As of Thursday, 13 meatpacking and food processing plants had closed at some point in the past two months, resulting in a 25 percent reduction in the nation’s pork slaughter capacity and a 10 percent reduction in beef slaughter capacity, according to the food workers’ union.

In addition to the action, which was taken under the Defense Production Act, a Korean War-era law, the Labor Department and OSHA issued guidance that would provide additional liability protections for companies seeking to operate amid the risk of outbreaks.

In its statement, the agencies said the United States would weigh in on the side of companies who were facing litigation for reported workplace exposures to the coronavirus, as long as the companies were following the standards that the C.D.C. and OSHA had issued for meat processing facilities.

As states begin reopening, businesses have begun pushing the Trump administration and Congress to shield American companies from a wide range of potential lawsuits related to restarting the economy.

Companies want assurances that they will not be held legally liable if a worker or customer contracts the virus at their warehouse, coffee shop or grocery store. That issue is expected to come to a head during the next round of congressional negotiations, with Republican lawmakers suggesting that any further aid to states would be conditioned on indemnifying businesses against lawsuits.

The Labor Department and OSHA also indicated that the federal government would assert authority over states, which have ordered many businesses to close.

“No part of the joint meat processing guidance should be construed to indicate that state and local authorities may direct a meat and poultry processing facility to close, to remain closed or to operate in accordance with procedures other than those provided for in this guidance,” the statement said.