U.S. health officials say testing showed that powdered whole milk used to make ByHeart infant formula could be a source of contamination that led to an outbreak of infant botulism that has sickened dozens of babies.

A Portland, Oregon, baby got sick with infant botulism after drinking contaminated ByHeart formula donated through a program that helps poor and homeless families.

The U.S. Food and Drug Administration sent warning letters to four top retail stores for failing to promptly pull contaminated infant formula tied to a dangerous outbreak from their shelves.

Federal health officials have expanded an outbreak of infant botulism tied to ByHeart baby formula to include any illnesses reported since the company began production in 2022.

The makers of ByHeart infant formula say tests of products tied to a botulism outbreak show that all of the company's products may have been contaminated.

At least five families say their babies were treated for infant botulism after consuming ByHeart formula months before a current outbreak was detected.

Health officials say at least 31 babies in 15 states have been treated for botulism as an outbreak tied to ByHeart formula continues to grow.

The parents of two babies who were sickened in an infantile botulism outbreak linked to recalled ByHeart infant formula are suing the company.

Baby formula manufacturer ByHeart recalled all of its products sold nationwide Tuesday.

ByHeart issued a voluntary recall for certain batches of its baby formula after concerns arose over potential cross-contamination, according to the Florida Department of Health.