WASHINGTON – Faced with worries of a meat shortage caused by the coronavirus, President Donald Trump on Tuesday ordered beef, pork and poultry processing plants to remain open despite safety concerns.

Citing his authority under the Defense Production Act, Trump declared in an executive order that "it is important that processors of beef, pork, and poultry ('meat and poultry') in the food supply chain continue operating and fulfilling orders to ensure a continued supply of protein for Americans."

Critics said the forced openings – some plants have closed because so many employees contracted the coronavirus – threaten the safety of workers who remain vulnerable to the disease.

Trump also told reporters he would seek to shield meat plants from legal liability if they are sued by employees who contract coronavirus while on the job. While Trump only mentioned Tyson Foods specifically, he suggested his plan would protect other businesses from liability as well.

Meatpacking:Tyson chairman warns of 'meat shortages' as industry faces scrutiny for worker safety during coronavirus

Some lawmakers have also called for liability shields to protect businesses in court if they are sued, though they would likely be challenged in court. Judges would ultimately decide whether coronavirus lawsuits against businesses can go forward.

White House officials said they would also issue safety guidance for plants to help protect their workers from the virus, the issue that union members said should be emphasized above all.

Marc Perrone, president of the United Food and Commercial Workers International Union, the nation's largest meatpacking union, said the government must put the safety of the workers first.

"Simply put," he said, "we cannot have a secure food supply without the safety of these workers."

Concerns about the nation’s meat supply have been growing, as the number of meatpacking facilities shuttered due to coronavirus outbreaks has accelerated over the past several weeks.

More than 4,400 meatpacking workers have tested positive for the virus, and at least 18 have died from the virus as of Tuesday morning, according to USA TODAY/Midwest Center for Investigative Reporting tracking. Workers have tested positive in at least 80 plants in 26 states, and there have been 28 closures of at least a day.

USA TODAY also found that 153 of the nation’s largest meatpacking plants, about 1 in 3, operates in a county with a high rate of COVID-19 infection, raising concerns that more workers at more plants will fall ill.

In a full-page newspaper ad over the weekend, Tyson Foods Chairman John Tyson said "the food supply chain is breaking," and "there will be limited supply of our products available in grocery stores until we are able to reopen our facilities that are currently closed."

Meatpacking:Coronavirus at meatpacking plants worse than first thought, USA TODAY investigation finds

Some plant employees have told reporters that Tyson did not adequately protect them from the virus, setting up the prospect of lawsuits.

Supply chain experts have mostly said a significant domestic meat shortage is unlikely, due to the large number of processing plants and resulting resiliency. But those assurances are being tested by steadily dropping production numbers from the nation’s meatpacking plants.

Department of Agriculture data show at least 838,000 fewer cattle, hogs and sheep were slaughtered for meat processing over the past week compared to the same time period last year, a 28% drop. Tuesday marked the worst day yet, with total slaughter falling 39% compared to the same day last year.

While some have offered assurances that the nation’s “cold storage,” or the amount of meat frozen in commercial warehouses, could act as a stopgap should production plummet, data indicate a limited supply. The most recent USDA figures show those supplies store only about a week’s worth of food compared to average monthly production.

Trump said Tuesday he did not fear any kind of food shortage.

"There's plenty of supply," Trump told reporters after meeting with Florida Gov. Ron DeSantis. "It's distribution."

Trump also said his executive order will "solve any liability problems."

The order was slammed by the Retail, Wholesale and Department Store Union.

"We only wish that this administration cared as much about the lives of working people as it does about meat, pork and poultry products," said Stuart Appelbaum, the union's president. "If the administration had developed meaningful safety requirements early on as they should have and still must do, this would not even have become an issue."

Chris Lu, who served as deputy secretary of labor during the Barack Obama administration, said new safety standards should be the priority, and "we shouldn't have to sacrifice America's workers in order to protect our food supply."

The food issue is a politically challenging one in the midst of a pandemic.

Some local officials said outbreaks of coronavirus at processing plants prove that the economy needs to be locked down to curb the spread of the disease. Industry leaders said their work is essential to maintaining the food supply, and are seeking protection from prospective lawsuits.

Congressional Republicans, including Senate Majority Leader Mitch McConnell, R-Ky., have said shielding companies from lawsuits will help the economy reopen after weeks of lockdowns.

Minority Leader Chuck Schumer of New York, the Senate's top Democrat, questioned McConnell's idea.

"Is he saying, if an owner tells a worker he needs to work next to a sick person without a mask and wouldn’t be liable?" Schumer told reporters. "That wouldn't make sense."

Trump spoke with reporters after a meeting with DeSantis in which he lauded Florida as a model for other states seeking to reopen their economies, despite the risks of resurgences in coronavirus cases.

Contributing: USA TODAY Network investigative reporter Kyle Bagenstose and Midwest Center For Investigative Reporting reporter Sky Chadde.