"Such closures threaten the continued functioning of the national meat and poultry supply chain, undermining critical infrastructure during the national emergency," the order says. "Given the high volume of meat and poultry processed by many facilities, any unnecessary closures can quickly have a large effect on the food supply chain."

The shutdowns have led to worries about meat shortages. Some economists warn that consumers could see fewer options at grocery stores starting in May if plants continue to shut down at the same pace.

But Trump played down any worries about lack of meat. "There's plenty of supply," he told the media earlier on Tuesday. "It's distribution."

Trump directed Agriculture Secretary Sonny Perdue to "take all appropriate action" to ensure that meat companies continue operating under guidance from the Centers for Disease Control and Prevention and the Occupational Safety and Health Administration.

The order did not detail additional precautions companies should take to protect workers, which has led to worries among unions and other worker groups.

The Agriculture Department has deferred to the CDC and OSHA instead of issuing its own rules. OSHA, however, has not imposed mandatory safety rules and instead only issued recommendations.

In a full page ad in The New York Times, the Washington Post and the Arkansas Democrat-Gazette on Sunday, Tyson Foods warned “the food supply chain is breaking" and said the plant closings are leading to shortages at groceries.

The plant closings at Tyson and numerous other large meatpackers have jammed the food supply chain, leaving farmers with a backlog of hogs ready to be slaughtered and nowhere to put them. Many are euthanizing animals. House Agriculture Chairman Collin Peterson said Tuesday that he's heard estimates as many as 160,000 pigs a day need to be culled because of the backup at slaughterhouses.

In comments to the media earlier on Tuesday, Trump said he would also shield meatpacking companies from legal liability from worker claims of not being adequately protection, though the order didn't spell out any specifics.