Your breast milk can't spoil inside your breasts, experts say.
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Um, Can Breast Milk Actually Go *Bad* Inside Your Boobs?

Turns out, your breasts are basically really great food storage.

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If you’re breastfeeding your baby, then you already know your breasts are pretty amazing. Filled with the world’s most nutritious food as if by magic, your breasts are, in fact, one of your super powers as a mom. But just because they can hold your baby’s food supply doesn’t mean there isn’t a lot of work on your part. For parents pumping or doing a combo of pumping and breastfeeding, concerns about breast milk spoiling inside your boobs can be a little confusing. Is there an expiration date for your body’s handmade liquid gold?

While it’s a completely reasonable question, especially if your feeding schedule is off and you haven’t been able to breastfeed in a while, your breasts are actually perfect regulators. If your body is producing milk, there is no way for it to spoil in the breast, according to the New Jersey Department of Health. This is because it is not a stagnant product of your body. “Breast milk is a living organism, unlike the pasteurized cow’s milk that we purchase at the store. The living components in breast milk are constantly changing based on your baby’s needs and the lactating parent’s microbiome,” Heather ONeal, a certified nurse-midwife and lactation consultant in West Virginia, tells Romper. “These dynamic properties serve to protect the breast milk, as well as optimize the health of the infant eating the milk. Additionally, the good bacteria in the milk will work to eliminate bad bacteria within the breast as well as outside of the breast in the form of pumped milk. In fact, freshly pumped breast milk can sit at room temperature for six to eight hours before we have to worry about it ‘going bad.’” Well that’s a relief.

Another reason that moms sometimes worry about the freshness of breast milk is if they’ve pumped at some point and witnessed the separation of “foremilk and hindmilk” after it sits in the refrigerator for a few days, according to ONeal. Not to worry, she says. “As your baby gets older and the time between feeds extends, there will be a separation of the components of breast milk within the breast, much like unpasteurized milk that sits in the refrigerator. This separation is completely normal and expected for milk that sits for a period of time. A gentle ‘swirl’ of the milk after heating will reconstitute the milky elements and make it look normal again.”

However, you should note the length of time that breast milk can be stored in the fridge. The Centers for Disease Control and Prevention (CDC) recommended that breast milk only be stored for six to eight hours at room temperature, in a cooler or cooler bag for 24 hours. Breast milk that's stored in the fridge, towards the back, at temperatures below 39 degrees Fahrenheit can be stored for a total of five days. In the freezer, it can be safely stored for three to six months. If you're lucky enough to have a deep freezer, it can be held safely for six to 12 months.

Speaking of timing, however, try not to go too long between breastfeeding sessions. Ashley Georgakopoulos, IBCLC and Motif Medical Lactation Director, tells Romper, “Breast tissue is also designed to reabsorb milk when milk sits for too long over time, such as during the process of weaning. On the flipside of this, while the milk is safe to provide, it’s not safe — and quite risky — to go long periods of time, typically four hours or more, between some sort of expression for the mother. This is because milk also serves as a flush for the breast tissue and its systems, and bacteria and yeast can travel into the tissue through the nipple, setting up things like mastitis and thrush infections.”

The body is a regenerating machine. While there are some things that can't be regenerated — like those brain cells you lost watching nine hours of Real Housewives as you cluster-fed your baby — most things in your body keep remaking themselves or healing from damage. So worry not, my lactating friends. The milk in your own personal udders lasts indefinitely. As long as you're producing it, it's safe to drink. However, that yogurt in the back of your fridge that you're eyeing? Do you even remember when you bought that?


Heather ONeal, a certified nurse-midwife and lactation consultant, Breastfeeding for Busy Moms

Ashley Georgakopoulos, IBCLC and Motif Medical Lactation Director

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