The HP Foods factory in Birmingham is to close and production of its famous sauce moved to Holland.
About 125 jobs are expected to go at the Aston site in the move in March 2007, said its owners Heinz.
The US firm, that bought HP Foods last year, said it would improve efficiency and productivity. Unions described the move as a "savage decision".
The bottling operation for Lea and Perrins Worcestershire Sauce will be returned to its site in Worcester.
Some 30 jobs will be secured and three administrative roles would become redundant in the proposed new organisation at the Worcester factory.
The Transport and General Workers Union (T&G) said it would seek an explanation from Heinz.
"When Heinz took over the HP Sauce plant last year they promised there would be no shift in production," said T&G food industry leader John Jordan.
"Now we see that Heinz's promises are as worthless as an empty sauce bottle."
Earlier this year the Competition Commission cleared the Heinz takeover of HP Foods from French firm Danone.
Mr Jones said: "The workers at HP Sauce in Birmingham are very bitter at this decision by Heinz.
"We are demanding a meeting with Heinz directors tomorrow to get a full explanation for why the company has broken its word to a loyal workforce."
David Hobin, Heinz vice president with responsibility for manufacturing said: "We deeply regret having to consider closing the HP sauces manufacturing site at Aston, and I understand the very serious concern that this news will cause for employees and their families."
He said there was spare capacity at Heinz's Elst site in Holland and it did not make financial sense to keep open the Aston factory, which normally runs three times a week.
"The Aston closure proposal and job impacts at Worcester do not reflect on the dedication and hard work of all employees at the sites and those involved in the HP Sauces business," he added.
John Lamb, from Birmingham Chamber of Commerce and Industry, said: "It is obviously devastating that such an iconic Birmingham brand is going. It is a very visible place as you come in on the main thoroughfare."
The city is now moving away from heavy manufacturing into the pharmaceutical and service industries, he said.
"It is very sad that more jobs will be lost in the city and the region but there is a massive skills shortage out there and those who are prepared to retrain will find other jobs."