What Happens if a Baby Drinks Old Formula?

(Last Updated On: November 29, 2022)

Baby drinks old formula, and you are worried about that. Well, no need to get 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 also 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. You sniffed the feeding bottle of your Baby and realized that you had just fed your Baby the bottle of old spoiled milk.

Now, you are thinking about what will happen and what to do.

This article is for you as it will answer all of your queries, including how to prevent it from happening in the future and what to do if your baby already drinks old formula.

What Do You Mean by The Old Formula?

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

Because 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 department of infant health to prove the dangerous effects of these bacteria on babies.

Plus, these bacteria can be deadly for babies that already suffer 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?

If you are unsure whether the formula is good for your Baby, it’s better to stay on the side of caution. If you feel like the milk is getting old, throw it away and don’t consider offering it to your Baby.

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 bad, 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

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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

Label the feeding bottles to prevent your little one from drinking spoiled and old formula. 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 any 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. If you delay discarding the old formula, the chances increase that someone will unknowingly give it to your Baby, and your Baby will get an infection.

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

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 the process of 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 afterward. In contrast, other babies experience fever, so you need to visit a pediatrician immediately.


After the Baby drinks old formula, diarrhea is how the body tries to eliminate the toxins. 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. Therefore, you need to monitor how frequent the vomiting is. 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 plays a vital role 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.

Quickly shifting your Baby from formula milk feeding to breastfeeding is not the key to keeping a baby happy and healthy.

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

It will help in preventing the contamination of the food of your Baby.

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.

But it would help if you kept the liquid formula properly sealed and according to the manufacturer’s instructions.

Avoid the Use of Microwave

Before feeding the Baby, it is not required to warm the formula. But if you want to warm the formula milk, then the microwave is not the best option.

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

Be Careful During the Preparation and Storage of the Formula

To prepare the formula milk for your Baby, close the lid after scooping correctly and make sure that it remains tightly closed during storage.

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 before touching anything in close contact with your Baby’s mouth, such as feeding bottles.

Related: Is There a Generic Nutramigen Formula?

Some of the Most Frequently Asked Questions About “Baby Drinks Old Formula” are Discussed Below:

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.

Where after growth, they can be harmful to the babies. 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?

After passing 2 hours, it is not safe for the Baby to drink that formula. This is because of the higher growth of the bacteria in the formula milk, which results in the breakdown of nutrients and vitamins present in the formula. After that, if the Baby drinks that formula, he will not get any nutrients that he needs.

A baby can also become sick after drinking 2 hours of old formula.

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 the formula 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, there is nobody you can do 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 formula far away from your sight.

Suppose you forget to check the date before purchase and mistakenly bought that already 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 normal 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. In that case, you need to call a pediatrician.

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. If you prepared a bottle of formula milk for the Baby and he did not drink from it before, you can reheat it once before giving it to him.

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 Together?

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

Can I Place the Leftover Formula Milk in the Fridge to Use Later?

No, you cannot do this. It is not recommended to use the leftover milk, so there is no need to put it in the fridge because that milk is more prone to bacteria and can be harmful to the Baby.

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

The powder formula of most of the big brands can be used for up to 1 month 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.

It is crucial always to follow the recommendations of the brands, and in case of any doubt, discard the powdered formula that is open for more than one month.

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 the money you spend on expired baby formula. But if you don’t want to discard the expired formula, then 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.

The Last Word from LookAfterBabies

You are well aware of what will happen if the Baby drinks old formula and what you are expected to do after that. 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 bad 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.