Workers at a second Bernard Matthews factory have tested positive for Covid-19.
A cluster of cases was discovered at their site in Great Witchingham near Norwich.
Norfolk's Director of Public Health said all those who have the virus are self-isolating at home.
“Norfolk Outbreak control team are working with the management team at the site to trace the contacts of those who have tested positive and to prevent any further transmission of the virus on the site", Dr Louise Smith, said:
“At this stage we do not believe this is an outbreak based on the Great Witchingham site but is a cluster of unrelated cases and reflects the generally rising cases across the community.
"However we are keeping this under close review with the management at Bernard Mathews.”
It comes after an earlier coronavirus outbreak at their factory in Holton in Suffolk.
Eighteen new cases of Covid-19 were identified at the plant last week, bringing the total number of positive cases to 36.
All affected members of staff are now self-isolating at home.
In total, 123 members of staff have so far been tested or are due to be tested, with most returning negative results. Food production at the factory is continuing as normal.
Residents across the county are being reminded to protect themselves as cases rise.
The seven day incidence rates of the virus was 37 per 100,000 for the period between 27 September and 3 October - up from 13 per 100,000 a week before.
While this figure remains below the national average, Public Health Norfolk is urging communities to pull together and act now to prevent rates climbing further.
“The rate of positive cases in Great Yarmouth, which has been an area of particular focus, are still higher than we want them to be", Dr Louise Smith said.
“We are continuing to work with our partners across the borough in an integrated approach which has seen us all working from the same action plan.
“We have seen some helpful responses to the local rise in cases including the James Paget Hospital’s reintroduction of temporary visitor restrictions.
“But although rates in Norfolk remain low compared to the rest of the country, they are rising across all districts.
“This is a moment where organisations and individuals across the county all have a vital part to play in doing everything within their power to disrupt the transmission of the virus