Your doctor will tell you which formula is best for your baby. Carefully follow the directions on the label for mixing and storing formula safely.

Keep your baby safe from germs:

• Always wash your hands before mixing formula. Use warm, soapy water and wash for at least 15 seconds. Dry with a clean towel. If soap and water are not available, you can use a hand sanitizer with at least 60% alcohol.
• Clean all work surfaces before preparing formula.
• Sterilize all bottles, rings, and nipples before using them for the first time. To sterilize: 
  • Place them in a pot of boiling water and boil for 5 minutes.
  • Use a bottle sterilizer or sterilizer bag made for the microwave and follow the instructions on the package.
• Wash bottles, rings, nipples, and the formula scoop after each use. Wash in the dishwasher or by hand in hot, soapy water. Rinse with clear water and let air dry.

How to store unmixed formula:

• Keep the formula container at room temperature in a dry area. Cover the can with the cap that came with it.
• Throw away unused formula 1 month after opening the can, or if today's date is later than the "use by" date on the can.

Preparing water for formula:

Tap water from the city or county is usually OK to use. But check with your doctor or local or state health department to be sure.

• Tap water from a well should be tested to make sure it is safe for your baby.
• If there is a concern that your water may not be clean, you can use bottled water labeled "sterile" and "for infants."

Special instructions for babies with a higher risk of infection:

Some babies have a harder time fighting germs, such as those who are younger than 3 months old; were born prematurely (early); or have a weak immune system.

For these babies:

• Doctors may recommend sanitizing bottles daily.
• Parents can consider boiling the tap or bottled water for a minute and then letting it cool for about 5 minutes (and no more than 30 minutes) before mixing it with the dry formula.

How to mix formula:

• Read the instructions on the formula package. Measure formula exactly as it says on the formula package unless the doctor or dietitian recommends mixing a different way. 
• It is best to make formula fresh for each feeding. But if needed, it is OK to mix enough formula to feed your baby for 24 hours. Throw away any unused formula after 24 hours. 
• Use water that is at room temperature.
• Measure the water first and pour it into the baby bottle as directed on the package.
• Use the scoop that came in the formula package to measure the powder as instructed on the package. Add the powder to the water in the bottle.
• Cap the bottle and shake well.

To feed your baby:

• Depending on what your baby likes, it's OK to feed your baby formula right out of the refrigerator, at room temperature, or a little warm.
• To warm formula:
  • Stand the bottle with the cap on in a bowl of warm water for up to 5 minutes. Make sure that the nipple does not touch the water.
  or
  • Use a baby bottle warmer.
• Do not microwave the formula because it can make hot areas in the formula that can burn your baby.
• Before feeding your baby, shake the bottle and then check the temperature:
  • Splash some formula on the inside of your wrist. It should feel comfortably warm or cool. If it feels hot or burns, hold the bottle under cold running tap water or set it in a bowl of cold or iced water until cooled. Then test the temperature again.
  or
  • Use a clean thermometer. The temperature should be 98ºF (36.7ºC) or lower.
• Do not keep leftovers from a feeding. Germs can grow in the leftover formula. Throw away any formula left in the bottle after 2 hours from the time you started to feed your baby.

How to store prepared formula:

• Prepare the number of bottles you need.
• If you mixed the formula with cool water, put it right in the refrigerator. If you mixed the formula with hot water, hold the bottle under cold running tap water or set it in a bowl of cold or iced water until cooled. Then put it in the refrigerator.
• Throw away any prepared formula not used within 24 hours.
• Do not put formula in the freezer.

How to transport prepared formula:

• Make sure the bottle has been refrigerated and is cold before transporting.
• Take the bottle out of the refrigerator right before you are ready to leave home. Put it in an insulated bag or cooler with ice packs.
• If the cooler bag does not maintain a temperature between 35º–40ºF (1.6º–4.5ºC), feed the formula to your baby or put it in a refrigerator within 2 hours. Throw it away if it is not properly chilled and has been out of the refrigerator for more than 2 hours.

You have any questions about mixing formula, or if your baby:

• is older than 5 days and doesn't have at least 5 wet diapers in 24 hours
• is having trouble pooping, has hard poops, or has diarrhea
• is vomiting
• gets a rash