A recent outbreak of a rare salmonella strain in New South Wales may be the source of the infection at a Victorian poultry farm that prompted an egg recall.
Some brands of free-range and barn-laid eggs with particular use-by dates have been recalled across NSW, Victoria, Tasmania and South Australia after a food poisoning outbreak.
The source of the infection was traced to Victoria's Bridgewater Poultry, which is in quarantine as authorities investigate.
"A potential link to a recent outbreak of salmonella enteritidis in people in NSW is currently being investigated as the source of infection," Victoria's Chief Veterinary Officer Dr Charles Milne said on Friday.
He said the Australian egg industry developed its own response plan which may include culling of affected birds and decontamination of affected infrastructure.
But farming experts estimate the business could lose millions if it's forced to cull the entire flock.
"It's an estimate but they could lose up to $10 million if they culled all the birds," Victorian Farmers Federation eggs group Vice-President Brian Ahmed said on Friday.
He said authorities had already culled flocks in the shed where they found the virus but veterinarians could order all the birds destroyed if the virus spread.
"If they cull the whole farm, supply will be affected," he said.
While not sure about exact numbers Mr Ahmed said there were around 500,000 to 600,000 birds at the farm that could be destroyed.
If the other birds are given the all clear within the next three-to-five days, the farm's eggs should be back on the shelf within 10 days.
However the four families who own the poultry farm have been devastated by the detection.
"It's just a horrific time for them," he said.
"To recover from this would be very difficult, it's not a couple of thousand birds we're talking about."
If all the birds were destroyed it could take the farm up to two years to return to their current stock levels.
Droppings from migratory wild birds may be responsible for spreading salmonella bacteria according to some in the industry.
Egg Farmers of Australia spokesman John Coward speculated the farm may have contracted the bacteria from birds flying overhead.
"It may have come from a migrating wild bird that can bring in this strain and infect the flock," he told AAP on Friday.
"You can't stop a bird flying over with this type of salmonella."
Symptoms of salmonella enteritidis include fever, headache, diarrhoea, abdominal pain and nausea.
They usually start six to 72 hours after eating the contaminated food and can last up to a week.
The company's free-range and barn-laid eggs are packaged as Woolworths brand, Victorian Fresh, and Loddon Valley, with best-before dates ranging from March 20 to April 29.
Australian Associated Press