Retailing giant Walmart recalled baby formula Enfamil this week after an infant who was given the formula died on Sunday.

Walmart voluntarily pulled Enfamil from over 3,000 U.S. stores beginning from Monday night, reported Reuters.

The infant who died was from Lebanon, Missouri. Preliminary tests indicated the boy died from Cronobacter, a rare bacterial infection, reported the Christian Science Monitor.

A Walmart spokesperson said the company pulled Enfamil out of an abundance of caution and may put the products back on their shelves depending on the outcome of health officials' findings.

Gena Terlizzi, spokeswoman for the Missouri Department of Health and Senior Services, noted it is unclear at this point whether or not the boy's death was caused by Enfamil ingestion or another source, reported the Christian Science Monitor.

One of the things every batch of product is tested for is Cronobacter. We went back and checked on the batch in question, and it had tested negative for Cronobacterm, stated a spokesperson for Mead Johnson Nutrition, which makes Enfamil, reported Christian Science Monitor.

Despite the lack of conclusion that Enfamil was at fault, investors are still wary. Shares of Mead Johnson Nutrition (NYSE:MJN) have plunged over 10 percent in a day the broad stock market rose.

A Walmart spokesperson said customers can return their purchase of Enfamil for a full refund or exchange, reported Business Week.