Workers at the Colman's factory and their families will have to wait until the new year to find out their fate.
Unilever, which owns the brand, has said it will reveal the findings of its review into the future of the Norwich site in 2018.
It follows neighbour Britvic announcing the closure of its factory in 2019, which will see 230 jobs lost or relocated to Rugby.
READ: 'A real kick in the teeth to the city of Norwich' - MPs react to Britvic factory closure
Unilever is considering possibilities including leaving Norwich altogether, moving to an alternative site in the area or expanding on the current site.
In a statement the company said: 'We are aware of Britvic's confirmation that it will be withdrawing from our shared Norwich site.
'We have been reviewing our own operations in Norwich in light of Britvic's closure proposal and have confirmed with our employees that we will announce the outcome of our review in the new year.'
Colman's Mustard has been made at the Carrow Works site since the 1860s and there are currently 113 people working at the factory.
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