Unilever is to close the the Norwich factory where Colman's Mustard has been made for 160 years.
The move will affect 113 jobs in the city, of which 40 will transfer to a separate Unilever site in Burton.
Meanwhile, 25 jobs will be created at a new mustard milling and mint processing plant near Norwich.
Manufacturing of most of the firm's other products is to move to elsewhere in the UK - mainly Burton upon Trent, already home to Unilever's Marmite and Bovril brands.
Some other work, involving the packing of dry sauces, will move to an existing factory in Germany, where the sauce mixes are already made.
Unilever took the decision after soft drinks maker Britvic said in October that it would close the Robinson's squash factory on a site shared with the Colman's plant.
That prompted a review by Unilever, which said at the time that the operations of the two companies were "uniquely intertwined" with shared infrastructure.
The conclusion of the review has now been announced, spelling a break in the long period of production of Colman's Mustard in the city.
Unilever said the factory would be closed at the end of 2019, "with a phased transfer of production likely to begin in 2018".
In a statement, the company said: "We will protect the historic link between Colman's and Norwich by retaining the production and packing of Colman's mustard powder, the historic mustard milling process, and mint processing in a new state-of-the-art facility in the Norwich area, created through a new long-term partnership with a consortium of local farmers, backed by significant investment from Unilever.
"We will also continue to source our mint and mustard locally as we have for generations."
The firm said it recognised the closure announcement would be "difficult news for our Norwich employees, their families, and the whole community in Norwich" and that it was "committed to supporting our employees during this difficult time".
It added: "We will also offer all employees whose roles would be affected by the proposals a package of support, including redeployment opportunities at other sites, and services to help people find new employment."
Trade union Unite, which has a small number of engineering members at Colman's, urged Unilever to reconsider the business case for closure.
Unite national officer Rhys McCarthy said: "It is a devastating day for Norwich that the production of Colman's mustard will cease production in 2019, ending a tradition stretching back two centuries.
"Our aim during the consultation period will be to retain as many skilled jobs as possible within Unilever and that there should be no compulsory redundancies."
Rebecca Long-Bailey, Labour's shadow business secretary, said: "The closure of Colman's in Norwich is a blow not only to the workers at Colman's and their families but to the town and region more generally."
A Government spokesperson said: "The government is disappointed Unilever has decided to close its Norwich plant, though we welcome Unilever's commitment to mustard milling and mint production in Norwich."
Jeremiah Colman started his mustard and flour business in 1814 in Stokes Holy Cross, four miles south of Norwich.
The current factory in Norwich was established in 1858. Colman's was taken over by Unilever in 1995.
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