As you may have seen from the title, I am attempting to tackle an interesting question that I've thought about quite a bit over the past few days. My recent writing about the government shutdown covering the less than ideal situation many formula feeding families may find themselves in should the shutdown impact formula accessibility, got me thinking about our current "best practices" regarding human milk feeding. I am specifically referring to our milk storage guidelines, which are recommended to ensure the safety and quality of expressed human milk.

If you are not currently familiar with the storage guidelines, here is an image for you to reference.

As you may see, the length of time it's "safe" to keep stored milk differs depending on the type of storage unit ( example: fridge vs. deep freezer vs. freezer compartment) and location within it. Additionally, it's commonly agreed that best storage practices include using milk within 24 hours and not refreezing once thawed.

Now I am not saying that storage guidelines shouldn't be followed. Following best milk storage practices, in my opinion, is essential, especially for premature or ill babies, who may be at an increased risk of adverse outcomes should there be any contamination or feeding of spoiled milk.

But I can't help to think how privileged I was to be able to buy a deep freezer during my pregnancy to prepare for all the possibilities my human milk feeding journey may present. And as I brought my premature baby home, after a month long NICU stay and equally long exclusive pumping journey, I couldn't have been more thankful for that deep freezer sitting in my garage.

Jump to 3.5 years later, and I have a better understanding of just how many people don't have the funds or space to have a deep freezer. Or how many people don't have the luxury of being able to throw out their whole stash of milk because their freezer stopped working. I can't help but think of all those parents who struggle with the decision of what is less harmful, feeding milk that has been sitting out unrefrigerated for 9 hours or going out to buy artificial infant formula and introducing it to their babe for the first time.

As a lactation professional, it is my job to help families have the information they need to make the decision that is best for them regarding human milk feeding. Assisting families to make those decisions means providing them with information on safe milk handling and storage practices. It also means being aware of how parts of these milk storage guidelines may be skewed towards those of privilege and doing my duty to provide information that can help families better navigate their specific situation.

In the world of infant feeding, it seems like there's a constant competition between having to decide what is less harmful. Similarly, which options are most affordable. For one family that is human milk feeding, what is less harmful and most affordable is going to be completely different than another family that too is human milk feeding.

I thought it might be helpful to share thoughts I have regarding milk storage in different situations. It may be beneficial for you as you consider how to navigate safe milk storage in your specific set of circumstances.

Safest Consideration

I would argue that the most important and non-negotiable aspect of safe milk handling and storage is proper hand hygiene and pump cleanliness. Hand washing before each pump session helps ensure that no harmful bacteria from other places get onto the pump parts that will directly touch the milk. When clean water and soap are not available, hand sanitizer (60% or more alcohol) will work in a pinch.

Washing your pump parts and storage containers assures that if any harmful bacteria have been introduced, they don't have time to populate and grow in number. Not everyone wants to or has the time to wash after every pump, so it's not uncommon to hear the recommendation to store in the fridge between pumps as the cold should slow down bacteria growth. With that said, depending on the number of times one pumps in a day, multiple washes may be warranted, and everyone should boil all pump parts for 10 minutes daily.

In cases where access to running water might be limited, and bottled water is inaccessible, the situation isn't as clear cut. For those who have frequent but not daily access to water, filling a stock pot with water for cleaning dishes could also be used to sterilize pump parts. Collecting rainwater to use for part washing and sterilization may be an option for those who live in an area that's wet or that rains frequently. Dry climate places pose even more of a challenge and sterilization may not be a feasible option in which direct nursing, when possible, may be the safest choice until you have access to water again. And when direct nursing is not possible, follow the guidelines at the most conservative time frames, such as less 4 hours at room temp, four days in the fridge, etc.

Human milk at room temperature

The Academy of Breastfeeding Medicine has a protocol that outlines safe milk storage guidelines (ABM Protocol #8). In it, it states that human milk can be stored safely at room temperature for 4-8 hours. The 4-hour recommendation is for rooms that sit at 85 degrees (Fahrenheit). The protocol mentions that milk can be stored at lower room temperatures for 6-8 hours, although it doesn't specify which temperatures allow for the upper end of those storage guidelines.

Human milk has antibacterial and antimicrobial properties that inhibit bacteria and organism growth and reduces the amounts of bacteria found in expressed milk. Milk sitting for 2 hours have FEWER numbers of bacteria than milk freshly expressed. The biggest concern is not the naturally present bacteria found in the milk; it's bacteria that may be introduced via contamination, such as E coli., Staph, and Salmonella.

I was unable to find any research that investigated bacterial cultures of unpasteurized human milk sitting at room temperature for longer than 8 hours. It is unclear if 8 hours is the max that milk can be deemed safe due to the difference in level of bacteria number at the 8 hour mark compared to hour 6 for example, or if after 8 hours, any harmful bacteria that's been introduced into the milk, starts to populate and proliferate at an exceedingly high rate.

In either case, it seems that 8 hours is not the time frame for when milk spoils in the sense of going rancid and though feeding milk sitting for longer than 8 hours is not recommended, it may not necessarily be inherently unsafe. ABM states in the protocol, one of the contributing factors to the variability of storage guideline times, stems from the differences in the cleanliness of expression technique. Ensuring proper hygiene can theoretically help mitigate the risks.

For those who rely on milk expression but do not have quick access to a refrigeration unit, reducing the temperature of your home may help in keeping milk for longer. The average room temperature in the USA is about 72 degrees Fahrenheit (well below the 4-hour max recommended by ABM). Decreasing ambient temperature (to between 60-65) may be done by lowering the thermostat temperature or by opening up the windows if the outside is colder than inside. Naturally, it's important for everyone to layer up and stay warm.

Human Milk and refrigeration

Refrigerators are a great tool to which not everyone has access. Many infant feeding families need to or choose to live off the grid, have living circumstances that make buying a functional fridge unrealistic or are in a situation where keeping a constant flow of electricity to their fridge is not an option due to financial constraints.

With prior planning and preparation, some families may be able to navigate not having a cooling device by timing expressions and feeds as not to exceed the recommended 4-8 hours guidelines. In cases where extra milk does need to be stored for much longer, families may be at a loss as to the best way to navigate.

Again referring to the ABM protocol as a guide, milk can be stored in a cooler on ice packs for up to 24. Unlike the room temperature guidelines, they do mention bacterial growth and mention that is was minimal in the first 24 hours. They do not, however, say how rapidly it grows after that time frame.

If you can continually supply ice or ice packs to keep the cooler cold, it may be an option to replace a refrigeration unit for short periods. The cooler must be well insulated, and the milk should be stored in a separate cooler unit away from other foods that might need to be accessed more frequently thus letting cold air out.

In some cases, especially in colder climates or fall/winter weather, setting the milk outside in a sealed container may be a viable option. This approach would be perfect for temperatures under 39 degrees Fahrenheit.

I should mention that refrigerated guidelines use two factors in establishing the timelines of milk storage: one, bacteriocidal properties of milk, as mentioned above, and secondly, bacterial growth in samples. The ability to prevent bacterial growth in the milk significantly decreases between 48-72 hours, BUT when there is little to no contamination during the expression process, it can be safely stored in the fridge upwards of 8 days.

Smelling and tasting may be a useful technique to establish if refrigerated milk has turned. If it has yet to, freezing or using immediately is recommended. The refrigeration (and freezing) process may impact the odor of human milk. It's not uncommon for milk to smell different due to lipase-mediated effects releasing fatty acids. Knowing the difference between this smell and spoiled milk may be helpful.

Human milk & Freezing

Of all of the points that I've discussed so far, I think the freezing guidelines are the ones I find the most problematic for certain people.

The majority of families in the US are going to have access to running water and have access to a fridge, so they may not need to worry about the room temperature guidelines. As the refrigeration guidelines allow for milk storage for upwards of a week, many families find that freezing milk is not necessary. They rotate the oldest milk out to for use first, and the freshest milk that doesn't go to the current feeding gets moved to the back.

For the average human milk feeding parent that nurses in conjunction with expressing, the reliance on a freezer may not be exceptionally high. The freezer recommendations may be confusing because it varies depending on the type of freezer and where it's stored in said freezer. In general, guidelines usually say to use within six months to a year.

So after a year, is the milk dangerous? It seems the answer is no. Assuming that there was never a drop in temperature for a period that allowed for rapid bacteria growth, the biggest reason for the guidelines is due to the deterioration of nutritional composition over time. The milk is still excellent just less nutritious than it was fresh or at 12 months. Many parents are encouraged to toss the milk away after 12 months for concerns of it being "bad" without even considering the costs of the expressing the milk (as explained below).

I would say that the majority of exclusively pumping parents, however, rely on their freezer stash to get them to their human milk feeding goals. Many parents can stop expressing months before their "goal date" because they have stored the volume necessary to reach it in advance. In the event of a mechanical failure or other situation that causes the freezer to lose temperature, these families are at risk for losing it all.

I see this question posted about this scenario quite a bit, so it's not just a hypothetical worst-case scenario that rarely happens. The commonly spouted guideline is that milk should not be refrozen, but ABM has this to say about refreezing milk:

Refreezing: There is little information on refreezing

thawed human milk. Bacterial growth and loss of antibacterial activity in thawed milk will vary depending

on the technique of milk thawing, duration of the thaw,

and the amount of bacteria in the milk at the time of

expression. At this time no recommendations can be

made on the refreezing of thawed human milk.

My go-to response for people facing this situation is can you afford to not refreeze? Though many parents get assistance with artificial infant formula through programs such as WIC, a large portion of people have to pay for formula outright. Though financial considerations aren't the only reason why someone may choose to human milk feed, in situations like these, it's something that needs to be assessed.

Additionally, expressing milk is not free. It takes time, energy and resources to establish and maintain a milk stash. Many parents have to decide between human milk feeding and their careers, many losing a considerable amount of money to make human milk feeding a priority. The effects of those sacrifices need consideration as well.

Lastly, whenever we offer formula as an alternative to human milk, we need to put a lot of thought into if the known risks of formula usage outweigh the theoretical risks of human milk feeding in various circumstances. In the context of this situation, saying that milk can only be refrozen if it has ice crystals in it, is a very privileged perspective. What are the long-term health costs in these situations?

My thoughts are that in the event of a freezer malfunction if the milk is still cold and/or hasn't thawed for an excessive amount of time AND the milk smells and tastes fine, then refreezing might be something some are comfortable doing. In cases like these, quick use after defrosting would be encouraged.

The reason for recommending using thawed milk within the first 24 hours after defrosting is because there is a significant decrease in the bacteria-fighting capabilities of the milk by that time. Again, it's a situation where the milk isn't spoiled but the risk of bacteria growth if introduced during the expression process increases. How probable adverse outcomes are in that situation have yet to be stated.

My thoughts on the storage guidelines are this: It's great if everyone could follow them to a T. But life happens, and circumstances aren't always compatible with best practices. It's up to each family to best mitigate risks while trying to decide what is best both short term and long term. I am not advocating that anyone feeds babies rancid milk or that anyone should disregard safe handling or storage guidelines completely. I think there needs to be an understanding that these guidelines give very little guidance to those who don't have situations that are conducive to following the recommendations entirely.

I would love to hear your thoughts on the subject though! Do you follow all of the storage guidelines? Are there areas you feel safe making a judgment call that's outside of the recommendations? Let's talk about it in the comments below.