Here's What Happens If You Give Your Baby Spoiled Breast Milk, According To Experts

We asked, they answered.

Storing breast milk is something most breastfeeding mothers have to do, regardless of whether they’re pumping all the time or just building up an emergency stash. But what if you didn’t notice that the milk you had spent so much time pumping and storing has gone bad? What happens if you give your baby spoiled breast milk?

The first thing to do is to figure out if your breast milk has actually gone bad. Sometimes moms may see their breast milk separating, but International Board Certified Lactation Consultant (IBCLC) Deborah Dominici of Babies' Breast Friend tells Romper that fat separation in breast milk is completely normal, and not an indicator your milk has gone bad. She says that sometimes when a mom has higher lipase in her milk, and when her frozen breast milk is defrosted, it could have a soapy or metallic smell, but it would still be safe to give to your baby.

Danielle Spradlin, Certified Lactation Consultant from Oasis Lactation Services, explains that when breast milk becomes not-so-fresh, it tastes and smells bad, with a sour, dirty sock smell.

If you find that your milk hasn’t passed the smell and taste test, and you’ve fed it to your baby, Dominici says they will likely throw it up. “Very rarely will milk spoil if you follow proper breast milk handling and storage guidelines,” she explains. "But occasionally it happens and generally, the result will be vomiting up the spoiled milk.”

There are steps you can take to make sure your milk doesn't go bad, too. Spradlin explains that human milk is a living fluid, with antimicrobial agents that keep it fresh and safe to consume after pumping, but unless you follow proper storage guidelines, like the ones set out by the Centers for Disease Control and Prevention and the World Health Organization, it could go bad.

How you handle your milk makes a difference, too. Spradlin suggests storing your milk in clean containers, and pumping with a properly cleaned pump to maintain fresh milk. She explains that cases of babies getting sick from pumped milk are usually due to cross contamination, which can occur when a caregiver is preparing a bottle while also preparing foods with a contaminant (like salmonella or E. coli), which is why good hand hygiene is even more important. “We forget that common objects we touch like computers, cell phones, diaper bags, and pump bags are not clean,” adds Spradlin, “and sometimes these items sit on the floor or in the floors of our cars.” Hand contamination is the easiest contamination to control, she notes, by just washing your hands well before pumping.

Seeing your baby squirm or reject your milk should be the first signs to stop feeding it to them. Spradlin says that for the most part, babies will probably let you know if it the milk tastes bad by refusing it and spitting it out. If you do find your baby is vomiting after consuming spoiled milk, they're most likely OK, but call your pediatrician if the vomiting continues, there are other symptoms, or if you just want to have some peace of mind.