Health chiefs have ordered an investigation into how a batch of liquid nutrients may have given babies blood poisoning.
Public Health England (PHE)said 15 cases of septicaemia, including the death of one baby, looked to be "strongly linked" to an intravenous product that is given to babies who are unable to feed normally.
The babies, many of whom were premature, were being treated in NHS neonatal intensive care units when it is thought they acquired the infection.
A statement from the health body said investigations with a manufacturer had already identified a possible incident that could have caused contamination.
The PHE's Incident Director, Mike Catchpole, said the body had "acted quickly" to alert hospitals to the potential problem and remove any remaining stocks of the product.