Breast Milk Storage Guidelines: Everything You Need to Know About Properly Storing Breast Milk

Breast milk is often referred to as “liquid gold” because of its high nutritional value, immune-boosting properties and its symbolic significance, standing as a form of love from a mother to her baby. However, in order for breast milk to retain its golden properties, storing it properly is key.

“Breastfeeding creates an unbreakable bond between mother and newborn. However, improper storage of breast milk can prevent the baby from receiving its full benefits,” says Megan Reynolds, patient care specialist with Lehigh Valley Health Network, part of Jefferson Health.

Not adhering to proper breast milk storage guidelines poses a health risk to your baby as improper storage can lead to the growth of harmful bacteria. Not only that, but breast milk has a complex composition that changes over time. Storing it properly helps preserve nutrients like proteins, fats and carbohydrates, as well as retain its natural anti-bacterial, antioxidant and immune-boosting properties, which are crucial for protecting your baby’s health.

Here are some guidelines to follow to make sure you’re storing breast milk safely.

When it comes to how long expressed breastmilk is safe for, it depends on how you store it. Here are the Centers for Disease Control and Prevention’s storage recommendations:

• Room temperature: Freshly expressed or pumped breast milk can be left at room temperature – which is 77 degrees F or colder – for up to four hours.
• Refrigerator: You can keep freshly expressed or pumped breast milk in the back of the refrigerator for up to four days. If you don’t plan to use it within four days, you should freeze it right after pumping.
• Freezer: You can store freshly expressed breast milk in a freezer (0 degrees F or colder) for up to 12 months, but it’s best to use the frozen milk within six months.
• Thawed, previously frozen breast milk: This depends on how the milk was thawed. If breast milk was thawed on the countertop (at room temperature), it must be consumed within 1-2 hours. If thawed in the refrigerator, the milk must be consumed within 24 hours from the time it is completely thawed, not from the time when you took it out of the freezer. You should never refreeze breast milk after it has been thawed.
• Leftover from a feeding: If you warmed a bottle for your baby and they did not finish it, the milk is OK to consume within two hours after the baby is finished feeding. After two hours, the milk must be discarded.
• Insulated cooler: Whether you’re traveling or there’s a power outage, you can store freshly expressed breast milk in an insulated cooler with ice packs for up to one day.

When storing breast milk, keep in mind that breast milk changes to meet your baby’s needs – which means breast milk expressed when your baby is a newborn won’t meet the baby’s needs when they are a few months older. Also, the longer you store breast milk – whether in the refrigerator or in the freezer – the greater the loss of vitamin C in the milk.

• Follow proper hand hygiene. Wash your hands with soap and water before pumping or handling breast milk.
• Store in the proper container. That is either in plastic breast milk storage bags that are specifically designed for milk collection and storage; a clean, capped food-grade glass container; or a hard plastic container that’s not made with the chemical bisphenol A (BPA). Make sure the containers have tight-fitting lids.
• Do not store breast milk in disposable bottle liners or plastic bags that are not intended for storing breast milk.
• Label each bag or container with the date you expressed the breast milk, preferably using waterproof labels and ink.
• Place the containers in the back of the refrigerator or freezer, where the temperature is the coolest.
• Store breast milk in quantities your baby will need for one feeding, such as 2 or 4 ounces. Storing milk in appropriate portions helps avoid wasting milk when thawing.
• When freezing breast milk, don’t fill containers or storage bags to the top because breast milk expands as it freezes.

Thaw the oldest milk first. Put the frozen container in the refrigerator the night before you intend to use it. Remember to discard any thawed milk that isn’t consumed within 24 hours.

You can also warm the milk by placing it in a bottle warmer, under warm running water or in a bowl of warm water. However, keep in mind that when thawing it in this manner, the breast milk must be used within two hours of bringing it to room temperature or warming.

Never thaw or heat milk in a microwave. Microwaving destroys nutrients and creates hot spots, which can burn a baby’s mouth. Also, never heat a frozen bottle very quickly on the stove. Some research suggests that rapid heating can affect the milk’s antibodies.

Never refreeze thawed breast milk.

You can serve the breast milk cold, room temperature or warm – but never hot. You can test the temperature of the milk before feeding it to your baby by putting a few drops on your wrist. It should feel warm, not hot.

Swirl the milk to mix the fat, which may have separated.

If your baby did not finish the bottle, leftover milk should be used within two hours.

Wash disassembled pump and feeding parts in a clean basin with soap and water. Do not wash directly in the sink because the germs in the sink could contaminate items.

Rinse thoroughly under running water. Air-dry items on a clean dishtowel or paper towel. Using clean hands, store dry items in a clean, protected area.

For extra germ removal, sanitize feeding items daily using one of these methods:

• Clean in the dishwasher using hot water and heated drying cycle (or sanitize setting).
• Boil in water for five minutes (after cleaning).
• Steam in a microwave or plug-in steam system according to the manufacturer’s directions (after cleaning).