There have been 37 confirmed cases of coronavirus at the Tyson poultry processing plant in Portland, Maine, as of Tuesday.
The Maine Centers for Disease Control and Prevention announced the outbreak last week when eight workers tested positive.
The plant will continue to be idle until Thursday, when workers who have tested negative will be allowed to return to work, according to Maine CDC Director Dr. Nirav Shah.
Tyson has offered tests to all 391 full-time employees at the plant, as well as 30 outside individuals and contractors, Shah said.
The 20 new cases at the Tyson facilities reported on Tuesday were not included in the state’s total numbers. Shah said they will be added to the state's total number of cases once all tests have been returned.
Shah announced four new deaths from COVID-19 in Maine during Tuesday's coronavirus update, bringing the state's total deaths to 61. There have been 1,226 cases in Maine as of Tuesday.
He also gave an update on the investigations into outbreaks at six congregate care facilities.
At the Augusta Center for Health and Rehabilitation, 48 residents and 28 staff have tested positive, for a total of 76 cases. Seven deaths have been reported, according to Shah.
Ten residents and five staff members have tested positive and one individual has died at the Edgewood Rehab and Living Center in Farmington, he said.
At Falmouth by the Sea, Shah said 29 residents and 16 staff have tested positive and two individuals have died.
There have been 32 cases among residents, 23 cases among staff and 12 deaths at the Maine Veterans' Home in Scarborough, he said.
At Tall Pines in Waldo County, 32 residents and 11 staff members have tested positive and 12 individuals have died.
Ten residents and five staff members have also tested positive and one individual has died at the Cedars in Portland.
Maine is continuing to provide personal protective equipment to congregate care facilities like nursing homes throughout the state, according to Shah.
As businesses in Maine continue to reopen, the possibility of a resurgence of coronavirus continues.
Shah said it could take between seven and 23 days to notice a resurgence, depending on how soon people seek medical help when they experience symptoms.
The CDC lab in Augusta aims to return test results within 24 hours after someone is swabbed, so that it is easy to see if a resurgence is occuring, he said.