How to Turn Breast Milk into Powder

How to Turn Breast Milk into Powder

Breast milk has long been known as the gold standard of infant nutrition. It's densely packed with all the essential nutrients that a baby needs for optimal growth and development. 

But because it is a living food, breast milk requires frozen storage to remain safe over the long term. And once frozen, it’s best used within 6 months (up to 1 year at most) due to the slow decline in nutritional quality. 

But what if we could extend the expiration of breast milk, making it as portable and convenient as infant formula? And what if there was a way to do so with little to no impact to its nutritional value?

Not only is this possible, human milk donor banks have been doing this since the 1950s. The answer lies in converting frozen breast milk into powdered form through a process called freeze-drying, or lyophilization. 

An Introduction to the Breast Milk Freeze-Drying Process

Before we talk about transforming breast milk into powder, we need to understand the underlying concept of freeze-drying. This method (the fancy term for which is lyophilization), is a way to preserve perishable materials, such as food items and biological samples, by very slowly removing water while they're in a frozen state inside a vacuum chamber.

The driving principle of freeze-drying is that in a vacuum, water can be a solid or a gas, but never a liquid. 

This gives us a way to safely remove the water in your breast milk without it ever needing to be thawed. When breast milk is under a very high vacuum, the water molecules can turn directly into a gas over time, bypassing the thawing stage and keeping the nutrients intact. This is called sublimation.

The freeze-drying process involves three main stages: vacuum-freezing, primary drying, and secondary drying. 

In vacuum-freezing, the frozen breast milk is placed under a deep vacuum. In primary drying, we remove the bulk of the ice through sublimation. Finally, the secondary drying phase eliminates the last remaining bits of frozen water from the product.

Not all Freeze-Drying is Created Equal

It’s important to note that not all freeze-drying processes are the same. At Milkify, we’ve developed our own patented process called SafeDry, with a few simple but very important advantages to traditional methods.

  • No Touching: at Milkify, we never physically touch your breast milk, or allow it to come into contact with any of our equipment (bowls, scoops, trays, etc). Each block of your frozen milk is transferred (using sterile techniques) into a specially engineered freeze-drying pouch that allows the water vapor to escape while protecting your milk from potential contamination via direct contact with our equipment. This also allows us to keep each bag of your milk labeled with your name and a unique Bag ID, even while inside the freeze-dryer, to eliminate human error or mix-ups.

  • No Thawing: at Milkify, your milk is never thawed for processing. It stays frozen the entire time. Other services may thaw your milk, then re-freeze it onto trays. This makes the process easier and faster (and therefore cheaper), but it’s actually a really bad idea. Aside from the safety concerns (there’s a reason the CDC says you should “never re-freeze breast milk after it has thawed”), thawing breast milk can also degrade the nutrients and change the taste and texture of your milk. So if a service sends you a “collection bag” for your breast milk that includes a spout, ask yourself – what is the spout for? Then throw that bag away and give us a call.

  • Low and Slow: at Milkify, we use a “low and slow” freeze-drying cycle to very gently dry your milk. A classic “shortcut” for cutting costs in the freeze-drying industry is to use high heat to shorten the cycle times, but we never use heat higher than body temperature in our process. This means our process takes up to 48 hours, but research has shown that this low and slow approach results in the greatest retention of nutrients and sensitive bioactive compounds like antibodies. 

  • Milkify is the only company that is GMP-certified for freeze-drying human milk – this means we have been certified as following the same standards the FDA recommends for human milk donor banks. 

    Also, we only freeze-dry breast milk in our facility, and nothing else. If a company advertises SQF or USDA certifications, you should know that these are only given to facilities that process raw meat and other products. There are many freeze-drying companies out there making all sorts of claims, but if you can’t find an address or a single picture of their facility, run – don’t walk – the other way. 

    Transforming Breast Milk into Powder: Step-by-Step

    Freeze-drying is a complex process that requires specific equipment and a strict adherence to hygiene and safety standards. Health experts advise against freeze-drying breast milk at home due to the need for specialized quality control equipment. It’s also very difficult to create a sterile packaging environment in one’s home. With that said, here is the journey your breast milk goes through when freeze-dried by Milkify.

    Step 1: Expressing and Freezing the Breast Milk

    The process begins with expressing your breast milk using a high-quality breast pump. It's critical that all the parts of the breast pump are meticulously cleaned and sterilized before use to ensure proper hygiene. For best results, freeze the milk flat as soon as possible after expressing it.

    Step 2: Shipping or Drop-Off

    Next, we need to get the frozen milk safely to our facility. If you live near the Houston area, we accept in-person drop offs on weekdays. Simply placing your frozen milk in a cooler will typically be enough to keep it frozen during the drive to Milkify. If you are coming from a few hours away or are bringing a small quantity of milk, or if you’re simply not sure, give us a call.

    However, most of our clients live outside of Texas. If that’s you, our medical-grade shipping kits come in five sizes and will keep your milk frozen for several days while in transit, without the need for any ice packs or dry ice. All of our breast milk shipping kits come with a prepaid Priority Overnight label from FedEx.

    Step 3: Preparing Your Milk for Freeze-Drying

    Once your milk arrives at Milkify, we immediately take a temperature reading and quality control check to ensure no rips, leaks, or tears in your bags. We then record information (or “metadata”) about your bags – including their weights, volumes, dates of expression, dietary notes, or any other notes you wrote on them. 

    Each bag of your milk will then be assigned a unique Bag ID, and will be labeled with your name. Your breast milk will be stored in your own bin in our commercial freezers, which are remotely monitored for power outages or temperature spikes and have backup power generation available (just in case). 

    The next step in the preparation process is transferring your frozen milk into our specially engineered SafeDry freeze-drying pouches. These pouches allow the water vapor to escape while protecting your milk from contact with equipment (such as trays in the freeze-dryer). 

    Step 4: Freeze-Drying Your Breast Milk

    Once your frozen milk has been transferred to a freeze-drying pouch, it goes into the freeze-drying queue in one of our commercial freezers (again, without ever being thawed). 

    When it’s your milk’s turn to be freeze-dried, your freeze-drying pouches (which are all labeled with your name and unique Bag IDs) are placed into a pre-chilled vacuum chamber. Your milk is kept separate from anyone else’s the entire time, and each of our technicians only works with one mom at a time.

    Your freeze-drying pouches will spend up to 48 hours in the vacuum chamber as the ice slowly sublimates from your milk. The ice turns from a solid into a gas before condensing onto the ice plates on the sides of the freeze-drying chamber.

    Step 5: Packaging and Quality Control

    After the freeze-drying process, each pouch will contain the solids in your milk – the macronutrients, micronutrients, antibodies, and other “good stuff” – everything except the water.

    Where there was previously water, now there is air. These air pockets must be broken down to make your freeze-dried milk into a silky powder, which is where another benefit of our freeze-drying pouches comes in. Rather than massaging your milk with gloved hands or a shared utensil that could contain contaminants from another mom’s milk (or from cleaning chemicals), the technician working on your order will simply massage the outside of each freeze-drying pouch. And voila, the air pockets are broken down and what’s left is a smooth, silky freeze-dried breast milk powder.

    The powder is then poured (under sterile conditions in a laminar flow hood) into the final packaging. This is done by matching the Bag ID on each freeze-drying pouch to the Bag ID on the final packaging, which prevents mix-ups and gives you comfort that the milk you receive back is actually your own. 

    The final step is quality control. To ensure your milk can be safely stored for up to 3 years on the shelf without bacterial growth, we test the water activity or “dryness” of your freeze-dried powder to ensure it meets our critical control limits. Your breast milk powder is then sealed, packaged, and sent back to you. 

    Final Thoughts

    In conclusion, transforming breast milk into powder through freeze-drying is a delicate and intricate process, but it’s one that Milkify has mastered with precision and care. 

    By maintaining the milk in a frozen state throughout, utilizing our unique SafeDry method, and ensuring strict quality control and hygiene standards, we’re able to provide a product that retains the essential nutrients and bioactive compounds crucial for your baby’s development. 

    Our patented process, coupled with a deep commitment to safety and quality, sets us apart in the industry and ensures that the breast milk you entrust to us is handled safely from start to finish.

    With Milkify, you can extend the shelf life of your breast milk, making it more convenient and accessible, without compromising on the safety and nutritional quality that is so vital for your little one.

    Pedro Silva

    About the author


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