By Stephanie Stahl

PHILADELPHIA (CBS) — Concerns are growing over potentially contaminated baby formula. The FDA is expanding its investigation following reports of infant illnesses and a second death.

The formula in question has been voluntarily recalled, and it comes at a time when parents are already dealing with a shortage of baby formula due to supply chain issues.

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“I was panicked,” a mother said. “I was crying.”

The parents of one of the babies with salmonella, possibly linked to baby formula.

“I just was like, how does that happen?” the mother said.

The baby’s formula was among four now recalled, all made by Abbott Laboratories in its Sturgis, Michigan plant. The CDC and FDA are investigating whether those powdered formulas contributed to infant illnesses and a second death.

“I panicked,” Kerry Caprino said.

Now parents like Caprino are scrambling to find alternatives.

“We have been getting calls,” said Caryn Robinson, a nurse at Children’s Hospital of Philadelphia.

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Robinson, a nurse with CHOP’s Center for Public Health Readiness and Response, is advising parents to stop using the recalled formula and to watch out for signs of infection.

“We’re telling parents to try not to panic, this is scary,” Robinson said, “especially when the product recall could impact or involve your child.”

In a statement, Abbott says stored samples of the recalled batches tested negative for both cronobacter and salmonella and that “at this time, the cause of the infants’ infections have not been determined.”

“What we’re seeing now is a major increase in demand for donor milk,” Human Milk Banking Association of North America Executive Director Lindsay Groff said.

From South Jersey, Groff says requests for donated milk are up 30% from last year.

“That’s already a huge surge and calls keep coming in from panicked moms and families wondering what the best thing to do for their babies is,” she said.

Pediatricians say there are a number of alternatives depending on the individual baby’s needs.

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Health experts say other formulas not recalled are safe to use.

Stephanie Stahl