Lots of parents use machines to quickly prepare their babies' formula. But are they safe?

The past few years have seen a jump in popularity in powdered infant formula preparation machines. These devices dispense portioned hot water to instantly create bottles for hungry babies, saving parents time and hassle.

But powdered infant formula machines have come under fire over the past few years over criticisms that they don't work as well as they claim. Now, a new small study has found the vast majority of these machines don't even create water hot enough to kill harmful bacteria that could be lurking in infant formula. With that, it's understandable to have questions. What's happening, and how concerned should parents be? Here's the latest.

What's happening

A new study published last week in the journal Maternal & Child Nutrition analyzed data from 200 parents in the U.K. whose children were a year old or younger. Of those, 151 fed their babies powered infant formula and 143 included information on the water temperatures they used to reconstitute the powder (i.e., change it into a liquid form).

The researchers discovered that 85% of the 74 infant formula preparation machines tested by parents didn't produce water that was at least 158 degrees Fahrenheit, the temperature that is required to kill bacteria that may be in powdered formula. By contrast, only about 22% of parents who boiled water in a kettle to make infant formula bottles had the same issue.

The researchers pointed out in the study that there is an "urgent need for stronger consumer protections regarding powdered infant formula preparation devices," noting that machines that don't create high-enough temperatures put babies at risk for gastrointestinal infections. The researchers also said that most parents didn't appear to understand the risks of bacterial contamination with powdered infant formula.

This isn't the first time these devices have publicly faced issues. The pricey Baby Brezza Formula Pro Advanced, which promises to automatically mix, heat and dispense formula in seconds, was the subject of a 2020 class action lawsuit filed by families who said the dispensers produce watery formula, leading to poor nutrition in babies. The Better Business Bureau also has several complaints on its website about the machines. (A spokesperson for Baby Brezza told the New York Times when the lawsuit was filed that the company was "confident" the machines worked well when they were used properly and cleaned regularly.)

Do I need to worry?

Experts say the findings are noteworthy. "If the water isn’t hot enough, harmful bacteria like salmonella and cronobacter could survive and cause gastrointestinal infections in babies, which can leave them seriously unwell," lead study author Aimee Grant, a senior lecturer in public health at Swansea University, tells Yahoo Life.

Dr. Gina Posner, a pediatrician at MemorialCare Orange Coast Medical Center in Fountain Valley, Calif., agrees that this is concerning. "Formula-fed babies have a much higher rate of gastrointestinal issues and diarrhea," she says. "It could be due to the preparation of formula and not adequately killing bacteria."

But Posner points out that this can be deadly, as well. "Two babies in the U.S. died after having contaminated formula in 2022," she says. "While those deaths are rare compared to all of the babies that have formula, it's not OK if it's your child. We need to cut that number down to zero."

Those deaths were connected to the Abbott Nutrition recall, which happened after four babies were sickened across three states, per the Centers for Disease Control and Prevention. The infections were caused by Cronobacter sakazakii, which can get into formula in a processing facility or in the home through contaminated surfaces and even in the water, the CDC says.

What can I do about it?

Posner says it's important for parents to understand that powdered infant formula isn't sterile, might have germs in it and could make your child sick if it's not prepared properly.

That includes making sure that any water you use to prepare formula is heated to at least 153 degrees Fahrenheit when it's mixed with the powder, Grant says. "This should always be done separately to making a bottle, as putting a thermometer into the bottle can contaminate it," she says. If the temperature of the water is too low, it shouldn't be used to make the formula, Grant adds.

The CDC recommends considering liquid formula when possible since it's made to be sterile, and cleaning all surfaces, feeding items and your hands before making a bottle and feeding your baby. It's also important to use prepared infant formula within an hour from the start of the feeding and within two hours of preparing the bottle, since the combination of a baby's saliva and formula can allow germs to grow, the CDC says.

Posner recommends being on the lookout for signs that your baby is having trouble with their formula, such as diarrhea, blood in their poop and vomiting. "All babies spit up to some degree, but big amounts of vomit with each feed should be evaluated," she says.

The main takeaway

If you're using a powdered infant formula preparation machine, Posner suggests checking it regularly to make sure it dispenses water at a high enough temperature. "If you start to find that the machine is not dispensing the right temperature, you need to find a different machine that does or just boil the water yourself," she says.

These machines are time savers for parents, and Posner says they can definitely be helpful. "Just stay on top of the manufacturer's instructions and temperature, and make sure that you have a machine that works well," she says.