A first nationwide study of listeria in mothers and babies - has found low rates of the infection

University of Otago research shows of those who contracted listeria over the past 20 years, more than 100 people were hospitalised and the lives of 12-unborn babies claimed.

It indicates food safety warnings are working to prevent significant complications.

Medical student Emma Jeffs, who did the research, says their suspicions of low rates of listeria were confirmed - which is a relief given the implications.

She says infection outcomes can be utterly devastating, with miscarriages, stillbirths... and meningitis in young children.

Pacific Islanders have the highest incidence of disease notification and hospitalisation.