Swinney said: “This is disappointing news for Scotland and particularly for those working at Hall’s of Broxburn and their families.
“Since Vion announced the proposed closure in July, the Scottish government and its agencies have taken every action in our power to secure the future of the plant, working with the company and stakeholders.
“We will continue to do so over the coming days. We are still working to secure a buyer, and the taskforce will meet again next week.”
The taskforce will draw up a recovery plan to address “the serious potential impact on the local area”, he added.
Confirming the closure of the plant, Peter Barr, Vion UK chairman, said: “We have done everything in our power to avoid having to take this extremely regrettable action. But we have been unable to identify any viable alternative to the closure of the plant.
“This is a very sad day for all those involved. But, unfortunately, the unsustainable losses which the plant continues to suffer, combined with the challenging economic conditions across all food sectors, have left us with no alternative.”
Speaking after the end of a 90-day consultation exercise with unions and workers, Barr added that the firm had invested “tens of millions of pounds” in the Hall’s site over a number of years. But it continued to record “unsustainable losses”.
Rural affairs secretary Richard Lochhead said: “With about 65% of the pigs processed at Hall's coming from Scottish farms, this difficult news clearly marks an unsettling time for Scotland’s pig industry. However, I can assure pig farmers that Scottish pork remains an important part of our food and drink offering going forward.”
Lochhead added one option was establishing an alternative plant capable of up-scaling to process the majority of pigs currently consigned to Hall's.
The taskforce was set up in July after Vion unveiled plans to close the West Lothian processing plant. The group includes: the Scottish government, West Lothian Council, Scottish Enterprise, Scottish Development International, Skills Development Scotland, trades unions, the company and local elected representatives.
It is due to meet on October 10 − the deadline Vion has set for buyers to bid for the plant.