Grocery stores large and small in the Boston area are taking steps to protect employees and shoppers from the novel coronavirus.

The food stores, deemed “essential” under the state’s public health emergency, are among the few indoor places of contact between otherwise self-isolated humans. Various stores have provided masks and plastic gloves to workers, marked six-feet distances in checkout lines, done deeper cleanings and installed hand sanitizer stations for customers and clear plexiglass to shield cashiers.

Despite the precautions, a small number of workers at several grocery chains have tested positive for the coronavirus, according to company spokespersons.

Wegmans confirmed to WGBH News Tuesday that a worker within its New England division tested positive for COVID-19. The company declined to specify which store.

“We are doing everything we can to protect all of our employees and customers. Prior to any positive cases in our communities, we worked with and followed the guidance of the CDC, state and local health officials to implement enhanced cleaning and sanitizing at all our stores,” said spokeswoman Marcie Rivera in a written statement. “We continue to implement additional preventative measures for sanitation, hygiene, and social separation guided by the most up-to-date recommendations from health experts."

The revelation came a day after Market Basket revealed two workers at its Chelsea store tested positive. Last week, a worker at the Market Basket in Chelmsford tested positive. Both stores are open and operating.

Last Friday, the multi-state cooperative America’s Food Basket also announced an employee at the store in Dorchester’s Codman Square had also tested positive.

The Washington Street location, one of four in Boston that serve mainly communities of color, was closed Friday, then professionally sanitized and re-opened Saturday, according to CEO David Siegel.

“The stores are closing early every evening for sanitation,” he said, pointing to heightened precautions since the diagnosis. The store is also limiting the number of shoppers inside the store at the same time.

Security guard stood outside Tuesday allowing four to five customers in at a time. The company has also ordered plexiglass panels to be installed at checkout counters.

The panels have been deployed at Stop and Shops stores across the region. A spokesperson told WGBH News vaguely in an email Tuesday, “there have been confirmed cases” across the New England-based chain.

Other smaller grocery store operations had no cases to report Tuesday.

Ronn Garry Jr., owner of Tropical Foods in Roxbury, said his store is taking similar precautions and he is the only one answering telephones.

“It’s a bad customer service look,” he said in an interview Tuesday, “but you just can’t have 50 different mouths on these phones.”

Garry said workers have taken tests, and all returned negative. He said he’s proud that the Dudley Square store’s workers have continued to come to work.

“They didn’t sign up to be essential workers at a dangerous time,” he said.

Michael Malmberg, chief operating officer of the not-for-profit Daily Table stores, said the company has “been moving quickly to adapt any new best practices and recommendations as they become available.”

He said measures implemented include an extended sick leave policy so symptomatic employees can stay home, and a $2 an hour emergency bonus for all retail, kitchen and truck drivers.

“Fortunately, we have not had any employees test positive for Covid-19 and are making our best efforts to reduce the likelihood of that happening,” Malmberg said in a written statement.

Aldi and Whole Foods responded to an inquiry but declined to disclose whether any of their employees have contracted the coronavirus. Star Market and Trader Joe’s did not respond to requests for comment.