SINGAPORE - About 100 tonnes of rock melons imported from Australia were on Friday (March 16) released back to importers for sale after clearing tests, the Agri-Food and Veterinary Authority (AVA) said.

The Australian authorities have identified one affected grower - Rombola Family Farms - that is linked to an outbreak of human listeria in Australia that made headlines earlier this month.

All consignments of rock melons from this grower that were imported from Australia into Singapore have been recalled and destroyed, AVA said.

All the other rock melons that are not from affected sources have been released back to the importers for sale.

AVA took samples of these rock melons for testing, and the samples tested negative for Listeria monocytogenes.

The authority had recalled all whole rock melons or cantaloupes sold in Singapore, from Australia, on March 8 as a precautionary measure while waiting for clarification on the sources of the melons.

Five people have reportedly died from the outbreak so far.

The Guardian said in a report on Friday that there have been at least 17 confirmed cases of listeria linked to the contaminated rock melon.

Listeriosis is an infection caused by listeria bacteria, which does not cause illness in most people, but can lead to sickness and even death for those with weakened or compromised immune systems.

These include newborn babies, pregnant women and the elderly. Symptoms include fever, muscle ache and diarrhoea.

Last week, the Ministry of Health said there was no report of anyone in Singapore contracting the bacterial disease as a result of eating the rock melons.

Doctors have been asked to refer suspected cases of listeriosis for testing and treatment and to notify MOH of suspected cases.