Infant formula: 7 steps to prepare it safely

4. Measure the formula

For ready-to-use formula:

• Shake the container of formula well before opening it.

• Pour enough formula for one feeding into a clean bottle.

• Use only formula — don’t add water or any other liquid.

For liquid-concentrate formula:

• Pour the amount of formula for one serving into a clean bottle.

For powdered formula:

• Use the scoop that came with the formula container. Make sure the scoop is dry.

• Determine the amount of formula you want to prepare, following instructions on the package. Note the number of scoops you’ll need.

• Fill the scoop with powdered formula, shaving off any excess formula from the top of the scoop with the flat side of a knife — not a spoon or other curved surface.

• Repeat as needed, depending on the amount of formula you want to prepare.

5. Add water to liquid concentrate or powdered formula

If you’re using liquid-concentrate or powdered formula, you’ll also need to add water to the bottle. Follow the instructions on the container for how much water to mix with the formula, and then shake well. Adding too little water can put a burden on your baby’s digestive system, and adding too much water may overly dilute the formula and deprive your baby of calories and nutrients.

You can use any type of clean water — tap or bottled — to prepare liquid-concentrate or powdered formula. If you’d like to use tap water but you’re concerned about the safety of your water supply or you use private well water, consider sterilizing the water before mixing it with formula:

• Use cold tap water.

• If you haven’t used the faucet for more than six hours, let the cold water run for as long as it takes to get as cold as it gets — up to two minutes. This helps reduce the amount of lead and other contaminants in the water.

• Pour the cold water into a clean pan and boil it for one to two minutes.

• Let the water cool.

You might also have well water checked for lead, nitrates and bacteria.

In addition, it’s 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 during childhood and beyond, but it’s possible to have too much of a good thing. Regularly mixing a baby’s formula with fluoridated tap water can provide enough fluoride to cause fluorosis — mild white streaks on the teeth or more severe pitting or staining of tooth enamel. Fluorosis can affect both baby teeth and permanent teeth.

Occasional use of water with optimal levels of fluoride isn’t thought to increase a child’s risk of fluorosis. Still, you may want to check with your local water utility for specific information about the level of fluoride in your tap water. If the water contains high levels of fluoride, your child’s doctor may recommend preparing your child’s bottles with alternate water sources lower in fluoride — such as distilled bottled water. Boiling tap water high in fluoride will only concentrate the fluoride.

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 or pan of hot, but not boiling, water and let it stand for a few minutes — or warm the bottle under running water.

• Shake the bottle after warming it.

• Turn the bottle upside down and allow a drop or two of formula to fall on your wrist or the back of your hand.

• The formula should feel lukewarm — not hot.

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

Shake the bottle well and feed the formula to your baby immediately. Discard any formula that remains in the bottle after a feeding.

7. Store formula safely

Store unopened formula containers in a cool, dry place. Don’t store formula containers outdoors or in a car or garage, where temperature extremes can affect the quality of the formula.

If you’re using ready-to-use formula, cover and refrigerate any leftover formula from a freshly opened container. Discard any leftover formula that’s been in the refrigerator more than 24 to 48 hours.

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

• Label each bottle with the date that the formula was prepared.

• Refrigerate the extra bottles until you need them — don’t freeze them.

• Put the bottles toward the back of the refrigerator, where it’s coldest.

• Discard any prepared formula that’s been in the refrigerator more than 24 to 48 hours.

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

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References

Formula feeding of term infants. In: Kleinman RE, ed. Pediatric Nutrition Handbook. 6th ed. Elk Grove Village, Ill.: American Academy of Pediatrics; 2009:61.

Feeding infants: A guide for use in the child nutrition programs. U.S. Department of Agriculture. http://www.fns.usda.gov/tn/Resources/feeding_infants.pdf. Accessed July 12, 2010.

Background: Infant formula and the risk for enamel fluorosis. Centers for Disease Control and Prevention. http://www.cdc.gov/fluoridation/safety/infant_formula.htm#6 . Accessed July 12, 2010.

Actions you can take to reduce lead in drinking water. U.S. Environmental Protection Agency. http://epa.gov/ogwdw000/lead/lead1.html. Accessed July 12, 2010.

Hoecker JL (expert opinion). Mayo Clinic, Rochester, Minn. July 13, 2010.

Zeratsky KA (expert opinion). Mayo Clinic, Rochester, Minn. July 21, 2010.