ByHeart Baby Formula From All Lots May Be Contaminated With Botulism Bacteria, Tests Show

“Based on these results, we cannot rule out the risk that all ByHeart formula across all product lots may have been contaminated,” the company wrote.

Tests of ByHeart infant formula tied to a botulism outbreak that has sickened dozens of babies showed that all of the company’s products may have been contaminated.

Laboratory tests of 36 samples of formula from three different lots showed that five samples contained the type of bacteria that can lead to the rare and potentially deadly illness, the company said Monday on its website.

“Based on these results, we cannot rule out the risk that all ByHeart formula across all product lots may have been contaminated,” the company wrote.

At least 31 babies in 15 states who consumed ByHeart formula have been sickened in the outbreak that began in August, according to federal and state health officials. In addition, other infants who drank ByHeart formula were treated for botulism in earlier months, as far back as November 2024, although they are not counted in the outbreak, officials said.

Clostridium botulinum type A, the type of bacteria detected, can be unevenly distributed in powdered formula. Not all babies who ingest it will become ill, though all infants under age 1 are at risk, medical experts said.