SAN FRANCISCO — Nara Organics recalled its organic baby formula sold nationwide in Target stores and online Saturday after a multistate outbreak of infant botulism, federal authorities said.

Three babies between 2 and 5 months became ill in April and May in California, Pennsylvania and Washington after consuming Nara Organics Whole Milk Organic Powdered infant formula, which is also sold on Nara.com, the U.S. Food and Drug Administration said.

They were hospitalized and treated with the FDA-approved treatment for infant botulism, the agency said.

Infant botulism is a rare but serious illness that occurs in babies under age 1, whose gut microbiomes are immature. It is caused when infants consume bacteria with spores that produce a toxin in the gut.

Symptoms include constipation, poor feeding, drooping eyelids, weak muscle tone, difficulty swallowing and breathing problems, among others.

Babies who develop those symptoms need immediate medical attention. The sole treatment is BabyBIG, an IV medication made from blood plasma of people immunized against botulism.

Nara Organics Whole Milk Organic Infant Formula makes up less than 1% of all infant formula sold in the United States, and the outbreak does not create shortage concerns for parents and caregivers, the FDA said.

People who have the formula are urged to stop using it immediately, the U.S. Centers for Disease Control said in a statement. The formula is manufactured in Europe but sold only in the U.S., it added.

The CDC recommended that anyone with an opened can take a picture, record the lot number and use-by date and watch their infants for symptoms.

“Label it ‘DO NOT USE’ and keep it stored in a safe place away from other items you feed your baby for at least a month,” the CDC said. “If no symptoms appear after a month, throw the leftover formula away.”