What should I know about preparing and storing baby formula?

Special care is needed when you prepare and store baby formula. If the formula is not prepared or stored in the right way, a baby has more chance of being exposed to bacteria and getting sick. You can reduce the risk of illness in a baby by making sure that all equipment used to make and store formula is clean and sterilized. This information is for normal, healthy newborns.

Please refer to a dietitian for formula preparation guidelines for infants in the NICU.


Before you prepare any baby formula, make sure your hands are clean and the equipment is clean and sterilized (see below). Use the following steps:

  1. Wash your hands thoroughly with warm water and soap. Dry your hands with a single-use paper towel or a clean cloth.
  2. Clean and disinfect the surface that you will be using to prepare the formula.
  3. Clean all feeding and preparation items inside and out with hot, soapy water. This includes the bottle parts.
  4. Clean the bottle nipples with clean bottle brushes.
  5. Rinse the equipment in safe water.


  1. Place the recently cleaned equipment into a pot of water, making sure all equipment is covered.
  2. Be sure there are no air bubbles trapped in the equipment.
  3. Put a lid on the pan and bring the water to a rolling boil, then turn off the burner.
  4. If you plan to store the cleaned feeding equipment, air dry completely or dry with a clean paper towel, then store bottles covered and with the nipple attached.


Baby formula comes in three types: ready-to-use, liquid concentrate, and powdered. Take special care in using powdered formula as it is NOT sterile.

Before you prepare any formula, make sure that the product is within the “Use By” or expiration date printed on the container. When choosing a container of formula, make sure that it is not dented or damaged in any way. The formula might not be safe if the container is damaged.

Tap water, well water and bottled water are NOT sterile and must be boiled before use.


  1. Fill a large pot with water.
  2. Bring water to a boil and boil for one minute.
  3. Cool boiled water, but water should still be hot when mixing in standard powdered formula, in order to kill bacteria. Bacteria can grow at lower temperatures.

The use of specialized formulas in the NICU will require individual instruction by the NICU staff.


For powdered formula:

REMEMBER: Powdered formula is NOT sterile.

  1. Wipe off the container.
  2. Decide how much formula you want to make, and follow the package instructions.
  3. Fill a clean bottle with the right amount of sterilized water. NOTE: If using plastic bottles, use hard plastic bottles that are BPA‐free. BPA (bisphenol‐a) has been found to cause harmful side effects in infants and children.
  4. Make sure that the scoop that came with the formula is clean and dry. Use only the scoop included in the formula can to measure the formula, unless told differently by your doctor or dietitian.
  5. Fill the scoop, making sure the amount is level. Pour the scoop of formula into the bottle. REMEMBER: Add the powder on top of the water.
  6. Attach the cap and nipple to the bottle and shake well.

NOTE: See Feeding Tips below to assure that the formula is safe to feed the baby.

For liquid-concentrate formula:

  1. Wipe off the container.
  2. Shake the container well and open.
  3. Fill a clean bottle with the right amount of sterilized water and formula for one serving.
  4. Attach the cap and nipple to the bottle and shake well.

To prepare ready-to-use formula:

  1. Wipe off the container.
  2. Shake the container well and open.
  3. Pour enough formula for one feeding into a clean bottle; do not add anything to the formula.
  4. Attach the cap and nipple to the bottle and shake well.


If warming formula is necessary prior to feeding, hold the bottle under warm running water or place the bottle in a bowl of warm water (not boiling) and swirl around for approximately 5-10 minutes before feeding.

REMEMBER: NEVER use a microwave to warm baby formula as the temperature can be uneven and the formula too hot.

Before feeding baby, make sure that the prepared formula is room temperature, not hot. Test the temperature by placing a few drops of formula on your inner wrist. If needed, you can cool the formula to feeding temperature by placing it in a container of cold water or holding it under a tap that is running cool water.

After baby starts feeding from the bottle, throw away any remaining formula that has not been consumed within one hour.


Making fresh formula for each feeding is best, but sometimes formula must be prepared in advance. Formula should be made in a clean, sterilized container or jar with a lid. The container should be no larger than one liter/quart. In the refrigerator, formula prepared from powder can last up to 24 hours. Ready-to-use formula or concentrated liquid prepared formula can last in the refrigerator for up to 48 hours. Label the formula with the time and date to ensure its quality.

If formula is not being fed within one hour after it is prepared, it should be stored in a refrigerator at temperatures lower than 40 degrees Fahrenheit. Bacteria can form at higher temperatures.

Last reviewed by a Cleveland Clinic medical professional on 03/24/2017.


  • World Health Organization. Booklet—“Safe preparation, storage and handling of powdered infant formula: guidelines.”
  • Foundation for a Breastfeeding Culture. Handout—“Formula Preparation: Protect Your Baby From Bacteria.”
  • AAP News. Handout—“Are you preparing your baby’s bottles correctly?”
  • U.S. Food and Drug Administration. Consumer Updates Accessed 3/24/2017.
  • NHS. Making up infant formula Accessed 3/24/2017.
  • American Academy of Pediatrics. Pediatric Nutrition, 7th Edition. 2013. Pg. 68.

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