Five workers at the Carroll Cuisine food-processing factory in Tullamore, Co Offaly, have tested positive for Covid-19.
Last week an employee of Carroll Cuisine informed the company that they had tested positive for the virus and were self-isolating.
Carroll Cuisine carried out testing of all 330 employees at the factory and four other staff members, who work with the initial colleague affected, tested positive and are now also self-isolating.
No other positive cases have been identified and the company says it will continue testing all staff.
Safety measures
In a statement, Carroll Cuisine added: “We are supporting our affected employees and are working closely and co-operatively with the HSE who are satisfied with the actions we are taking.
"Since the first outbreak of Covid-19 in Ireland, we have implemented stringent health and safety measures to protect our employees and to help prevent the spread of the virus."
Carroll Cuisine said a deep clean had taken place in the factory and it would continue production as normal.
Food processing plants have been among the hardest-hit settings for Covid-19 in Ireland.
Up to the beginning of July, there were 1,115 cases at meat and poultry plants with the first case recorded on St Patrick’s Day. Cases peaked in May and have fallen dramatically since.