Home > Health > Is there a “best if used by” date for breastmilk?

Is there a “best if used by” date for breastmilk?

There are many questions asked by households when mothers start breastfeeding their children. Here are some examples: Is breastmilk better than formula milk? How do I store breast milk? Is there an expiration date for breast milk? What’s the shelf-life of breast milk? How long should I breastfeed my baby?

However, there is one important question most parents fail to address or even think about:

What is the expiration date for breast milk?  Is there a "best if used by" date?

Is there a “best if used by” date?

Most people do not think twice about the quality of the food products they buy until the “sell-by” or the “best-by” date.  Breast milk also has a “best if used by date,” yet we shouldn’t view it quite the same as other foods.

Adults can afford to lose some freshness, they can afford to lose some nutrients, and they can even afford not to eat it at all. Newborn babies, on the other hand, have a strong need for “fresh” breast milk. This is because the immune system of babies during their first few months of life is heavily dependent on the mother’s antibodies that they have been receiving from birth. Therefore, any extra help from the mother’s breast milk is always welcome.

Breast milk is dynamic as it is filled with living microbes and immune cells [1]. Along with the more commonly talked about nutrients, breast milk has bacteria that is good for the gut and contains antioxidants, vitamins, and many other micronutrients. However, since breast milk is not pasteurized like cow’s milk sold in the supermarket, it has a short “shelf life.” And even if breast milk were pasteurized by milk banks, many of its touted benefits would be lost.

Breast Milk vs. Formula Milk?

Breast milk vs Formula milk

This question has been exhaustively answered by many organizations and other health-related websites. There are also forums which faithfully promote breastfeeding and other sites which utterly denounce cow’s milk.  There is absolutely nothing criminal feeding your baby with baby formula – one should not feel guilty about this at all.  Everyone needs to understand that breastfeeding is an intimate and personal choice which should never be subjected to other’s opinion.  There are certain situations in which babies cannot be breastfed – such as mothers with hepatitis B and AIDS along with other private circumstances. In addition, having a child breastfed takes more planning and a certain level of commitment which working mothers do not have the luxury of time.  Medically speaking, breast milk is the better choice when considering the well-being and health of the child but formula milk is a good choice too.

Another Viewpoint about Milk

Milk is Species Specific

Milk is species specific. When it comes to animals, horse’s milk is best for foals, goat’s milk is best for kids, cow’s milk is best for calves, and so on. The general public knows that nursing and feeding animals from the same species provide the best results. So the same logic should apply to humans. Where is the argument showing that cow’s milk is better for humans? Moreover, haven’t we engineered our cows enough to provide us with knowledge that “milk does the body good, so pass it on”?  The truth is that cows have been bred for their milk to provide the maximum output as opposed to the maximum nutritious value. Furthermore, baby-formula milk companies have tried their best to create processed cow’s milk as close to human milk as possible but have failed and acknowledged this failure. Despite our advanced technology, human breast milk is more easily digested by humans than cow’s milk. This argument is not about fostering nutrition (i.e., calories, fats, proteins, carbohydrates, etc.) but about immunological factors that cannot be synthetically duplicated.

Mothers Tailor Their Breast Milk Especially for Their Children

tailor made for the baby

Besides the numerous immunological benefits that breast milk provides, mothers create “tailored” milk that is perfect for their children in their specific environments.

When there is a viral or a bacterial infection in the household, the mother, who is also exposed to such threats, creates antibodies for that particular infection. These antibodies are also transferred to her breast milk and hence made available for the baby. In addition, the baby’s immune system is very immature. If the baby unfortunately falls ill along with the mother, the child will suffer a milder form of the sickness because of the antibodies against the illness that are present in the mother’s milk. In other words, breast milk provides support for the child’s immune deficiency. Furthermore, breast milk may protect babies from other possible diseases that are also lurking in the environment.

Is your baby sick with diarrhea? Then you should breastfeed directly from the breast. This is absolutely the best medicine by which to nurse your baby back to a healthy state.

Human milk is clearly the best choice for human babies.

What Exactly Is in Breast Milk That Makes It Better Than Formula Milk?

Nutrition Facts on Breast Milk

Breast milk contains immune cells, antioxidants, antibodies, and many immunological elements that are tailored for a mother’s baby. Human milk is even considered a treatment modality for premature babies born under 37 weeks. Numerous studies have shown that premature infants fed with breast milk enjoy a better outcome than those fed with formula. In fact, they have a lower incidence and severity of various diseases such as diarrhea, bacterial meningitis, respiratory tract infection (colds), and ear infections. [2]

The full breakdown of antioxidants in breast milk has yet to be revealed, but a few can be named: vitamin C and E, superoxide dismutase, catalase, glutathione peroxidase, and other enzymes. All of these substances play a strong role in protecting an infant from oxidative stress.

What Is the Shelf-Life of Breast Milk?

shelf life of breast milk

Breast milk certainly has an expiration period where the milk does start to spoil. The reason for this is simple. Breast milk contains enzymes such as lipases that can break down fat and other elements in the milk. Breast milk also contains bacteria that can multiply more quickly in warm conditions and release toxins, and this will eventually cause the milk to spoil. As time passes, the natural enzymes in breast milk do break down its nutritional value. Meanwhile, for those who want to preserve their milk in cold temperatures, lipases in breast milk are even active in the freezer. This is why some people heat their breast milk in high temperatures before placing it in the freezer to deactivate the lipases in it. (However, there are more cons than pros with this process.)

It is important to remember that breast milk is not pasteurized like cow’s milk sold in the supermarket. Despite pasteurization, cow’s milk still contains living bacteria, which will cause the milk to go bad after a certain time. Although there is a “sell by” date that consumers take for an expiration date, the “real” expiration date is determined when milk becomes undrinkable. The shelf-life of breast milk is mainly determined by its temperature and the place where it is stored. And for those who drink milk directly out of the carton, remember that your mouth contains plenty of bacteria. Milk provides a great medium through which bacteria can grow, so you need to finish drinking it quickly! Please refer to the previous article, “How to Store Breast Milk,” for more detailed information.

What Happens to The Quality of Breast Milk After It Is Expressed?

How to store breast milk

There are three ways to store breast milk: on the kitchen countertop (room temperature), in the refrigerator (around 4°C, 39°F), and in the freezer (around -20°C, -4°F).

At room temperature:

  1. One study seems to suggest that the storage of breast milk beyond 3 hours at room temperature will show altered biochemical and nutritional qualities of the milk [3].
  2. Antioxidant activity will also decrease from the start. It is best preserved by freezing milk to a temperature below -80°C (-112°F) [4].
  3. Creamatocrit (concentration of fats and other compounds in breast milk) values decrease significantly after 30 minutes [5].

When refrigerated:

  1. Glutathione peroxidase (bodily enzyme that scavenges for free radicals) activity begins to decrease significantly from the onset of refrigeration [6].
  2. By day 1, there is a significant reduction of antioxidant activity while vitamin-C levels are decreased by 1/3 [7].
  3. By day 2, a significant decrease in “total antioxidant capacity” can be observed.
  4. Creamatocrit values remain stable up to day 14. [5]

In the freezer:

  1. Significant declines in fat concentrations are the highest during the first seven days (yet this slows down afterwards).
  2. By day 1, a greater increase in antioxidant levels is seen in comparison to refrigeration.
  3. By day 2, there is also a significant decrease in “total antioxidant capacity.” [4]
  4. By day 15, there is a significant decline in total nitrogen (which is used in the human body to make proteins in DNA, muscles, blood, hair, skin, and nails).
  5. Up to day 28, creamatocrit values remain stable [5].
  6. By day 30, vitamin-C levels decrease on average by 1/3 [7].
  7. By day 90, there is significant decline in lactose (which supports the growth of bacteria needed to fight undesirable organisms and promote intestine health; galactose also comes from lactose and is vital for a healthy brain and nerve tissue development in babies).

From these figures, it is clear that breast milk begins to deteriorate from the start, whether at room temperature, refrigerated, or frozen. Freezing breast milk will have destructive properties by killing all immune cells. The process of thawing breast milk is even more difficult so that further deterioration of the milk’s quality will occur. In addition, the type of container in which the milk is stored will affect its preservation. Glass is the least destructive container followed by plastic. Also, one should also never use a microwave for reheating [8].

Is There a “Best If Used by Date” for Breast Milk?

Does breast milk have an expiration date?

Does breast milk have an expiration date?

Finally, we are back to our core question! The absolutely best way to feed your child is right after the milk is expressed by using a breast pump or directly from the breast—milk is most nutritious and contains the most effective immunological benefits for your newborn child.

Reputable organizations such as the CDC [15], U.S. Department of Health and Human Services, the Mayo Clinic, and even La Leche League International have guidelines on storing milk. These guidelines are all wonderful in preventing the spoiling of breast milk. But isn’t the purpose of storing anything to protect and maintain its full value? After all, mothers choose to give breast milk to their babies not only for the nutritious elements but also for its immune-strengthening properties—living cells, antibodies, immunological proteins, anti-inflammatory factors, etc. [8].  Sadly, all major organizations fail to explain the consequences of storing breast milk in the freezer or in the refrigerator for that matter.  Parents need to know what happens to breast milk when it is subjected to such storing methods and for how long.

What Strategy Should I Consider When Feeding Breast Milk to My Child?

Aim to use the freshest milk first

Always feed the best possible milk to your child. Contrary to the American Breastfeeding Academy’s recommendations of giving the oldest milk first, parents should always aim to give the freshest milk first. One good meal will always be better than 2 poor meals—nutrition can always be supplemented, but immunological factors, once lost, are lost forever.

So What’s the Verdict for Storing Milk?

Don’t store breast milk in the freezer when possible & don’t store breast milk in the refrigerator for longer than 2 days!

Some people like the 5-5-5 rule, which is as follows: 5 hours out in room temperature, 5 days in the refrigerator, and 5 months in the freezer. However, basing the quality of milk on research studies, a 3-2-1 rule for breast milk is more appropriate: 3 hours in room temperature, 2 days in the fridge, and 1 month in the freezer.

3-2-1 Rule for Breast Milk

If you absolutely have to freeze breast milk, make sure to keep the milk on the freezer shelf in the rear where it is the coldest. Freezing breast milk the “correct” way will preserve some of the immunological benefits—such as certain antibodies—for a good 3 months[9]. But the bactericidal (bacteria killing) activity of human milk is reduced after 1 month of freezing[10]. Antioxidant activity of breast milk is significantly decreased by refrigeration but more so by freezing and thawing [4]. There are many other immunological factors that are also reduced simply from freezing. Conversely, fewer days in the freezer will mean greater retention of nutrients such as fats which are lysed (dissolved or destroyed) due to lipases (enzymes) present in breast milk. Also with regard to storage, “consumer” refrigerators cannot maintain a steady cold temperature and also have a wider cyclical temperature control with a defrost function. This feature makes is difficult to keep breast milk at a nice, constant, cold temperature. And as already discussed, the thawing process after freezing is even more difficult. Sometimes parents place frozen breast milk in the microwave to thaw it faster, but in this case, a greater destruction of beneficial immune components will occur. The best way to thaw breast milk is to place it in the refrigerator overnight or place it in warm water. Unfortunately, even thawing frozen milk correctly will still cause destruction of some nutrients and immune components.

What About Buying Human Milk from Milk Banks Online?

Breastfeeding is not an easy commitment to make.  One alternative way to obtain breast milk is from online milk banks as there are mothers who sell or even share their milk. However, there are serious health risks involved with this option. For example, some breast milk banks resort to pasteurization. This process and storage of breast milk on a long-term basis not only kills the bad elements but also destroys nutrients and beneficial immunological components, which normally make breast milk the perfect baby food [11]. Despite this issue, the benefits of “pasteurized” breast milk still have an advantage over the best baby formula brands.

Another problem regards recent reports in the news that most breast milk sold online contains a high measure of E. coli [12]. There are some businesses that pasteurize breast milk, but this sends a false message to consumers that such breast milk still has the same nutritional and immune value but without the harmful bacteria. It must be reiterated that while pasteurization kills off harmful bacteria, it also kills off the beneficial immune cells and reduces antibodies and other immune elements. [8] Human milk also possesses antimicrobial properties that are lost in one stage of thermal processing.[1] Another research study has shown that pasteurizing donor human milk using the current practice for Holder pasteurization is detrimental to the bioactivity of human milk [13].

For How Long Should I Breastfeed My Baby?

The American Academy of Pediatrics recommends exclusive breastfeeding for 6 months and continued breastfeeding for one year “as mutually desired by the mother and child.” However, the immune health of babies drops to its lowest levels around 6 months [14]. This is the period when the mother’s antibodies go away and the baby’s immune system takes over. For this reason, breastfeeding should continue at the very least through 9 months to a year to fully support the baby during his/her low immune period. To put this in perspective, consider that by age one, the baby’s immune system is only 60% of an adult’s.

Unpasteurized Cow’s Milk

On a side note, there are some advocates for using unpasteurized cow’s milk to feed babies. But as already described above, cow’s milk is best for calves, and human milk is best for humans. As a matter of fact, feeding unpasteurized cow’s milk to babies can be lethal. Such related diseases include Listeria, E. coli, and Salmonella.

Happy Baby USA strongly advises against purchasing from unknown breast milk dealers or unpasteurized cow’s milk online. The strong wish of mothers to continue feeding their babies breast milk is understandable, but the risk for causing great harm to your precious child is unwarranted. For instance, there are communicable diseases that can go unnoticed. Would you risk your child being exposed to HIV or hepatitis B? Furthermore, breast milk is not regulated like other foods that are sold in stores. And the great benefits of breast milk go away upon freezing and heating from pasteurization.

In Conclusion…

Is there a “best if used by date” in milk? Absolutely, the answer is yes. What can we take from this article?

  • Feeding your baby directly from the breast or right after expression is the best way to maximize the immunological and nutritional potential of breast milk.

  • A mother’s milk is tailored perfectly for her baby—not only as food but also as the perfect baby medicine.

  • Mothers shouldn’t even consider freezing as an option unless production outweighs demand.

  • Always feed your baby the freshest breast milk possible. Every hour counts!

  • Don’t even think about unpasteurized cow’s milk or another mother’s human milk.

  • Use the 3-2-1 rule for breast milk.


  1. Microorganisms in human milk: lights and shadows. Civardi E, et al. J Maternal Fetal Neonatal Med. 2013 Oct, 26. Suppl 2:30-4
  2. Blaymore Bier JA, Oliver T, Ferguson A, Vohr BR. Human milk reduces outpatient upper respiratory symptoms in premature infants during their first year of life. J Perinatol. 2002;22:354–9
  3. Eteng MU, Ebong PE, Eyong EU, Ettarh RR. Storage beyond three hours at ambient temperature alters the biochemical and nutritional qualities of breast milk. Afr J Reprod Health. 2001 Aug;5(2):130–134.
  4. Hanna N. Ahmed K. Anwar M, et al. Effect of storage on breast milk antioxidant activity. Arch Dis Child Fetal Neonatal Ed. 2004;89:F518–F520.
  5. Silprasert A. Dejsarai W. Keawvichit R, et al. Effect of storage on the creamatocrit and total energy content of human milk. Hum Nutr Clin Nutr. 1987;41:31–36.
  6. Silvestre D. Miranda M. Muriach M, et al. Frozen breast milk at –20 degrees C and –80 degrees C: A longitudinal study of glutathione peroxidase activity and malondialdehyde concentration. J Hum Lact. 2010;26:35–41.
  7. Buss IH. McGill F. Darlow BA, et al. Vitamin C is reduced in human milk after storage. Acta Paediatr. 2001;90:813–815.
  8. Lawrence RA Milk Banking: the influence of storage procedures and subsequent processing onimmunologic components of human milk.  Adv. Butr Res.  2001; 10:389-404
  9. Santana et. al. J. Dairy Sci. 2012 May; 95(5); 2319-25
  10. Takci S. et. al.  Effects of freezing on the bactericidal activity of human milk.  J. Pediatr Gasroenterol Nutr. 2012 Aug; 55(2):146-9
  11. Silvestre D et. al.  Effect of Pasteurization on the bactericidal capacity of Human Milk.  J. Hum Lact.  2008 Nov: 24(4):371-6
  12. http://www.nytimes.com/2013/10/21/health/breast-milk-donated-or-sold-online-is-often-tainted-study-says.html?_r=0
  13. Charles Czank et. al. Retention of the immunological proteins of pasteurized human milk in relation to pasteurizer design and practice.  Pediatric Research (2009) 66, 374-379
  14. Babies and Infection – Why does my baby keep getting sick? https://happybabyusa.org/2011/11/09/babies-and-infection-why-does-my-baby-keep-getting-sick/
  15. Center for Disease and Control Prevention:  Proper Handling and Storage of Breast Milk. http://www.cdc.gov/breastfeeding/recommendations/handling_breastmilk.htm


Additional readings:

  1. Marsha Walker.  Breastfeeding Management for the Clinician:  Using the Evidence.
  2. Tully et al.  Donor milk: what’s in it and what’s not.  J Hum Lact. 2001 May; 17(2): 152-5 http://www.eatsonfeets.org/docs/Donor_milk-What.s_in_it_and_what.s_not.pdf
  3. http://womenshealth.gov/breastfeeding/index.html
  4. C Weiner, Q Pan, M Hurtig, T Borén, E Bostwick and  L Hammarström.  Passive immunity against human pathogens using bovine antibodies http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1905285/
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