Bottle feeding correctly

celtic_owen

Hi,

would greatly appreciate some help here as we have a newborn and have been given very confusing conflicting information regarding the best way to bottle feed.

To start with we decided to bottle feed from the beginning.

We did an ante natal course a while back and the midwife mentioned there how for the last while people have recommended that you pre make bottles and store them in the fridge for up to 24 hours and heat when you need them. However she said that this has now been decided not to be the best way as the milk can go off etc...

This was confirmed in the coombe when before we checked out they midwives came around with some brochures on various things. One being feeding. She said to ignore the last page or page 7 or something like that as it is now decided your better off not making up feeds in advance.

So we started to make up the bottles with the sterile water and when the feed was due we would add the formula. This has been working great. baby is 2 weeks old. Already 5oz over her birth weight. Loves the feeds at room temp and we dont have to heat.

Next thing the pubic health nurse calls out and is horrified to hear this is how we are making the feeds and says we should make them in batches and refridgerate or make them one at a time. One at a time is not an option. Boiling a kettle and leaving cool for 30 mins, mixing formula, cooling all before you start to feed. Seriously without sounding lazy but thats not an option. We are more then happy to pre make the feeds and refridgerate them but this is what the first midwife said not to do. So confusing but also very infuriating as its not like were getting mixed advice from nosey neighbours or know it all mother in laws. These are the professionals, not only offering different advice but being adamantly against what the other one says.

Were we wrong to make up the bottles with sterile water then ad the formula when feeding? My partner is so upset that she has been "doing it wrong". I had two weeks off work to help with feeding and getting a routine and now just as i go back to work it has been all thrown out of order and my partner is very worried about doing the right thing at home alone.

Any advice would be very much appreciated. I understand there will always be several schools of thoughts on different aspects of raising children / feeding etc.. but its just with the two polar opposite views from the midwives we are completely at a loss.

Sorry to drag on but on a side note the baby was happy to take the bottles at room temp and now by refreidgerating them we are forced to heat them to make them drinkable and feel we are now giving our baby warm feeds that she doesnt need when we were lucky enough to have a baby happy to take them cold. She spits up more when they are warm and has much worse gas.

advice pleeeeeeaaaaase.....


Thanks!

edellc

OP I breast feed my fella but did give the occasional bottle he is now 19mths and still getting 3 bottles a day and I do exactly what you do.....His day time bottle I boil a fresh kettle fill up a bottle with the required water and store in the middle of the fridge, then once he needs it I take it out fill with the required formula and put it into a container of boiling water to heat it up.

His bed time bottle I make at least and hour before he goes to bed so it is sufficiently cooled and add formula

And he still wakes in the middle of the night so I bring a freshly made bottle with freshly boiled water to bed with me and bring the formula up separately and when he wakes up I dont bother heating the bottle nor do I need to cool it as it is at room temp I just add the formula and give it to him

My little fella is rarely sick and loves his bottles and really who on earth has the time to be making fresh bottles all the time especially if you have a new born and are bottle feeding exclusively

So IMO your doing nothing wrong and as long as your not adding formula to the bottle and storing for 24hours then whats the problem its water, boiled and cooled all the badies have been boiled out of it and its cooled in a sterile environment

Welcome to motherhood and the start of the worrying I didnt have a grey hair until I had him and now well I wont say the state of my hair

pwurple

The reason they advise you to make the bottles with freshly boiled water, rather than letting it cool first, is that formula powder is not sterile, and is not required to be.

So, to sterilise the formula, you put it in hot water.

Why this changed recently was there were two cases in the US where babies got something nasty. It was found to have originated in the formula powder. Hot water would have killed the bacteria, cold water does not.

There has has never been a case of it here in Ireland. It is nothing to do with weight of the baby, or anything else. The advice is to make the bottles freshly every time with hot water and then cool it under a tap. If you can't do that every time (out and about or something) then the next best thing is to make the bottles up in advance with hot water and formula mixed, and them store cold.

It's a risk, albeit a small one, to add the formula to cold water, but the chances of getting anything nasty are small. I didn't like to take the risk, as e coli can kill a child and I'm paranoid like that, but loads of people do it and are grand altogether.

newmammy2011

Hi there,
Firstly congrats on your new arrival!
I had the same issue last year after having twin boys, getting conflicting opinions from different healthcare professionals about how to make up bottles.
The hospital told me that ideally you shouldnt make them in batches, but if you really have to, to add the formula to hot water, cool quickly and refridgerate.
My Phn told me to cool the water quickly, refridgerate and then add the formula when the bottle was being given.
Also my friend had a baby around the same time and her Phn said to add the formula to hot water, cool and then refridgerate.
I then rang Safefood and they said that if making bathces(which they dont recommend) to boil kettle, wait 30 mins,add formula, cool and refridgerate. Their reason being that because the powder is not sterile it should be added to hot water, ideally 70 degrees, so that the water sterilises the powder but isnt so hot that it kills the nutrients.

I made bottles like this for about 3 months, but then we were going on holidays and I didnt want to be carrying around made up bottles, so I began making bottles exactly as you have been. My boys have never had an upset tummy!

Hope thats been of some help and not confused you further!

cbyrd

I boil the water fill the bottles and before i add the formula i heat the water up to how hot he likes it.(40 secs in the microwave :eek:) I don't make the batches and cool cos i ended up throwing out more bottles this way cos he'd only drink an oz or 2. If you want to heat your bottles up fairly hot then add the formula powder and cool down under a running tap while shaking the bottle..i find its the quicker way to do it..;) and just a note on the phn... if its working for you don't let the phn undermine you.. they're really good at that :rolleyes:

wmpdd3

In 2007 when my sister had her first she was told the 'non sterile baby food' story leading to upset stomach etc. But still the advice was make up 24hrs worth of bottles with just water and add powder at needed. I did this for my first in 2010 as well, with out issue. I think as long as you always wash hands before making the feed and store the scoop in the lid of the formula, there is very little chance of the powder getting infected with a bug. In the book i have from the hospital from jan 2012, it says to prepare bottles as above!!

How Strange

The issue isn't formula becoming infected once opened and in your home, it's that the product could be contaminated by the time it gets to your home. The Sanlu Group/China Milk scandal is the one I remember and that contaminated milk came from New Zealand.


Op, the I think the advised process now is make them individually with boiled water however how realistic or practical that is for most parents is another matter.

Hannibal Smith

We were told in 2009 that the best way to do it was to make a batch of water bottles, keep them in the fridge and put the formula in as you go and reheat. The reason for this at the time was because the formula isn't sterile so the least amount if time it spends in the water the less chance it has to contaminate the water. We were also told that the world health organisation change their recommendations on how to make the bottles on a regular basis.

Our second arrived last Oct and we've made the bottles exactly the same way.

Now it seems to have changed but the reasons are the same, the formula isn't sterile.

Congratulations on your new arrival...this is just the first of many confusions

How Strange

It's like everything to do with parenting; whatever you do right today will be wrong tomorrow!

Hannibal Smith

How Strange wrote: »

It's like everything to do with parenting; whatever you do right today will be wrong tomorrow!

Ain't that the truth how strange and then you'll get the grannies 'back in my day we did such and such and mine are all grand

Lola92

Going by the HSE guidelines:

1st Best Option - Make up bottles one at a time as needed. Boil a kettle of fresh water, leave to cool in the kettle for 30mins. Add water to sterilised bottle, and necessary amount of formula. Cool in a tub of ice water/ under running tab until cool enough to drink and feed to baby.

2nd best option - Do as above but make up a batch of bottles in one go, cool rapidly and store in fridge for up to 24hours. These must be drunk within 2 hours max of leaving the fridge and discarded once baby is finished and not re-refrigerated.

3rd best option - Add freshly boiled water to a steralised bottle(s). Close top and leave to cool to room temperture. Add necessary amount of formula powder to bottles as needed. (very handy if out for longish periods of time, more than 2 hours)

littlefriend

Lola92 wrote: »

Going by the HSE guidelines:


2nd best option - Do as above but make up a batch of bottles in one go, cool rapidly and store in fridge for up to 24hours. These must be drunk within 2 hours max of leaving the fridge and discarded once baby is finished and not re-refrigerated.

3rd best option - Add freshly boiled water to a steralised bottle(s). Close top and leave to cool to room temperture. Add necessary amount of formula powder to bottles as needed. (very handy if out for longish periods of time, more than 2 hours)

I do the 2nd best option mentioned above there. When I put her down for the night I make a batch of 6 bottles, allow them cool, then put them in the fridge. I take one out about 30 - 60 mins before the next feed is due. It works very well for me doing it this way. This is going to sound ridiculous but I find it kind of soothing knowing that all her food is ready and waiting for her. I also find it really relaxing preparing the bottles at night when she has gone to bed.

If I'm going to be out and about, I tend to buy those little cartons and bring a sterilised bottle with me.

pwurple

Hannibal Smith wrote: »

The reason for this at the time was because the formula isn't sterile so the least amount if time it spends in the water the less chance it has to contaminate the water.

The above doesn't make a lot of sense to me. Both the formula and the water are going into the baby.... Doesn't really matter if they contaminate eachother.

vibe666

Lola92 wrote: »

3rd best option - Add freshly boiled water to a steralised bottle(s). Close top and leave to cool to room temperture. Add necessary amount of formula powder to bottles as needed. (very handy if out for longish periods of time, more than 2 hours)

this is us, ours is going to be 8 months old very shortly and has always been fed on demand and you don't have the time to do anything else when you have a screaming baby demanding to be fed.

caprilicious

Just to confuse matters further, the guideline about making bottles up fresh as required was extended to nurseries also & has been done as such the past few years.
i.e, when leaving my daughter to creche when she bottle fed, I had to leave sterilised bottles into the creche each day & a tin of food.
They would then boil the water as required & add formula.

I recently enrolled my daughter for a different nursery for when I return from maternity leave and they told me the Hse now require them to take bottle in pre-made in batches only.

I tried making up bottles fresh but in the middle of the night when you're beyond exhausted it is not safe.
I ended up with more scalds from half asleep burning myself, or wasting bottles as being half asleep couldn't remember if I had added 4 scoops of formula or 5 :rolleyes:

My daughter took her bottles at room temperature, so I used option 3

Lola92 wrote:

3rd best option - Add freshly boiled water to a steralised bottle(s). Close top and leave to cool to room temperture. Add necessary amount of formula powder to bottles as needed. (very handy if out for longish periods of time, more than 2 hours)

I then had the formula pre-measured in a sterilised formula measure container.

It is so frustrating the way they keep changing the 'rules', it just guarantees whatever way you do it with your first child, by the time you have child 2,3 etc you will have done it 'wrong' on at least one child :rolleyes:

Congrats on your new baby OP

Hannibal Smith

pwurple wrote: »

Hannibal Smith wrote: »

The reason for this at the time was because the formula isn't sterile so the least amount if time it spends in the water the less chance it has to contaminate the water.

The above doesn't make a lot of sense to me. Both the formula and the water are going into the baby.... Doesn't really matter if they contaminate eachother.

It matters to me if the food junior gets is contaminated, hence I do it the way I was told

How Strange

pwurple it's not that either formula or water contaminates the other or that the water could get contaminated after cooling down but that the formula could be contaminated during production. Formula isn't sterile although a lot of people suppose it is.

In China in 2008 the formula contained a substance called melamine which killed 6 babies and affected another 300,000.

In Dec 2011 Walmart had to recall their infant formula after 2 babies died. It was a precautionary measure as both were fed on that formula.

So while the risk is probably very low in western developed countries that is the reason why formula companies and health agencies now recommend making formula with boiled water.

vibe666

How Strange wrote: »

So while the risk is probably very low in western developed countries that is the reason why formula companies and health agencies now recommend making formula with boiled water.

pretty much just to cover their own asses even though the chances of you actually feeding your baby contaminated formula are lower than anything you could do in pretty much any of the billions of other things you will ever do with them.

ignoring the chinese thing for a minute since melamine is actually legally used (in very small doses) in baby formula anyway and boiling it isn't going to remove it, think about all the babies in the world, even in just the last 10 years, being fed formula on a daily basis without dying due to contamination.

the chances of it actually happening are so low, that in any practical terms its so close to zero that there is pretty much no difference.

then think of the number of babies who die every day from pretty much any other cause, accidental or otherwise. from just picking them up, choking on toys, SIDS, drowning in the bath, car accidents and anything else, all will be much much higher.

if you are going to sterilise formula, you might as well wrap them in cotton wool and hide them in a nuclear bunker away from the world just in case some other impossible thing happens to them.

it's just another bullsh1t kneejerk overreaction by the nanny state to a tragic one in several billion chance accident.

give it another year and some other tragedy will change their minds and you'll have to do it all differently again anyway, so just trust your own gut and do what you think is right.

How Strange

vibe666 of course they're covering their asses so if you ignore their instructions and your baby gets sick they have no liability.

Hannibal Smith

I thought the Chinese baby thing was down to poor food products. I'm just going by memory here, I haven't googled yet. But I thought the babies died from malnutrition because the formula was 'watered down' in a sense

Ah...just googled...in 2008 it was melamine, four years before it was watered down food. Presumably in both these instances though it wouldn't have mattered what way you prepared the bottles. They weren't filled with the right nutrients.

The fact that the formula isn't sterile is a given....its what you do to/with it seems to be the crux

Lola92

vibe666 wrote: »

pretty much just to cover their own asses even though the chances of you actually feeding your baby contaminated formula are lower than anything you could do in pretty much any of the billions of other things you will ever do with them.

ignoring the chinese thing for a minute since melamine is actually legally used (in very small doses) in baby formula anyway and boiling it isn't going to remove it, think about all the babies in the world, even in just the last 10 years, being fed formula on a daily basis without dying due to contamination.

the chances of it actually happening are so low, that in any practical terms its so close to zero that there is pretty much no difference.

then think of the number of babies who die every day from pretty much any other cause, accidental or otherwise. from just picking them up, choking on toys, SIDS, drowning in the bath, car accidents and anything else, all will be much much higher.

if you are going to sterilise formula, you might as well wrap them in cotton wool and hide them in a nuclear bunker away from the world just in case some other impossible thing happens to them.

it's just another bullsh1t kneejerk overreaction by the nanny state to a tragic one in several billion chance accident.

give it another year and some other tragedy will change their minds and you'll have to do it all differently again anyway, so just trust your own gut and do what you think is right.

I have to admit I don't really agree with you here. Yes, the formula companies are 'covering their own asses' as you put it, but why would they suggest anything other than the safest (currently known) way to prepare formula bottles?

The whole point of boiling water is to ill any bacteria which could make baby ill. The point of adding formula powder to hot water (70 degrees) is so that any harmful bacteria present in the formula will be killed, but the nutrients intact. This is because formula is not sterile when you buy it in the shop, but also particularly when the tub is getting opened, sitting on your kitchen counter at various points throughout the day or whatever frequency it may be. I mean who knows what possible bacteria is floating around your kitchen, even with the most stringent hand washing etc. Also sterilising bottles, you are trying to control for any possible cause of illness in your baby and prevent against it.

Thankfully the incidence of babies dying from gastroenteritis here is very low, but why would you honestly take that chance with a new baby when there is a very manageable preventative measure available? (I am referring to batch making bottles). It is easy to do and doesn't take much more time that preparing one single bottle. It's a no brainer for me tbh.

There are a whole lot of things in life that you can not really control, some which you have listed above - accidents, SIDS, but we do our best to protect against the things we can. We use stair gates, car seats, strap baby into a highchair so they won't fall etc. Why wouldn't we do the same when preparing the only food they will consume in their first 4-6 months of life when they are at their most vunerable?

vibe666

personally i wouldn't make up a 24 hour batch of formula and refrigerate it as i think it would be a lot more likely to go off than when made fresh, based on how badly a bottle of formula smells after just 2 hours from being made.

i'd much rather give the baby freshly made formula using boiled water that has been put into bottles and sealed and until these new 'rules' came out over the knee-jerk reaction to those two kids in the US, the way i do it would have been considered the standard way to do it and is still perfectly valid and has worked just fine for us and millions of other people before us.

and yes, the whole world including your kitchen has bacteria floating around everywhere in it, and it's right next to where you sit your baby in his or her high chair to feed them and unless you seal them in an air tight sterile bubble and only feed them 100% sterile things in a 100% sterile environment and never take them out of it, they WILL be exposed to bacteria 24/7, just like every other baby in the world.

pwurple

Hannibal Smith wrote: »

It matters to me if the food junior gets is contaminated, hence I do it the way I was told

That was exactly my point... if the powder is contaminated, then you want to uncontaminate it with hot water. The time at which the water and formula meet doesn't make any difference, it's the temperature of the water that kills the bugs. Maybe I read you wrong... nevermind.

Hannibal Smith

pwurple wrote: »

Hannibal Smith wrote: »

It matters to me if the food junior gets is contaminated, hence I do it the way I was told

That was exactly my point... if the powder is contaminated, then you want to uncontaminate it with hot water. The time at which the water and formula meet doesn't make any difference, it's the temperature of the water that kills the bugs. Maybe I read you wrong... nevermind.

But if that was the case, why can't you put the formula in the boiling water, cool them and store them in the fridge?

Lola92

Hannibal Smith wrote: »

But if that was the case, why can't you put the formula in the boiling water, cool them and store them in the fridge?

If you add formula to boiling water it damages the nutrients as well as killing the bacteria, so not as good quality for baby. That is why they recommend to leave it to cool to 70 degreed C, approx 30mins in the kettle, before adding the powder. Once it is made up it will go off within a few hours, or a day in the fridge so that is why it is recommended to do it in small batches or as needed.

cbyrd

But there again if you look at the bottle design the most vulnerable part is the teat.. the very part you have to hold to get the thing put together.. :eek: (using a tongs is just impracticable) when i was breastfeeding i didn't sterilise my boobs i know it's not helpful but i just had to throw it in there

http://www.safefood.eu/Publications/Consumer-information/How-to-prepare-your-baby-s-bottle.aspx

Hannibal Smith

Ah thanks Lola, I always wondered what the 30 mins was about.

But if the water is sterile...and you put the feed in at 70 degrees, the feed also becomes sterile doesn't it? So if the length of time the food and the water are together contamination wise...then why can't you make a batch of feeds at 70 degrees, cool them and store them in the fridge? That seems to be w big faux pas now.

Cbyrd...I put the teat and white round bit together when putting them in the steriliser? Otherwise you're defeating the purpose I would have thought ?

pwurple

Hannibal, that is exactly what is recommended for batches. Make them at 70 degrees and stick in fridge. That's what we did.

We seperated the teat from ring before sterilisation, because you want to let the steam get into all the nooks. Just wash your hands before assembling.

Anyway, we have an formula industry in ireland with an excellent safety record, and beyond the first few weeks, unless you have an immunosuppressed baby the sterilisation is probably overkill as well.

Hannibal Smith

But pwurple, that seems to be a major no-no now. No matter what way we were told to do the bottles, making up a batch with the formula in it was never an option. Even if you see people out and about you'll see them all with their dispensers and bottles of water?

cbyrd

All 4 of mine were bottle fed from various times after 6 weeks... i did the making up from batches, make them one at a time and making from water already in the bottles.. over 13 years everything i was doing 13 years ago is wrong

Including injections, bottles, tummy time, how to lie them down to sleep at night, how many blankets, how to hold their head, let them support their weight then don't.. it's all a question of if it's working for you, you're baby's relatively happy content and sleeping (as much as they will) then you're doing ok.. there's no strict hard and fast rule of how to do it, if there was it would be written down by me and i'd make a flipping fortune.

What works for one baby may or may not work for another.. everything is changeable It's called a personality..one baby is quiet one is loud.. so cries and doesn't cry too much.. one is affectionate one is standoffish.. loves to be held and doesn't.. i have one of all of the above

pwurple

Hannibal Smith wrote: »

But pwurple, that seems to be a major no-no now. No matter what way we were told to do the bottles, making up a batch with the formula in it was never an option. Even if you see people out and about you'll see them all with their dispensers and bottles of water?

I don't think so Hannibal. Making with hot water and cooling afterwards is safer than using the dispensers. It says it on the tin of formula to do it that way (hot water), the hospital advises it that way in the babycare classes before the birth, and again at the hospital in the nursery.

The only place that seems to advise the use of the those dispensers with cold water, is the place that sells them.

We sterilse the bottles, the water and the formula. If you do it the other way, you don't sterilse the formula.


I'm not judging anyone who does it the other way, we all take calculated risks, otherwise we wouldn't step outside the door of our bedroom. But that is the lowest risk method at the moment, so it's no harm to be at least aware of it.

Lola92

pwurple wrote: »

I don't think so Hannibal. Making with hot water and cooling afterwards is safer than using the dispensers. It says it on the tin of formula to do it that way (hot water), the hospital advises it that way in the babycare classes before the birth, and again at the hospital in the nursery.

The only place that seems to advise the use of the those dispensers with cold water, is the place that sells them.

We sterilse the bottles, the water and the formula. If you do it the other way, you don't sterilse the formula.


I'm not judging anyone who does it the other way, we all take calculated risks, otherwise we wouldn't step outside the door of our bedroom. But that is the lowest risk method at the moment, so it's no harm to be at least aware of it.

You are correct that batch making is advised over the other method pwurple, except in the event that the bottle would be out of the fridge for 2 hours. After this there is a chance that bacteria will grow so they recommend you make up the bottle with boiled cooled water and formula powder.

I used to do this for my daughter if we were going out for the day. Say we left at 9.30 and she would have her morning bottle at 10.30 - I would have this made up and left in the thermal pocket of her change bag. But for her 3pm bottle I would bring a bottle of boiled cooled water and formula.

pwurple

Lola, I tried it when we stopped sterilising the bottles when she got older... I put the coiled water water into bottles and put in the powder when needed. I found it didn't dissolve properly in cold water even with some vigorous shaking. Clumps of powder would sink to the bottom. I was using SMA, maybe it's just that powder?

Hannibal Smith

Hi pwuple, I understand what you're saying and it makes sense that the water sterilises the food when put in at 70 degrees, but we were always told, if you're not going to do it the way they say on the tin, you have to store the bottles of water in the fridge and add the formula as you go. Everyone told us that, from gp to phn. They made it clear that in no way were we to make up batches of bottles and leave them in the fridge with the formula on them. This thread is the first place I've heard people are still doing this.

I never add formula to cold water. We obviously heat the bottles as we go and put the formula into heated water that way though. Otherwise it doesn't mix properly.
I swear, head out to Avoca some day, you'll see everyone with their dispensers

Lola92

I used Aptamil and Cow and gate 1st infant formula that way and never had any lumps at all. We just gave it a vigorous shake and that seemed to do the job for us!

I had been told no to batch making too and then read a brand new HSE formula making guideline that came out which put them as I said in my last post. I have it on my other laptop which I won't have access to for another week or so but I will post it up when I can.

pwurple

Different powder must make the difference Lola. The SMA is clumpy as heck in cold water. It kinda floats in it!

Hannibal, I'm naturally a cynic. I don't believe anything anyone says unless I know the reasons for it, see it for myself or double check elsewhere. I take nothing as a given and question every tiny thing in life. (Driving the other half utterly mad with my constant Why Why Why Why. )

So, as the reason for the hot water is sterilisation of formula, loads of mammies not sterilising tells me lots of people either have the out of date information... or have made the choice, like we did, to stop sterilising at some point.

I reckon we were told different things because the instructions were updated recently enough. My small one is 13 months.

Hannibal Smith

I know Pwurple...I'm just at pains to point out that the reason I do it the way I do it, is because I was told it was perfectly safe to do it that way, not because I think 'ah to hell with it sure he needs a few germs' lol I wouldn't take those kind of risks with his food, or do anything with his food unless I was sure it was safe to do so. So I asked the phn and the doc when my first was born, and double checked when the second was born in October and they told me the same thing again.

The easiest way to do it would be to make a batch up with formula and all, I would have loved to do it that way, so I'll definitely double check next time I'm with the GP.

Just goes to prove the point the OP was making though and kind of explains why they're so confused about the whole thing, when we're all given different information

bionic.laura

I think you're both right. According to this document from the food safety authority you can do it both ways. http://www.fsai.ie/WorkArea/DownloadAsset.aspx?id=764

The recommended way is to make up the formula using water that has been boiled and left to cool to 70 degrees for half an hour. Using boiling water isnt recommend as it damages nutrients in the formula. The bottles should then be cooled quickly. This kills any bacteria as formula isn't sterile. They worry is about e sakazakii in the formula. That document says storing the formula made up in the back of the fridge for 24 hours is ok. if it's stored below 4 degrees in the back of the fridge and used within 24 hours you should be ok as bacterial growth will be very slow at that temperature. They say to store at the back of the fridge as it is the coldest part.

Adding the powder to a sterilised bottle with cooled boiled water is seen as ok for when youre out. There's no need for storing the bottles of water in the fridge as you hear some people doing. It should be fine left out as there shouldn't be anything in the boiled water that will grow. When you add the powder you should use the bottle as quickly as possible. At room temperature bacteria will start to grow but if you use the bottle quickly it should be ok. The container for the powder should be clean. In this case the formula hasn't been sterilised but using it quickly means that colonies of bacteria won't have time to grow to harmful amounts.

When the powder and the water are mixed once it's above fridge temperature bacteria can grow. Bacteria can even grow in the fridge that's why they don't recommend storing it too long. So that's why they recommend using a bottle that is out of the fridge too within two hours.

What I do is make up bottles for the day and store them in the back of the fridge and heat them up as needed. I make up a sterilised bottle with water and add the powder for the first bottle of the day as if I had one in the fridge it would have been there 20 hours or so. Anyway hope that helps. I knew doing microbiology in work would come in useful one day...