2 Sisters said it will shut its poultry processing plant in Essex in October, following a consultation over the fate of the site.
In May, the firm said it wanted to close the plant and reduce the number of its UK poultry sites in order to produce shorter, more efficient supply chains and make it more competitive.
It said in May it would seek to redeploy staff at other sites, but has now confirmed 400 jobs will be lost with 102 workers redeployed at its Thetford site and at Bernard Matthews’ plant in Holton, Suffolk.
The site has now ceased production and is being decommissioned. It will close for good in October.
A spokesman said: “Following our colleague consultation process, it is with regret we can confirm the closure of our poultry processing site in Witham. Unfortunately we have not been able to identify a viable alternative to closure.”