Kowalski's Markets and Coborn's are following the lead of Target and Lunds & Byerlys and will require masks to help stem the spread of COVID-19.

A spokesman for Cub Foods and Jerry's Foods said it will mandate customer masks, according to Center for Disease Control guidelines, starting July 28.

Hy-Vee at this time will still encourage mask-wearing but not require it. Spokeswoman Christina Gayman responded in an e-mail that "Hy-Vee has no change at this time."

Employees at Hy-Vee have a mandatory mask rule. Last week, a Facebook group calling itself "Iowa Educators for a Safe Return to School" urged its members to contact Hy-Vee CEO Randy Edeker to require shoppers to wear masks.

Hy-Vee is against the tide. Also announcing a customer-mask mandate are Walmart, Sam's Club, Aldi and Whole Foods, joining Costco. Target's begins on Aug. 1.

Kowalski's Markets said disposable masks will be available for those without them.

"Our employees will be continuing to wear masks as well as practicing our already intense cleaning, sanitizing and restocking measures," said Kowalski's spokeswoman Laurie Bell.

Coborn's Inc. began its mandate Monday in its Coborn's, Cash Wise and Marketplace Foods and its liquor stores. Customers without a mask will be provided one.

Until Monday, Trader Joe's stores across the country requested but did not require masks except in states or cities such as Minneapolis that required them. All stores now have the mandate, according to the company's website.

Not all the orders are in effect yet. Aldi starts its mandate July 27. Lunds & Byerlys order begins July 31. Cub, which reopened its riot-damaged store at 701 W. Broadway on Monday, requires masks starting July 28.

Local co-ops in Minneapolis and St. Paul require masks by city mandate, but most suburban co-ops are recommending them. Lakewinds Food Co-op in Chanhassen and Richfield require employees to wear them but not customers. The Minnetonka Lakewinds will require them starting Thursday when the city's mandate goes into effect.

Valley Natural Foods in Burnsville has required masks for weeks.

River Market Community Co-op in Stillwater requires customers to wear masks daily from 8 to 11 a.m.

On May 4, Costco became the first major U.S. retailer to require masks.

In other supermarket chains around the nation, Cincinnati-based Kroger mandated masks last week.

A spokesman for Jacksonville, Fla.-based Winn Dixie, the country's 25th-largest supermarket chain, said last week that it is not requiring masks due to potential friction between customers and employees. At Target, an employee's arm was broken during an argument with a customer refusing to wear a mask.

Twin Cities-based Caribou Coffee also announced a mask policy in effect Monday. Starbuck's started requiring masks July 15.

Stores generally do not generally require masks for those with underlying medical conditions and young children. Shoppers unable to comply with the mask requirement can choose a retailer's online or curbside service.