Another case on Tuesday was identified in mandatory hotel quarantine, another two via drive-through testing and three cases were under investigation.
Experts say time will tell if the Cedar Meats cluster is a setback that will push back the future easing of social distancing restrictions in Victoria, or evidence health authorities are beginning to find cases that would have otherwise gone unnoticed in the community.
The state is in the midst of a coronavirus testing blitz and Professor Catherine Bennett, chair of epidemiology at Deakin University, said it was not unexpected that as authorities looked harder for cases, they would find them.
“We’ve protected the people who are most vulnerable and we [now] are chasing the usually silent part of the transmission,” she said.
A measure of the most serious cases, the number of coronavirus patients in intensive care, continues to fall, with six in Victoria’s hospitals on Tuesday.
Professor Bennett said the large new cluster did not necessarily mean other cases would follow, as the diagnoses could prevent the infected spreading the disease to others.
All 350 staff at Cedar Meats remain in isolation, including general manager Tony Kairouz, who has tested negative, a spokeswoman for the company said.
Plans are in place to reopen the abattoir on May 18.
Mr Kairouz said the company was working to access JobKeeper payments or other assistance for workers but until it was available they were being advised to use any other entitlements they had.
“Like all businesses impacted by COVID-19 we are devastated that this has provided temporary financial uncertainty and potentially financial loss for our people,” he said.
Professor Mary-Louise McLaws, an infection control expert and adviser to the World Health Organisation’s COVID-19 preparedness group, said it would be important to identify the source of the cluster, or index case.
She said if it was a case of unknown community transmission there may have to be delays to relaxing social distancing.
“If that index case comes from a well-known risk group such as a traveller for somebody from a nursing home, then it’s all very understandable, but if it comes from an unknown source that is when it becomes very problematic,” Professor McLaws said.
Aisha Dow reports on health for The Age and is a former city reporter.