Premier Foods is to shed up to 580 jobs following a review of its UK manufacturing facilities.
Premier, maker of Branston Pickle and Oxo stock cubes, said it intended to close six of 11 sites covered by the review and would invest significantly in the remaining five.
Th factories marked for closure by 2009 include those at Bristol, Droylsden (Manchester), Ledbury (Herefordshire), Middlewich (Cheshire), Reading (Berks), and Wythenshawe (Manchester).
This is expected to affect up to 900 jobs, but 300 posts will be created in the remaining five sites in Nottinghamshire, Staffordshire, Cambridgeshire, Kent and Suffolk.
Premier said it had identified potential cost savings of £85m a year from integrating the two companies and confirmed that this target remained on track.
Robert Schofield, chief executive of Premier, said: “These proposals will enable us to enhance our efficiency while giving us the capability to drive our branded sales growth. Our proposals include significant investment in five of our sites while six sites will close.
“We appreciate the impact our proposals will have on employees at those sites and we will work with them to explore opportunities for redeployment within the group or outside of the company,” he added.