New South Wales Health has closed its investigation into the deadly salmonella outbreak that affected 32 people in aged-care facilities across the Illawarra, Shoalhaven and the ACT.

Director of Illawarra Shoalhaven Public Health Curtis Gregory said that since February 23, no additional residents had become unwell with salmonellosis.

The rare strain Salmonella bovismorbificans was found in 32 infected residents at 10 aged-care facilities operated or supplied by IRT. Two of the residents have since died.

“We’ve deemed the outbreak is now over as more than four weeks has elapsed since the last confirmed case. This means any incubation period for additional cases has now passed,” Mr Gregory said on Friday.

The NSW Food Authority shut down Betta Maid – an IRT supplier – on March 5 after traces of the rare strain of salmonella linked to the outbreak were found in food samples and on a contact surface. The Food Authority confirmed this week the Unanderra wholesale bakery remained closed.