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Freeze-dried breast milk is not sterile. Breast milk powder should be stored and prepared properly in order to prevent contamination with Cronobacter and other bacteria that can cause serious illness if safe handling guidelines are not followed.


(These recommendations were developed using guidance from the CDC on safe storage of breast milk and of powdered infant formula).


  • Store sealed pouches in a cool, dry, indoor place—not in vehicles, garages, or outdoors.

  • Once a pouch is opened, store in a cool, dry place with the zipper tightly sealed. Do not store it in the refrigerator. Discard unused powder after 3 days.

  • Do not use if past expiration date printed on the custom label.


  • Once milk is rehydrated, use within 2 hours of preparation and within one hour from when feeding begins. Rehydrated breast milk can spoil if left at room temperature.

  • If you do not start to use the rehydrated milk within 2 hours, immediately store the bottle in the fridge and use it within 24 hours.

  • Do not freeze rehydrated milk.

  • Throw out any milk that is left in the bottle after feeding your baby. The combination of milk and your baby’s saliva can cause bacteria to grow. Be sure to clean and sanitize the bottle before its next use.


Before preparing milk, wash your hands thoroughly with soap and warm water!

1. Add water to bottle

  • Add room temp or pre-warmed purified water to a pre-sterilized bottle. The measurements on your custom bag label will rehydrate the powder back to your breast milk’s original consistency. For different sized bottles, add 0.1 oz of breast milk powder per 1 fl. oz. of water (this is approximately 1 Tbsp. powder per 2 fl. oz. water).

    • Always measure the water first and then add the powder.

      • Too much water may not meet the nutritional needs of your baby.

      • Too little water may cause your baby’s kidneys and digestive system to work too hard and may cause your baby to become dehydrated.

  • Place the bottle under running warm water, taking care to keep the water from getting into the bottle or on the nipple. You can also use a bottle warmer, or let the closed bottle sit in a bowl of warm water from a kettle, microwave, or stove top. Do not let the bottle nipple contact the water when warming.

  • Never heat a prepared breast milk bottle in a microwave. Microwaving can destroy nutrients in breast milk and create hot spots, which can burn a baby’s mouth.

2. Add powder to bottle

We recommend propping open the pouch to stand and then pouring into your bottle. Pouring is the safest method for getting the powder into the bottle, but if using only a portion of the powder, use a clean, dry measuring scoop.

3. Mix it up

Close bottle and swirl it. Depending on the fat content of the milk, it make take a bit longer for the fats to dissolve. If any clumps remain, gently heat bottle under warm running water (with bottle nipple covered) and continue swirling. Shake if needed. 

  • In some cases, adding slightly warmer water may be necessary to get the fats in the milk to dissolve. In this case, the milk may be too hot for feeding. To use right away, cool the milk to ensure it is not too hot before feeding your baby. Run the prepared, capped bottle under cool water or place it into an ice bath. Do not let the cooling water get into the bottle or on the nipple.

  • Some studies have suggested that when breast milk is heated to just 100.4°F (38°C)—slightly above body temperature—its proteins begin to break down. This means that caution should be taken when rehydrating breast milk powder since it can lose important immunologically “active” and digestive components that benefit babies. For example, enzyme activity (amylase, which breaks down carbohydrates and lipase, which breaks down fats) begins to decrease at 104 degrees F (40 C). Take care not to overheat the milk during preparation.

4. Feed that hungry little one

Don’t forget to check that the temperature is not too hot!  Test the milk’s temperature by putting a few drops on the inside of your wrist. It should feel warm, not hot.


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​Your powdered breast milk can also be incorporated into solid foods even after weaning for a nutritional boost! Simply sprinkle a little on your child's favorite foods, and mix in. Here are a few tips:


  • Each ounce of frozen breast milk will yield approximately 0.1oz (2 teaspoons) of breast milk powder.


  • Make sure that the powder is mixed in thoroughly to the food to prevent accidental powder inhalation.


  • After you open a bag of your breast milk powder, remember to re-seal the zipper! The powder will rapidly start to attract moisture if left unsealed, which can lead to bacterial growth as your milk was not pasteurized during the freeze-drying process. For this reason, once the bag has been opened, it should be re-sealed and used within 3 days.


Each lactation bag of frozen breast milk you provide to Milkify turns into its own powdered pouch.


When we receive your milk, the starting volume of frozen milk in each lactation bag is recorded. The instructions on the back of each barrier bag of powder you receive will indicate how much water to add back to the breast milk powder. This rehydrates the milk to its original consistency. Please note that the volume in your bottle will be about 10% larger once the water is added to the powder.

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