How Many Times Can You Reheat Formula? Your Guide To Formula Safety

It is common for babies to only drink a portion of the formula that you have made up. If you have made up a bottle of formula and your baby has left a couple of ounces, you may be wondering if it is sage to reheat. We take a look at the guidance on reheating formula and how you can reduce formula waste. 

It is best to prepare formula as and when you need it and it can be heated once It is not advisable to reheat formula as it may be unsafe. 

If you are familiar with the baby formula you will know that once it has been heated for a feed it should not be reheated if there is any leftover. This is because once the formula is prepared and heated it will begin to grow bacteria which can be harmful to your baby.

This information is something that you are likely to be aware of if you have read the manufacturer’s label on the formula packet or you have sought advice from friends. If you are not sure exactly why you cannot reheat the formula, we tell you why here. 

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What The Experts Say

While you may be able to heat certain food types more than once, it is not safe to do so with formula.

The US Food and Drug Administration (FDA) declares that “it’s not a good idea to repeatedly reheat formula because lots of nutrients can be lost.”

It adds, “Never use a microwave oven to heat bottles of breast milk or infant formula. They may explode or the milk may get too hot” 

Safely Storing Formula

To make sure that you can heat formula safely you need to adhere to the following CDC guidelines. They say that formula can be pre-prepared but it should be stored in the fridge for no more than 24 hours.

If the formula has been left at room temperature it will begin to spoil pithing two hours. 

The main reason that formula begins to spoil is due to bacteria growth. Warm temperatures encourage germs to multiply quickly, which is why after two hours the formula will be inedible.

While bacteria grow faster in warmer temperatures they will still grow at lower fridge temperatures which is why pre-prepared milk needs to be stored in the fridge and only taken out when you are ready to heat up.

In addition to bacteria growing in warm conditions, it starts to grow when your baby begins feeding and the saliva enters the bottle. There is no cause for alarm here as some level of bacteria is normal and this will not harm your baby.

However, if you then allow the half-consumed formula to sit and develop more germs then this can be an issue if you then re-use the formula

Warming Pre-Prepared Formula

As stated, the pre-prepared formula should be stored in the fridge, and then the following steps should be taken:

  1. Remove from the fridge immediately before you are going to reheat
  2. Place the bottle or container in a bowl of heated water for 10-15 minutes or you can use a bottle warmer
  3. Test the formula to make sure that it is not too hot for your baby to drink
  4. Use within 2 hours and discard any remaining formula

How long does the formula last once heat?

The formula should be consumed within 2 hours after being heated as after this time the chances of bacteria forming increases. Some people falsely believe that bacteria will only start to grow if their baby starts to drink from the bottle.

While bacteria will grow more rapidly once the baby’s mouth starts to suck on the teat of the bottle, it will still be present as soon as the formula is left, even within the first hour. 

Can I Put Heated Formula Back in the Fridge?

Unfortunately, once you have heated the formula it should not be put back in the fridge. If your baby does not drink all of the formula you prepare it will need to be discarded.

Bacteria thrives in the heated formula as it is warm and moist and it can be harmful to your baby. You may think that putting the formula back in the fridge will prevent further bacteria from growing but it can still grow at refrigerator temperature so it is best to be safe. 

If you are putting leftover or unused formula back in the fridge you are likely doing so intending to reheat it when your baby is hungry again.

Reheating the formula will encourage a bottle that is already growing bacteria to grow even more which will put your baby at risk of becoming ill.

Can Formula be Refrigerated More Than Once?

As you have read, putting formula back in the refrigerator more than once is not advised. If you have only taken the formula out of the fridge for a short time and you have not heated it then it may be safe to put it back in.

If you cannot be sure how long the formula has been out of the fridge, it is a very warm day, or you have had kept the bottle in a warm place, such as a baby full changing bag, then it is not advisable to put back in the fridge.

Taking the formula out of the fridge for any period of time will encourage bacteria to grow and the longer it is left out the more the germs will multiply.

It is important to note that if you do take the formula out of the fridge for any period of time and then you put it inside again the original 24 windows should be adhered to for safe heating of the milk. If you believe that the formula in the fridge has been in the fridge for more than 24 hours then it should be thrown away.

When making multiple bottles of formula to be heated at a later time you should label the containers so you know exactly how long they will stay fresh. 

Can you Reheat Ready-Made Formula?

If you sometimes buy ready-prepared formula instead of powdered formula you may be wondering if the rules on reheating are different. The heating process is the same as if you have made up your formula.

The ready-prepared formula should be stored in the fridge for as long as the date in the packet allows and once it has been heated it should be consumed within 2 hours. No leftover formula should be put back in the fridge and if has been left out to get too warm then they should not go back in.

If you happen to open the packet of formula but you don’t use it straightway it can be stored in the refrigerator for up to 48 hours. 

4 Ways to Avoid Formula Waste

As we have learned, you must adhere to strict preparation, storage, and heating guidelines for baby formula. We know that it is hard to throw away formula as it is expensive and you will have spent tired hours preparing it.

However, there are ways that you can prevent wasting formula. Here are just four ways you can stop wasting formula:

1.Don’t pre-prepare when traveling

If you are traveling and want to be as prepared as you can, you may end up making up bottles that end up going to waste as it is nowhere safe to store or heat on your journey. Instead, you can take a portion of formula and water separately and mix as and when you need to.

If you think this will be too difficult you can plan for ways to keep the formula cool while traveling and have a stop at a place where you can safely heat the formula.

2. Make smaller portions

One of the biggest mistakes when it comes to preparing formula is making too much.

If you find that your baby varies how much formula they want you can make smaller portions and you can always make up another if your baby drinks all of the first batches.

If you know that your baby will not wait for the second batch to be made yup you can prepare two smaller portions and just heat them one by one.

3. Try a milk pitcher

If you do find that your baby is wanting a few ounces at a time, instead of having multiple bottles or containers in the refrigerator you can buy a milk pitcher so that you can store it all in one container and pour into bottles when you need to.

4. Set a schedule

As your baby gets older they will be able to depend less on feeding on demand and be able to stick to a schedule that will help you predict how much formula will be consumed

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