Malton Foods, which owns the Wharton Bridge-based factory, announced the closure last Thursday - despite refusing to comment when the Guardian investigated the issue a month ago.
The company's bacon slicing operations will now be centralised at its Ashton factory in Greater Manchester where 1,100 staff are employed.
The closure will more than double the number of unemployed in the town, which currently stands at 495.
A company spokesman said: "We are disappointed to have to take this decision and are very sensitive to our responsibility to support our employees during this difficult period and will do everything possible to alleviate the effects of this closure."
Malton Foods cited continuing competitiveness in the UK retail market as the reason for the closure and added that it was in no way related to the foot and mouth outbreak.
The plant will cease operations by the end of May this year.
Staff have said they are shocked and upset at the news and the way in which they were told.
The Union of Shop and Distribution Allied Workers (USDAW) was into its second day of talks with Malton Foods yesterday, Tuesday, and was due to brief factory staff today, Wednesday.
A spokesman for USDAW said: "We've been given some rational as to why any Malton Foods' factory had to close and why Harris of Winsford was chosen.
"We are awaiting more information from the company before we decide whether to accept the closure."
Deputy leader of Vale Royal Borough Council, Clr Brian Lloyd, said: "We are extremely saddened by the news of such large job losses.
"Harris has been a major part of the fabric of the Winsford community for more than two decades. This will have a major impact on the town as there are so many Winsford families with such strong links to the factory.
"The borough council will work with other agencies to help find new jobs or train for a new career."
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