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What Happens if Baby Drinks Old Formula?

Exhausted and sleep-deprived parents make some blunders with their baby care duties. One of the most common mistakes they commit is letting their baby drink old formula. What happens if your baby drinks old formula, then?

Thankfully, most of the time, there are no serious consequences if your baby drinks old formula. This article will explore if there are any dangers associated with old baby formula together with the things you should watch out for if ever it happens.

When Can You Consider Baby Formula Old?

It has been revealed that baby formula can already be considered old two hours after its preparation. It is the result of the formation of Enterobacter Sakazakii or Cronobacter Sakazakii. It is a type of naturally occurring germ that can settle in dry foods like herbs, powdered milk, and baby formula.

This germ can make anyone ill but can be dangerous for babies, specifically premature babies as well as those who have preexisting medical conditions such as problems with the immune system.

woman in teal tank top drinking milk from feeding bottle

Why Does Baby Formula Go Bad After One Hour?

Although the safest and best way to feed formula to your baby is to let him drink from the bottle right after you prepare it, most parents often give the formula to their baby a little while after mixing it.

While the baby formula doesn’t instantly turn bad after one hour, bacteria may start growing, and feeding it to your baby will become more harmful as time passes.

The baby formula may also go bad when you leave it out at room temperature because bottles of prepared formula should be properly stored inside the fridge for no more than 24 hours.

When you let the bottle sit for one hour at room temperature and it remains untouched, it would be best to tip it away. If your baby already drunk a few of the bottles, the safest way is to keep the rest of the formula for up to 2 hours.

It is unsafe to feed the formula to your baby after 2 hours because the combination of the saliva of your baby and the spoiled milk may lead to the growth of harmful bacteria.

What Symptoms Will Babies Show After They Drink Old Formula?

Did your little one drink some old formula? Keeping a close eye on your baby is the best way to determine if the old formula affected your baby negatively.

Make sure you seek medical advice immediately if you notice any of the following:


It is not easy to spot dehydration, but you have to watch out for symptoms of dehydration. The skin of your baby may start to look pale and flush. Dehydrated babies may also refuse liquids and may not pass as much urine.

See to it that you call your baby’s doctor right away once you notice any symptoms of dehydration. The thing about dehydration is that it can happen very fast, particularly when your baby is vomiting or suffering from diarrhea.


It is important to remember that diarrhea will lead to a more severe case of losing electrolytes and fluid compared to vomiting.

This means that you need to give salty water to your baby to keep him hydrated and call the doctor for medical assistance.

If your baby’s diarrhea remains unchecked, this may result in dehydration that can be quite fatal for your little one.


When your baby drinks old formula, he may contract the cronobacter infection. As mentioned earlier, cronobacter is considered the most harmful bacteria found in old formulas. This bacterium can survive in powdered milk with the ability to multiply fast enough.

Cronobacter infection can result in bacterial meningitis or secondary bacterial infections that can be both be fatal. Unlike meningitis in adults, your baby will only suffer from fever without a stiff neck.

If your baby is suffering from meningitis, he will also be unresponsive and sluggish. Call your doctor immediately once you notice any of these signs.


Drinking old formula can also make your baby throw up as a result of food poisoning that can occur within 24 hours.

Your baby’s body may quickly try to flush out the bacteria and spoilt food from his system. If your baby starts vomiting, make sure that you give him bits of salty water to help him stay hydrated and substitute the fluids he lost.

Remember that all of the above symptoms are the result of your baby’s little body attempting to get rid of the bad bacteria. The only problem is that the symptoms may lead to dehydration which can be quite serious and fatal.

Once your baby shows any of the symptoms and he doesn’t get better after several hours, you need to call your doctor immediately. Again, dehydration can be quite dangerous for babies, especially if they don’t take or drink any new liquids to replenish the lost ones.

What to Do to Prevent the Dangers of Old Formula?

If there is still any leftover old formula, make sure that you throw it away immediately to avoid making the mistake of feeding it to your little one.

Also, if a daycare provider is looking after your baby, make sure that you label all the formula bottles complete with the time when they were prepared to make it easier to feed your baby with the ones that were prepared the earliest.

This should also be practiced at home to prevent all of the risks associated with your baby drinking old formula.

Wrap Up

In general, babies don’t get sick if they drink formula as long as it was prepared 12 hours or lesser prior to feeding. Make sure you watch out for signs of drinking old formula so you can address the problem right away before it gets worse for your baby.

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