Colman's Norwich factory jobs may be at risk
Twenty jobs could be at risk at Colman's factory in Norwich.
Unilever, the owners of the company which is best known for its mustard, said it was "undertaking a 60 day review of dry mixing operations".
The company said the review was to ensure its supply chain was "as efficient and cost-effective as possible".
The GMB union said the decision would be met with "dismay" by the workers and promised to try to prevent job cuts.
Alan Black, GMB national officer, said: "It is especially disappointing in a part of the UK where manufacturing jobs are in short supply."
Colman's was established in 1814 and received the Royal Warrant-branding on its products in 1866.
The company was bought by Unilever in 1995.
A spokesperson said the review would look at how the factory could "work in partnership" with its factory in Germany to "improve our competitiveness and ensure a sustainable future for the site".