Danish Crown said 120 employees tested positive in an initial round of tests on 600 employees.
He retested all negative cases and detected 22 additional infections.
“For this reason, we are closing the slaughterhouse for at least a week to try to break the chain of transmission between the employees on site,” Danish Crown said.
All employees must quarantine themselves.
The company is one of Denmark’s largest exporters and the largest producer of pork products in Europe.
Several European slaughterhouses have been affected by the virus in recent months, especially in Germany.
The virus cluster in Ringsted is the main asset in Denmark, where the number of cases has risen sharply in recent days.
The resurgence has forced the government to abandon plans to ease restrictions on concert halls and nightclubs, and prepare new curbs instead.
Several dozen infections have been recorded in Aarhus, the country’s second largest city.
Prime Minister Mette Frederiksen said on Friday that Denmark intends to make masks compulsory on public transport.