The outbreak has contributed to one of the largest clusters of COVID-19 in Victoria, with the state reporting a total of 1440 cases as of Wednesday.
The first infection at Cedar Meats, Brooklyn, was reported on April 2.
A state government spokeswoman said the person had not been at Cedar Meats for four weeks, so the workplace was not considered an exposure site.
The second case linked to the workplace was diagnosed on April 24, followed by a third case just over 24 hours later, found in a worker who attended Sunshine Hospital, prior to diagnosis or displaying symptoms.
As soon as the second case was identified, the department began contact tracing, in conjunction with the business.
When more cases were identified on April 29 the department advised the workplace to take additional actions across the entire workforce - including the testing of all staff, which began the next day.
The company's 350 staff have since been tested, bringing the total number of infections at the meatworks to 49 as of Wednesday.
Cedar Meats general manager Tony Kairouz said he was devastated coronavirus had infected his staff.
"From the moment we learned of COVID-19, we took every possible step, and consulted the experts, to keep our people safe and protect our business."
The company's focus had been on protecting staff, ensuring animal welfare and closing down the processing side of the business.
Mr Kairouz rejected claims the company had sought to hide the outbreak.
"We have been accused of hiding, we are deeply saddened by that," Mr Kairouz said.
"This is something that is not of our making, it is an outbreak of a worldwide pandemic, that has hit our people, at our plant."
The state government's decision not to name the abattoir, now at the centre of what is becoming the state's most significant coronavirus cluster, has caused a stir in the industry.
Robert Radford, Radford's Warragul, said after it was revealed workers at a Melbourne abattoir had tested positive to coronavirus, he'd received about 20 phone calls from people inquring about which works was involved,
"I thought it was up to the health department or government to notify the public, as it's in everyone's interest to know where it is," Mr Radford said.
"I would think it's in everyone's best interests to notify the public, no matter where the outbreak is, as they have done with nursing homes.
"Everything else they've mentioned is open and upfront."
Cedar Meats processes and sells mutton, lamb, goat and veal to the European Union, North and South America, South-East Asia, China, the Middle East and Africa.
All staff are being tested, the plant is undergoing deep cleaning and it's expected to reopen in about a fortnight.
Mr Radford said he would report any outbreak, at his plant.
"I think it's in everyone's interests, you have all your workers, and related families, subcontractors and everyone involved in the day to day running of the plant," he said.
There were also livestock transporters to consider.
"I feel sorry for the boys down there (at Cedar Meats).
He said the Warragul plant was doing everything necessary to avoid introducing coronavirus to the plant.
"We are doing heaps," he said.
"I have extra staff doing everything we have to do, social distancing, sterilising, handwashing, and if anyone shows any symptoms of any sickness, they are not to come to work."
Authorities response
But Victoria's Chief Health officer Professor Brett Sutton has defended his handling of the coronavirus cluster at a Melbourne abattoir, saying it's up to operators to notify the public if staff contract the virus.
Premier Daniel Andrews also said he believed the outbreak had been handled appropriately, at all stages.
Prof Sutton said meatworks were particularly vulnerable, with extensive outbreaks in America.
"As soon as that cluster was identified, (Cedar Meats) have been moving to a shutdown at the earliest possible time," Prof Sutton said.
"There were some logistic constraints with having everyone cease work immediately.
"You need a minimum staff on-site, to make sure animal welfare is being looked after."
He said the plant was not identified, as authorities had the names and contact details of everyone in the site.
"We are not concerned about the general public being exposed, so there is no public health reason to name those places," he said.
"I think it's the role for that specific meatworks to say "it's us'," it's not for us to declare that it's a particular setting.
"If the meatworks wants to name itself, to make it clear it doesn't involve other places, then they are free to do so."
JBS reassurance
In a letter obtained by Stock & Land of on Victoria's biggest processors, JBS has also sought to reassure suppliers and producers.
"We thought it critically important to let everyone know that our meat facility, in Brooklyn, Victoria, continues to be 100 per cent free from coronavirus with no employee testing positive for COVID-19," JBS' southern chief operating officer Sam McConnell said.
"We continue to review and implement stringent and best practice people and food safety controls, including strict access criteria, thermal temperature and imaging testing, upgraded PPE for our people, diligent social distancing controls and company-funded flu vaccinations for our team members."
Those measures, and others JBS would continue to review and implement, gave the company confidence' business as usual" would continue, at Brooklyn, he said.
The Centre for Disease Control in America has reported more than 4,900 workers, or four per cent of the meat processing industry's workforce, have contracted the virus.
Mr Kairouz said the plant was made aware of the outbreak on April 27, after a worker sought treatment at Sunshine Hospital, as a result of a workplace injury.
He later developed symptoms and tested positive, for COVID-19.
"On Wednesday, April 29, we were informed that four of our staff had contracted Covid-19," Mr Kairouz said.
"All staff worked in one area of the plant."
The following day the company mandated all staff had to get tested for coronavirus.
By the end of the day, on Friday, May 1, all staff had been sent for testing.
The state government has been at pains to stress there are no concerns for food safety.
Victoria food safety regulator PrimeSafe said the Department of Health and Human Services (DHHS) was managing a COVID-19 outbreak linked with a Victorian meat processing facility.
" PrimeSafe is assisting DHHS to determine that the facility has met food safety regulatory requirements, and to understand supply chain connections to assist with staff tracing," a spokeswoman said.
"All meat processed at PrimeSafe licensed facilities must be fit for human consumption and produced in accordance with Australian Standards for food safety.
"This includes meat processed at the Victorian meat processing facility."
The PrimeSafe spokeswoman said in accordance with advice from Food Standards Australia New Zealand there was no evidence that COVID-19 could be transmitted to people through food or packaging.
"Based on this information, consumers can have confidence that meat processed at the facility is safe to eat."
Drivers concerned
But Victoria's peak livestock transporters association has slammed the state government, for its secrecy over the outbreak.
Livestock and Rural Transporters Association of Victoria president John Beer said his members were extremely concerned the government had refused to name the plant.
"I think we are classified as essential services, but we are being classed as mushrooms," Mr Beer said.
"They need to tell us what's going on, we have families, and I just think it's so wrong, what they are doing."
"No-one, even top brass in Agriculture Victoria, none of them want to tell us what's going on," he said.
"We have just gone through two months of lock-down, and now we are putting up with this."
Mr Beer said he estimated about ten drivers would enter the plant, each day.
"But you also have transporters who cart the meat out; it's not only, in it's out, as well.
"Let's be honest here, let's be upfront, tell us what's going on, instead the bush telegraph is going berserk."
Start the day with all the big news in agriculture! Click here to sign up to receive our daily Stock & Land.