The Victorian government begun its rollout of coronavirus surveillance testing in the state's abattoirs and meat processing plants yesterday.
The testing is also being carried out in supermarket and temperature-controlled perishable distribution centres.
Victoria's COVID Testing Program commander Jeroen Weimar said a new workplace saliva testing trial would also take place at Hazeldene's Chicken Farm, Longwood, from next week.
"I'm always worried about coronavirus re-entering some of these facilities," Mr Weimar said.
The risk of more rapid transmission was far higher in meat processing works, he said.
"That's why we have asked the industries to take all these additional measures - this is our way of saying we will run some surveillance, to ensure we spot this, at the earliest opportunity."
Testing started in Nhill, on Thursday, then would move to Bacchus Marsh, Ararat and Stawell and other operators across regional and metropolitan Victoria.
"We are organising proactive surveillance testing, around a quarter of the workplaces, every single week," Mr Weimar said.
"The reason we are doing surveillance testing in those critical areas is to make sure we have a really good understanding of whether the virus, in any shape or form, is still circulating in those industries," he said.
"Once the virus penetrates, it can spread very quickly, and we thank all the operators in all those industries, for the exceptional measures they are taking with their workforce in terms of PPE, distancing and all the other things we have asked them do."
Mr Weimar said the testing would continue "in the weeks ahead' to ensure there were no traces of the virus.
"They are all operating in an environment where, if the virus was to get in, the risk of transmission is really high," Mr Weimar said.
"We know the virus survives particularly well in cool conditions we know it survives better on stainless steel metal type surfaces.
"And we know that by the very nature of meat processing plants, is that there's a lot of cold, cold metal surfaces a lot of fluid fly around the place."
"We've seen that with, from memory, 1617 significant outbreaks over the last three months in abattoirs and meat processing centres
He said this was despite the fact operators had done "a shed load of work to be COVID safe."
He said it the testing would give authorities a really good sample of an active workforce, that was moving around the state.
"It gives us a sense of how well those protective measures are operating," he said.
Mr Weimar said Australian Lamb Company, Colac, was already getting its staff tested, at a local centre.
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