"It's where brands like Victoria Bitter have been made for 100 years so their concern is that whoever owns the company understands that historical link.
"It may not necessarily matter where the ownership of the company is located but it does matter obviously to the workers but also to Australians where the beer is produced."
She said there was no indication as yet regarding job losses but said the union would meet with staff and management in coming days to ensure job security at the brewery.
"Workers are understandably worried but at the same time they're very confident in the work that they do down there and they're the heart and soul of the company," she said.
"They've been making those iconic brands of beer for generations down there and they expect that SABMiller is going to respect the contribution that they make."
Foster's chief executive John Pollaers said he believed SABMiller was committed to doing "what's right" to keep the Foster's workforce in Australia.
"All I can say is that I had a very personal, warm conversation with Graham Mackay, the CEO of SABMiller, the day before last and he believes, as I do, in the future of this business and in the people and the importance of this business to Australia," Mr Pollaers told ABC TV.
But he would not be drawn on the possibility of future job cuts.
"There will always be changes with an event like this," he said.
-AAP