A growing number of retailers are mandating face masks for people who wish to shop in their stores. Kohl’s, Kroger, Sam’s Club and Walmart join others including Best Buy, Costco and Starbucks that have put mask mandates in place. “We will require all shoppers to wear a face covering starting Monday, July 20,” Walmart U.S. COO Dacona Smith and Sam’s Club COO Lance De La Rosa wrote in a company blog. “This will give us time to inform customers and members of the changes, post signage and train associates on the new protocols.”