WASHINGTON – President Donald Trump late Tuesday signed an order compelling meat processing plants to stay open under the Defense Production Act to protect the nation's food supply.

The decision comes as at least 20 plants across the country — including at least three in Minnesota — have been shuttered temporarily by outbreaks of COVID-19.

The order came after Tyson Foods, other companies and Sen. Mike Rounds of South Dakota — where Smithfield Foods in Sioux Falls has a huge outbreak and is temporarily closed — warned of possible shortages of pork, beef and poultry.

The five-page order, which was developed in consultation with industry leaders, is designed, in part, to provide companies with additional liability protections in case workers get sick. Trump on Tuesday described the issue as a "legal roadblock." The order, he said, would "solve any liability problems where they had certain liability problems and we'll be in very good shape."

The order coincided with a renewed call by union leaders for more extensive testing of meatpacking and processing workers. The United Food and Commercial Workers International Union (UFCW) represents most workers in meat and poultry packing and processing plants across the country. Its leaders have made virus tests for employees a priority for protecting them.

The union believes packers and processors must be declared first responders to the coronavirus pandemic in order to qualify for broad-based testing. At a daily COVID-19 press briefing Tuesday, state Health Commissioner Jan Malcolm said Trump's plan to keep meat and poultry plants open seemed "counterintuitive" based on current coronavirus outbreaks that caused shutdowns.

"At a time when we we're seeing such explosive increases in numbers of cases and the impacts on surrounding communities, it seems problematic to say the least," she said.

The state Health Department said that, as of late Tuesday, the Pilgrim's Pride plant in Cold Spring had 17 confirmed cases of COVID-19, while the Jennie-O plant in Melrose had four. Both plants are still open. The department said another 23 cases have been confirmed among workers at two Jennie-O plants in Willmar, which were closed late last week due to COVID-19 concerns.

Nobles County had 697 cases of COVID-19 as of late Tuesday, including 239 people who worked at the JBS plant in Worthington, according to the health department. The pork-processing plant, which handles 4% of the nation's pork supply, closed indefinitely April 20 after 26 workers had been diagnosed with COVID-19.

Details of how Trump intends to safeguard workers remained unclear Tuesday after the White House confirmed that the president would declare packing and processing plants "critical infrastructure" using a national security law. The administration promised more protective equipment and guidance. No one could say exactly how the plan will deal with COVID-19-affected plants that have closed. The workers in these processing plants work in close quarters, sometimes shoulder-to-shoulder, which provides an ideal environment for the coronavirus to spread.

It is unclear whether Trump's decision would undo voluntary guidance issued Tuesday by the CDC and the Occupational Safety and Health Administration. Those agencies urged packers and processors to separate employees by at least 6 feet.

Workers and union officials say such distancing is impossible given the current design and operation of the plants. Some companies, including Minnesota-based Cargill, have installed systems to take the temperatures of every employee heading to work in order to find those with fever that might signal a viral infection.

Cargill's Texas beef processing plant also includes plexiglass barriers in lunch rooms and sheets of plastic hung between workers on processing lines.

Workers from the JBS plant in Worthington were offered COVID-19 tests April 23-26 at the local fairgrounds, said Matt Utecht, head of UFCW Local 663, which represents those workers. Utecht said he didn't know how many workers sought tests or the results.

Utecht will attend an event with U.S. Rep. Collin Peterson, D-Minn., in Worthington at 1 p.m. Wednesday at the city's airport. Peterson will discuss plant closures and Trump's order. Gov. Tim Walz is expected to join Peterson.

Pork farmers in the state were finalizing plans to euthanize up to 200,000 hogs because there is no end market for them with the plants closed. Utecht and farmers said the state was finalizing a deal to allow for the euthanizations to take place at the JBS plant. A spokesman for Walz said he "believes meat processing is an essential industry. He also believes worker safety is an absolutely essential element of the safe and sustainable operation of these plants. He will review the president's executive order when it is publicly available."

Staff writers Jeremy Olson and Mike Hughlett contributed to this report, which includes material from the Washington Post and the Associated Press.