The Highlander crisps plant at Bathgate, West Lothian, closed on July 31 with the loss of 28 jobs.
The Italian parent company, Unichips SpA, said it was closing the factory due to a slump in demand for the Highlander brand.
At its peak, the Highlander factory employed around 150 people.
But staff say they have seen sales of the crisps plummet over the past five years, making the factory unviable for the Milan-based firm.
Highlander Crisps was originally set up by Forth Valley Foods after the demise of the Golden Wonder plant in Broxburn 26 years ago.
After the company entered receivership in 1991, it was relaunched as Highlander Snacks by Unichips.
One staff member said: “For the past five years, the sales of the crisps have fallen fast and we knew there would be something to come from it.
“The Italian bosses came over about a month or two ago and said they had plans of closing it, but we have now got it in writing that it’s definitely closing.”
A spokesman for Unichips said: “Highlander looked at ways of avoiding having to close the factory but no solutions could be found.
“They have gone through all correct procedures and people will get the redundancy money that is due to them.”