Mandela Grocery Cooperative recently celebrated 10 years in West Oakland with a block party. It has many reasons to celebrate: It’s the city’s only worker-owned grocery, and it’s in expansion mode right when many national grocery-store chains are struggling.

The cooperative is in the process of organizing a sister market in East Oakland in collaboration with the urban farming nonprofit Acta Non Verba and other local organizations. It is also deciding whether to relocate to a larger space in one of two high-rise developments coming to its immediate neighborhood near West Oakland BART. Its eight African American worker-owners, who reflect the historic demographic of the neighborhood, say their combination of healthy and affordable food and an alternative business model have earned them the support of neighbors over the past decade.

“I believe we’re succeeding because we are committed and sticking to the cooperative ethic,” said Adrionna Fike, one of the grocer’s worker-owners. “We’re also running our business in a way that people respect.”

Fike said customers express their support daily that the workers are the owners at the store. The grocery is also the only source of fresh and healthy food, including competitively priced local and organic produce, in its immediate vicinity; the big, new Community Foods Market is 2 miles away.

A decade in, the grocer finds itself in a neighborhood in transition. Two new pending developments, one at the West Oakland BART Station across the street, the other two blocks away at 500 Kirkham, are set to bring in about 1,200 new apartment units and dozens of new businesses. Mandela Grocery has been approached by both developers to take over a ground-floor retail space, said worker-owner Andrea Talley.

“We’re just having to really think critically about how we are going to grow with this drastic change of our neighborhood,” said Talley, who added that it’s a sensitive topic because of neighbors’ concerns about gentrification.

The way the cooperative sees it, since the developments are each going to have a food retailer, one of them might as well be Mandela Grocery, she said. Their first choice is the complex next to BART because of its foot traffic.

Strategic Urban Development Alliance, which is heading up the West Oakland BART development, is setting aside 15 percent of retail space at a below-market rate for local businesses like Mandela Grocery, said partner Regina Davis.

“We want to make it economically feasible for them, not to just have them as window dressing but to be able to stay for the long term,” Davis said.

She said they’re interested in bringing in cooperatives specifically because they provide training and living wages to people within the community. But in order to offer below-market rent, the development will need support from other partners, including the city and BART, she said.

The same goes for plans for a new cooperative in deep East Oakland, the area from 73rd Avenue to San Leandro. Acta Non Verba, which runs after-school and summer urban farming programs for youth, was able to start brainstorming the idea and gathering community feedback with a grant from the East Oakland Neighborhoods Initiative.

Oakland Community Land Trust is looking into possible retail spaces, and Acta Non Verba approached Mandela Grocery to develop a curriculum for those who decide to be worker-owners at the new East Oakland cooperative. They will do their training at Mandela while their store is being built.

“A cooperative really keeps the dollars in the community,” said Ayano Jeffers-Fabro of Acta Non Verba, who is in the process of recruiting community members in East Oakland to be part of a steering committee for the store and become worker-owners. “In terms of empowerment and need out here in East Oakland, it makes sense for us to shift the way we think about the economy.”

Fike gets inspiration from learning about the history of the black cooperative movement, which had a heyday in the first half of the 20th century with roots in the Underground Railroad, according to “Collective Courage: A History of African American Cooperative Economic Thought and Practice,” by Jessica Gordon Nembhard.

“It was a good way for me to think about the depth of cooperation in organizing ourselves to the greatest ends, to create solutions to our own problems,” Fike said.

Deep East Oakland mostly has corner and discount groceries with a few national chains, but the area of about 6 square miles could use more fresh and healthy options, said Jeffers-Fabro. Many community members have expressed that need and said they’re familiar with Mandela Grocery and support what it’s doing in West Oakland, she added.

“Mandela is the model — they’re sort of the bright star in the sky that we hope to be one day,” said Jeffers-Fabro, who also plans to bring Oakland-grown produce to the new cooperative.

If the new cooperative succeeds, it will be counter to national grocery-store trends. The U.S. grocery-store industry has stayed at a flat 2 percent rate of growth over the past decade and will face increasing threats from changing consumer habits and competition from discount, online and nongrocery outlets, according to a report from the management consulting firm McKinsey & Co.

In West Oakland, where Mandela Grocery is considering its own growth into one of the pending high-rises, Talley said they’re sensitive to neighbors’ concerns about how the development could transform their community.

“Once we decide and it’s for sure, we need to figure out a way to communicate to community members so that they know we are growing with the community, we’re not replacing community,” Talley said.

Mandela Grocery Cooperative, 1430 7th St., Oakland. 510-452-1133 https://www.mandelagrocery.coop. Open 7 a.m. to 8 p.m. weekdays, 9 a.m. to 6 p.m. weekends.

Tara Duggan is The San Francisco Chronicle’s assistant food editor. Email: tduggan@sfchronicle.com. Twitter: @taraduggan