The interim guidance from the Labor Department's Occupational Safety and Health Administration also recommended temperature checks and the wearing of cloth face coverings as a protective measure.

The guidance was issued jointly with the US Centers for Disease Control and Prevention.

“As essential workers, those in the meatpacking and processing industries need to be protected from coronavirus for their own safety and health,” OSHA's deputy assistant secretary, Loren Sweatt, said in a news release.

COVID-19, the respiratory disease caused by the novel coronavirus, has spread widely through US slaughterhouses where large groups of employees often work shoulder to shoulder.

More than 5,000 US meat- and food-processing workers have been infected with or exposed to the new coronavirus, and 13 have died, the country’s largest meatpacking union said on Thursday.

Meat suppliers including Tyson Foods Inc, Brazilian-owned JBS USA , and WH Group Ltd's Smithfield Foods have all closed pork plants.

Many labour unions, Democrats and worker advocates have criticised OSHA for what they say has been an inadequate response to the pandemic. OSHA had recommended employers take various steps, rather than adopting emergency standards requiring them.

The slaughterhouse shutdowns are disrupting the US food supply chain, crimping the availability of meat at retail stores and leaving farmers without outlets for their livestock.