Why Does My Breast Milk Smells Like Vomit?

  • By: Sandra
  • Date: March 18, 2022
  • Time to read: 6 min.

A mother’s breast milk is supposed to be a nutritional powerhouse for her infant. It’s usually sweet-tasting and smelling. But what if your fresh milk smells like vomit? What does it mean and can your baby still drink it?

Why does my breast milk smell sour?

So, what causes breast milk to smell like vomit? There are several reasons why your breast milk may have a sour or rotten odor. One of the most common causes is excess lipase activity. This enzyme helps break down fats into fatty acids and glycerol, but if it’s present in excess, it can cause the milk to smelll like vomit.

Another common reason for milk that smells bad is bacteria in the refrigerated milk, either by storing it incorrectly or inadequate washing of bottles. If this is a once-off problem, this could be the issue and just throw the milk away and thoroughly clean and sterilize your bottles and pumping equipment.

Lipase activity is high in mother’s milk.

Lipase is an enzyme that helps break down fats into fatty acids and glycerol. It’s a good thing because it allows your baby to digest the milk better. However, too much lipase can cause milk to smell sour or like vomit. It is perfectly safe for babies even if the milk tastes not nice. This can happen with both fresh milk and expressed breastmilk.

What does excess lipase mean in breast milk?

When you store expressed milk at chilly temperatures, high lipase activity may accelerate the breakdown of lipids in the milk, resulting in a change in flavor and fragrance. It just means too many fatty acids in the milk.

How do you know if breast milk has high lipase?

The presence of high lipase in human milk can be determined by its smell. If your milk smells sour or like vomit, it’s likely that the lipase enzyme is breaking down the fat molecules in the milk.

Will babies drink high lipase fresh milk?

Yes! Although it may not smell as sweet as you’d like, your baby can still drink it. The sour or rotten odor is caused by the high lipase activity and is not harmful to your child. However, if you are uncomfortable with the smell, you can store the milk in a fridge or freezer until it’s consumed.

High lipase levels have no effect on the infant whether they consume the stored milk or breastfeed directly from the breast. Freshly pumped breast milk can smell just as bad as thawing breast milk or breast milk stored in the fridge if you have high lipase issues.

However, some newborns will reject stored milk with a distinct odor and flavor of sour milk, necessitating the development of a treatment to make the milk more appetizing. Although the milk smells unpleasant to us, this is just the milk fats and high lipase milk is perfectly safe for babies.

What About Frozen Milk with High Lipase?

If you’ve frozen your milk and it smells like vomit, don’t worry. The smell is caused by the high lipase activity and is not harmful to your child. However, if you are uncomfortable because the breast milk smells, you can store the milk in a fridge or freezer until it’s consumed and follow some of our tips below.

High lipase levels have no effect on the infant whether they consume the stored milk or breastfeed directly from the breast.

Chemical oxidation can occur in milk.

Chemical oxidation is a process that happens when oxygen molecules interact with certain chemicals, often causing them to change color or smell. This can happen to your breast milk if it’s stored in a container that’s not airtight or if it’s been exposed to light for too long. The milk will usually smell like vinegar or ammonia.

Improper storage can make breast milk smell like vomit.

The way you store your expressed milk can also lead to it smelling like vomit. If you don’t store it in an airtight container, the milk will be exposed to oxygen molecules which can cause it to smell like vinegar or ammonia. Likewise, if you expose the milk to light for too long, it will undergo chemical oxidation and change color and smell.

If you don’t store your breast milk properly, it can become oxidized and start to smell like vomit. This is especially likely if you use plastic containers that allow air in. Glass jars or bottles are the best options for storing expressed milk.

Storing milk in unclean containers or using an unclean breast pump will result in an off-taste and odor in the breastmilk. Breastmilk is vulnerable to contaminants, and even a trace of one will cause the milk to sour.

Mom’s Diet Can Cause Breastmilk to Smell

When a woman consumes polyunsaturated fat or drinks water containing iron or copper ions, chemical oxidation happens in her breast milk, causing it to smell like vomit. Other meals and drugs can also have an impact on the flavor of breast milk.

Changes in milk caused by the nursing mother’s diet will impact both stored milk and new milk suckled straight from the mother.

Because of their past exposure to varied food flavors through breastmilk, breastfed newborns enjoy a greater range of food sooner than formula-fed babies.

High Breast Pump Speed

Some moms claim that when they used their breast pumps at greater rates, their breast milk smelled like cheese and was frothy, but the odour improved once they reduced the pumping pace. If you are struggling to produce enough milk, read our ways to increase milk supply by pumping advice.

Is scalding my breast milk a solution to my lipase problem?

Yes! If your breast milk has a high lipase content, scalding it can help to reduce the odor. When you heat the milk to just below boiling point, the enzyme will be destroyed and the milk will smell more pleasant. It is quite easy to scald milk and it is still fine for breastfed babies.

Boiling your pumped milk will destroy the lipase enzyme and stop it from breaking down the fat molecules, which will reduce the unpleasant smell and stop it from having to taste sour. Put it on a rolling boil until you see tiny bubbles.

The most frequent method for preventing a soapy smell in milk is to scald the fresh milk. If you have a freezer stash of milk, you can scald the milk as you defrost rather than use a bottle warmer.

How to Scald Breast Milk

In a saucepan, heat the milk until little bubbles form around the pot’s edges. It must not boil; else, the nutrients in the milk will be destroyed. Scalding prevents enzymes from rapidly digesting milk. Cool the milk fast, ideally in ice, and keep it in the refrigerator.

Make sure to cool the milk quickly after scalding it. Putting it in a container and submerging it in ice will help to do this. You can then store the milk in the fridge or freezer bag.

Take Away

Although high levels of lipase can make breast milk smell sour or like vomit, it’s still safe for your baby to drink. The enzyme is not harmful and has no effect on the infant whether they consume the stored milk or breastfeed directly from the breast.

However, some newborns will reject stored milk that has a distinct odor and flavor. If this is the case, you may need to develop a treatment to make the milk more appetizing.

Chemical oxidation can occur in milk when oxygen molecules interact with certain chemicals, often causing them to change color or smell. This can happen to your breast milk if it’s stored in a container that’s not airtight or if it’s been exposed to light for too long. The milk will usually smell like vinegar or ammonia. Improper storage can make breast milk smell like vomit, and the way you store your expressed milk can also lead to it smelling like vomit.

If you don’t store it in an airtight container, the milk will be exposed to oxygen molecules which can cause it to smell like vinegar or ammonia. Likewise, if you expose the milk to light for too long, it will undergo chemical oxidation and change color and smell. If you don’t store your breast milk properly,