.

To ensure the long-term quality of unopened Fortisip, follow these guidelines:

Maintain Temperature: Store bottles in a cool, dry location with a temperature typically between 5°C and 25°C. Avoid areas with extreme heat or cold.
Avoid Sunlight: Direct sunlight can degrade the nutritional content over time. Keep bottles in a cupboard or pantry away from windows.
Respect the 'Best Before' Date: Even with UHT treatment, the product has a finite shelf life. Always check and respect the printed best-before date.

The Mandate for Refrigeration After Opening

The storage protocol changes immediately after the bottle is opened. At this point, the product is no longer sterile and is exposed to airborne bacteria. These microorganisms can multiply rapidly in the nutrient-rich liquid, leading to spoilage and potential illness. To prevent this, refrigeration is essential.

The official instructions for handling an opened bottle are as follows:

Seal Tightly: Immediately after pouring a serving, close the bottle securely with its original lid or a suitable alternative to minimize air exposure.
Refrigerate Promptly: Place the opened bottle in the refrigerator. It should not be left out at room temperature for longer than 4 hours.
Adhere to the 24-Hour Rule: The contents must be consumed within 24 hours of opening, even with continuous refrigeration. After this time, any remaining portion must be discarded to prevent the risk of contamination.

Consequences of Improper Storage

Failing to follow these guidelines, particularly for opened bottles, poses a risk to both health and product quality. The rich mix of protein, carbohydrates, and minerals in Fortisip provides an excellent environment for bacterial growth once exposed. Improper storage can lead to:

Foodborne Illness: Consuming a spoiled product can cause symptoms such as nausea, stomach cramps, and diarrhea.
Nutrient Degradation: Exposure to light and high temperatures can cause heat-sensitive vitamins to degrade, reducing the product's nutritional value.
Changes in Taste and Texture: Spoilage can cause a noticeable change in flavor, smell, and consistency, making the drink unpalatable.

Comparison: Storage for Unopened vs. Opened Fortisip


Feature	Unopened Fortisip	Opened Fortisip
Location	Cool, dry place (pantry, cupboard)	Refrigerator
Temperature	5-25°C	Approx. 4°C
Shelf Life	Until best-before date (typically 9-12 months)	Maximum 24 hours
Microbiological Risk	Low (product is sterile)	High (once exposed to air)
Ideal Serving	Best served chilled (place in fridge before use)	Ready to drink immediately (chilled)

Creative Serving and Temperature Alternatives

While Fortisip is best served chilled for taste, a common recommendation from the manufacturer, it offers versatility beyond just a cold drink. For those who dislike the taste or prefer variety, there are several options:

Heating: Fortisip can be gently warmed on the hob to create a comforting hot drink, especially in winter. It should not be boiled, as this can affect taste and destroy sensitive vitamins.
Freezing: For a summer treat, Fortisip can be frozen into ice lollies or used as an ingredient in a frozen dessert. Freezing does not impact its nutritional content significantly and provides a new texture experience.

Conclusion: The Final Word on Fortisip and Refrigeration

In conclusion, the necessity to refrigerate Fortisip is conditional. While it is stable and safe for storage at room temperature while unopened, refrigeration becomes a non-negotiable food safety requirement the moment the seal is broken. The UHT sterilization provides a robust defense against spoilage in its sealed state, but once that protection is gone, the clock starts ticking. Always refrigerate an opened bottle and use it within 24 hours, and store unopened stock in a cool, dry place to ensure you consume a safe and effective product every time.

For more detailed product information and specific instructions for different Fortisip variants, it is always best to consult the official manufacturer website: Nutricia UK.

Expert Handling and Safety Protocol

Check the Seal: Before opening any bottle, ensure the seal is intact. Do not consume if the seal is broken or compromised.
Taste Test for Freshness: If you are ever unsure about the freshness of an opened bottle stored in the fridge, give it a quick smell and taste test. If it tastes or smells off, discard it immediately.
Personalised Advice: For complex health conditions, always follow the specific usage and storage instructions provided by a healthcare professional. They may have tailored advice for your situation.

Frequently Asked Questions

No, an opened bottle of Fortisip should not be left on the counter. Once the bottle is opened, it must be refrigerated and consumed within 24 hours.

Signs that your Fortisip may have gone bad include an unpleasant smell, a changed consistency, or a strange taste. If you notice any of these, discard the product immediately.

No, it is not safe to drink. High temperatures can cause the nutritional supplement to spoil and potentially make you ill. It's best to discard any product that has been exposed to extreme heat.

Yes, some Fortisip products, like the Neutral flavour, can be added to both sweet and savoury foods. You can also mix it into smoothies or milkshakes to vary the flavour.

For a better taste experience, serve Fortisip chilled. You can also mix it with other ingredients to make smoothies or desserts, or try a different flavour.

Freezing Fortisip does not destroy its nutritional content. In fact, freezing it into ice lollies or desserts can be a great way to consume the product.

Once the protective seal is broken, the product is no longer sterile and can be exposed to bacteria. The 24-hour window, even with refrigeration, is a safety measure to prevent bacterial growth.