LEBANON, Mo. » Walmart has pulled a batch of powdered infant formula from more than 3,000 of its stores nationwide after a newborn Missouri boy who was given the formula became gravely ill with a suspected bacterial infection and died after being taken off life support, the retailer said Wednesday.

No government recall had been ordered for the 12.5-ounce cans of Enfamil Newborn powder with the lot number ZP1K7G. Manufacturer Mead Johnson Nutrition said its records showed the lot tested negative for the bacterium before it was shipped.

But Walmart spokeswoman Dianna Gee said the company decided to pull the lot "out of an abundance of caution" while health officials investigate Sunday’s death of 10-day-old Avery Cornett. The product could go back on shelves depending on the outcome of the investigation, but customers who bought the cans have the option of returning them for a refund or exchange, Gee said.

Gena Terlizzi, spokeswoman for the Missouri Department of Health and Senior Services, said Wednesday that samples of the formula given to Avery were sent to the Centers for Disease Control and Prevention and the U.S. Food and Drug Administration for testing.

"At this point it has not been determined whether the illness is linked to the formula or an outside source," Terlizzi said in a statement.

The Lebanon Daily Record reported (http://bit.ly/vwyAs5) that Avery was taken to St. John’s Hospital-Lebanon late last week after appearing lethargic and displaying what his family said were signs of a stomach ache. He was later moved to St. John’s Hospital-Springfield, and preliminary tests showed that he had contracted a rare bacterial infection, Cronobacter sakazakii, the newspaper reported. He died Sunday after being removed from life support.

Avery had been fed Enfamil Newborn powder bought at a Walmart store in Lebanon. The store stopped selling the product after learning of his death.

Christopher Perille, a spokesman for Glenview, Ill.-based Mead Johnson Nutrition, said Enfamil Newborn powder is sold at a variety of retailers, but he didn’t have information about whether other companies received units from the lot now being investigated.

Perille said all of the company’s infant formula products are put through a battery of tests as they are produced, packaged and sealed.

"One of the things every batch of product is tested for is Cronobacter," Perille said. "We went back and checked on the batch in question, and it had tested negative for Cronobacter."

Public health investigators seeking the source of Avery’s infection will also look at environmental factors, such as the water used in preparing the powdered formula, and at anything else the baby might have ingested, Perille said.

The Missouri Department of Health is advising parents to follow World Health Organization guidelines for safely preparing powdered infant formula, Terlizzi said.

"This includes washing your hands with soap and water, thoroughly sterilizing all feeding equipment in hot, soapy water and preparing enough formula for only one feeding at a time," she said.