Infant formula: 7 steps to prepare it safely

Updated: 2024-12-20

Safe preparation and safe storage of infant formula are important for your baby's health. Follow these steps to make sure your baby's formula is nutritious and safe.

1. Check the expiration date

Look for an expiration or "use by" date on the formula container. You can't be sure of the formula's quality after that date. Don't buy or use expired infant formula.

2. Wash your hands

Before mixing the formula, wash your hands with soap and water. Dry your hands well. Clean the area where you will prepare the formula.

3. Prepare the bottle

Before using new bottles, sanitize them to get rid of as many germs as possible. All parts of the bottles, including the nipples, caps, and rings, need to be sanitized. Also, sanitize the tools you'll use to clean the bottles later, such as bottle brushes.

Sanitize the items as directed by the manufacturer and then let the items air-dry. Don't wipe with a towel. Sanitizing usually includes one of these methods:

• Use a dishwasher. Some dishwashers even have a sanitizing setting. With a dishwasher, you can combine cleaning and sanitizing.
• Boil the bottle and accessories in water for five minutes.
• Use a microwave steam sanitizer bag.
• Use a stand-alone electric steam sanitizer.

If you can't use any of these methods, you can make a bleach solution to get rid of germs. In a clean container, combine 1 gallon of water and 2 teaspoons of bleach. Make sure the bottle parts and other tools are completely covered by the solution. Soak for two minutes and then let the items air-dry.

After the first use, you usually don't need to sanitize bottles and their parts. But you do need to clean bottles and tools after every use. Wash these items with soap and hot water. Bottle brushes and nipple brushes can help you clean them well. You also can use a dishwasher to clean bottles.

You might continue sanitizing bottles daily if your baby:

• Is younger than 2 months.
• Was born prematurely.
• Has a weakened immune system.

4. Add water to concentrated liquid or powdered formula

Formula comes in three forms:

• Ready-to-feed liquid.
• Concentrated liquid.
• Powder.

Do not add water to ready-to-feed formula. But you need to add water to concentrated liquid and powdered formulas. Follow the instructions on the product label.

Water safety

You can use clean tap water or bottled water for concentrated liquid or powdered formula.

If you use well water, have the water tested for chemicals, germs, or minerals that may be harmful. Your local health department may provide a testing service.

If you worry about your tap water or your baby has a weakened immune system, boil the water for one minute. You may need to add more time based on your elevation. For every 1,000 feet (305 meters) above sea level, add one minute to the boiling time. After boiling, measure the amount of water you need for the bottle and let the water cool to room temperature. But use the water within 30 minutes of boiling or throw it out.

Fluoride

Tap water may have the chemical fluoride added to prevent tooth decay. Fluoride also may be found naturally in well water. Drinking water with high levels of fluoride over a long time can raise the risk of faint white lines or streaks on the teeth, called fluorosis.

If your baby drinks only concentrated liquid or powdered formula, you can use low-fluoride bottled water some or all the time to make the baby's bottle. Labels on this type of bottled water will say:

• Deionized.
• Purified.
• Demineralized.
• Distilled.

If your baby uses only ready-to-feed formula or you only use low-fluoride bottled water for formula, talk to your healthcare professional. Fluoride-containing bottled water or fluoride supplements may be suggested.

5. Measure the formula

Carefully measure the amount of water and formula following the instructions on the product label. Too much water might mean your baby doesn't get enough nutrients. Too little water might cause your baby to have digestive problems or not have enough fluids.

• Pour enough formula for one feeding into a clean bottle.
• Use only formula — don't add water or any other liquid.
• Attach the nipple and cap to the bottle.

• Pour the amount of water needed into a clean bottle.
• Pour the amount of formula needed into the bottle.
• Attach the nipple and cap to the bottle and shake well.

• Determine the amount of formula you want to prepare, following the instructions on the product label.
• Measure the amount of water needed and add it to a clean bottle.
• Use the scoop that came with the formula container to scoop the powdered formula. Add the number of scoops needed into the bottle.
• Attach the nipple and cap to the bottle and shake well.

If your baby is younger than 2 months, was born prematurely or has a weakened immune system, some extra steps can lower the risk from cronobacter bacteria:

• Boil water.
• Measure the water after boiling.
• Let cool for five minutes.
• Prepare the formula.
• Put the baby's bottle under cold running water or in an ice bath to cool. The formula should be at body temperature, 98.6 degrees Fahrenheit (37 degrees Celsius).
• Test that the formula is lukewarm — not hot — by putting drops on your wrist or the back of your hand.

6. Warm the formula, if needed

It's fine to give your baby room temperature or even cold formula. If your baby prefers warm formula, place a filled bottle in a bowl of warm water or run under warm water.

Test the temperature by putting a couple of drops on the back of your hand or wrist. The formula should feel lukewarm — not hot.

Don't warm bottles in the microwave. The formula might heat unevenly, making hot spots that could burn your baby's mouth.

7. Know when to throw or store

If your baby doesn't drink all the formula in the bottle in an hour, throw the rest away. Bacteria from your baby's saliva can grow in the formula, even if the bottle is in the fridge.

If you've poured ready-to-feed formula into the baby's bottle but have some left over in the original container, you can cover and refrigerate it. Throw away any leftover ready-to-feed formula that's been in the refrigerator more than 24 hours.

Sometimes it makes sense to get bottles ready before you need them. If you want to prepare a few bottles of formula for the future, do the following:

• Add a label that says the day and time the bottle was made.
• Keep bottles cold but not frozen, ideally in the refrigerator.
• If the bottles have been in the fridge for more than 24 hours, toss them.

If you're not sure whether a container or bottle of formula is safe, throw it out.