How Long Can Formula Sit at Room Temperature?

baby formula

Breast-milk is the best and the only food that babies require for the first 6 months of their lives. However, parents introduce their babies to the formula for a variety of reasons.

Mothers who had a difficult time with breastfeeding often struggle to find good and comprehensive information on the usage and storage of infant formula.

If you plan to feed your baby with infant formula, there are certain important safety and health guidelines you must follow to ensure the best health and safety of your baby. 

One of the most common questions about infant formula is how long can formula sit at room temperature? The Centre for Disease Control and Prevention, suggests the following:

  • Use the prepared infant formula within 2 hours of preparation and within 1 hour from when feeding starts.
  • Throw away any infant formula that is left in the bottle after feeding your baby.
  • If not to be used immediately, store the formula milk bottle in the fridge and use it within 24 hours. 

It is best to prepare the formula as and when you need it, but it isn’t a feasible option on many occasions, especially at night, or while you are traveling or when you have to leave your baby for longer durations with the care-takers.

While it is important to prepare your infant’s formula as per the instructions, it is equally necessary to store the formula safely because the formula-fed babies don’t have the immunity that breast-fed babies have. 

Always check the expiration date on the formula containers. Emphasis on cleaning and sterilization is also necessary at least for the first 4 months of your baby’s life. 

  • Wash your hands thoroughly before preparation.
  • Wash the can and its lid and completely dry it before opening. This step is necessary as dirt and germs on the lid can fall into the can while opening. 
  • Wash your can openers with soapy water.
  • After opening the container, check for the presence of any foreign particle and the consistency of the powder or any curdled or discolored milk in terms of liquids.
  • Sterilize the bottles, nipples, caps, and rings by boiling for at least 5 minutes before using for the first time as well as after every feed.
  • Carefully mix and measure the formula as per the instructions.
  • Pay attention to the water you use. It is advisable to boil water for at least 2 minutes to sterilize it. Never use mineral water to prepare the formula.  

Since babies need to be fed round the clock, it isn’t possible to make fresh formula each time. Here’s our guide to happy and safe formula storage.

How to Store Formula Containers?

  • Powdered Formula: Store unopened formula containers at room temperature. Avoid exposure to heat and sunlight. As a rule of thumb, temperatures between 55 to 75 degrees Fahrenheit are considered good. An opened powdered formula should be stored in a cool and dry place with the lid safely in place. Do not refrigerate the powdered formula, as the humidity might cause clumps. Once opened, use the powdered formula within 1 month and throw away any unused dry powder. (Tip: Place a sticker with the date of opening on the formula can)
  • Liquid Concentrate Formula: Store it in a closed container and refrigerate after opening. Use it within 24 hours of preparation. 
  • Ready-to-feed Formula: Place it in a sealed container and use it within 24 hours.

What Should I do with a Leftover Formula?

You must discard any leftover formula.

The combination of your baby’s saliva and milk can lead to contamination. Reheating the milk or even refrigeration will be ineffective in destroying the bacterial growth.

Hence, any leftover formula or even breast milk must be thrown if not consumed within 1 hour of feeding. 

How to Store Prepared Formula in The Refrigerator?

Prepared formula should be stored in the back of the refrigerator, where it is the coldest. Never store formula in the refrigerator door. Discard formula after 24 hours in the fridge.

Do not freeze the formula, as it causes separation of milk and protein content. (Tip: Check your fridge temperature. The formula should be stored at 4 degrees C or 40 degrees F).

Does Formula Really Go Bad After an Hour?

Yes, room temperature is a favorable condition for bacterial growth and hence, the prepared formula must not be kept at room temperature for more than an hour. As per the CDC (Centre for Disease Control & Prevention), you must throw away any unfinished formula after one hour.

The contamination from your baby’s saliva makes the formula highly susceptible to bacterial growth, these bacteria then multiplies and doubles at every 10 minutes. Thus, even though this short time of 1 hour sounds extremely cautious, but is recommended for the safety of infants.

How to Store Formula While Travelling?

If you are carrying prepared formula bottles, then you must store them in an insulated ice bag and use them within 2 hours. However, if you plan to be away from home for more than 2 hours, the best option is to carry an unopened ready-to-feed formula and use it as and when required.

You can also carry pre-measured powdered formula into a clean, dry container and bring just-boiled water in a thermos. (Tip: Don’t forget to cool down the formula to room temperature before giving it to your baby).

How to Reheat a Bottle of Refrigerated Formula?

If you wish to warm a refrigerated bottle, then you can place it in a bowl of hot (not boiling) water for 10 to 15 minutes. Never use a microwave to heat the bottle, as it heats the milk unevenly and creates hotspots that can burn your baby’s mouth.

To evenly spread the heat, shake the bottle vigorously and test the milk temperature by pouring a few drops on the back of your wrist. Make sure that the bottle ring or nipple don’t get wet from the water, if it does, then discard the formula. Once you start the feeding, use it within an hour. Throw any leftover formula. Do not reheat the formula during a feed. 

This handy chart below has all the answers to your formula storage questions.

Bottles at room temperature If untouched, room temperature formula should be thrown away at a 2-hour mark.
Leftover formula Discard any formula that is left after one hour from when feeding starts.
Reheating the formula The formula should never be reheated.
Storing the formula in the fridge A prepared but untouched bottle of formula can be stored in the back of the fridge for up to 24 hours. Open containers of ready-to-feed and liquid concentrate formulas can be stored up to 24 hours.
Freezer storage The formula should never be frozen.
Storing the formula while traveling Carry prepared formula in an insulated ice bag or carry unopened ready-to-feed formula. You can also carry pre-measured powdered formula in a clean, dry can and just-boiled water in a thermos.

Related Questions

How to store sterilized infant feeding items?

After sterilizing, allow the bottles, nipples, rings, caps, etc to air dry. The best way to store sterilized bottles is to keep them in an airtight container and refrigerate. 

There are different types of infant formulas, how to choose the right one for my baby?

You can take the advice of your pediatrician in case your baby needs any special formula (like a soy-based formula for babies with galactosemia).

There are 3 types of formulas:

  • Powdered Formula
  • Liquid Concentrates
  • Ready-to-feed

Ready-to-feed formulas are sterile unless opened, powdered formulas are not fully sterile. Hence, powdered formulas are not advisable for these babies:

  • Babies born prematurely, i.e. before 37 weeks and are under 2 months of age.
  • Babies who weighed less than 2500 grams at birth and are under 2 months of age.
  • Babies with compromised and weakened immune systems. 

Babies who are healthy and are born at full term can be fed any type of store-bought formula. 

(Tip: Never use the formula from a container that has been damaged with dents or bulges.)

How long should a child drink infant formula?

Infant formula is generally recommended until your child is 1 year old, but it is best to consult your child’s doctor for specific guidance. Whole milk can be given after the child is 1 year old, until age 2.

Skimmed milk is generally not recommended before the age of 2 as it doesn’t have enough calories and fat to promote early brain development.


Hi there, I am Monica mother of one and this is my blog. I share some useful tips about pregnancy and specially parenting. xoxo

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