Ray Coyle said the company had no choice or face moving out of Donegal altogether and relocate the operation to Britain.
Mr Coyle confirmed the 60 full-time and part-time jobs will most be from the packaging department of the plant which is to be automated.
Despite the job losses, Deputy Dinny McGinley said he is confident about the future growth of the plant in which a total of €3 million in grants has been invested.
There are still approximately 152 jobs left at the plant which has been open for 16 years.
Mr Coyle added “There’s going to be about 38 full-time job equivalent losses, probably about 60-odd people between part-time and full-time,” he said.
“The issue is that Donegal is geographically disadvantages for exports to the UK.
“We’ve had to put in automated equipment. We’re spending €3.7m between R&D and putting in new equipment to take down costs.
“If we don’t do that, the whole plant closes.”