Infant formula: 7 steps to prepare it safely

Are you measuring your baby's infant formula correctly? Storing it properly? Keeping the utensils clean? To make sure, follow these seven steps.

By Mayo Clinic Staff

You've chosen your baby's infant formula with care — but are you preparing it properly? Follow these steps to ensure proper nutrition and avoid food-related illness.

1. Check the expiration date

Look for an expiration or "use by" date on the formula container. If the expiration date has passed, you can't be sure of the formula's quality. Don't buy or use outdated infant formula.

2. Wash your hands

Before preparing formula, wash your hands thoroughly with soap and water. Dry your hands well. Make sure the area where you'll be preparing the formula is clean.

3. Prepare your bottle

Sterilize bottles, nipples, caps and rings before using them for the first time. You can boil the bottle and accessories in water for five minutes, use a microwave steam sterilizer bag or use a stand-alone electric steam sterilizer.

After the first use, there's usually no need to sterilize your bottle and accessories. Wash these items with soap and hot water. Bottle and nipple brushes can help you clean nooks and crannies. You can also use a dishwasher.

However, if your baby is younger than 3 months, was born prematurely or has a compromised immune system, you might consider continuing to sanitize feeding items.

4. Add water to liquid-concentrate or powdered formula

If you're using liquid-concentrate or powdered formula, you'll need to add water. Follow the manufacturer's instructions for how much water to use.

You can use any type of clean water — tap or bottled — to prepare liquid-concentrate or powdered formula. If you're concerned about the purity of your water supply, talk to your baby's doctor or your water provider. Many public water systems will test drinking water upon request. If you use well water, boil it for about one minute and cool it to body temperature, 98.6 F (37 C). Measure the water after boiling it.

It's also important to consider the amount of fluoride in the water you use to prepare your baby's liquid-concentrate or powdered formula. Exposure to fluoride during infancy helps prevent tooth decay. However, regularly mixing powdered or liquid-concentrate formula with fluoridated water might increase your child's risk of developing faint white lines or streaks on the teeth (fluorosis) if these kinds of formula are your child's main source of food.

If you're concerned about fluorosis, consider ways to minimize your baby's exposure to fluoride. For example, you might use ready-to-feed formula, which contains little fluoride, or alternate between using fluoridated tap water and low-fluoride bottled water — such as purified, demineralized, deionized or distilled bottled water — to prepare concentrated formula. However, if you feed your baby only ready-to-feed formula or concentrated formula mixed with low-fluoride water, your baby's doctor might recommend fluoride supplements beginning at 6 months.

5. Measure the formula

Carefully measure the amount of water and formula you add. Too much water might cause the formula to fail to meet your baby's nutritional needs. Too little water might cause your baby to become dehydrated.

For ready-to-use formula:

  • 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.

For liquid-concentrate formula:

  • 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.

For powdered formula:

  • Determine the amount of formula you want to prepare, following instructions on the package.
  • 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.

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 and let it stand for a few minutes — or warm the bottle under running water. Test the temperature by putting a couple of drops on the back of your hand. The formula should feel lukewarm — not hot.

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

Discard remaining formula at the end of each feeding if it has been more than an hour from the start of a feeding. Resist the urge to refrigerate a bottle once you have fed your baby from it, since bacteria from your baby's mouth can still multiply in the refrigerator.

7. Store formula safely

If you're using ready-to-use formula, cover and refrigerate any unused formula from a freshly opened container. Discard any leftover formula that's been in the refrigerator more than 48 hours.

If you prepare and fill several bottles of liquid-concentrate or powdered formula at once, do the following:

  • Label each bottle with the date that the formula was prepared.
  • Refrigerate the extra bottles until you need them.
  • Discard any prepared formula that's been in the refrigerator more than 24 hours.

If you're unsure whether a container or bottle of formula is safe, throw it out.

March 04, 2021 See more In-depth