What Happens if a Baby Drinks Old Formula?

(Last Updated On: September 15, 2023)

Baby drinks old formula, and you are worried about that. Well, no need to panic.

Parents or caregivers also evolve during parenting, along with babies. As parents, you try different routines and processes and stick to the one that best suits you.

During this period, you learn other things about your Baby.

It’s a beautiful journey, but mistakes can happen on this path. One of them is that your Baby was hungry and started crying in the middle of the night.

You wake up half-asleep to prepare a formula feed for your little one. After feeding him, you feel like something is wrong. Now, you are thinking about what will happen and what to do.

What Do You Mean by The Old Formula?

As per pediatricians’ recommendations worldwide, you should not offer your baby formula milk prepared 2 hours before.

According to them (pediatricians) or different mothers, the formula milk becomes old or spoiled after 2 hours of preparation.

Enterobacter sakazakii is the bacteria responsible for the spoilage of formula milk if left open for a more extended period. This bacterium is present naturally and settles in dry food, including Baby formula, powdered milk, herbs, etc.

These bacteria can cause disease in anyone but are more harmful to babies. Many studies were conducted in the infant health department to prove these bacteria’s dangerous effects on babies.

Plus, these bacteria can be deadly for babies suffering from some medical conditions because of their weak immune systems.

Related: Does Foam in Formula Cause Gas?

How Do You Know That The Formula Has Gone Bad?

To prevent foodborne diseases, it is advisable to follow good hygienic practices. Therefore, make it a habit to properly wash and dry your hands before preparing the formula feed for your Baby. Also, observe the milk keenly for any signs of spoilage.

Read more: Can I Use Bug Spray on My Infant?

When Baby Formula Begins To Go Wrong, You Need To Look For The Following Signs:

  • Bad smell
  • Clump formation
  • Separation of the formula’s ingredients
  • The Baby might start disliking the feed or refuse it
  • The Baby became sick after feeding the bottle of feed

Related: How to Dress Baby For the Winter Months?

How Can You Prevent Your Baby from Drinking an Old Formula?

Here are some of the guidelines that you can follow to prevent your Baby from drinking old and spoiled milk and, ultimately, from getting an infection:

Label the Bottle of Formula Milk

Mention the date and time of the preparation of formula milk on the label, just like you do for the expressed breast milk.

This will help your partner and caregiver know which one to feed first and avoid unwanted mishaps.

Related: What Kind of Water Should Babies Drink?

Discard the Old Formula Instantly

Several guidelines are available that clarify how long you can feed prepared formula milk to your Baby.

According to some studies, maintaining the right temperature for storage can increase the viability of the prepared formula milk for up to 24 hours.

Still, throw away the old and spoiled formula to be on the safe side as soon as possible.

Related: Does Foam in Formula Cause Gas?

Store it Properly

It is very crucial to store the formula correctly. Make sure that the place of storage and preparation of formula milk is free from any material that can be harmful or dangerous for your Baby, including the bottle of old formula milk.

After the birth of your Baby, the first few months are crucial, so be careful during this time.

Be Observant

It is also possible that the formula milk becomes infected way before the expiration date because of any contamination.

So, immediately contact the doctor if you notice any unusual symptoms in your Baby after feeding him the formula milk.

Avoid Blaming Each Other

It is straightforward to continue the blame game whether your Baby’s illness is yours or your partner’s fault. But in the end, it brings nothing.

Therefore, concentrate and identify what wrong you both did, work on it, and try to prevent it from happening in the future.

Related: Is Ready-to-Feed Formula Easier to Digest?

What Are the Signs of Infection After Baby Drinks Old Formula?

Many parents want to know what will happen if the Baby drinks a 12-hour-old formula. So, some of the symptoms of a baby drinking spoiled formula are mentioned below:


When your Baby drinks old formula, you will first notice vomiting or sometimes diarrhea.

Through vomiting, your Baby’s digestive system attempts to get rid of the old, spoiled food.

For some babies, vomiting works well, and they feel relaxed and settled afterwards. In contrast, other babies experience fever, so you must visit a paediatrician immediately.


During this, the body treats the spoilt food differently compared to vomiting.

But remember that both these processes can lead to dehydration and weakness in the Baby and affect their appetite. Also, you need to offer water to the Baby for rehydration. After that, visit a doctor immediately.

What Are the Steps You Need to Take to Prevent an Infection?

It seems like breastfeeding is vital in reducing the risk of different bacterial infections. Still, it is also important to note that formula milk works best for many families around the globe.

The more important thing is maintaining hygiene and taking the proper precautions while feeding your Baby, regardless of the feeding method.

Some of the precautions that may help you during this journey are given below:

Read More: Why Does My Baby Get Startled While Sleeping?

Properly Sanitize Everything

Sanitization of everything required for preparing and storing the formula feed is essential.

Bacteria are everywhere in nature, and you cannot do much about that. They can also settle on surfaces, so paying attention to good hygiene is better.

In the case of breastfeeding, if you use breast pumps, it’s also required to sanitize every part of the pump before and after usage.

Use Liquid Formula

Enterobacter sakazakii bacteria responsible for the spoilage of powdered formula milk has less adherence to the liquid formula. This means that if you use liquid formula milk, there are fewer chances that your Baby will get an infection caused by these bacteria.

Avoid the Use of Microwave

The microwave does not evenly warm the food, leading to temperature variations in the different parts of the food, favoring the growth of other bacteria.

Be Careful During the Preparation and Storage of the Formula

Confirm that the water you use to prepare formula milk is clean and has been boiled and cooled already.

Remember to feed your infant within 2 hours of preparation and discard any remaining milk.

Ensure That Your Hands Are Clean

Pay attention to the cleanliness of your hands. Always wash them with soap and water after using the bathrooms or changing the diaper of your little one.

Also, remember to clean them before preparing formula feed and touching anything in close contact with your Baby’s mouth, such as feeding bottles.

Related: Is There a Generic Nutramigen Formula?

FAQs – What Happens if a Baby Drinks Old Formula?

What Happens if the Baby Drinks an Hour-Old Formula?

The reason you cannot give old formula to your Baby is the bacteria that are present in the mouth of the Baby.

These bacteria first come from the nipple into the babies’ mouths, which can transfer to the formula.

However, some parents or caretakers follow the rule of two hours.

What happens if a Baby Drinks Old Formula

After drinking one-hour-old formula, your Baby may be fine. But then again, you need to be more watchful.

What Happens If Your Little One Drinks a 2-Hour-Old Formula?

This is because of the higher growth of the bacteria in the formula milk, which results in the breakdown of nutrients and vitamins in the formula.

After that, if the Baby drinks that formula, he will not get any nutrients he needs.

What Happened if I Accidentally Gave an Old Formula to My Baby?

An old formula is not suitable for the Baby in any case. The outcomes will be the same, whether you feed them accidentally or intentionally. Giving your Baby an old formula can make them ill, especially if it has been prepared two hours before.

Can Expired Formula Make the Baby Sick?

Suppose you already gave your Baby an expired ready-to-feed formula. In that case, you can do nothing about it other than regret it. It may cause your Baby to have an upset stomach.

But don’t ever try to use that formula again, and throw the rest of the expired procedure far away from your sight.

Suppose you forget to check the date before purchase and mistakenly bought that expired formula from a store. In that case, you can get them and explain the issue. They may offer you a refund.

The smell of expired formulas is worse, and their color also varies from the standard color of the excellent formula.

What If the Baby Found an Old Bottle and Drank It?

Mainly, it did not cause any harm to the Baby, and he did not fall ill. So you don’t need to be worried.

But in other cases, he may show some signs of the old formula, such as vomiting and diarrhea.

Can I Reheat My Baby’s Formula? “OR” How Many Times Can I Reheat the Formula?

Well, the answer to this question will depend on the scenario. But if the Baby drinks from the bottle but does not finish it, don’t reheat it. Instead, discard the remaining milk.

Can You Mix Breastmilk or Formula?

Yes, you can give your Baby breastmilk and formula milk after mixing them and within the same feeding bottle.

How Long Can We Use Powdered Formula After It Is Opened?

However, suppose you purchased the powdered formula of an organic brand.

In that case, it may not go well earlier than one month, depending on its ingredients.

What To Do With Expired Baby Formula? 

It may be appealing to use expired baby formula, but never. Your kid’s safety is more significant than spending on expired baby formula. But if you don’t want to discard the expired formula, look for other options.

Some of these are:

  • Please return it to the grocery store from where you purchased it.
  • Exchange with a new one.
  • Donate it to an animal shelter.

Conclusion – What Happens if a Baby Drinks Old Formula?

It is essential to be careful while preparing formula milk for your little one.

You need to follow all the precautions properly, especially if your Baby has a weak immune system because some infections can even lead to the death of the Baby.

Remember, a prepared formula can only be used for 24 hours if appropriately stored under the right temperature. However, it cannot go well within an hour without the proper storage conditions.

Mostly, nothing terrible will happen if the Baby drinks old formula. However, sometimes, there are chances that it will cause foodborne illness and lead to vomiting, diarrhea, and dehydration. In that case, you need to visit a doctor immediately.