How to Prepare Baby Formula Safely

Before you mix

• Wash your hands, and clean the surface you are working on.
• Sterilize bottles, nipples and rings before first use, and clean them thoroughly after every feed.
• Check the expiration date on the tin, and note the date you opened it — most powdered formula should be used within a month of opening.

Mixing

• Follow the tin’s ratio exactly. Never add extra water to stretch a tin — diluted formula can cause dangerous drops in sodium — and never add extra powder to concentrate it, which strains the kidneys and dehydrates.
• Add water to the bottle first, then powder. Reversing the order changes the final volume and therefore the concentration.
• Use the scoop supplied with that tin. Scoops are not interchangeable between brands or even sizes.
• Level each scoop; do not pack it.

Water and temperature

For babies under three months, born prematurely, or with a weakened immune system, guidance is generally to prepare with water at about 70°C (boiled and cooled for no more than thirty minutes) to kill bacteria in the powder, then cool the bottle quickly under running water before feeding.

Check your local guidance and your provider’s advice — recommendations differ by country. Whatever the method, always test the temperature on the inside of your wrist before feeding: it should be lukewarm, not warm.

Storage

• Prepared formula: refrigerate immediately if not used, and use within twenty-four hours.
• At room temperature: use within two hours.
• A started bottle: finish within one hour, then discard.
• Store powder in a cool dry place with the lid sealed — not in the fridge, where moisture causes clumping.
• Never microwave a bottle. Uneven hot spots can scald a baby’s mouth even when the bottle feels cool.