Euro Quality Lambs, which employs around 100 staff in Craven Arms, confirmed eight of its employees had tested positive for coronavirus over the last two weeks.
The Dale Street-based abattoir said a further 18 people were tested as a precaution and returned negative tests.
Rizvan Khalid, managing director, said: "We have eight employees who are currently positive for coronavirus, tested at different times over the last two weeks.
"A further 18 were tested as a precaution and returned a negative test. The positive employees work in different parts of the site and tested positive at different times.
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"Our investigations lead us to believe the majority of these cases are not connected and were picked up external to our premises as we already have in place numerous steps to ensure the virus does not spread within the site.
"We have placed an additional 10 people in quarantine because they live with someone who has tested positive for coronavirus, totalling 18 including the positive cases.
"These colleagues are only allowed back after the government-advised isolation period.
"Anyone who displays any sign of illness is not allowed to come to work. We also have thermometers on site to conduct checks.
"This applies to any other member of that persons' household if they are working for us.
"We continue to be vigilant and will do all we can to ensure the safety of all colleagues during this worrying time."