15 employees have tested positive for Covid-19 at three meat plants around the country.
Nine people tested positive for the virus at ABP's meat processing facility in Cahir, Co Tipperary, while the company has also said that two positive cases have been confirmed at its plant in Clones, Co Monaghan.
A further four cases have been confirmed at the Rosderra Irish Meats plant in Clara, Co Offaly.
In a statement the ABP Food Group said that "assessment protocols highlighted a potential concern with a member of staff" at the Cahir plant last week.
The employee was sent for a test and the company was subsequently notified of a positive test, ABP has said.
Following testing of close contacts of the worker involved A further eight employees at the plant have tested positive.
ABP has said that it will now begin testing all staff members at the Cahir facility.
The company said the testing will be carried out by a private company in conjunction with the HSE to alleviate the pressure on local Covid-19 testing.
The testing is is expected to commence in the next 24 hours.
ABP also said all staff members at its meat processing facility in Clones are undergoing Covid-19 testing, after two positive cases of the virus were confirmed.
In a statement, the company said the testing is being carried out as "a precautionary measure" and the plant remains open.
ABP said it was notified of a positive case among the workforce at the Clones facility and "following HSE testing of close contacts of the worker concerned, the company has been notified of a second case."
The food company said the testing will be carried out by a private company in conjunction with the HSE.
ABP said it has "taken a range of actions on foot of the positive diagnoses" and it said it will continue to take direction from both the HSE and the Health and Safety Authority in relation to the matter.
The company also said it has introduced a range of "industry leading protection measures" since the onset of the pandemic which include "limiting site access to essential personnel, temperature checks at the entry to the site, staggered break times, perspex partitions where appropriate, social distancing measures in canteens and all other communal spaces, as well as detailed protocols for colleagues who display any symptoms."
Separately, four more workers have tested positive for Covid-19 at a meat factory in Co Offaly.
The test results came following a full test of staff carried out at the Rosderra Irish Meats plant in Clara last Friday.
A total of 68 staff were tested. It is understood another round of testing of all staff will take place later this week.
While the staff effected have been isolated, the plant remains open.
The company's sister plant in Edenderry, which had a major outbreak of Covid last May, has already had a full site risk assessment screening test of over 400 staff where nobody tested positive.
Reporting by Fergal O'Brien, Ciaran Mullooly