The two leading manufacturers of infant formula for premature babies scored a big win on Thursday after a Missouri jury handed them a defense verdict.

After about three hours of jury deliberations, Abbott Laboratories Inc. and Mead Johnson, owned by Reckitt Benckiser Group, were found not liable for product defect, failure to warn and negligence claims in a trial alleging their cow’s milk-based infant formula caused a premature baby to contract a potentially lethal gastrointestinal illness called necrotizing enterocolitis, or NEC. Abbott makes Similac, and Enfamil is made by Mead Johnson. The jury also found a third defendant, St. Louis Children’s Hospital, not liable for negligence.