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Ohio State University Extension


Keeping Baby Formula Safe

Family and Consumer Sciences
Ana Claudia Zubieta, PhD; Director, Ohio SNAP-Ed; College of Education and Human Ecology; Department of Human Sciences; Ohio State University Extension; The Ohio State University

If you have decided to formula-feed your baby, you need to know the right ways to mix the formula, and how to make and keep the bottles safe. Use these tips to help your baby start out on the right path to good health.

Step-by-Step Guide for Making Baby's Formula Safe

Step One: Washing

man feeding a bottle to infant

Wash your hands with soap and hot water. Wash all bottle items: bottles, nipples, covers, can openers, and other things, inside and out, in hot, soapy water. Rinse and let air dry. Wipe off formula can each time you use it.

Step Two: Measuring Formula and Water

Ask your doctor if you should boil the water you will use with formula for at least five minutes before you mix the formula. If you boil, allow the water to cool to room temperature (35–75°F) before mixing with the powder. Use the type of formula suggested by your doctor. Follow the doctor's instructions, and use strict measurements when you make the formula. You do not need to wash the scoop in the can.

Step Three: Filling the Bottles

Fill each bottle with formula for just one feeding. Make only bottles needed for one day, and do not keep premade bottles longer than 48 hours. Write the date on the bottle before storing to help you remember.

Step Four: Storing and Reheating Formula

Make sure the premade bottles are kept between 35–40°F until ready for use. Any formula left outside the refrigerator (or a cold cooler) for more than 2 hours is spoiled and should be thrown out. Foodborne illness in infants can be fatal.

You may heat the bottle of formula so that it is warm to the touch, but not hot. If you want to heat the bottle, you should place the premade bottle in a pan filled with water and heat it on the stove. If you choose to heat the bottle in the microwave, make sure the bottle is not too hot. Microwaves cause hot spots in food and liquid. Test the formula before you feed it to your baby. It may feel warm, but as the baby drinks, he or she may burn his or her tongue or throat from formula in a hot spot. To be safe, heat 6- to 8-ounce refrigerated bottles for 30–45 seconds and 4-ounce refrigerated bottles for 25–30 seconds. In addition, shake the bottle after heating and let it sit for a minute or two before testing it and feeding it to your infant.

Don't put the bottle back in the refrigerator if the baby does not finish it. Bacteria from the baby's mouth can grow and multiply in the refrigerator and after reheating. 

Safe Storage Times for Formula
Refrigerator 2 Days
Freezer Not Recommended


Food and Drug Administration. (2014). Food Safety for Moms-To-Be: Once Baby Arrives. Accessed at

Satter, E. (2000). Child of Mine: Feeding with Love and Good Sense. Palo Alto: Bull Publishing.

This fact sheet is a revision of the original, written by Cheryl Barber Spires, Extension Educator, Family and Consumer Sciences.

Originally posted Nov 25, 2014.