Keeping Breast Milk Safe

Contributors: Karen Ansel, MS, RDN, CDN
breast feeding


Breastfeeding has big benefits for both mother and baby. It strengthens baby's immune system, encourages bonding and saves money. Plus, breast milk is naturally fresh, readily available and always arrives at the perfect temperature. Here's how to keep it as pure and safe as possible:

1. Make cleanliness a top priority: While breast milk is naturally bacteria free, you'll want to keep it that way. "Get into a pumping and cleaning routine that ensures all pump parts and bottles are thoroughly washed before using to prevent contamination," says Academy spokesperson Caroline Passerrello, MS, RDN, LDN. "Don't forget to thoroughly wash your hands before and after each pumping session and wipe down any pump equipment as needed. While collecting milk in plastic or formula bottle bags may be tempting, these can drip and spill. Instead opt for bottles with screw caps or bags that are specially designed to fit inside of a baby's bottle."

2. Store it safely: After it's expressed, breast milk can safely stay at room temperature for up to four hours. After that, move it to the refrigerator where it will stay fresh for up to four days. And never add fresh breast milk to a container that contains older milk. To prolong freshness, you can freeze it up to six months at temperatures below 0°F. "To prevent waste of the product, it's a good idea to store breast milk in small portions, put date labels on storage containers and use the first in, first out method when selecting stored milk to feed baby," advises Passerrello.

3. Reheat with care: Although it may seem innocent enough, microwaving milk can cause hot spots. It can also destroy some of breast milk's most important proteins and vitamins. Instead, gently warm it in a bowl of warm water. If you're defrosting frozen breast milk, you should thaw it in the refrigerator or a bowl of warm water. Breast milk that has been warmed should be used within 2 hours.

4. When in doubt, toss it out: Once breast milk has been defrosted, it should be used within 24 hours or discarded. "If you are able to pump and freeze milk for later use, be sure to store it properly throughout the freezer to feeding process, and don't refreeze thawed milk," Passerrello says. "Milk stored in appropriate bags and stacked in thin layers will thaw more quickly and evenly than milk stored in a bottle or a bag sat upright, and it will take up less space." Due to changes in temperature, it is also recommended that breast milk not be stored on the door of a refrigerator or freezer.

Find Nutrition Experts

Need serious help making a plan? The nutrition experts in our professional membership are ready to help you create the change to improve your life.

Find a Nutrition Expert