430 jobs are at risk at Bodmin meat firm Tulip Ltd - nearly half the factory's workforce.
The Danish owned company says it's planning to move jobs to other UK sites after reviewing some of its contracts.
It says it is expanding some of it's operations in Bodmin, but the majority of jobs will move elsewhere.
With 840 workers it's the town's biggest single employer.
The Bodmin factory at Newton's Margate produces pork, bacon and cooked meats and is one of the town's largest employers. It also has a factory in Redruth.
Two years ago the firm announced a £16 million investment in its Cornwall operations aimed at securing jobs. That money was targeted at its Bugle and Redruth sites.
A spokesperson for Tulip Ltd said:
"As a result of recent supplier reviews with some of our customers, we are proposing to make some changes to our operational footprint.
While this proposal includes expanding our cooked bacon operations at our Bodmin site, we are also proposing to move cooked meats operations from Bodmin to alternative sites within the UK. This option would result in approximately 430 positions at Bodmin being placed at risk."
Scott Mann, the Conservative MP for North Cornwall, told ITV News he's surprised by the news:
Tulip Ltd says it's now consulting with staff and will explore all viable alternatives to reduce any unecessary redundancies.