Up to 700 staff at the Spalding site of Bakkavor look set to go out on strike for a month.
Union members of Unite had previously agreed strike action earlier this month, but it was called off to allow further discussions.
But following a ballot the company has now been given formal notice that the strike will start on Friday, November 25 and end at 5am on Monday, January 2.
Union members have been told by Unison they will be paid £350 a week while on strike.
The union and the company met last week in a bid to resolve issues, but no agreement on a pay offer of more than 6.5 per cent could be reached.
The union acknowledged that the announced factory closures were ‘a cause for concern’ but not linked to strike action in Spalding.
The union is pushing for a 7.5 per cent pay rise. Bakkavor has been paying workers 1p over the national minimum wage.
