Co-operative Poultry Products is to close its Cavan plant with the loss of 90 jobs.
Workers at the Cootehill plant were informed of the decision yesterday afternoon. A liquidator has been appointed to the company.
Siptu union organiser Jim Finnegan said the closure of the co-operative "will have a devastating effect on the local community".
"Not only must 90 workers and their families deal with the loss of their livelihoods but more than 25 local growers have also lost their source of income."