Instructions for Safe Formula Preparation in 5 Steps

Infant formula provides complete nutrition for babies who are not breastfed, or who receive supplementation in addition to breastmilk. There are various forms of formula available, such as powder formula, liquid concentrate, and ready-to-feed formulas. Each type may require specific preparation steps and proper storage to remain safe for consumption. This guide summarizes the steps provided by the World Health Organization (WHO), Center for Disease Control (CDC), and American Academy of Pediatrics (AAP) for preparing formulas safely at home.  

Instructions for Safe Formula Preparation in 5 Steps

Step 1: Wash Your Hands and Clean Surfaces

• Wash hands thoroughly with soap and warm water for at least 20 seconds.

• Clean and disinfect the surface where you’ll prepare the formula.

• Make sure bottles, nipples, caps, and utensils are washed in hot, soapy water with dedicated brushes and sterilized (by boiling in water for 5 minutes or using a steam sterilizer).

Evidence: WHO and AAP both emphasize hand and equipment hygiene as the most effective step in preventing contamination.

Step 2: Ensure A Safe Water Source

• Use bottled water or fresh, cold filtered water or tap water (if safe in your area).

• Your pediatrician may recommend you to boil the water and allow it to cool, to at least 70°C/158°F before adding powder

Why 70°C/158°F.? At 70°C, bacteria like Cronobacter sakazakii and Salmonella are effectively killed, but nutrients in formula are not significantly degraded.

• The CDC and AAP discuss considering using additional precautions when providing powdered baby formula to infants who are at higher risk for infection, born prematurely, and/or who are younger than 2 months old.

• Do not use a microwave to heat water — it heats unevenly and can cause hot spots.

Step 3: Measure Formula Precisely

• Always follow the manufacturer’s instructions on the formula container.

• Add the correct number of level scoops of powdered formula to the measured water.

• If using a concentrate formula, add the correct amount of water as seen on the label. 

Tip: Use the scoop that comes with the formula and do not pack it tightly.

Step 4: Mix and Cool the Formula

• Gently swirl or shake the bottle until the powder is completely dissolved. Do not stir.

• If needed, cool the bottle quickly by placing it in a bowl of cold water or running cool tap water over it.

• Check the temperature before feeding — it should feel lukewarm, not hot, on your wrist.

Step 5: Feed and Store Safely

• Use the formula within 2 hours of preparation.

• If not used immediately, store it in the refrigerator at 4°C (39°F) or lower and use it within 24 hours.

• Discard any formula left in the bottle after a feeding — bacteria from the baby’s mouth can multiply quickly.

Evidence: Studies show that bacterial growth in formula can double every 30 minutes at room temperature, especially in warm environments.

In rare cases, bacteria in formula powder or contaminated bottles can cause serious illness in infants. Keep up-to-date on any recalls of the formula you are using and keep your pediatrician updated on how you are feeding your baby.

Using Liquid Formula

Ready-to-Feed

If safe water is a concern, consider ready-to-feed liquid formula, which is sterile and requires no boiling or mixing. Once opened, refrigerate unused portions immediately and use within 48 hours. Do not add extra water or powder to ready-to-feed formula.

Note: Ready-to-feed options are strongly recommended for premature infants or babies under 2 months, who are more vulnerable to infections.

Liquid Concentrate

Liquid concentrate is an infant formula that comes in a can or bottle and must be mixed with an equal amount of water before feeding. This offers you convenience with less preparation error than powder, but at a slightly higher cost. Unopened liquid concentrate formula can be stored at room temperature, but once opened it should be tightly covered, refrigerated, and used within 48 hours.

Common Mistakes to Avoid

1. Storing prepared formula at room temperature for more than 2 hours.

2. Reusing leftover formula.

3. Adding extra water to formula (can cause electrolyte imbalance).

4. Using formula past its expiration date.

5. Formula doesn't have to be warm when fed. If you prefer warm, best way is to place it in a hot water bath. Never microwave formula.

Special Considerations

During Emergencies: If clean water and sterilization are unavailable, use ready-to-feed formula only.

Travel: Prepare bottles as needed using boiled bottled water; keep prepared formula on ice and use within 24 hours.

Premature or Immunocompromised Infants: Should always receive formula prepared with boiled water cooled to 70°C or sterile ready-to-feed formula.

Disclaimer: The information on Mone does not replace professional medical assessment, diagnosis, treatment, or advice. Please seek medical advice from your physician or other qualified health care providers.