Illinois grocery stores are being advised to prohibit shoppers from using reusable bags to protect their workers and other shoppers from contracting the coronavirus.

The reusable bag measure was one of several new best practices that Gov. J.B. Pritzker announced during his Saturday briefing that were aimed at preventing the spread of the virus.

“To be clear, there’s nothing new that customers need to know before shopping, other than to be vigilant about their social distancing practices,” Pritzker said of the guidance, which was developed with the Illinois Retail Merchants Association.

Mayor Lori Lightfoot’s office previously shot down the request to temporary ban, citing a lack of evidence that reusable bags transmit the coronavirus, but said Saturday it will “continue ensuring that all new protocols and the latest restrictions are complied with in Chicago.”

Businesses are advised to have signage at the entrance and throughout their stores alerting shoppers that they must maintain a six-foot distance from others to practice social distancing, Pritzker said. Stores should also continuously announce these guidelines over their PA systems.

Other best practices include installing floor markers at checkout lines, encouraging cashless purchases for speedy checkouts and placing shield guards in front of cashiers and baggers, Pritzker said.

Grocery stores should also have dedicated staff walking the floor to ensure shoppers are following the new best practices.

“We’re asking stores to make their requirements as clear as possible, but it is up to each individual to follow our social distancing requirements,” Pritzker said. “Be courteous and respectful in any interaction with the grocery store clerks and workers, especially as they go to work everyday when so many are staying at home.”

Zack Koutsky, a spokesman for United Food and Commercial Workers Local 881, which represents Chicago grocery and pharmacy workers, said Friday that switching to plastic bags would bring peace of mind to workers worried about becoming infected with the coronavirus.

Shoppers for Instacart, an online grocery delivery service, have also expressed concerns about safety in grocery stores during the coronavirus pandemic. Some workers are threatening to strike Monday if the San Francisco-based company doesn’t meet their demands for more safety protections and better pay.

Pritzker also announced during Saturday’s briefing that the total number of coronavirus cases in Illinois has jumped to 3,491.

Forty-seven people have died of the coronavirus in Illinois, including an infant and a state employee who were among the most recent deaths.

Contributing: Mark Brown