A further eight workers at the O'Brien Fine Foods plant in Co Kildare have tested positive for Covid-19.
It follows the discovery over the past two weeks that 86 staff at the Timahoe meat processing plant had the virus.
Normal operations were suspended on 5 August after 80 cases were identified and a deep clean of the premises began.
On 7 August, a further six staff tested positive for the coronavirus and the decision was taken to extend the testing programme to retest employees on day seven and 14 of the possible incubation period.
That day seven testing was then carried out by the Health Service Executive last week.
"Of 177 tests conducted on day seven, we can confirm that eight employees have received a positive result, 169 employees have tested negative," the company said in a statement.
"As with previous cases, the level of asymptomatic infectivity appears to be very high."
The family-owned company said those who have tested positive have been advised to isolate and full risk assessment and contract tracing procedures are under way.
"All close contacts of those affected are being notified, advised to self-isolate and to contact their GP," it added.
The firm said it is in daily contact with the HSE and is planning for the roll-out of a regular testing programme.
"We firmly believe that to reduce risk and to best manage and control the spread of this virus, rigorous and regular testing procedures are required," it said.
"We will be testing all employees routinely and continue to work with and be guided by the HSE in this regard."
The company is still aiming to resume full operations on Monday, pending the full approval from the HSE.
It had hoped to reopen on 11 August, but a decision was taken to adopt a slow, controlled and phased approach to reopening.
Employees have been receiving full pay during the period of suspension of operations.