How to Prepare Formula Safely for Healthy Term Infants

Preparing infant formula safely is critical for your baby’s health. Not preparing formula safely can lead to serious illness in an infant. Ensure you are sterilizing all equipment every time you prepare formula. Be sure to read the directions on the label.

Download the Infant Formula - What You Need to Know booklet for more information and check Health Canada’s Recalls and Alerts for formula recalls. 

Use safe water

Use safe water to prepare formula and have your well water tested first.

How to sterilize equipment

Follow these step-by-step instructions to sterilize equipment.

How to prepare formula

Infant formula comes in three forms: powder, liquid concentrate and ready-to-feed. Instructions are different for each kind of infant formula. Be sure to read the directions on the label.

Check the packages of infant formula

  • Check the expiry date on each package. Do not use after this expiry date.
  • Make sure the packages are clean and have no dents.

Tips for preparing infant formula

  • Use glass bottles if possible.
  • Wash your hands with soap and water.
  • Wash the top of the cans.
  • Make sure the countertop is clean and dry, and all of your equipment has been sterilized.
  • Read the directions on the label and measure carefully. It could harm your baby if you add too little or too much water.
  • Use a glass measuring cup for accuracy and safety.
  • Mix the formula as it is needed.

Tips for mixing infant formula

  • Run cold water for at least 2 minutes. Use an approved filter to remove lead if you have lead pipes.
  • To prepare powdered and liquid concentrate infant formula always use boiled water.
  • You can use an electric kettle to boil water.
  • Use water within 30 minutes after boiling to prepare infant formula.
  • Do not use carbonated, distilled or mineral water to mix infant formula.
  • If you use bottled water, it still must be boiled first.


  • Cover open can of powdered infant formula with a plastic lid. Store in a cool, dry place. Use within 1 month.
  • Tightly cover open cans of ready-to-feed or liquid concentrate and put in the refrigerator. Use it within 48 hours after opening.
  • Do not freeze any kind of infant formula. Freezing changes the fat in infant formula.

How to warm infant formula

  • Put the bottle of infant formula in warm water for up to 15 minutes, or hold it under warm running tap water.
  • Shake bottle to heat evenly.
  • Check the temperature by putting a few drops on your wrist.
  • Do not heat bottles in the microwave or on the stove.

Watch for early feeding cues

Your baby:

  • Starts to wake up
  • Makes rapid eye movement under the eyelids
  • Licks/sucks/moves her mouth
  • Turns her head while opening her mouth (rooting)
  • Makes smacking and grunting sounds
  • Brings hands to mouth and fists become tight
  • Cries (the last sign of hunger)

Do not put your baby to bed with a bottle.

Changing infant formula

  • Talk to your baby’s health care provider first.

Signs your baby is finished or full

  • Your baby looks sleepy and calm.
  • Your baby lets go of the nipple.
  • Your baby closes his mouth.
  • Your baby turns away from the bottle.
  • Your baby does not look for more milk.
  • Your baby may still have small sucking movements. This is a reflex and does not mean your baby is hungry.
  • If you see signs your baby is full, stop feeding. Throw away what your baby does not drink within one hour.

Going away from home

  • Prepare infant formula, cool and place in refrigerator.
  • Transport in cooler bag with ice packs.
  • Use infant formula within 2 hours or place in refrigerator.
  • If you are unsure about the safety of the water where you will be visiting, ask your healthcare provider.

Adapted from Toronto Public Health.