Mixing infant formula with hot water
September 9, 2011 6:05 AM   Subscribe

Question about infant formula milk and hot water

Hi all

The UK NHS's guidelines on formula preparation (pdf) say that formula should be mixed with boiled water that is no cooler than 70oC, in order to sterilise it. But I've read on some blogs that mixing the formula with hot water also kills some vitamins and other good stuff in it. Does anyone know if that's right, and if so, how to remedy it without compromising sterility?

posted by low_horrible_immoral to Health & Fitness (10 answers total)
In my experience, while you need to boil the water to achieve sterilization, you can close up the boiled water in a (hopefully also sterile) container, and refrigerate it after that.

Anyway, the formula that I've used had some cornstarch in it. So, mixing it with hot water caused it to seize up into an unusable mess.

The key with sterilization for infants is to get as close at you can to bacteria-free given a typical home environment. You're not trying to achieve scientific clean-room perfection, you're just trying to keep bacterial load below the point where it can overwhelm an infant's not-quite-developed immune system.

posted by Citrus at 6:26 AM on September 9, 2011

Vitamins aren't alive. You won't kill them.
posted by odinsdream at 6:37 AM on September 9, 2011 [2 favorites]

Some vitamins are denatured by heat. I think that's what the OP is talking about.

We always did the same thing as Citrus, and mixed up the formula with boiled, cooled water. We gave the kids the formula at room temperature, too. Neither of them ever showed any sign of becoming ill as a result.

Advice about sterilising baby stuff is a bit like advice about cooking meat. The offical line is always very much on the safe side.
posted by le morte de bea arthur at 6:44 AM on September 9, 2011

In my experience, while you need to boil the water to achieve sterilization, you can close up the boiled water in a (hopefully also sterile) container, and refrigerate it after that.

The NHS guidelines say:
Important: Allow the boiled water to cool to no less than 70º C. This means in practice using water that has been left covered, for less than 30 minutes after boiling.
The "no less than 70C" is so that the hot water sterilises the formula, it doesn't mean you can't store sterilised water in the fridge.

More info from that link:

Why is powdered infant formula not sterile?
The bacteria Enterobacter sakazakii is ubiquitous in the environment and may contaminate powdered infant formula during manufacture. It is impossible to be sure of avoiding this contamination. The bacteria may also be present on work surfaces in homes and nurseries and can contaminate feeds while they are being prepared by parents or carers.

Why should the water be 70 degrees Celcius?
Water at 70° C will kill most of the bacteria present in the powdered formula. This is the most important step in making up powdered infant formula as powdered infant formula cannot be guaranteed to be free of bacteria.

If water is boiled and put into the sterilised feeding bottles can it be stored in the fridge like this until the powder is added?
No, the water must be above 70° C when the powder is added otherwise the bacteria in the powder will not be killed.

posted by EndsOfInvention at 6:44 AM on September 9, 2011

I just used bottled or filtered water (you can get nursery water here in the US). I never heated up bottles or boiled water for them. My baby got used to room temperature bottles, it was easier all around. He's a happy healthy 1 year old now, so I obviously didn't kill him by not boiling his water!
posted by katypickle at 8:53 AM on September 9, 2011 [1 favorite]

How many children die from infections they pick up from their formula each year? Enterobacter sakazakii seems to be the concern listed most often. I can't find much info on anything else. Is there another nasty bug I'm missing??

Since 1958, 120 cases of Cronobacter sakazakii infection in infants have been reported, an average of fewer than three cases per year worldwide. Powdered infant formula, which is not sterile, has been implicated repeatedly as a vehicle of Cronobacter infection.

If that stat is correct, does 120 cases (not deaths) worldwide since 1958 justify the economic/environmental impact of a trillion boiled bottles of infant formula? At a 40% morality rate for an infection, a fatal auto accident is about 2,500,000% more likely.
posted by pjaust at 9:38 AM on September 9, 2011 [1 favorite]

Thanks for answers so far. Just to be clear, I don't want to debate sterilising versus not sterilising formula with hot water. I know lots of people don't and their kids are fine.

My question is, does adding the hot water denature (thanks le morte!) or otherwise destroy or render inaffective vitamins or other good stuff in the formula powder? Thanks!
posted by low_horrible_immoral at 11:35 AM on September 9, 2011

Yes, adding the hot water can denature or render ineffective vitamins etc. in the formula. However....

-without testing, it is impossible to stay whether this will occur to a significant degree. Since so many children ingest 70C-dissolved formula and still develop normally, I would wager that a significant amount of the denaturables remain effective.

-other things can also cause denaturation of the good stuff in the formula: exposure of the powder to light, heat and/or oxygen. Obviously, the effects of these things will occur more slowly than what happens with hot water, but then again, some things may stand up well to hot water or heat, but rapidly decompose with oxygen or light. (This is a part of how dry foods spoil, in addition to the whole rotting thing).

If you wanted to have the most nutritious formula, you could mix it immediately on opening the airtight container, with cold or room temperature water, and then filter sterilize it with a filter that's small enough to capture microbes (0.2 microns). But then again, some of the protein in the formula would be probably get lost form sticking to the filter and those filters are expensive.... Probably not worth it in the end. There are probably plenty of studies of how different vitamins get denatured, but the fact that the vitamins are dried and stored in the presence of milk proteins will help to preserve them. The fact that the proteins are themselves a mixture will help to preserve the proteins.

So to sum up, perhaps there are some studies on the effects of hot water on formula, but given that people feed their children formula prepared in a myriad of different ways, hot water, heat, light and oxygen all cannot prevent a sufficient portion of the vitamins from reaching the children. I'd be more worried about the disinfection factor, but even then, not too concerned, based on pjausts's numbers.
posted by Tandem Affinity at 2:44 PM on September 9, 2011 [1 favorite]

Thankyou, Tandem, that's really interesting and useful - I like the idea of using microfiltration!
posted by low_horrible_immoral at 2:31 AM on September 10, 2011

You're setting yourself up for a world of hassles by over-doing something like this. Yes, you'll certainly want to deal with BOILING WATER in the middle of the night when prepping a bottle... NOT. What you want to avoid is making the formula ahead of time and leaving it at room temperature conditions as that makes for a horrendous breeding ground for bacteria.

Work with your pediatrician to see of a multivitamin is warranted.

Billions of children are fed in all manner of "unsanitary" first world conditions and live to tell the tale. Don't over think this.
posted by wkearney99 at 1:54 PM on September 10, 2011

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