by Marion Nestle
Dec 27 2011

What’s with the problems with powdered infant formula?

Mead Johnson Nutrition says it has tested additional samples of its Enfamil baby formula and still does not find the bacteria responsible for the death of one newborn infant and the illness of another.

The bacteria at fault are Cronobacter sakazakii, formerly known as Enterobacter sakazakii (bacterial taxonomists proposed this reclassification in 2007).

Last week several retailers pulled Enfamil infant formula from their shelves because of fears that Enfamil was contaminated with this organism.

Walmart was the first to issue a recall.

The retailers actions were unusually cautious.  Neither Mead Johnson nor federal investigators had evidence that the formula caused the illnesses.  Federal agencies had not asked for a recall.

But the retailers must have connected the dots:

  • The most likely source of C. sakazakii is powdered infant formula.
  • The two infants ill with C. sakazakii were fed Enfamil powdered formula (although the second ill infant drank several kinds of formulas).

In the chapter on infant feeding in my book, What to Eat, I noted that the main difference between one kind of infant formula and another is its cost.  Powdered formula is much cheaper than the already reconstituted kinds.  I asked:

Beyond the difference in cost, does it matter which level of convenience you choose?

It might.   Powdered formulas are not sterile.  In this, they differ from concentrate and ready-to-serve formulas, which have been heated to sterilize them.

In 2002, the FDA warned pediatricians that powdered milk formulas could be contaminated with Enterobacter sakazakii, a type of bacteria that causes rare but terrible and sometimes fatal infections in infants, especially those who are premature, weak, or in hospitals.

The FDA says it is not aware of any E. sakazakii infections in healthy full-term infants in home settings.

Reports from other countries, however, suggest that even healthy babies may sometimes acquire such infections [see Kwan Kew Lai, “Enterobacter sakazakii infections among neonates, infants, children, and adults: case reports and a review of the literatur,”(see:  Medicine, Vol. 80, pp. 113-122, March 2001.]

In 2001, the CDC published a case report on this type of infection.  It pointed out that “…in 50-80 % of cases, powdered infant formula is both the vehicle and the source (direct or indirect) of E. sakazakii-induced illness.”

The CDC’s conclusion:

Clinicians should be aware of the potential risk for infection from use of nonsterile enteral formula in the neonatal health-care setting.

The World Health Organization has a Q and A:

3. How does infant formula get contaminated with Enterobacter sakazakii? Can other foods also be contaminated?

Basically there are three routes by which Enterobacter sakazakii can enter infant formula:

a) through the raw material used for producing the formula;

b) through contamination of the formula or other dry ingredients after pasteurization; and

c) through contamination of the formula as it is being reconstituted by the caregiver just prior to


Enterobacter sakazakii has been detected in other types of food, but only powdered infant formula has been linked to outbreaks of disease.

So the recalls were precautionary.  It’s hard to argue with that—unless you are a stockholder; Mead Johnson stocks declined by 5% as a result.

At the moment, the source of these particular C. sakazakii infections is unknown.  Let’s give the retailers credit for taking precautions to protect the public.

As for infant feeding in general: Breastfeeding is best, of course.  If you are using formulas to feed your infant, the liquid ones are safer—but much more expensive.

  • is the formula or the bottles that must be sterilized?

  • Anthro


    It’s my guess that the formula should be sterilized IN the bottle. People used to have sterilizer kits, much like home canning equipment, for this, back when baby bottles were always glass.
    It seems that sterilization would be the way to go–especially for babies with health issues.

    At the risk of sounding judgmental (heaven forbid!), I wish more could be done to encourage and support breastfeeding.

  • Miriam

    Liquid formula is safest in terms of sterilization, but what about BPA and goodness-knows-what-else leaching into the liquid product? I would think a lot more would leach into liquid than powder, because of how it moves around.

  • Cathy Richards

    When using formula for whatever reasons, there are new Canadian federal guidelines now for how to mix powdered formula to ensure any of the common bacteria are killed. It involves mixing the formula with barely cooled boiled water (no colder than 70 degrees celsius) and then letting it cool to serving temp and using it right away or storing in fridge for no more than 24 hours. Previous recommendations were to boil water, then cool it, then mix the formula.
    Details at:
    Ready to serve or concentrate formula is recommended rather than powdered for babies with health risks (premature, immunosuppressed, etc).

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  • Dawn

    World Health Organization guidelines say that babies under one month shouldn’t be getting powdered formula. Their immune systems just aren’t developed enough to deal with these kinds of infections. When will the FDA recognize that the lives of infants are worth more than the profits of Big Pharma that are involved here??

  • mousehouse

    Here’s the big problem with ready-to-serve and liquid concentrate formulas, though: the packaging likely contains BPA ( So the safer option vis-a-vis BPA is to use powdered formula, which the FDA promises is in BPA-free containers.
    So what’s a concerned parent (who for whatever reason cannot breastfeed) to do?

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  • tibichon

    Both. The bottle to keep anything from contaminating the formula and the powder to kill any pathogen (cronobacter (i.e. E. Sakazakii), salmonella, etc.) that could be in the powder. Powder is not already sterile. Parents, caregivers, etc. must boil the water for a minute or two then cool the water to NO LESS than 158 degrees F. (70 degrees C.). , use a candy thermometer to watch for the right temp. Then add to the formula to kill any pathogen. Make your bottles for each feeding. Don’t make extra to put in the refrigerator for later.

  • Lindsay Halley

    Not everyone can breastfeed, it’s not anyone else’s place to say whether or not someone should breastfeed. People are quick to judge mommies that don’t breastfeed but don’t know their situation, ex latch issues, low supply etc. not saying you are being judgmental, but many people are. I would do anything to be able to breastfeed but unfortunately I was not able to keep my supply up no matter what I did, and let me tell you I spent atleast 15 hours a day pumping, trying different angles with the pump, little tricks I figured out to get the pump to suck harder trying to squeeze out every last drop until it just got so exhausting and painful for no results that I stopped. But people don’t see that part of it. And Im not ignorant I know that not all people try but a lot do and we are still looked at as if we are feeding our babies poison by feeding them formila, like we don’t love our babies as much as someone who is able to breastfeed.

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