An elderly man has died and a woman has miscarried as a result of the nationwide listeria outbreak, which has been linked to contaminated rockmelon.

The Victorian man in his 80s was the fifth person to die as a result of the outbreak.

The source of the outbreak has been traced to Rombola Family Farms in the Riverina region of NSW, according to authorities.

There have been at least 17 confirmed cases of listeria linked to the contaminated rockmelon, including two deaths in NSW and three in Victoria.

Victoria’s deputy chief health officer, Dr Brett Sutton, said all people affected so far ate the rockmelon before the national recall on 28 February. The latest cases have been linked to the outbreak through microbiological testing.

The bacteria listeria monocytogenes can cause miscarriages in pregnant women and can be fatal for elderly people or people with a compromised immune system. For healthy people, it usually only causes mild illness.

Mild illness and a temperature may be the only sign of infection in pregnant women. However, the infection can be transmitted to the foetus through the placenta.

Heath authorities have emphasised that rockmelons currently available for sale are not affected. People at risk should consult their doctor as soon as possible if symptoms appear.